DIAB Foam

[MarineSurvey]

I wanted to share an experience I had with DIAB foam and their processes: I am an old boat builder in China at present. I was called and asked to survey a non complete sailing vessel in China. The vessel is a 50' catamaran. The process used for construction was and is infusion. Please look at the pictures posted and you will noticed many areas of dry-glass indicating a failed infusion. The builder has given permission to use the pictures. The builder contracted DIAB to come and give training and instruct workers on the infusion process. DIAB set up and ran this class and actually did the infusion on this deck (noted in the pictures). The builder contacted me as they were apprehensive as to the end product. According to DIAB this is a easy fix. When I contacted them ask for help no call back from them. I had the gel-coat sanded off most of the deck and that is when you see most of the problem. Has anyone had similar experiences?

[Landlubber]

I have had dealings with DIAB in China (Shanghai specifically), yes they do come and do in house training and instruction, and yes there are stuff ups, but that is not the fault of the DIAB crew, it is rather the standard Chinese way of doing things "Their way"...they have some sort of desire to show us all how wrong we are and how right they are....this is typical of the results....I personally can only thank DIAB for all the help and genuine support that they have offered my work collegues and myself whilst "trying" to teach locals the way it is.

[rwatson]

If this was a DIAB demonstration, and they got it wrong - what are the chances a new user would get it right ?

I have selected the DIAB products for my next project, and they state in their literature that I can expect a good result even by hand layup using their cores.

If this happens during infusion, I am a bit worried about my first effort of using core material with hand layup methods.

[Alik]

Was it Prout catamaran?

[MarineSurvey]

Thank you to those who have replied so far. To clarify, it was actually DIAB who conducted the actual infusion, not the workers at the plant. I have seen Chinese workers who are unwilling to change their ways as well, but that wasn't the case this time unless it was DIAB's employees (including their technical director in Asia) who were unwilling to follow DIAB's plan.

Rwatson, I can understand your apprehension, which is why I posted this message.

As a further note, DIAB's Asia office contacted Winfair last Friday and said that a DIAB manager from Sweden would contact Winfair and then fly to Winfair in China to resolve the matter. In what seems to be a pattern, they have not done so.

[Alik]

As a further note, DIAB's Asia office contacted Winfair last Friday...
OK, this means it was Prout. Don't really understand what is happening there.
http://concordiayacht.blogspot.com/2009_06_01_archive.html

[themanshed]

This is why I like Bagging better on a hand layup. I know it is more work but it's not hidden.

[rwatson]

This is why I like Bagging better on a hand layup. I know it is more work but it's not hidden.

I am confused - "what is "bagging better on a hand layup" ?

Can you explain a bit more please ?

[Landlubber]

rwatson,

I do not agree entirely with that statement, but I do understand what he means.

Vacuum bagging is done with the resin already rolled (or in th ecloth in the state of prepreg), so there is no risk of voids as the resin is done by hand and eye manually. Resin infusion is done after set up, any faults along the process from the start are not all that simple to either see or fix as you go.

However, like all building processes and techniques, it is all up to the operator....even ferro built boats are exceptionally well done if exceptionally well done......

[rwatson]

Thanks for that landlubber - it just needed translating.

Time and efficiency permitting, doing the hand impregnation, and then vacuum bagging *has* to be more reliable. Look at all the shenaningans you have to do with extra taps, inlet hoses etc to control the infusion on a dry stack of materials.

You cant always see what is going on under all the layers during infusion, so if you have done a pre-impregnation, there is a lot of worry removed.

To quote Mr Roger MacGregor when asked why he doesnt use foam core on his boats
"Foam cores are also widely used for stiffening hulls, however, they offer less than 200 pounds of adhesion per square inch. That is not much better than rubber cement. "

And thats a *good* layup.

I will be starting some test panels with foam soon - it will be interesting.

[Alik]

I don't see much advantages of infusion in Asia where labor is still cheep. Yes, some boats are built here with infusion (including some our designs), but this requires more expensive resins and fabrics, but still depends on human factor and staff training. I have seen few unsuccessful infusions here, however the customer will never know what the builder did with unsaturated areas. I won't buy a 50' 'hi-tech' cat with such 'surprises' in the structure.

For my new cat (that is in construction now) we use DIAB H130 foam, but builder just vacuums it to the bottom, so all process is under control. Rest of hull and deck areas are in HexaCor that is also vacuumed. All lamination is done in by hand lay-up, in multiaxial fabrics.

In Asia, ‘infusion’ sometimes if is a kind of fashionable marketing trick, often not justified to the purposes and realities of build.

[Landlubber]

Alik,

All very true, the Asian example of anything high tech is in many cases " just a cardboard cutout of the real thing".....I have seen it so many times, looks real, smells real, tastes real (did you know that the Chinese can make eggs), but it is not real, caveat emptor.

[themanshed]

Resin Infusion is where you have your dry laminated in place in a vacuum bag. Then from the vacuum you draw the resin from one end through your lay-up to the other end into a run-off pot. It is the vogue way to do the wet out. I’ve seen it work and I’ve seen it with disastrous results. The problem is that you cannot “see it” so you hope that Murphy does not bear his ugly head. The problems that I’ve seen are dry spots as with this post or pooling of resin, which causes a brittle or heavy spot. If done correctly - without any problems they say it is fast and good.

What I’ve found is a good glass man can work himself out of the corner with problems. But with this technique you do not see the problems they show up later. Prepreg is nice but who has the ovens, and in a tropical climate Prepreg needs to be frozen. For the price I can get Carbon Fiber at $18 / yard and do a hand wet-out with West Systems then Vacuum Bag it. At least I know the glass is wetted out and the extra resin is sucked out into the bleeder cloth in the vacuum bag process and tossed out with trash.

[themanshed]

"Foam cores are also widely used for stiffening hulls, however, they offer less than 200 pounds of adhesion per square inch. That is not much better than rubber cement" Quote

Not sure what adhesion quality he speaking of but the foam core is used to physical separate strong laminated skins and transmit shearing forces across the sandwich. It has an I-beam effect usually measured in Tensile strength, Tensile Modulus, Ultimate Elongation, and Shear Strength.

An example if you took a solid glass skin and called that "T"

Then make a composite cored lay-up twice as thick as "T" and split the glass layup half on top and half on the bottom with a "T" thickness of a core in the middle. It would be 700 times stiffer, 350 times stronger and only weight 3% more.

[rwatson]

"Foam cores are also widely used for stiffening hulls, however, they offer less than 200 pounds of adhesion per square inch. That is not much better than rubber cement" Quote

"It has an I-beam effect usually measured in Tensile strength"

Yes, that is a good explanation.

I think what he is getting at is that if either skin separates from the foam, the I- beam is considerably weaker.

The propensity for the gap to be filled with water, (especially of the break is caused by violence), cant be good either.

[themanshed]

Yes but it would be local if proper construction methods were used and easily repaired. Many times only the outer skin will be holed leaving the inner skin intact. I think you have epoxy sheathing over ply coming off much more then the problem with foam. Foam will absorb impacts more then wood but they all have breaking points. A much more serious problem with wood products is dry rot; you do not have that problem with foam.

Wood and modern age epoxies are excellent material, but you are somewhat limited to square and angular designs. But if you want to give your lady curves foam works best.

[rwatson]

I have comitted to foam for my next project, hence my interest in the trimaran build.

In making this decision, I have tried to research all I could on different boatbuilding techniques.

I hope a lot of what you say is true, but one thing that seems to be mentioned from lots of sources is that timber (plywood etc) absorbs more impact than foam ever can, is less prone to heat fatigue and of course is much stronger.

The factor that pushed me to try foam is lower weight and lack of water absorbtion.

The term "proper construction methods" is also fraught with peril. DIAB state that hand layup will produce satisfactory results in their product information, but then you read that hand layup is the most problematic method of applying glass from one of their chief chemists.

You have to watch the "spin" from the manufacturers.

I guess Iwill have to try it to see.

[themanshed]

Most builders in Florida have gone with foam because of the problem with rot in a tropical climate. Make sure you pick quality foam. There are two methods the vertical strip method like the newer Farrier designs from the bilge to deck and the horizontal strips like my method. The best bet on horizontal strips to cut the cove and bead on the strips. American Eagle www.eagleamerica.com sells a combo router bit so you just have to purchase one bit the part number for the 3/8 bit is P14-3425 @ $44.97 US. This allows the strips to blend nicely on a curve for less fill & faring. I'll give you the heat fatigue and also condensation plays into decks. Boats with large decks often use Balsa core for the decks then edge it out with foam to aid in the faring. It depends on whom you read in what can take hits better foam or wood and which is stronger. The density of the foam and type of laminates play heavily into the factor also.

If you do the One-Off method building with foam it is great and the bond between the foam and skin is very good. I used West System epoxy with a bit of 407 powder mixed in to make a runny bog for the first layer of epoxy between the foam and carbon. The bog with 407 makes the lay-up stiffer fills any voids and gives an excellent bond. All other layers were just straight epoxy with the carbon. If you use more then one layer of fabric in lay-up vacuum bag. A vacuum compressor cost about $150 US from harbor freight sales for a good pump. I built my own tank.

Right now I'm messing with the repair of a carbon A-Cat mast, most shy away from such a repair, make sure if you use carbon to paint it. Direct sunlight deteriorates carbon fiber.

Good luck let me know if I can be of any help. What design are you going to build; purchased or your own? I’ve collected a few tips on the way

[rwatson]

Your web site has given me a lot of help already, but there is lot more to learn.

My project is a 28ft trailer/sailer, and I have minimised the foam work - I may not even need to vacuum bag.

You can see that there are two "mould lines" around the hull. The sides are made up of two developable flat panels, while the bottom of the hull will be done in a female mould with no foam. I am planning on using VinylEster only, to save costs dramatically.

The idea is to lay the fibreglass out on a flat bench, apply the foam and just lay flat boards on top of the foam for weight till they cure.

Then I will mount the panels in a basket, and layup the interior by hand.

Doing the full mould for the bottom will be the most time consuming, but since I plan on building more of these boats, it should save time in the long run.

[wardd]

putting a vacuum on your layup table would be simple and bullet proof and you could use an old refrigerator compresser

[themanshed]

If the panels are to be bent into shape it is best to mold them to the shape not flat. Once a composite panel is made it is very stiff and will not want to bend. I’m not familiar with a basket. But if you can shape the foam in the basket then glass it you are better of.

The usual way is to construct the foam shape then glass up the foam. I agree if you have a lay-up table it would be better to lay-up the complete panel in one step and a great chemical bond, very simple. Lay down some 3M- plastic, glass wetted out, bog on the foam, foam, bog the back side of the foam, then your laminate, peal ply, felt, then plastic bagging material fasten the bagging material to the table and pull a vacuum and it makes a great panel.

Nice design.

[Alik]

Back to delamination issues - before using any foam make sure it does not peel off. Some 'good quality' light density foams are easy to peel off in the center of core.

I have never seen this happen with honeycombs, so I prefer to use honeycombs in deck and cabin.

[rwatson]

Well, I think non-vacuum methods are far easier and cheaper than layers of peel ply, vacuum bag, pipes, joiners, gauges, pumps etc.

If I lay 1/2" waxed melamine faced, chipboard panels on the top of the foam which is on top of CSM which is on top of the 200 gsm which is on the flat layup bed, this thould give good compression I would think. I am planning on putting holes through the foam to ensure I dont get airlocks.

As you say, its better to glass the foam in its bent shape. I am planning to only put one layer of 200 gsm + CSM under the foam for the initial flat join. I am expecting this to provide a good self-fairing panel that wont require a large number of moulds. Its a bit like making one big sheet of plywood, and laying it along the frames like you would with stitch and glue.

This should not put significant internal pressure on the foam/glass interface, but keep it nice and rigid and fair for the internal hand layup. I think the layup schedule requires Bi-ax 400 gsm on the inside and outside.

Its a bit of an untried method, and as you say Alik - I better check it out on some test pieces.

[apex1]

It´s not that uncommon watson! Lookup bateaux.com they recommend it on some larger boats.

Regards
Richard

[f250]

T+T+core= T+3% I dont think so
= 2T + 3%

[Herman]

I wanted to share an experience I had with DIAB foam and their processes: I am an old boat builder in China at present. I was called and asked to survey a non complete sailing vessel in China. The vessel is a 50' catamaran. The process used for construction was and is infusion. Please look at the pictures posted and you will noticed many areas of dry-glass indicating a failed infusion. The builder has given permission to use the pictures. The builder contracted DIAB to come and give training and instruct workers on the infusion process. DIAB set up and ran this class and actually did the infusion on this deck (noted in the pictures). The builder contacted me as they were apprehensive as to the end product. According to DIAB this is a easy fix. When I contacted them ask for help no call back from them. I had the gel-coat sanded off most of the deck and that is when you see most of the problem. Has anyone had similar experiences?

I see there are dry spots, which means there have been air inclusions, very probably caused by "race tracking" in the corners.

I also see the shape is somewhat more complicated, in which case it is more difficult to generate an infusion strategy by intuition and/or experience. A computer simulation (www.polyworx.com) would have helped.

There are several stages at which things might have gone wrong: choosing layup, actual laying up, infusion strategy. It is impossible for us to find out what exactly went wrong, without knowing the complete story.

Infusion is about getting the details right. Either you need to cut up the work in very manageble pieces, and have untrained people do it (I have seen it working) or have trained professionals who do the job, or at least supervise it. (which is an art in itself).

Anyhow, as long as so called professionals still screw up, the infusion debate lingers on, and infusion will not be a widely accepted production method, even if it has certain advantages over traditional methods. (and yes, there are downsides as well)

[rwatson]

It´s not that uncommon watson! Lookup bateaux.com they recommend it on some larger boats.

Regards
Richard

Thats good. I couldnt find anything after a quick look. I thought they only did plywood kits. Do you have a link ?

[themanshed]

T+T+core= T+3% I dont think so
= 2T + 3%

T ; then compared to T in core of foam and the T laminate splt 1/2 of T on each side is 103% was the calc I used. Your formula is over kill, sorry if I was misunderstood.

[themanshed]

I am not an infusion fan at all. It's been done but my jury is still out. I compare it to Stevie Wonder in the subway trying to catch the 7:05.

I'll keep my thought to boats for the US markets built in China private:p

Hole in the foam is not keen in my book that is chance to de-laminate. The sheer force cannot be transfered between the skins. I drilled 1/8 inch holes 1 inch on center to raise the sheer in places. The holes were filled with bog. It is recommended to not have any voids in the foam. If you have a void it should be filled with a bog. They do make foam with small holes for the vacuum to suck resin though the foam to wetout both sides of a "panel" layup. The voids are filled with resin it does increases the weight.

One layer of 200g E-glass unidirectional 90 degree may bend, perhaps you may want to try just one side first. Edge glue the sides of the foam with epoxy careful to not get any on the plane surface, if you do clean it up. The foam and glue sand at different rates, usually the foam will dish out..

More next post.....

[themanshed]

If you want to make a panel and not want to use a vacuum do one side at a time foam down and perform your layup on the top with peel ply or 3M masking film and squeege it out very good. This will get the air out and make the cloth lay very flat / Let me see if I can find non-copyright material on the 3M masking film. I've used both; peel ply although more expensive works best. In your case once the top side is cured flip it over and do the process again. This way you will be sure that the air is out and the cloth will be very tight and have a nice finished surface. You will not need to weigh it down with peel ply and again have a very nice finished surface. Let it cure out completely before you try to remove the peel ply. Since I'm using West Systems I mixed some 407 powder to make a runny bog, ask your supply co. for the resin for something to add to the resin to make a thin bog for the first wetout. It is also recomended to flash coat the foam first with a thin coat of resin before you lay-up any glass. This will keep from dry spots during lay-up if the resin getting sucked up in the foam.

(For your panel you may want to fore go the bog it tends to make the panel stiffer, save that for the inside. You may want to test with the lay-up on just one side only - Listen for cracks as you bend the foam panel, you may get away with it using E glass. It has been recommended for large panel lay-up to scrim one side of the foam to stiffen it, perhaps even thin mat for the scrim if 200g cloth proves too stiff.)

I just used the peel ply method without a vacuum bag on a carbon mast repair last night and pulled off the peel ply tonight. It came out smooth, even though it was curved, and the cloth compacted very nice. The vacuum bag tends to wrinkle the cloth on a tight curve of a tear drop shaped mast of a A-Cat Catamaran.

But my friend it is your job and I do not want to sound directive. I've studied this method for a decade and have become experienced with my project. I've been around boat building and studied with many boat builders of racing multihulls, and have about $1,000 US in design and consulting fees on my project from my NA.

In the Aug edition of Sailing there is a story named Backyard Tri. I meet with Kevin Cook several times, prior to the article, in his house to learn from his experience. I've also meet with another NA on a different matter (purchase), specifically carbon fiber, foam, and vacuum bagging. I wanted to do my homework before I started my project. I also have the mold that Kevin used to build his boat and his plans for free. Kevin works with this stuff in his real job in the building of submarines for the US Navy. I meet Kevin though another forum, and ran into Kevin when I doing some work for the NCIS in Washington DC at the Navy Ship Yard.

[rwatson]

To all - sorry for this bit of thread hijacking, I just dont want to end up like the original post

Hi themanshed - All this info is very,very welcome - dont apologise for saying too much :-)

Hole in the foam is not keen in my book that is chance to de-laminate. The sheer force cannot be transfered between the skins. I drilled 1/8 inch holes 1 inch on center to raise the sheer in places. The holes were filled with bog. It is recommended to not have any voids in the foam. If you have a void it should be filled with a bog. They do make foam with small holes for the vacuum to suck resin though the foam to wetout both sides of a "panel" layup. The voids are filled with resin it does increases the weight. .

Ths is very interesting. In my mind, having places where the inner and outer skin joined seemed a good idea, (obviously only after the bend has been put in place.) I was thinking if is was a substantial join (say a 1/2" hole filled with resin) that it would be advantageous. I will need more advice on this. I might start another thread about it under fibreglass.

One layer of 200g E-glass unidirectional 90 degree may bend, perhaps you may want to try just one side first. Edge glue the sides of the foam with epoxy careful to not get any on the plane surface, if you do clean it up. The foam and glue sand at different rates, usually the foam will dish out.

yes, sorry, I didnt make myself clear obviously - on the flat layup table I only lay one outside skin of 200 gsm and CSM layer. When that cures, I bend the panel into the basket.
I plan to only glue one side of the foam sheet (yellow) to the thin layer of glass , (grey) (see crude illustration)

The rest of the layup is done once the bend is in.

Thanks for all the input

[Jimbo1490]

I like to think of a cored panel as a 'planar I beam'.

[apex1]

Thats good. I couldnt find anything after a quick look. I thought they only did plywood kits. Do you have a link ?

http://www.bateau.com/proddetail.php?prod=LB26 start there.

But I would leave the plastic cr@p where it belongs and use Kiri and Epoxy instead! When you calculate that thoroughly, with a 19mm wood core you come out at the same price than with foam and vinylester, but have by far the better result!
No matter what others say, pound per pound and cent per cent you do´nt beat wood (except for CF in some case). There is no dry rot or other issues when done right.

Regards
Richard

[themanshed]

No matter what others say, pound per pound and cent per cent you do´nt beat wood ...

I do not disagree with this but the reason for foam is to reduce the pound for pound and foam can make some sweet curves. You could steam wood until it becomes rice and never curve it like foam. If you are keen on wooden cores, there is nothing wrong with wooden cores, check out Kurt Hughes CM method it is what drew me to his designs. Using this method you basically construct your own continuous sheet of curved plywood then cut out the sides and stitch the sides of a hull together. I like the built in curve this method provides. The wood foam debate may go on forever or at least until all of the trees are gone. Each side has it merits and minus points.

Personally I like foam one reason you don't have stringers and in the tropics where a pinhole can start rot rather quickly I shy away from wood, even in my house. Foam may be considered new wave although it has been around for 20 some years. Foam also has built in buoyancy. After many years of poly resins I have converted to epoxy.

[apex1]

When you look at my gallery you may know why I´m saying what I said.

Richard

[themanshed]

Very nice woodworking! The boating world has many Facets a nicely fitted motor yacht should be wood; a sleek racing sailing boat should be foam. Now if you want to cut some weight out of her foam and fiberglass does polish up nicely.......:p

The same reason I do not live in a wooden house in Hurricane country.

[MarineSurvey]

An update for everyone: A few weeks ago, a manager, Benny (he called from his cell phone), at DIAB’s Asian offices called us to inform us that one of the bosses from Sweden was going to come to China to meet with us to resolve the mess that they created. It is fortunate for us that we did not believe them. It turns out that this was, indeed, another deceitful tactic from DIAB to try to get out of the agreement that they signed to a Chinese company by stalling us. It has seemed rather obvious to us for some time that DIAB believes that a Chinese company must be run by idiots who cannot see what DIAB is doing. We have spoken with other individuals and have heard the same thing about western suppliers: that the suppliers have an attitude toward them because they are Chinese. We refuse to simply lie down and take this kind of behaviour. We would greatly appreciate if anyone who has had any similar experiences would let us know.

[Landlubber]

"We refuse to simply lie down and take this kind of behaviour. We would greatly appreciate if anyone who has had any similar experiences would let us know."..........

can you enlighten us further.....I do not quite get what it is that the behavior is that you are so upset about, being Chinese or western suppliers.....

ta...

[Alik]

It is something new in marine survey business - 'marine surveyors' publish survey information in the Internet.

Well, what will be next step? :)

[apex1]

I guess that this one is as much a Marine Surveyor as I am the lesbian daughter of the Pope!

Richard

[themanshed]

I've had good luck from the DIAB foam. Application of the use of the foam is up to the builder.

I've had good saws they seem to still have a problem cutting straight.

[rwatson]

I like to think of a cored panel as a 'planar I beam'.

That was a great analogy Jimbo.

I did start another thread to stop mucking this one up on this subject.

http://www.boatdesign.net/forums/fiberglass-composite-boat-building/joining-skins-through-foam-cores-29516.html

in case anyone wants to "pitch in"

OK - now back to the wicked DIAB people.

[Ruby Tuesday]

Personally,I can empathise with 'MarineSurvey', & would like to contact him to discuss our respective experiences.

I have just had an infusion done on my 42' powercat by the DIAB "experts" & it has turned out a complete disaster! I used DIAB foam & CNC cut kits, used "Polyworx", had my workers do the DIAB training course, & had the local DIAB team themselves do the glass lay-up & infusion.

The result is tens of thousands of dollars in repairs to fill & fair & paint the hull & deck. There is print-through of the fibreglass cloth on 100% of the hull & deck, & large "suck-ins" all along the chines, knuck;es, sheers, stems, windows, etc., in fact at every foam edge.

There's no problem with the foam - it's actually great to use & easy to work with. I've infused all my bulkheads, hull longitudinals, tanks & floors & never had a problem.

I was totally sold on the infusion process until all this happened. I still think it is the way to build boats, but obviously there are major obstacles to overcome first.

I'd like to hear first-hand of 'MarineSurvey's' problems.

Cheers

[Herman]

What was the problem with the infusion? From what I can tell from your story, the boat filled perfectly. So the Polyworx software has done it's job, the foam has done it's job, but choices in glass fabrics, gelcoat and barriercoat might have turned out wrong. Also the layup might have suffered a bit. (along foam edges).

How did your test panels look? I presume you made test panels on a sheet of glass to test all the materials?

[AndrewK]

Ruby Tuesday, so sorry to hear about your infusion result.
Are the DIAB people saying what went wrong? and will they fix the problems?
I think infusion process advantages outweigh the disadvantages and would like to see it used more widely.
Can you describe the infusion strategy used for your boat, are the defects due to air leaks or resin flow path lockouts, photos always help.
The more information you can provide can only help others avoid the same bad experience.

regards
Andrew

[Ruby Tuesday]

Herman - I am unable to discuss certain specifics at this point in time for legal reasons.

Being an absolute newcomer to infusion, I am at a loss to explain what went wrong. DIAB handled the whole infusion process. We did a few infused panels with my vinyl ester resin during the DIAB infusion course we attended, but they never did a full-on test panel with gel coat, tie layer, CFM, etc. After a two-day course I did not have sufficient knowledge to have insisted on a test panel, unfortunately. There was a lot of bridging evident after removing the bag & peel-ply, along the chines & knuckles, where the glass had not been forced right into the mould, but those weren’t the only areas that have ‘sucked in’.

Andrew K – DIAB hasn’t said what went wrong & have made little effort to fix the problems, or to tell me how to avoid them in future infusions.

The laminate was as follows –

Gel coat, tie layer 225g CSM with vinyl ester resin, cure 3 days

450g CFM, 2 x 850 BiAx, foam, 2 x 850 BiAx, also vinyl ester infusion resin

Peelply

We hired the pump & catch-pots, & the resin supplier’s rep was present & did the tests with the catalyst percentages, & supervised the mixing of the resin before & during infusion. DIAB’s personnel supervised, participated & were in attendance daily from when the first layers of glass were laid in until infusion was completed. The infusion itself went smoothly, except that we used more resin than DIAB had calculated. We had longitudinal resin lines in the hull, feeding sequentially up the topsides & up the tunnel, & did the VolvoIPS implants at the same time. There were no air leaks or resin lock-outs – the hull is sound. Very little resin got through the resin-breaks & into the catchpots. Total infusion time was just less than an hour. The deck was done according to Polyworx’s programming. Infusion time around 40 mins.

Really disappointing! I have dozens of photos & I’ll put some together over the weekend so you can see the results for yourselves.

Cheers.

[AndrewK]

Ruby Tuesday, based on your description it appears that the only thing done wrong was ensuring that there was no bridging during the laying of reinforcements. With infusion you have to pay attention to every little detail.
With 225g CSM & 450g CFM, I am surprised that print through was very evident, what type of foam was used, grooved and perforated only or double cut as well?

Cheers

[Ruby Tuesday]

Hi Andrew, the feedback I'm getting from third parties is that the 225 CSM is far too light in this application, & that CFM is primarily a resin-transfer medium, not a print blocker. Some say that a 2mm Soric layer would have helped a lot. Print through was very, very evident over 100% of the hull & deck!

I've infused a panel with gelcoat, 450 CSM, cure, 2mm Soric, 850 BiAx, 6mm core, 850 BiAx. It was absolutely perfect when it came out the mould, but within two days it had started to show the BiAx printing through. After a few days in the sun it's as bad as the hull & deck were (without the bridging)

We used both types of foam, with the curves of the deck using more of the double cut than the hull.

I thought by using DIAB's services that they would have 'paid attention to every little detail' & made sure there was no bridging! It's a pretty daunting undertaking infusing a 42' cat, especially when you've never done it before.

Thanks for your interest, I'll keep posting if anything new comes to light.

SeeYa

[rwatson]

What colour is the gelcoat?

Dark colours are renowned for print through in the sunlight for epoxy, so I guess VinylEster would be worse. One boat builder leaves his boat under cover for a month before exposing it to UV.

[Ruby Tuesday]

G’day RWatson - The gel coat colour is white, or WAS white – it’s now an International Paints undercoat, after four weeks of filling & fairing.

The hull & deck were both in their moulds for at least two months after infusing, while we made up & fitted bulkheads & floors etc. The painter I have repairing the hull & deck refused to do any work on them until I had post-cured them, as he’d had similar problems (also with a DIAB infused boat incidently) in Western Australia. We put tents over the hull & deck & used gas heaters to heat them up to 65 degrees C for a few hours, & we still noticed a bit of movement. As I understand it, infusion resins have a very low exotherm (curing) heat while under vacuum & once out the mould & exposed to sunlight, they can continue to cure & distort.

I saw a Princess at Riviera recently ($4m second hand!) & its hull was dark blue & it was unbelievably bad! The entire hull had serious print-through problems. Doesn’t help much knowing that I’m the only one having problems. I still believe in spite of all my hassles that resin infusion is the way that boat-building will be going in the future, but it will be a long & expensive learning curve for most. Making the infused components for the bulkheads, floors & even fuel tanks on a flat table was very interesting & rewarding work, & once you have the hang of it, it is really very simple if you follow the rules, or as AndrewK says, “you have to pay attention to every little detail”. Very true.

Cheers

[rwatson]

Interesting you mention Riveria. One Diab dealer has a lot of pre-cut kits of foam and cloth that they are trying to unload since Riveria went broke.

I am about to try a hand laid Vinylester over Diab foam layup on a 28 footer.

I have some trial material to hand - it will be interesting to see how it turns out. I will be using Diab Divilette as the foam coating rather than CSM. This print through problem is a worry.

[waikikin]

Hi rw, using a core bedding putty is a reliable way to go, there's less chance of print with plain sheet with vent holes or with knife cut rather than saw cut contour foam so far as "block print" goes. All the best from Jeff.

[Herman]

Also take a critical look at your resin.

I sell a lot of polyester resins in NL, and I have plenty to choose from. (for various applications). Some do shrink much more than others. I have abandoned already a couple of resins due to excessive shrinkage.

So ask around, get a couple of samples of resin, and do tests. I do the same in NL, as a supplier, but not every supplier is willing to do that.

[AndrewK]

Ruby Tuesday, infusing any size boat for the first time is daunting, you did the right thing by hiring DIAB's expertise to guide you through the process but unfortunately they let you down.
Print through is a separate issue, CFM is just as effective as CSM for blocking print through. I have only infused with epoxy but a friend had infused with Huntsman AME600 vinyl ester and 750g triax on both sides of 16mm grooved foam and I had not noticed any print through.
You mention only the biaxial showing up but not the blocks from the double cut foam.
I would expect the other way around especially in curvy areas where the slits open up.
What is the resin supplier saying?
Is there any evidence of resin gassing up and collecting between the biaxial yarns or are the laminates translucent and void free?

Cheers
Andrew

[Ruby Tuesday]

Thank you all for the positive & helpful advice you are offering, it is all very much appreciated.

Attached are (I hope) some pics of the hull & deck so you can see the issues I have. The gel coat was sanded back with 80#, and then sprayed with a high-build primer. This was then also cut back & the remaining voids were filled. The pics show the hull with the (white) filler, while the deck is ready for filling. You can see that even after all this sanding there are substantial areas that need filling.

The resin manufacturers have said that their resin is in no way responsible – end of story. It’s impossible for me to prove otherwise, but I’m not convinced it didn’t contribute - there was further shrinkage when I post-cured the mouldings two months later, in spite of their chemist telling me there could be no more shrinkage after the first week. Several people have refuted his statement, even from within his own company. There’s not a lot of choice in Australia in infusion vinylesters. One’s made by the same company & marketed under different names.

I am starting to have doubts about the wisdom of using 850g BiAx – it’s a very coarse fabric as you can see from the print through. I’ve had a number of people look at the boat & some have raised this issue, saying a tri axial would have been preferable, & would have conformed to the chines & knuckles far easier.

Andrew - The foam was used with the resin grooves & cuts facing inwards so there was no evidence of any print through from it. Where there were tight curves, we “V’ed” the grooves until it fitted, but never had the grooves facing the mould. I infused all the bulkheads, etc, & had no problems at all, although that’s far easier to control than a 42 foot mould, & there was no gel coat or tie layer involved. I wasn’t aware that you could use CSM during infusion? During the course we did it was demonstrated that CSM is very poor for resin flow. We used it in the resin breaks (peel ply & CSM) to slow down resin entering the vacuum lines. The laminates all appear to be void free.

I’m stumped - & out of pocket!

SeeYa
36546

36547

36548

36549

[Landlubber]

Ruby,

The CSM is used prior to the infusion game, it is laid over tissue that is laid oved the gelcoat, and set down by hand. It is cured before the setup for the infusion, that way the "outer" skin is hard and shown less print thru.

I have had very good results using their barrier coat, on a dark blue hull you need everything you can get.

[Herman]

Attached are (I hope) some pics of the hull & deck so you can see the issues I have. The gel coat was sanded back with 80#, and then sprayed with a high-build primer. This was then also cut back & the remaining voids were filled. The pics show the hull with the (white) filler, while the deck is ready for filling. You can see that even after all this sanding there are substantial areas that need filling.

I know above is not the route you wanted to go. Anyhow, the end result will be great, however, with more expenses then expected. So be it for this time.
If you ever want to go this route again, please be aware that there is also available some easily sandable gelcoats. (we call them "sanding gelcoat", but I guess we are not creative...)


The resin manufacturers have said that their resin is in no way responsible – end of story. It’s impossible for me to prove otherwise, but I’m not convinced it didn’t contribute - there was further shrinkage when I post-cured the mouldings two months later, in spite of their chemist telling me there could be no more shrinkage after the first week. Several people have refuted his statement, even from within his own company. There’s not a lot of choice in Australia in infusion vinylesters. One’s made by the same company & marketed under different names.

The resin is not responsible? What did shrink then? All polyester and vinylester based resins shrink further somewhat at curing. I must also say that postcuring is an art in itself. Please do not ramp up the temperature more then 10 degrees C / hour. This implicates you need to be able to control and distribute the temperature. Ramp up untill you have reached your target temperature. Keep it there the desired amount of time, then ramp down again, or just turn of heating, and keep the oven closed.
About choice of resin: I guess we are lucky in Europe. Stil I do suggest ordering samples of polyester and vinylester from as many places as possible, and test them. If there is no expert available, you just need to be the expert...
We have a mould which produces a half-round piece of rod. The mould is exactly 400,0 mm long, and made of polyester. The most slippery of mold releases is applied in it. Resin is cast in it, and allowed to cure. After demoulding, the sample is measured. After postcuring, it is measured again. This will give you insight in the behaviour of the resins. At least you can compare them.


I am starting to have doubts about the wisdom of using 850g BiAx – it’s a very coarse fabric as you can see from the print through. I’ve had a number of people look at the boat & some have raised this issue, saying a tri axial would have been preferable, & would have conformed to the chines & knuckles far easier.

Do you have a picture of the biax? Is it a 0/90? These can be pretty course. Best is to plan a +/- 45 on the outside, as these are usually a lot nicer.

Andrew - The foam was used with the resin grooves & cuts facing inwards so there was no evidence of any print through from it. Where there were tight curves, we “V’ed” the grooves until it fitted, but never had the grooves facing the mould. I infused all the bulkheads, etc, & had no problems at all, although that’s far easier to control than a 42 foot mould, & there was no gel coat or tie layer involved. I wasn’t aware that you could use CSM during infusion? During the course we did it was demonstrated that CSM is very poor for resin flow. We used it in the resin breaks (peel ply & CSM) to slow down resin entering the vacuum lines. The laminates all appear to be void free.

CSM can be used in infusion. However it needs to be no more then one or perhaps 2 layers, and needs backed up by more permeable material. For instance, infusion of a panel made from 450 CSM / Soric / 450 CSM is no problem.
However, in this case, layup should be (and probably is):
Gelcoat
Optionally a barrier coat
Optionally a veil
Low tex CSM
Peelply

After cure you can remove the peelply (carefully) and then build up. You could start with a Soric TF1,5 or 2, to prevent further print. All is optional, and you can perform some tests to see what works for you.

[AndrewK]

Ruby Tuesday, the more open (lover fiber volume) biaxial cloths are good for infusion due to the larger channels between yarns. I use a 600gm2 version for infusion but do not have issues due to much lower shrinkage epoxy resin. Same goes with triaxial some have large gaps between yarns, out of the 4 cloths available locally I found that the cheapest actually wet out most easily, draped best and had smallest gaps between the yarns.
I also use CSM at times for resin breaks this is emulsion bound stuff. But also have found that DB with CSM backing actually infuses faster than DB without the CSM. The reason for this is that the CSM is stitched to the DB and not emulsion bound.

You say that the infused bulkheads had no print through, was the 850g biax used in these?
If it was then I would recommend that the below mentioned panel you made, you sand through the gelcoat/CSM/soric and check that the biax did infuse correctly.

[Ruby Tuesday]

Landlubber – who is the “their” as in “their barrier coat”? I think I may have missed something you posted? The process DIAB used is essentially as you have described it.

Herman – Thanks for the technical information, I’ll be trying those out shortly. The BiAx is 0* & 90*, & at 850g is very, very coarse. Others have suggested that a lighter (600g or 650g) DB would have been far more suitable. Also a heavier tie layer than 225 CSM would have helped, as would the Soric. All this expert knowledge I expected would have been provided by DIAB.

Andrew – The main bulkheads were two layers of 850g BiAx on each side of the 25mm foam, & the thinner floor supports were 2 x 650 BiAx each side of 12mm foam. The surface on the under side is smooth as, & the top side is typical peel ply finish.

Trying to digest all this information, plus supervise the repairs to the boat, & keep the internal build going with the hull & deck, leaves little time for experimentation. I’ll have to mould the hard top, sliding roof & radar arch soon too, but I’m seriously considering laying these up by hand until I know a lot more about infusion. If the experts can’t get it right, I don’t know if I’m likely to.

Thanks to all for the input. Cheers.

[Landlubber]

This is a copy of the layup of a boat we did in Shanghai with Diab.
The resins used are DSM, as follows:
The end result showed very clear on the gelcoat surface, as you can see the RAL 5003 is a dark blue, difficult colour to get right.

DSM Gelcoat RAL5003
DSM Barrier Coat
300 CSM
VectorPly E-LTM2408 ( 813g +275g mat )
VectorPly E-BXM1708 (600g(+-45) +275g mat )
VectorPly E-QX3600
VectorPly E-LTM1808 (600g(0/90)+275g mat )
Diab H100 pvc core 20mm
Diab H80 pvc core 20mm
450CSM
VectorPly E-QX3600
VectorPly E-LTM1808 (600g(0/90)+275g mat )

[AndrewK]

Ruby Tuesday, since the bulkheads with the same biax do not show print through then the resin shrinkage is not the issue.
If it was me I would be sending trough the gelcoated panel down to the biaxial to see what is different about it. And to make sure there are no nasty surprises hiding under the gelcoat and CSM.

Cheers
Andrew

[jim lee]

Marine survey, was there any spray glue used to hold the laminate together? It looks like your gel-coat or skin coat was contaminated before the dry-stack went on. Possibly was someone using PVA nearby?

Also, what was the vacuum at when you shot the part? If you shut down your pump, could you see the vacuum drop?

What resin did you use? Was it an infusion resin? Or did someone dump styrene in standard resin to thin it out?

Were there holes drilled in the core to let the resin pass from one side to the other?

How long was the resin flowing?

-jim lee