Infusion Q&A

[jiggerpro]

Hi Andrew, with the scotch brite we did not plan on filtering the air out, what was thought, was to induce the formation of bubbles with the scotch brite only to suck them out of the inline resin feed line before it entering the bag ....... but If Herman says no problem then there will be no problem.

[jiggerpro]

Hi Jim; yes we do have Duratec in Spain but my supplier "fooled" me into thinking that Crystic´s Glosscoat was a very similar product (probably it is but we had bad luck wit a can) anyway as is usually the case with anything resin related we had to redo some tedious work just to get to where we where before so for me this product is forever out of my purchasing lists.

There are many products out there (compatible with polyester resin and its solvents) that produce a shiny blemishless surface, and for sure most ot them are friendlier than those polyester based ones ( anything is friendlier than poly) due to larger working times and easieness of sanding

We should have gone thorough the proven way which is Duratec.

[AndrewK]

Originally Posted by jiggerpro

Hi Andrew, with the scotch brite we did not plan on filtering the air out, what was thought, was to induce the formation of bubbles with the scotch brite only to suck them out of the inline resin feed line before it entering the bag ....... but If Herman says no problem then there will be no problem.

Sorry, I got that impression based on your description, sounded like a filter to me.
De gassing is a batch process and takes time for the bubbles to form and rise to the surface. I found that 5 minutes in a vacuum pot is about the minimum time required, so only practical for small jobs.

[Herman]

Originally Posted by bntii

I have never done any infusion molding. Looking at the videos, I am surprised that saturation is seemingly easy to obtain on the mold side of the core.
The core material must be specifically designed with capillaries to allow the transfer of resin?

There are several ways, but in general the foam indeed is perforated. Also it is made sure that the bottom layer of laminate is slightly more permeable than the top layer (can be done by adding grooves to the foam, adding unifilo, soric, or whatever). This way the bottom laminate is saturated well, and the grooves make sure the front levels out nicely between top and bottom laminate.

[Herman]

Originally Posted by jiggerpro

Changing of subject a bit, we are facing now a problem with the last coat for our plugs, we tried using Scott Bader´s Crystic Glosscoat and we are experiencing some fisheyes, we even bought a new screw air compressor ( not only for this offcourse) with the very best air filters we could find ( Sagola 5300) to ensure air purity, but the proof of the problem lying in the product was some tests we conducted applying it by a (new) brush instead of spraying it, the fisheys are less but still some are present.

I remember you (Herman) telling me that this last glossy coat neccessary to get a nice surface plug could be done using two part polyurethane paint ... is this correct and is it a good procedure for the last coat on a mould plug ???

Is there a car detailer or anything similar in the direct neighbourhood? (spraying cockpit spray all over) or even worse, did someone do that in your building? How about floor wax, or even shaving cream (some shaving creams can f*ck up coatings, I am NOT kidding.) Also these plastic armbands which say "fight cancer" or "peace for all" should be banned.

On PU paint: Yes, this can be done. Most PU paints don't even need a primer for polyester. (check with your supplier). PU paint in general needs at least a 7 day cure to be completely and satifactory styrene resistant. Many, many moulds are made this way over here.
Find out which PU paint and which colour levels out best. Usually the dark colours are better. Also, spraying PU paint can be different from spraying acrylic. In general one single wetcoat should do the job, but you need the bollocks (and the skill) to do that. In that case a perfect surface can be reached. (without orange peel). I have also seen people roll PU paint with the same great result. (maintain your wet edge for best results, do a search on this forum for these terms).
Of course you can polish and rework the paint, but starting with a near-perfect surface does not harm...

And never forget the 12th commitment: Thou shalth do tesths. (the 11th is "thou shalth make backuphs")

[bntii]

Herman- thanks very much.
I think I will give this a whirl in my shop & see if I can make use of the technique for the parts I have to produce.

[jiggerpro]

Anyway, this Crisytic Glosscoat is absurdely difficult to sand polish and I would definitely can not advise anyone to use it.

If PU paints allow the same gloss, in no way would I prefer the Polyester based products due to the short working time, and problematic nature when compared with other chemistrys

As the purpose is only to pull one piece from our plugs which will be the female molds we are going to try making some demoulding test panels to check if we can finish our plugs with the polyurethane sprayable filler/Primer with which we already primed our plugs because the product is very easily sandable and polishable allowing for a high gloss without much effort. ( RM Basic Filler)

So we are going to conduct some tests to see which product allow our intended purposes without unnecessarily inconveniences

Something else I want to try is the use of styrenated paraffin inside common Poly resin becuase I remember this was all I used when I was a student and made some surfboards and it always produced a shini glossy surface without much effort.

In fact I wonder if those plug finishing products like Duratec or Crsytic Gloss coat are somthing else than just that but with a higher price tag ( opinions on this please )

[jiggerpro]

Yesterday, we sprayed some test panels with PU paint ( industrial grade, nothing fancy) and the paint layed very flat and shiny giving as Herman forecasted a near perfect surface, what a relief when comparing spraying polyester based stuff, no hurrys no worrys of it hardening inside the spray gear .......... and as bonus which is no small bonus, the suface had only a very slight orange peel which should sand away quite fast due to it not having enough depth. I find it strange, that is not more common the use of PU instead of poly products for the finish of male plugs .......

I can not wait to go to the workshop to test its sandability and polishability, but if it does so satisfactorily ......... IMHO, and much to my surprise the vast majority of plug for molds fabricators have been playing the fool by using those unfriendly poly products just to attain a glossy surface wich is only going to be used once for the obtaining of the female molds. ( Not to mention the mega price of products like Duratec, which is IMHO again completely unjustified since it is not much more then polyester resin with some additives that does not have to be expensive.

[Herman]

Why it is not used more? Because it needs 7 days to cure properly, to be styrene resistant. People do not want to wait for 7 days. They are always in a hurry.

[jiggerpro]

Crystic Glosscoat needs 3 weeks ..................... so PU still advantageous, By the way our test panels worked out to be good, with good sandability and polishability so we sprayed our hull and "top deck" male plugs I will post some pics hopefully tomorrow.

[magnus]

EnkaFusion Anyone? This looked like an alternate to flo lines. Anybody ever play around with this. http://www.colbond-usa.com

I have had good luck with this product. I am doing a skin finish with no Gel coat. I infuse at 125-150 degrees F and have accidentally gone well beyond recommended cure (235 degrees F) with no print-through. I believe the resin system must be the important element. I was using Jeffco which is now Rhino coatings. I went to them because vinylester was giving me huge print-through problems with no Gelcoat; so I reluctantly made the switch to epoxy. Shrinkage and print -through have no longer been problems.
Enkafusion is 4" wide, since I am building very thin walled paddling/rowing craft and do not need the volume of resin or the heat build up, I razor cut it into thirds after thermocompressing it at the cut sites. 1 and 1/3" width delivers considerable resin for most jobs. I have not purchased from Rhino yet and they seem not as friendly to the small shops like myself. I suspect I will stick with epoxy.

Jim

[Herman]

I regularly sell this product for flow lines (we call them "Ce-Sense Flat Runner"). The flow is about 1/2 of that of a 9/12mm spiral. Keep that in mind. Imprint is very low, even in thicker laminates.

For main runners I would not recommend it, but for the fishbones Jiggerpro can definately use it. Remove the skin at intersections with the main runner, to promote flow into the Flat Runner.

[jiggerpro]

Herman; In regards to this flat runners, I read that as they "store" a certain amount or resin it gets hotter than the rest of the laminate causing imprints of it ....

[Herman]

Yes, that is true. but that is also true for round runners, probably even more. Flat runner is only some 3mm thick.

[magnus]

The Enkafusion is 4mm thick. I infuse at about 100F and with small parts like my outriggers (keel line Enkafusion at 1/3 normal width and only a 200mm pull up to the perimeter spiral wrap) I was infused in 15 minutes and would then raise the temperature to 125-145F as per the manufacturers instruction. I was getting about a 50F rise in temperature with a pyrometer on the enkafusion than I was 1/2 inch into the part. This concerned me even though the final parts looked good, so I now hold up on the ramp up temperature for 20-30 minutes and only get a 25F rise in temperature in the Enkafusion. In a thick infusion (a large part) with the approriate long gel/cure times this may not be an issue. My outriggers are less than 1mm wall thickness (kevlar) and the glass/polyester molds are only 6mm thick so are unable to absorb much of the exotherm.