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Thom V
Administrator
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Posted: Mon Aug 7th, 2006 06:45 pm |
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Cal, a messer in Oregon, gives his receipe for primer over ply.
"If it is good enough to build, it is good enough to keep from leaking and/or rotting away. Besides I hate re-doing painting, so it needs to be easy as possible. Recoating with the best stuff later is often not possible, due to stronger solvents or other product conflict or contamination. I do a couple coats of primer with fillers in the can, 1 or 2 topcoats and done. That way I can add cosmetic coats, but really don't have to for years.
I use UMA (Urethane Modified Acrylic – Bonder from X-I-M) primer ONLY, water based and nothing else will be as tough and allow as many other kinds of finishes over it. Dries in 3 hours (warm weather time). I have it mixed with 16 parts black per gallon or 4 parts black per quart to make a good neutral grey color, but it can be tinted to match topcoats otherwise. Topcoats with latex, oil alkyds, lacquers, epoxies and urethanes, so it works for all - even on metal!! Yes you can roller coat this on, XXfine rollers best, water wash up, and also saves bucks because it does not form a film in the can, you can use it ALL. This is Industrial paint, they are the toughest coatings !
I add either or both of two fiberglass fillers to the can of UMA primer BEFORE PUTTING IT ON THE PLY, so I don't have to fill the raw wood. Base coat gets 1/8" fine glass fibers to prevent checking on RAW fir ply, then finer milled glass fibers to fill faster and add strength at the same time. Coarse prevents checking, fine fills enough to sand, use a mask filter when working with these loose fibers as you would on glass cloth, this is just making a "liquid glass" surfacer and filler in the can.
The finest milled fiber alone in UMA primer, can be used over glass cloth as a super filler that I still want harder and protected. The thing I noticed is that these fibers mix very smoothly with UMA, may not work with other primers."
Below is Cal's 17' Garvey
Attachment: Cal's Garvey.jpg (Downloaded 150 times) Last edited on Thu Aug 10th, 2006 04:14 pm by Thom V |
arvent
Member
| Joined: | Thu Oct 26th, 2006 |
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| Posts: | 3 |
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Posted: Thu Nov 2nd, 2006 12:54 am |
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Hi,
New member here. This article really caught my attention. I am wondering where one can obtain the glass fibers used for filler in this article? Particularly the coarse one used to prevent checking of raw plywood.
Much appreciated,
Nels
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arvent
Member
| Joined: | Thu Oct 26th, 2006 |
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| Posts: | 3 |
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Posted: Thu Nov 2nd, 2006 08:22 pm |
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Me Again
I found a source for the chopped glass and milled fibers. Now I have another question. How much of each product is added to the UMA to get the best combination of adhesion and strength? And what is the preferred way to apply it?
Thank you,
Nels
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Thom V
Administrator
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Posted: Sun Nov 5th, 2006 07:13 pm |
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Hello Nels,
Cal wrote to SBF on the amout of chopped glassfibers he uses to add heft to UMA and we quote:
"There is no real "formula" on adding the micro fibers to UMA, just that the more you add the more the paint gets thick, I think that makes it easier to paint, thicker coats, and tougher to sand as a primer coating film. I wouldn't add more than say 10 percent by volume to any paint film, and half that would probably do just as well. It is well to remember that this is now a fiberglass you are sanding, any primer is toxic, but with the added glass fibers being sanded a respirator is an absolute necessity.
Just a thought, I have the primer tinted a bit, in my case a light grey so I could see where more (or too little) primer was applied, and it differed from the dry (or sanded) color. Makes it a lot easier to find where you have been, and a lot easier to follow the primer with a top coat. I do three or four primer coats close together so needs just a little sanding to smooth a spot or two -- sand the whole thing once with a fine sandpaper to be sure it is eveny smooth, and do one or two coats of color top coat. Then I wait till it is fully set up, from over 30 days to as far as the end of summer boating season, before I take off the fittings, sand and do another coat. Replace fittings over the winter, and I'm ready for another season with fully cured paint. No, I do not get full protection with the first coat or two, but it is set up, and ready for me to look good for each succeeding season. Painting in the fall helps with the insects in paint too. "
Nels, could you give us your source for the glassfibers or microfibers -- Thanks!
Hope the above helps.
Thom V
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arvent
Member
| Joined: | Thu Oct 26th, 2006 |
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| Posts: | 3 |
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Posted: Mon Nov 6th, 2006 07:34 pm |
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That information is just what I was looking for. I think I will do a couple of test panels before building. One with just the primer mixtures over bare G1S fir and another with 4 oz glass.
Great forum!
I plan to get my fillers at Duckworks:
http://www.duckworksbbs.com/supplies/additives/index.htm
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David Parker
Member
| Joined: | Fri Dec 14th, 2007 |
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Posted: Fri Dec 14th, 2007 08:38 pm |
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Hmmm..... I thought that Nutmeg was all about cheap. I went to my local Home Despot and found 2 gallons of their best exterior latex in the OOPS! section (the cans were dented but not leaking) for $5 a gallon. Seemed like a deal to me.
Cheers, David
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