Final Finishing of Race Board

[peterwSUPr]

So, I have a board pretty much ready to paddle (in fact it's already been on the water for testing) but I'm not overly happy with the finish.  The plan is for a lightweight finish, but a solid colour, not brushed carbon, although some bits of carbon are being left exposed and glossy. I have used 2 part paint and a air sprayer in the past, but it's expensive, toxic and my sprayer is not the greatest.

So, for this one,  I've been using the "epoxy" "appliance" paint in rattle cans.  I had heard they were pretty good, but not so far for me.  I find that despite multiple coats it seems to show through the  fine texture of what's below, like if there is an area with microballoons and filler, it has a different texture or surface pores than if its over smooth resin or if any fibers have been sanded into slightly.  It's much worse than any other paint I've ever used before in that respect.  Or maybe it would be better with a clearcoat of it??

I guess life would be simpler if I just loaded on a pile of resin and hot coated it and sanded it all, but my record with fisheyes is not that great either.  Plus, on rails with thin carbon on it, the risk of sanding though things is high.   

Maybe about 25 years ago I was making a windsurfer and my dad set me up with some kind of primer that was grey and that you paint on quite thick with a brush.  You would then sand it with wet sandpaper, and about 95 to 99% of it would be taken off, but what's left would fill any slight imperfections.  The beauty of it was that it sanded so easily that you were using fine paper, not risking going through the one layer of carbon or even taking much of any of it off.  It sands WAY easier than any kind of resin and filler or autobody filler type stuff.

Has anyone used anything like this in modern times?  A quick look online and I did not find anything like this.  Or, any other suggestions or words of encouragement?

Thanks,
Peter

[PonoBill]

It was probably something like 2K high build primer, which is intended for finishing metal but works fine on fiberglass. I think it would look great just sprayed on and sanded off.

[supuk]

you can get 1k or 2k high build primer that works well for that and in various colors. Some board companies just use it as there Finnish but I would seal it with a clear after.

[peterwSUPr]

Thanks, am I correct in assuming that 1K is a one-part and 2k is a two-part?  I glanced online but have not found an easy source for it here near me.  I'm sure it's around, I just need to figure out a big name brand and who normally uses this.  Is this mostly a car thing used for body work, or is this going to be with a marine place that sells epoxies?

The stuff I used many years ago was not in a spray can like the stuff I just saw online.  I was much too viscous and went on much thicker than a spray paint.

Peter

[PonoBill]

Yup, 2k is an archaic way of saying two components, it's not a brand. Any catalyzed polyurethane primer can be called 2k as well as epoxy primers. High build refers to the nature of the pigment which has relatively large particles that layer up to fill scratches or sanding marks. For metal you need to use an etching primer first, then high build, then a sealer, and then a chromatic primer. Needless to say Earl Scheib doesn't do that, which is why their paint jobs suck and why a good paint job costs so much.

High-build doesn't fill more just because you put in on thick. All that means is that you get hills as well as valleys when you really just wanted flat. The deepest scratch a primer will fill is about 200 grit, though some people say 150. I don't believe that. Sand well and coat light. Works great.

For your application you can directly apply high build--either epoxy or poly--sand most of it off, and then either apply a sealer or a color.

Paint-on primer used to be popular with people who loved fine brushes, good technique, and watching paint flow out. Now it's generally not. You can get a good sized particle through a gravity feed HVLP gun, so why bother. Siphon guns didn't like heavy particles and left some in the bottom of the can. HVLP guns, especially the really good ones, get everything. Even a cheap one is better than a good siphon gun, which is irritating because I have a lot of old Devilbiss stuff. I painted my Vincent frame with traditional brushed on enamel. Took forever to do it right and it came out 80 percent good. Next time I spray.

[peterwSUPr]

Well, when in doubt, go ask Dad.  I called him, and I think I used this stuff in 1987.  He found the mostly hardened can of what I used still in the back corner of the workshop.  Amazing because he's not a total hoarder or anything.  It was called "Dupont high speed lacquer type primer surfacer 30-s".  I'm not sure if is the same as the 1k stuff you are describing.  It can be thinner and sprayed if needed it says.  I only had painted with a brush though  I wonder what is the new improved version of that?  Then again, I think I was able to buy West System epoxy in the exact same containers with the same pumps back then, so maybe this stuff does not change!

Peter

[TallDude]

You can get a new air-sprayer for pretty cheap, and they do a great job. A lot of the rattler cans come with nice spray tips, that give you a wide even stream. They have 2K in one can now. Watch the video on this link.

http://www.eastwood.com/paints/2k-aero-spray-paints.html

[PonoBill]

That's pretty good for a rattlecan.