Wipe hull with Lacquer thinner before final coat of FG resin?

Builder's Forum
1

HI all, a question that I'd appreciate hearing any and all opinoins on. I'm building a Solo microBootlegger and am at the final sanding stages prior to varnishing her.

Setup: When I fiberglassed the exterior, I put on two light fill coats of resin, expecting that I might need another eventually, which I now think i do. After having rough sanded the hull, there are some places where I think the resin is a little thin so I’m going to put on another fill coat before final sanding. I've rough sanded the kayakk with 80 grit, to knock down the high spots.

Quesiton one - Should I wipe the hull down after sanding, before putting on the final layer of resin? I've not done this before when building but...

I was just putting a little extra resin on either side of the exterior seam tape, just to allow me to feather it in a little better. In one spot, where I think I may have sanded into the glass a little, there are some very small white-ish spots that show under the new resin that I just put on. Suspecting that it may be dust that was in the cloth before I put the resin on, I wiped off the new resin and wonder what  you suggest. I can't leave it in there, it will drive me nuts. I'm guessing that I will need to sand off the resin that I put on so that I can get to the dust.

I vacuumed the exterior thoroughly before putting on the resin, but I don’t think it got up all the dust, especially in the micro-sized holes? When I applied the resin, I did not warm it up ahead of time as I usually do. I wanted it to go on fairly "heavily", and not run, so that I could have more material to sand. Perhaps this was the problem? If it was warmer, and the viscosity of the resin was lower, it may have worked its way into the "crevices" better? 

After sanding off the resin that I just put on, should I wipe the hull with lacquer thinner prior to the final coat of resin, to make sure all dust is gone prior to putting on the final coats of resin?

Thoughts? Thanks very much!

 Best, 

Rob

2

   I would use acetone but if I had none but had denatured alcohol, I would use that. 

3

Thanks Wing... I've got denatured alcohol and will use it. In doing a little further reading in here that seems to be the common suggestion -thanks again!

Rob

 

4

Rob,

The things that I believe you have to pay attention to are additives in the solvents you use for wipe down as well as the speed with which the solvents evaporate.  The wrong additives can inhibit adhesion by subsequent coats of resin, varnish or paint  Many different additives can be used to denature alchohol.  If a solvent is too volatile, it will evaporate before you have actually picked up all the contaminants from the surface you are cleaning.  Acetone is an good example of this.

Because my labor is the main investment I put into building my boat, I want to be very careful not to be "penny wise and pound foolish" when selecting materials.  I've been using Interlux 202 Fiberglass Solvent Wash to do my final wipe downs and have had no problems with subsequent adhesion of resin or paint.

Cheers!

5

Hey thanks Dick for the great information, I greatly appreciate it! 

I agree with your philosophy of using the right materials for the job, after all the work that's gone into this so far it would be a shame to "cheap-out" on some of the final steps!

Thanks again for taking the time to share your knowledge, 

Rob