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Apr 25, 2018, 12:30 PM
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Ward Hagaman's Avatar
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Discussion

Veil necessary for paint in the mold?


I’ve just started to play with painting my wing molds. When I was doing bare carbon I found that I could get a better look by using 1 oz glass as a veil layer...fewer pinholes. But now with paint I wonder if the veil is necessary at all. I imagine there might be some print through, but maybe someone has some experience? I’m using rattle can paint and 6 oz. plain weave carbon for a 60” sloper.

Ward
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Apr 26, 2018, 06:16 PM
Scott
Pylonracr's Avatar
Ward, 2 things come to mind.
First, make sure your paint is compatible with your resin. A test spray onto glass and some resin brushed on will tell you in a hurry.
Second, is print through a problem for you. You can go straight to the carbon fabric, but it will definitely print through. A layer of 1 ounce will minimize but not eliminate the print through. Obviously keep the paint to a minimum, just enough that you can't see through it. You could gob on the paint to eliminate the fabric print through but it would kind of defeat the purpose.
This is all assuming the wing will be bagged.

Scott
Apr 26, 2018, 07:02 PM
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Ward Hagaman's Avatar
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Scott, havent seen print through yet, but I’ve just started to try paint in the mold and so far I’ve used a veil. I was hoping to save the 1/2 oz. of the veil...maybe I’ll see how bad the print thru is.

Ward
Apr 26, 2018, 08:41 PM
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T.D.'s Avatar
Ward, is it carbon cloth you are laying up or uni? I've tried both straight carbon and with veil and for me the veil is worth doing as the chance of getting a prefect finish with the veil is higher IMO. I put the .5oz or .75oz veil in the mould, wet it out and go over it gently with a bubble roller, then I lay in the carbon and go over it with the bubble roller and a wall paper roller...you want to really mash the fibres into one another and generally I get good to excellent results. In my experience this mashing frees up some of the excess epoxy which I soak up with paper towels.


Tony
Apr 26, 2018, 10:00 PM
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Ward Hagaman's Avatar
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Tony, I’m using 6oz plain weave carbon. When you say “perfect finish”are you talking painted or bare?

I’m totally with you on the rolling...certainly with one layer of bare carbon. Do you think rolling is as necessary for a painted mold?

Ward
Apr 27, 2018, 02:51 AM
chetosmachine's Avatar
Ward,

Use the veil. Been there, done that. It may not print through the first week, or the first month, but you can bet that the first time that wing gets hot (SUN!), it will get print through. And it get get very awful very fast.
There's a trick some manufacturers use, is to lay the veil the night before doing the layup. So you paint in the afternoon, lay the veil (room temperature, no vacuum), then next morning resume the layup with carbon and everything else. It may work for you.

Also, if you press hard your cloth after putting the resin, with a hard roller to sort of "spread" the fibers, print through is much much less after. Even when using plain old skool 6oz carbon
Apr 27, 2018, 04:55 AM
plane destroyer and builder
skybattle's Avatar
I'm using transparent 2k paint and even with a thin veil layer of FG it has marks, although almost no bubbles.

I was thinking it was a matter of paint 'curing' and I will try next time to wait more than 2 days the paint to dry.
Apr 27, 2018, 10:38 AM
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T.D.'s Avatar
"When you say “perfect finish”are you talking painted or bare?" Both, I've had the best finish and surface quality when using veil as it helps close the weave on the carbon and with the veil I tend to get away with using less epoxy...sounds crazy as using the veil should mean more epoxy but I think that since the veil closes the carbon weave it take less epoxy to get a smooth finish.

"Do you think rolling is as necessary for a painted mold?" Yes I do as even when the lay up is evenly wet out there is a good chance of air still being in the cloth and rolling helps force it out...just be careful to not move the cloth around too much after rolling in a painted mould as there is a good chance the paint will lift...I've had this happen and it really put a crimp in my day.



T.D.
Apr 27, 2018, 11:35 AM
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Ward Hagaman's Avatar
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Thanks everyone, I just ordered some 0.7 oz. glass.

Ward
May 01, 2018, 09:41 PM
Themadartist
Ward, a couple of quick comments.

1. I use a very tight weave 100gsm glass for the veil on my bagged wings - it is fantastic. I'm not sure (only time will tell) if the 0.7oz cloth might even be too light if used with 6oz cloth.

Another experience I have had is with a 100gsm veil I used when I had run out of my usual stuff, but it was a more open weave. The wings came out of the bag looking ok, but anywhere tape was applied, it actually pulled the paint straight off the wing, leaving, for all intents and purposes, large pin holes.

2. I have been cautioned to not "mash down" the weave too much on the likes of 6oz carbon cloth, as it can actually break the fibres. I know Phil Barnes does this in the videos but he is basically using uni-carbon, which has much less transverse material.

Anyway, just my 2c.

Cheers, Steve.
May 05, 2018, 11:06 AM
Registered User
Ward, maybe unwoven carbon veil cloth would do the trick? I have not tried in in a mold however.

Seems like any print through is coming from vacuum bagging since it is the nature of woven fabric (hard spots where the threads cross and voids between filled with epoxy, hopefully). I'll bet you do not get print thru with uni-carbon.

I have not had print thru when I have painted wing mylars with Klass Kote, which is a two part epoxy paint. It does go on thicker than rattle can paint and being epoxy, has some strength to span the air bubbles in the first layer of cloth, so you get a pin hole free finish.

Tom f.
Jun 01, 2018, 11:46 PM
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T.D.'s Avatar
Ward, how did you make out with the veil?


T.D.
Jun 02, 2018, 11:01 AM
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Ward Hagaman's Avatar
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I sort of got weary of chasing the perfect cosmetic look and I got sidetracked playing with a quick cheap foam design lately.

My wings came out good thanks. I wouldn’t say “perfect” as I can still see a very slight cloth pattern if I look very closely at a very shallow angle. This is with Rustoleum Universal Paint and Primer from Home Depot. It’s funny; it comes out of the mold a little tacky so the wings need 2 days to firm up or I’ll leave fingerprints.

I did have the local Automotive paint store bottle up a can of two component paint into a spray can to try. It ends up costing about $8 for the paint and $12 for the spray can/hardener that way but I figure it’s worth a try.
Jun 04, 2018, 08:03 AM
Registered User
Ward, I did the same thing (car paint store) to get a color match. The color matched but the finish came out with an orange peal finish.

Some clear coat filled it in and over all it came out OK.

Tom


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