mhayes462

I am building a Dumas outrigger and was wondering if it would be alright to spray the outside wood hull with sanding sealer before painting? I used finishing epoxy on it and then painted it, but every imperfection showed up. So I sanded it smooth and got past the epoxy and into the wood a little in a couple of spots. I dont want to hassle with adding another layer of epoxy and then sanding it smooth and starting the process over again, so I was wondering if a couple of coats of sanding sealer would be o.k. before painting? Any help would be appreciated.

Dreamin Hemi

Keep things simple...I worked in a body shop for years to get myself through school. Buy a good quality spray primer can. You can get one labeled "High Build". Make sure your surface is clean and apply a medium coat. Let dry about an hour and sand with 220 grit. Come back again with another coat of primer and spray that one about the same thickness. Allow to dry, and sand again with 220. Lightly sand with a lighter paper, say 300 / 330 grit??? Make sure you use a sanding block for thoes large areas otherwise your finger pressure will dig in too much. You won't notice it untill you go to paint. When your 330 grit is done, wipe down and apply whatever finish coat. There are so many ways to do what you're trying to accomplish. This might be the easiest. Just take your time. My hull I just completed took about 5 hours of sanding, adding glazing compound, primer...over and over again untill I was pleased with the result. My gel coat final finish was absolutely flawless.

mhayes462

But what did you use to seal the wood on the outside of the hull?

Dreamin Hemi

I only use high build primer. The 1'st coat seals the wood, subsequent coats with sanding between fill any scratches or slight imperfections.

mhayes462

What is the purpose of using the finishing epoxy then? It adds weight, and on a small rigger like this it would mean a lot.

martno1fan

If your worried about weight why not wrap the rigger with vinyl after sealing the wood? then seal the vinyl with a cpl coats of clear coat after?.

Dreamin Hemi

Hmmm, wonder how "MonoKote" would work, it definately seals well. Used it for years on my airplanes.

mhayes462

I just want to make sure the wood doesnt soak up any water and do this the easiest way possible. Would the sanding sealer work, or just a light coat of finishing epoxy on the bare spots and sand it smooth?

dannyual777

You said that you already coated the outside of the hull with finishing epoxy, right? If you did, then the outer hull should be sealed from water. What you're trying to do now is fill the grain of the wood.

What rigger did you build; old Quickie 40 or Lil Rascal or one of the Hawks? I know the Quickie 40 tub used "mahogany" that had lots of deep, hard to fill grain. The Lil Rascal had smooth, aircraft ply tubs that required much less filling. I've never built a Hawk so I don't know but I'm going to assume that their tubs are smooth aircraft ply as well.

The best way to seal smooth aircraft ply is to use thin epoxy resin. Don't use a brush to apply it. Pour or puddle some of it on the hull and then use an old credit card like a squeegee and spread the resin around the hull. You'll see the wood changing color as it soaks in and you'll be amazed at how far a very small amount of resin goes (saves a bunch of weight!) Let it cure and then you can lightly sand it. If you want, you can repeat the process a second time for better sealing.

After that, its time to hit it with high build primer. I use automotive urethane paint, i.e. PPG. Sand this and all the grain should be completely filled and your surface should be smooth as glass. Then its time for color and finally, urethane clearcoat.

I don't really know what shape your hull is in right now but you might want to consider sanding it down and just starting over. If you don't, your boat's weight gain may be more than you want. Just something to think about.

dannyual777

I just reread your original post and you've already sanded the paint back down and you've reached wood in some places. Good! This is exactly what I would've done!

The credit card method of spreading a small amount of epoxy resin works like magic. Please try it. It'll go on so thin and quite smooth that your sanding will be minimal. You'll end up with a better sealed hull. After that, you can hit it with a coat of your sanding sealer and I think that you'll be fine, however, I still recommend the automotive primer and paint.

mhayes462

Thanks. I did exactly what you described with the finishing epoxy. I put it on with a brush and then used a credit card to spread it. The first coat was just a little. The second coat was almost thick enough to run just as the manual says to do. I sanded it then, but didnt want to sand too much as to not sand through the epoxy and into the wood. Then I sprayed on 2 coats of Model Masters primer, and then 2 coats of pearl orange. Thats when I noticed that I couldnt leave it like that because it just wasnt smooth. Then I sanded it back down to smooth it, and when I got to the point that it was smooth it had sanded the epoxy off the wood in some spots. I was real excited about getting this boat done and now Im starting to lose interest. I just dont want to start the whole process over again. Thats why I was just thinking of spraying sanding sealer on it because its not thick enough to leave dips. It is the hawk 3.5 boat.

Dreamin Hemi

What are you sanding with? For a smooth final surface, you should be wet sanding. You have less of a chance of burning through to the wood.

dannyual777

I think that "almost thick enough to run" is way too much resin which results in way too much work sanding and too much epoxy wasted.



I would do what has been suggested on your other thread: apply another THIN coat of resin and let it soak in a bit then wipe it off with a paper towel. After it cures, you'll have very little sanding to do and the epoxy will have sealed the bare wood areas back up. Then hit it with your sanding sealer for a smooth surface to apply color.

dannyual777

You have to be very careful wet sanding a wood hull. If you aren't super, super careful with what you're doing, you can sand through the epoxy (in spots here and there) and now you are water soaking bare wood [X(] ! The wet sanding procedure cuts so well and so fast that you can go right through several layers of epoxy resin and lightweight glass cloth without even realizing it. Ask me how I know this.