Refinishing the Interior

[Rick Harmer]

I want to start refinishing the interior of the Boler. We're going to repaint everything from the floor up and I want to start sanding right away. Since the finish on the fibreglass appears to be the original (gelcoat??), I'm wondering what grit to use to get the surface prepared for painting. I have an unusual sander that Ryobi made (Makes? not sure) and rebranded under the Canadian tire house label (mastercraft). This little gem has 3 small orbital sanding heads that have some flexibility. When told that Cdn Tire was dicontinuing them, I bought another, along with an extra supply of pads. So,I've got grits of 80, 120, 240, and 400 that I could use here. These are generally for wood, but, given that this is what I've got, why not try.

So, any direction from those who have already done it would be welcome!

[Raya]

Hi Rick,

Are you talking about sanding the smooth, gelcoated parts of the trailer, like the outside of the closet/cabinets? Or the inside walls (normally a more "globby" type surface that was not molded)?

It sounds like you mean the walls, but I wasn't sure because I didn't know they made any with molded gelcoat walls.

I would start by reading the instructions on the paint or primer you are going to use. They will typically recommend which grit you should stop at (usually something in the 150-220 range, but that could vary).

I would probably start with the 120, but I wouldn't choose until after finding out what my particular paint instructions called for.

80 would be the absolute roughest I would start with, but if you do, be careful. And it's probably too rough for what you are doing (but I can't see your walls).

You can use really rough grits on fiberglass (I've used 36 many times), but that's usually when you are trying to remove material in preparation for fiberglassing - when you want to make a bevel. It's quite possible to sand right on through.

Because our trailers are relatively thin, and assuming your interior is not smooth molded gelcoat but is the rougher, "backside," like mine is (I can see it inside the closet even though my walls and ceiling are covered with Ensolite), I would almost be tempted to use something more flexible and to sand by hand, so as not to remove much material. So just be careful with the power sander until you get a feel for it.

Raya

[Rick Harmer]

Not the walls,just the cabinets.the walls on mine are Ensolite,so I'll take any info there,although I'm assuming latex paint,and "gap-filling"with caulking instead of tape.So that in another post and liked it!!

[Raya]

Ah okay, I got confused by the "everything from the floor up" part.

I would still advise to read the instructions on the exact primer/paint you are going to use. They will no doubt specify a grit they want things sanded to. That doesn't necessarily mean you have to start with that grit, but you will know where to end up (and you may be able to start there too).

Given the new info, I would say that I probably wouldn't go rougher than the 120 (since your only other choice is 80 below that). But again I would check with the paint you are going to use. I'm also not sure that I would use a power sander. If you do, be careful. The thing is that you are only giving it a little "tooth" for the paint to grip. And the gelcoat on these cabinets is not very thick. You also want to keep it flat (except where there are curves, of course).

I think I'd use a pretty mild grit (again, check the paint) on a flat, manual, sanding block. Maybe on a flexible block or sponge on the inside corners. Probably very gently by hand on outside corners (they are easy to burn through on). I think once you had the hardware off and the Ensolite taped off, it wouldn't take long to prep the cabinets by hand.

Granted if I were doing the entire hull of a 30 foot boat, I would use a power sander. But that's a lot more surface area with fewer places to burn through (corners, etc.).

Raya

PS: And don't forget to remove the mold-release wax before you start sanding (or you will just sand it in). Use plenty of clean rags so you don't recontaminate. I use Interlux 202, but there are others (Prep Sol, or perhaps acetone). Yes, it will still be there after 35 years. It even remains on boats that have been in the water for that long!

[Rick Harmer]

Thanks,Raya!Us Boler people have to stick together!!