Beam Pin Vacuum Infusion Help Please

[Fanie]

Attached is a pin for my folding beams I'm about to vacuum infuse. It is very tightly wound around the former. Length is 650mm and the glass is 16mm thick.
It gets a layer peel ply also.

Initially I was convinced the resin will seep through it easily, but seeing how thick the glass is I have a bit of doubt.

Would any one comment on this please

I was thinking of feeding the resin from the ends to the centre.
Or feeding it from the bottom horizontally to the top horizontally.

I have about 30 minutes before the resin begin to kick.

[kroberts]

Based on the time of your post, you have either already wasted a pot of resin or you have tried it out and it either worked or you wasted the whole project.

Have you done infusion before? I have not, but I've done some reading, some tools collection and some talking to those who do it commercially. So I have book learning but no experience yet.

In my understanding, how well the resin infuses into the part depends both on the viscosity of the resin and on the weave of the glass. And the size and shape of the part, of course.

Some weaves are designed for infusion, to let the resin in. Also, the thinner the resin the easier it is to infuse. If that pin is regular woven glass, then I think it would be hard to infuse completely, especially with a standard epoxy.

The guys I talked to use resins specifically designed for infusion, and they seem to run like water. Those resins (that they use) need a post-cure in an oven though. I understand some people use standard epoxy but thin it down until it's pretty runny.

Either way, let us know how it turns out.

How big is that pin?

[Fanie]

Hi ken,

I have done a little, but limited.

The pin is 150mm ID, 600mm long and I want the wand thickness 16mm.

The resin I have is for injection, much thinner than the regular stuff, almost like water.

I have just done a test vacuum on it and it is not going to work as is. The vacuum compress the glass so much that it makes unregularities on the glass surface as a result of the diameter declining. Despite that I have wound it extremely tight.

There is another method I have been pondering and that is to make a metal jig, take the glass off the former and put it inside the metal jig, Put a baloon or tube inside and pressure form it instead... I can then go to 5 to 10 bar on it. That should make it tight :D

[kroberts]

Is the strength direction mostly shear or something else? Maybe you could use unidirectional and orient it all the same direction, or maybe wrap two layers at a time, each oriented slightly differently. That might make the compression ripples go away.

I tried the pressure thing once. I got the same thing you got, only in reverse. The glass tries to stay small and an epoxy "bubble" happens, where there is no glass but epoxy. I got ripples on the inside then.

Here's another possibility. If you wind such that the cloth weave is at 45 degrees to the axis of the pin, then when you hit it with vacuum on your existing form, the part will actually lengthen a bit maybe, or at least with the pressure thing and a female mold it would shorten as it expands.

[Fanie]

Hi Ken,

I have considered the 45 degree but it's a lot of work and difficult because there are then so many loose pieces of glass. this also makes it difficult to maintan an even thickness all over. The woven I have just rolled up, took probably half an hour to get it done properly.

If the former could expand the bubbles may be forced out, but how to make the former axpandable.

As far as I know pressure formers have a male and female, you lay the wetted glass in it and the two gets squished together under high pressure.


I have another question. Is the pin strength compromised if it is two halves that fit into the beam and the housing instead of a solid round ? It can't fall out or go out of position. The same idea is used in automotives ie the valve stem clamps are two thick washers contained by their housing.

How about if the pin has a slit in the one side ?

The idea is to give the glass room to expand to when it gets vacuumed.

[kroberts]

Re: 45 degree layup: You can buy cloth which is woven in a 45 degree orientation instead of 0/90. Slightly more expensive, but not if you count the time you waste cutting all that glass, or the number of cycles it takes to wash the glass fibers out of your clothing after you got done. Well worth it IMO, for something the size of your project. Just about every glass vendor I've found online has it, or did a couple years ago when I last looked.

Strength of a split pin: I'm not an engineer. I can't answer that for you.

Female mold and pressure former: I used a piece of pipe and a bladder made of vinyl-coated nylon made just for the project. My project wasn't nearly as massive as yours, particularly in number of layers. The bladder was bigger than the ID of the project, which did not matter that much. What mattered is that half the glass fibers prevented the thing from expanding to the pipe, and the epoxy bubbled in there.

Keep in mind that on a project the size of yours I don't know if a 45 degree weave is going to scrunch down enough to avoid your ripples, but it might be. You wouldn't be able to wind it tight, but you also wouldn't WANT to.

You can get metal split pins (can't recall what they're called) at the hardware store, it's a spring steel tube with a split down the side. It's sound in principle, the pin expands to fit the hole exactly. Your application though I can't say. You're not really doing the same thing. IMO your groove would simply fill with epoxy and create a weak spot.

[Rick Willoughby]

Fanie
This is something I have only given a moments thought and not something I have tried.

I expect your glass wrap is still quite porous. I think if you mounted the tube vertically with resin feed from a bottom ring while pulling a vacuum from a top ring with the whole thing sealed wrapped the resin would migrate quite quickly and disperse evenly.

You could do a preliminary check to see how easily the vacuum pump pulls before you add resin. I do not think you will need any channel material. In fact this may cause preferential flow up the outside.

When you think how far you can infuse resin through a thin layer this one "should!!" be easy.

Will watch with interest.

Rick W

[Fanie]

Thanks Ken and Rick,

I have a simple question regarding hand layup vs vacuum infusion.

If one have the same amount of glass, does the vacuumed item come out stronger or is it only stronger for it's thickness.

Ok I understand you use less resin and you gain on weight by vacuum infusion.

My logic tells me that the same amount of glass, though a bit thicker should be just as strong when you hand layup as what the vacuum infused part will be, in fact, the hand layed up part should be stiffer than the thinner infused item due to the additional thickness.

Have I got it wrong ?

[Fanie]

On the glass wrap, yes the vacuum draws the bag flat quite quickly and the roll should be porous enough.

Ken I was going to use HDPE extrusions of 110mm dia for the pins, it would be easier to buy them as to making these. The HDPE pins can carry 30 tons of shearing which would be enough, but they were friggin expensive and the glass at 16mm can carry > 100 tons. Never the less, I want the pins, beams and their bulkheads to be an overkill, you never know that gets throwed your way and it must not even be an issue in any kind of weather.

The pins are only big on your lap. Out there they are going to look very small :D

[Rick Willoughby]

Thanks Ken and Rick,

I have a simple question regarding hand layup vs vacuum infusion.

If one have the same amount of glass, does the vacuumed item come out stronger or is it only stronger for it's thickness.

Ok I understand you use less resin and you gain on weight by vacuum infusion.

My logic tells me that the same amount of glass, though a bit thicker should be just as strong when you hand layup as what the vacuum infused part will be, in fact, the hand layed up part should be stiffer than the thinner infused item due to the additional thickness.

Have I got it wrong ?

Glass is stronger than resin. The more glass you can get into a given volume the stronger the part. Any air bubbles give potential to get water logged and the water will eventually destroy the glass to resin bond as it works its way in.

The main advantage of vacuum is the air exclusion and high clamping force with no need for heavy weights or hydraulic rams. The bagging will also conform to the shape.

If you are concerned about infusion then wrapping a pre-impregnated glass will work. You can add the wrap and vacuum after you have formed it. That will provide the pressure and pull out any air.

Rick W

[Fanie]

I would defenately like to vacuum every item for the boat. On the pins alone I can save a lot of weight.

The glass per pin is 5kg. If I hand layup it the weight will be around 10kg per pin. A vacuumed pin will weigh around 7.5kg's. In total that's 60kg's vs 45kg's. Which girl do you prefer, the 60 kg one or the 45 kg one :D

Doesn't sound like much but it calculates to 15kg's. If everything gets added 25% in weight the boat will become unnessesary heavy and cost 25% more in resin. Quite a bit in total. On a 2000kg boat it adds 500kg's. It's going to haunt you when you trailer, launch or sail the boat, and you may have to leave some drink on the beach to save on the payload :D

I'll take a bit of time and see if I can come up with something sensable. It always feels to me like I'm missing the obvious.

[jim lee]

What side is critical? Inside or outside?

-jim lee

[Fanie]

Hi Jim, the outside is.

Once it's done it will be trimmed with a lathe, varnished etc to form a very smooth fine fiberglass outer surface.

The beam housing will be formed as wet glass around the pin for a snug no play fit. I tested doing it that way and the play is 0 while it hinges very nicely.

[jim lee]

If it is the outside then I'd try a mold shaped like a cup. Maybe split down the middle for release? Shoot the gel inside, drystack it. Bag it from the open end. Flow from the bottom, breath at the top.

But 16 mm is really thick, your going to get a lot of heat going on there. can you find a resin that will work for this?

Where does the 16mm bit come from?

-jim lee

[Fanie]

Vacuuming it on the inside brings other problems Jim, for one you cannot see and you cannot 'help' the flow.

Besides, if the outer diameter is shorter than the cup then the glass won't fill the cavity, it's going to be either an air pocket or a resin pocket.

The 16mm thickness is to make it strong enough to keep the beam attached to the hull and the beams hold together, The boat is foldable, so the beams fold in half and the hulls can be moved together or apart.

[KnottyBuoyz]

Hey Fanie

I've tried infusing some tubes, although not as big as yours, without any success. The last one was a 2 meter stern tube, 55mm dia. The vacuum compressed the stack to the point of choking off the flow. I did this vertically feeding from the bottom. It went well till about the half way point. I was using biaxial fabrics which I think might have been part of the problem.

I found http://www.solarcomposites.com/ who have a different method that I'm about to try. They recommend biaxial sleeves and shrink tubing in their method. This way you can hand lay up your tube on the mandrel and use the shrink tubing to give you the compression you need working from the center out. Here... they can describe it better than I.

Scroll down to "Professional Looking shafts....."

on this page

http://www.solarcomposites.com/composites/carbon%20fiber%20sleeves.html

They also have carbon fiber and basalt sleeves. I've got the basalt sleeves and they look like they'll work ok, cheaper than carbon and stronger than glass.

Just a thought.

[Fanie]

I've made a decision to get something else.

If I get some 45 deg woven. Chances are 90% it's going to come out a lot better and in theory there shouldn't be any problems. Just one problem now is how do one roll it tight over the former ? or is it a matter of rolling it relative loosely and it expands sideways... Using a wider than required 45 deg glass and pulling it just enough to become the width required might make it. When you vacuum it will want to expand sideways.

Any one have an opinion on this ?

If I get some uni directional glass, how is it going to be different ? I've never seen it or used it.


Just for the sake of knowing I dismantled the current rolled glas's vacuum stuff and tried to wound it up tighter. I put a wedge pole through the former end and really cranked it. It worked, the ridges are almost non existent when I vacuum it.

[Fanie]

Hi Rick,

The main consideration for vacuuming the glass is to minimise the weight without compromising the strength.

[Fanie]

Ok I've made another few observations :D

Winding the glass on the former with the wedge pole makes the glass nearly as dense as when vacuuming it. When I switch the vacuum on the OD of the tightly reeled spool of glass reduces so little it's not going to make much difference.

I anyone considers doing their tubing the same way, that makes for quite a bit of forcefull cranking. The wider the glass obviously the more force you need to achieve the same density.

I'm going to use hand layup, it is going to rule a few questions out and reduce the risk of possible flaws, though more physical work and would probably take a bit longer.

The glass I have despooled from the former onto a 50mm pipe. I'm going to wet the glass on the former then tighten it, two layers at a time. The excess resin will squish out to the surface and help wet the next wound layers out.

One thing I noticed is that the woven does not despool when you've tighten it.

[KnottyBuoyz]

Hi Rick,

The main consideration for vacuuming the glass is to minimise the weight without compromising the strength.

I haven't tried mine yet but I think, so I've been told, you'll get more compression of the stack from the shrink tubing than you would from a full vacuum pull. Just some thoughts. We need a materials engineer methinks! :D

[Fanie]

Aye Rick, guys,

First pin DONE !!

Pic 1 is the first 2 layers wound on the plastic, ready to begin glassing. I phone one of my friends to come help, shame he worked today and was tired but he came never the less. He was going to restore a small cathedral hull before but gave up before he started, so had 50kg's of resin in his garage. I swapped it for one of my small anchors which I had a few exta made last time.

Pic 2 glassing in progress. Note my clothes how poor I am... :D
We'd glass 500ml of resin in at a time and then rotated the two reels oposite to squish the excess resin out. It worked quite well.

Pic 3 The completed pin. It took about two hours but it probably was like an hour and 15 mins worked on the pin itself. The pin is already hard, be ready tomorrow to pluck off with the block and tackle. The resin used wasn't measured exqactly and a little was left over, but I'd say I used about 3.6 kg's or resin. The peel ply was in the way so I draped it, it wasn't nesserary though.

Thickness is just over 17mm, will get cut to 16mm. One down five to go...

[Rick Willoughby]

Fanie
It looks good and no doubt about the saturation of the cloth - more reliable than infusion.

From your explanation and photos I gather you did not vacuum bag it.

You could get a tighter layup if you bag the glass tube and pull a vacuum on it. The bagging can just be a plastic sheet wrap taped to the PVC tube. Having 15psi over the surface of the glass tube will force any air out of it once you pull the vacuum. It will also get rid of excess resin.

Would be something you could try on the next one and compare the result.

Rick W

[Jimbo1490]

Don't forget shrink tubing works for compaction and is simpler to use on tubes. I have some shrink tubing about that size in the shop right now.

You could use an epoxy resin for your infusion. Choose a BPF resin like Epon 862 or 863, then thin it further with Heloxy 62 or 68, about 10%. The resulting resin will be around the viscosity of the typical polyester resin. Use Emi-24 cat at about 5% . Do your infusion and take your time as this resin takes about 5 days at ISO std (25C). When you are ready to cure just heat to 120*F (just nice and warm, really:D) for 4-6 hours and you're done. Post cure as necessary if you need high temp service

Jimbo

[Fanie]

Hi Rick, not so easy ! I tested the tight wound layup and compared with the vacuumed of it while wound so tight, made little difference. That pin you see there was pulled tight with force rotating the jig, so much so the red pin you see in the pictures got bent. I can hang on it ok without bending, but we extended it with a piece of sqr tubing to add some leverage. That did it :D

I also used normal resin since I have it, the inner layers were probably gelled by the time we finished the outer layers, so vacuuming would not have made much difference.

It is currently a very pleasing temperature to touch. I ripped the peel ply and the glass is stone hard already. It looks good...

[Fanie]

Jimbo and the other Rick :D

Will the scrink tube provide enough crimp force ? I wonder. Usually crimp sleeve does make a bit of pressure, but not nearly as much as vacuum or even close to the way I did it above, unless your crimp sleeve is really something else... ? I did have a look at the link, but I still wonder. It may let it look really good and give an excellent finish, but remember the pins will not be visible, they will be enclosed into the structure they will live in.

This reminds me. When the pins are cut in the lathe and polished to very smooth, I have to give it a varnish layer. What to use ?

I would also like to put something like a pollish or grease on it so the beam housing that gets glasses around it doesn't want to stick to it firstly and secondly should act as a lubricant for the pins so they won't rotate dry. Preferably something that is water resistant or water repellant... Any ideas ?

I could add a grease nipple :D

[Fanie]

Thanks everyone for your help, comments, advice etc etc. I pulled the first pin off the former today, and it looks really good. It is un be friggin lievable hard.

The two trees is all I have to pull it apart with :D

[kroberts]

Fanie,

I'm sorry I missed all the excitement.

The way you did this one really looks nice.

For all practical purposes, the weight of any extra resin is entirely wasted. Any stiffness you get from the resin is going to be there with the "minimum use" strategy of vacuum infusion. On the other hand, I'm not sure if you're losing much with your rig.

If you decide to try infusion, I like Rick's idea of putting the pin on its end and pulling resin from the bottom, but with one modification:

Instead of trying to pull resin through the entire pin, put several feeds on it. One on the bottom, one 6" or so higher, and one more 6" higher than that until you get to the top. The feeds are rings. All feeds start clamped shut, except the bottom one. When the level gets as high as it will get, you clamp off the bottom feed and turn on the one just below the current epoxy level.

The first pin you do this way will tell you how far apart you can make your feed rings. The biggest cause of failed parts in infusion, from my reading, is failure to get the entire part saturated. It won't hurt you to have too many feeds, but it will hurt to not have enough. You never know until too late how well the part will allow resin to flow.

If you wanted an inside mold, you can sometimes find clear acrylic tubing for not much money. You could put the channels on the inside, vacuum bag using whatever and then just break the mold off the part.

[Fanie]

Hi Ken,

Not much excitement however, just donkey work.

Tbh, I'm a bit scared to try and vacuum infuse this thick a layup. The method of rolling and tightning the layup works very well. Winding the supply reel and the layup opposite directions makes for quite a tight layup.

Initially I thought the resin content is too high, using about 4kg of resin per pin, then I weighed them. The pins weigh about 10kg as is, so there is 6kg's of glass and 4kg's of resin. Not perfect but ok.

I think I will use this method again to make round things. I must say, the pins are fairly rigit :D Good exercise winding them too.

Pin #2 done. I got another friend to come help me this time. I better give them all a chance to help with one pin before the word goes around :D

You can see the resin squish through when you wind it up some.

[Fanie]

Since I plan another boat similar to this one just smaller (8m for daysailing and fishing) I can just as well make it's pins as well. With all these pins I hope I remember to do the rest of the boat :D

Since we're kind of on the topic of wetting glass and layups and vacuuming.

I was thinking of a glass wet out bin. The idea would be to wet all the layers out as it gets feed through the bin, in one go. The bin hangs over the hull and can be moved backwards, either from a beam or a trolley extending both sides of the hull.

If you then precut and lay all the layers and stitch or glue them together (somehow), as the glass goes through the wet out bin it gets layed on the hull former. Once all the glass is on the hull and in place. you pull a bag over the hull and vacuum it in one go. Any excess resin will be sucked out and you may have less problems with resin not flowing where it should.

What do you think ?

[kroberts]

The problem with that IMO is that the vacuum won't really squeeze anything out, at least not a lot of it. Chances are your resin will have started to heat, and you will get minimal resin out.

One of the main attractions of infusion is that you never mix a drop until after the bag is turned on and at a hard vacuum. Another attraction is that you never even draw resin unless you need it.

Every document I've read so far concerning infusion, they focus on getting the feed channels set up properly so that resin can flow properly.

I think that if you put the layers of feed channel close enough together, you will be able to use infusion properly without too much trouble.

[apex1]

[QUOTE=Fanie;273347
Initially I thought the resin content is too high, using about 4kg of resin per pin, then I weighed them. The pins weigh about 10kg as is, so there is 6kg's of glass and 4kg's of resin. Not perfect but ok.

[/QUOTE]

You are too humble here Fanie. 60% glass is a perfect result! A handlayup by the average novice is 35%, industrial is way below 50% and a 55% is expected a good result in industrial Vac Infusion on complex shapes. So, you´re much better than the most professional done items.

Regards
Richard

[KnottyBuoyz]

I was thinking of a glass wet out bin. The idea would be to wet all the layers out as it gets feed through the bin, in one go. The bin hangs over the hull and can be moved backwards, either from a beam or a trolley extending both sides of the hull.

If you then precut and lay all the layers and stitch or glue them together (somehow), as the glass goes through the wet out bin it gets layed on the hull former. Once all the glass is on the hull and in place. you pull a bag over the hull and vacuum it in one go. Any excess resin will be sucked out and you may have less problems with resin not flowing where it should.

What do you think ?

I've actually seen pictures of that kind of setup, possibly on here, where they're laying up large yachts by hand. I would think you'd need a resin formulation with an extremely long pot life. It'd be a "sticky wicket" if the resin in the bin kicked off while you're trying to lay it out! I think most amateur builders will wet out their glass on a long plastic covered table, roll it up, transport it to the hull, they unroll it. If you were in a large production facility doing a lot of hulls your idea is/will probably work.

[Fanie]

Hi Ken,

Yes you're right. What I described above is called vacuum bagging, resin infusion is what you think of.

As long as the resin doesn't kick it should be fine. The idea as I said would be to get all the layers in place in one go, wetted out and in as little as say 5 to 10 mins. Another 10 to 15 mins to get the bag sealed, say in total 30 mins.

You get resins that give you an hour, and if done while it's cold, you may even have a bit longer.

[Fanie]

Hi Richard,

The setup I have doesn't allow for much harder cranking the glass up. It may however with a more sturdy setup do better. I have neve made such thick glass items before, and I must say I'm surprised at how hard this 16mm layup is. Normally if you tap the hull with your nuckles it makes that klonking sound and feel. This stuff however hurts, it's like the wall :D

Main concern however is it may not break, no matter what.

[Fanie]

Aye Rick,

I know such processes exist, I haven't see one before and haven't seen one work. The big systems I assume is for mass production, I don't know if it practical to build something like that for such a small scale as mine. It is not a system one person can run, you will have to have a few people to help in such a setup, while vac infusion can be a one person operation if you are well organised.

I absolutely believe that a boat should be glassed in one go. It scares the daylight out of me if I see how some boats are built, where some have multiple joints and layups over dried glass.

Aparently epoxy males a good join on polyester. Manie is going to glass again soon and we're doing a couple of experinments with epoxy on polyester and we'll see if wetted epoxy joins properly to wetted polyester. If the wet epoxy properly adhere to wetted polyester it may be a good way to join new glass on old glass, but I want to see that for myself. I've had some bad experiences with polyester delaminating and I'm not taking any chances.

[Fanie]

This is how the pins fit in the beams. Only the end pins are drawed in, the beam hinges's pins were left out for clarity. The beams are 300mm w x 400mm h and about 2m long each.

I didn't like the scissors that cat2fold used, they take up more space in the hulls due to their extra length. Once the beams are finished I'll draw a cavity off the assembled beams to make a proper housing they will fit into in the hulls.

I still have to figure out how exactly to make the beams, so any advice will be welcome.

The intent was to glass a sleeve around the pins that they will turn in. This sleeve is also glassed into the beams itself.

[kroberts]

Fanie,

Nearly all my experience is with hand layups, either in open air or in a partial vacuum bag. I've just started collecting equipment to do things properly. Since I'm an amateur this is a slow process.

I usually cut the glass to shape, stack it in reverse order and then lay it up one layer at a time, using a paint roller with a short to medium nap. Then, if I intend to vacuum bag it, I put it in the bag and wait for a cure.

I have no desire to go into production on anything, I just got sick of hand layups and excess epoxy.

[Fanie]

I'm not particularly fond of the work myself, I prefer fishing instead, without work however there is no fishing and I always console myself it's a once off.

Doing a hand layup I have pretty much the same method, but I'm thinking of ways to get larger pices of glass wetted out faster for layup. The roller is ok for small things, but a hull is a lot of glass to put down with a roller. I'm thinking of a wet out bin and rollers with a feeder motor on it. Laying a width of glass, ready wetted out will be much much faster and less tiring. Do the full layup in a couple of hours.

[kroberts]

You and I are on opposite ends of the scale.

My biggest project is an 18 foot long hovercraft, and it's mostly wood. The roller is for "big" projects, and those projects probably have never had as much glass in them as one of your pins. For small stuff I use a paint brush or bondo spreader.

Unless I'm using a full-sized roller, my biggest mixing container is a disposable plastic drinking cup.

[apex1]

Hi Richard,

The setup I have doesn't allow for much harder cranking the glass up. It may however with a more sturdy setup do better. I have neve made such thick glass items before, and I must say I'm surprised at how hard this 16mm layup is. Normally if you tap the hull with your nuckles it makes that klonking sound and feel. This stuff however hurts, it's like the wall :D

Main concern however is it may not break, no matter what.

That will not brake! even if you go icebraking with it. Anything else may!? And again 60% glass is far above best industrial standard!
To your "preprep" method: look how the most professional and economical (in terms of efficiency) "yard" in the world does:

http://www.bavaria-yachtbau.com/index.php?id=749

HANDLAYUP.................................................................................
and they do not waste a single penny, nor a single minute in producing a boat!

Regards
Richard

[Fanie]

I have made four pins now. The 25kg container is now just slightly below half full, that means I have used say 14kg of resin for 4 pins. That is about 3.5kg's of resin in a 10kg pin. Can it be ?

Lets say I've used 15kg's of resin to now, that's under 4kg's per 10kg pin.

If this is true, then I'm changing the way I'm doing layups on boats !!

[apex1]

Lets say I've used 15kg's of resin to now, that's under 4kg's per 10kg pin.

If this is true, then I'm changing the way I'm doing layups on boats !!

You´re the only one who can tell us if its true, I guess.

It is hard to buy the 35% figure but as mentioned twice, 40% resin is impressive already.

[Fanie]

Five pins done. Friggin boring to say the least. I really had to convince myself tonight to begin and the smell will be really good :D

[kroberts]

Open the door at each end of your shop and turn on a huge industrial fan to pump the air through. No reason to breathe fumes. Can't help with the boring part.

Have you examined the earlier pins to make sure they are entirely wetted out? Your epoxy use figures are amazing, I'm sure some folks are wondering.

[Fanie]

No Ken, I like the smell. One of the fewe pleasures of life remaining :D

On the resin quantities I'm surprised myself. I have examined and there are no dry spots. If there are you will see the white clearly. The pins are a green colour when I pull them off the jig. I leave them in the sun for a few hours to cure the resin properly, they come off the jig easier then.

You have to keep in mind the winding makes the glass extremely dense.

I think if one have a winder motor that can attach to the jig through a gearbox, a feedthrough wetout contaption with compressed rollers to squeegee the excess resin out and a clutch to keep tension on the supply roll it would go much quicker. It takes me two hours per pin.

Imagine you can rotate a boat like this while continuously spinning the woven around it. It is possible, even where the boat tapers off towards the heel and stern. It's going to be really quick to do a couple of layers this way, and you do the complete hull in one go. Lastly you can just add some peel ply.

[kroberts]

Fanie,

Do yourself a favor and work out the torque you are delivering to that pin, and then work out the forces you would need to deliver the same torque to a boat hull. Then, do some figuring to see how strong your pre-glassed boat hull is and how much you will deform the hull by adding that force.

[apex1]

Imagine you can rotate a boat like this while continuously spinning the woven around it. It is possible, even where the boat tapers off towards the heel and stern. It's going to be really quick to do a couple of layers this way, and you do the complete hull in one go. Lastly you can just add some peel ply.

Maybe the "Plastic" association should redesign their hulls to be produced that way??????????

[Jimbo1490]

This is exactly how Boeing is manufacturing sections of the 787 airliner fuselage. It's called tape winding, by the way.

31731

"Alenia Aeronautica, a partner-supplier to Boeing for the 787, uses a massive Ingersoll tape layer to produce Section 44 of the Dreamliner fuselage. Tape layers are ideal for long courses that allow machinery to reach maximum speed. Most fiber placement projects, however, require a larger quantity of short courses, which is where AFP excels."


Jimbo

[Fanie]

If someone around here would just think for a change good grief :D I WEIGHED (new concept) the resin tonight before I started the last pin. 3kg +/- 100g. So I'm using 3kg's of resin to 8 kg's of glass. Sounds about right to me. I can do better too if I have a proper made jig.

Regarding 'tape winding a boat. If you squeegee the excess resin out of the glass prior to laying it, then one may not need such excessive force to wind the glass. The width is also important, a 1m300 glass needs double the force to be wound as tight as a 650mm wide reel.

Even if the 'mold' or jig bends a little when you wind the glass, I'm sure it will be tolerant of that little bending movement over the length. The beam's jig also bent some, no effect to the pins.

Such a method may be close to perfect. You tape wind the inner first and around a premade colapsible jig, premade bulkheads in place as well. Then you drape your foam around it and you can tape wind the outer layers the same way. Last layer will be peel ply to help sanding down.

If you're organised and have a few guys to help you you can do a hull inside and outside in one day. Very little risk of failure and no air leaks and bags to fiddle with :D One doesn't need special resins either.

Anyway, I'm glad the big pins are done. My fiberglass expert calculated the pins can handle 250 tonnes, in his words, 'very conservative for in case you don't know how to work with glass'.

The cost saving was worth it. The HDPE pins at 30 tonnes would have cost me > R 4000, while these conservative :D fiberglass at 250 tonne pins cost me about R 1900. I used one reel of glass and less than 20kg's of resin, so there's a bit spare on the R1900 as well.

Amazingly, now that I have saved all that money, why don't I see it anywhere :rolleyes:

[apex1]

Why not?
PREPREG
is already on the market, at very , very, very competitive rates.

[McFarlane]

good to see apex your looking into pre-preg glass ive been using it for the last 10 years, it does work well if you have the correct oven temps. :D

[Fanie]

The problem is getting a big enough oven to put the boat in.

When we say SA is hell to live in it's not because the temperature is so high :D

[Fanie]

Finally... a 6 pack :D The un-wetted glass you see on the insides is where the plastic on the former overlapped the glass. I used a block and tackle to pull the glass off the former. Thumb suck about 300 to 500kg's to pull them apart.

An up close picture of the glass on one of the pins.

If I am to make a stand alone mast from fiberglass, I would do it using the same method. Inside layer 50% overlap so the inside layer is double, do this twice so you have four layers inside. Then wind uni glass in it's length to whatever requirements, repeat the four layers on the outside. Nice fat diameter and nothing would bend it.

[kroberts]

Yes, but look at the supports they have there so they don't crush their project.

[apex1]

good to see apex your looking into pre-preg glass ive been using it for the last 10 years, it does work well if you have the correct oven temps. :D

Thats all you have to contribute? Your usual blabla?
And where did you use prepregs, on your tugboat in Alaska?

Fanie
the closeup shows a perfect surface, I doubt you would have done as good in infusion.

Regards
Richard

[Fanie]

Thanks Richard. That was 12 hours well worth spending then.

The guy with the lathe is full this week, maybe he can cut the pins next week. Have to start on the beams then.

[apex1]

Thanks Richard. That was 12 hours well worth spending then.
.

Well, whats 12 hours for a perfect job. Remember 3 to 5 lbs per manhour is a real good result for amateur building!

Did you temper them? Or have´nt you used a slow hardener? If you have.... temper them. If there are no spec.s provided by the supplier, heat them up to max 80°C going up from ambient temp. in 5°C steps every 15 minutes, let them sit for 8 hrs., reduce temp in slow steps again. Remember, you cannot "overcook" Epoxy by leaving it on high temp for too long time.
If there might be no noticeable gain in strength, there is one in high temp stability.
Fast hardeners usually have no gain from tempering.

Regards
Richard

[Fanie]

Hi Richard,

So, now I'm an ammateur eh :D

It is a good tip to remember that one can harden epoxy that way...

I used polyester resin, not epoxy. Polyester resin as far as I know mature over a few months. Heating it would probably accellerate it, but should not be required. The green colour it is currently will turn to a bleak yellow to a bleak white over time. It will be fully cured then, hard as hell and unbreakable. The only thing that remains is to use it ;)

[apex1]

Hi Richard,

So, now I'm an ammateur eh :D



Well, for a pro you were too slow.:D

[Fanie]

I have to start on the beams... complicated :(