Aluminum boat paint prep

[Iyme]

hello new here, is 40 grit too rough of a sandpaper to remove all the residue from the foam and paint? I also am wondering how to go about painting and using an epoxy sealer. From what I can tell you wanna sand, acid wash, primer, epoxy like goop it then paint the boat. is that correct?

 

[airshot]

Outside or inside ?? Goop is not an epoxy, but gluvit is. Epoxy would go on before primer. Gluvit isn't designed for the outside of the hull. If you have a base coat of paint that is in good shape, no need to remove it all, just the loose, chipping, or peeling areas. Wha do you mean by acid wash?? To many questions we need answered in order to help.

 

[Iyme]

Sorry about that! I gutted the inside of the boat of all the foam and want to paint inside then outside but still have all this residue from the foam, is 40 grit too aggressive to remove that and the black bedliner? What I meant by acid was is to clean the aluminum with a restorer of some sorts like alumabrite? Thank you for letting me know about the goop it, so gluv it goes on before the primer.

 

[airshot]

Bed liner is tough to remove, perhaps others with more experience may chime in here. From all my research your idea of an acid wash of some form is needed due to oils etc in the bilge. Once again if the interior coatings are that difficult to remove, leave them on, only loose coatings need to be removed. On the exterior, was it already painted? If not then clean it and scuff the surface, a special primer for aluminum is required !! If previously painted, then remove loose, peeling, chipping paint, scuff the surface, prime any bare aluminum spots then finnish painting. Any sealing like gluvit should be used inside then over coated with paint as it is UV sensative..lots of posts that talk about refinnishing aluminum boat hulls, you have a lot of reading to do !!!

 

[thill]

You can use 40, but it depends on how. Don't put 40 in an angle grinder and start grinding away. If you use some by hand or in a 1/4 sheet finish sander to scuff the surface, it should be okay, but don't grind away the tops off the rivets.

Bedliner can be tough to remove. You are often best to remove the loose stuff, clean those areas, fill in those areas and then topcoat the whole thing for a nice finish.

 

[LDUBS]

Looking at the pics, 40 grit seems like overkill for the underfloor bilge areas. I'm not sure of the benefit of painting under the floor, but if you want to paint there, I would just get all the loose stuff off then have at it.

If you google how to remove bed liner the suggestions are citrus based paint striper or use a heat gun and stiff putty knife.

 

[Ray Clark]

I'm with thill on this. I've joked before that 40 grit is just gravel glued to sandpaper.

An angle grinder would be a no-go. I also think 40 grit in a random orbit sander would still be too aggressive; one slip can go through aluminum pretty quick. A palm sander (aka 1/4 sheet sander) would be safer, but very slow.

40 grit will also leave a pretty significant scratch pattern; if you're looking for a really smooth finish, you'll spend a lot time with varying grits to smooth it out.

Another abrasive alternative might be a polycarbide abrasive wheel. These do go in angle grinders; I used one to strip paint from my boat when I first bought it three years ago. It worked well; available at Harbor Freight. I've never tried to remove bed liner with it, so I don't know how that would go. If the bed liner is in an area that would otherwise be covered up, I think I'd just topcoat paint it and let it go.