Rustoleum topside question re: finishing - how much wet sanding can I do?

[Buzz Killington]

I have three good coats of rolled/tipped Rustoleum topside on the neverending project. I started wet-sanding with 1000 grit to get some runs and brush strokes knocked down, but before I get to far I wanted to ask:

Just how much can I sand down? One firm pass? A couple? I don't want to hit primer and I just have no frame of reference, never having done this before, and would appreciate advice from someone who's BTDT. Obviously I want to have a mirror finish but I don't want primer spots to get it!

Thanks!

Dave

 

[ljc1957]

Re: Rustoleum topside question re: finishing - how much wet sanding can I do?

Buzz, You will want to sand until the blemish is removed. One trick I used when painting my boat with Rustoleum Marine paint was to mix it with 30% mineral spirits. This thins the paint just enough, so the paint will "lay down" smooth, giving you the desired finish. I only wet sanded the primer, not the paint. I'm not trying to be a wise ***, but the best way to fix a run/brush stroke is to avoid them. I used a 4" foam roller, then, after applying a light coat of paint, I meticulously watched the paint for drips/runs. I used a 4", high quality, paint brush to knock down imperfections. The paint will then settle, giving you the finish you desire. Also, make sure it's dry and hot, at least 70 degrees. It took 3 coats and I'm really happy with the finish.

 

[Buzz Killington]

Re: Rustoleum topside question re: finishing - how much wet sanding can I do?

Buzz, You will want to sand until the blemish is removed. One trick I used when painting my boat with Rustoleum Marine paint was to mix it with 30% mineral spirits. This thins the paint just enough, so the paint will "lay down" smooth, giving you the desired finish. I only wet sanded the primer, not the paint. I'm not trying to be a wise ***, but the best way to fix a run/brush stroke is to avoid them. I used a 4" foam roller, then, after applying a light coat of paint, I meticulously watched the paint for drips/runs. I used a 4", high quality, paint brush to knock down imperfections. The paint will then settle, giving you the finish you desire. Also, make sure it's dry and hot, at least 70 degrees. It took 3 coats and I'm really happy with the finish.

Thanks for the reply. The boat's been painted for a few months now. I'm NOT repainting it to remove runs and brush strokes I think I did a light sanding job after I primed it, but I didn't start using Penetrol until my second or third hull coat.

I suppose I could choose one small area underneath the waterline to test to see how much sanding it can take before a "perfectly" smooth finish.

Oddly enough the white Rustoleum seemed to flow much, much better than the red. Don't know why. The top of my boat is white and it looks really good. Only a light wet sanding pass should be necessary on that.

 

[emoney]

Re: Rustoleum topside question re: finishing - how much wet sanding can I do?

If you can find an opening that doesn't have trim around it, you might be able to get an idea of how thick your topcoats are. Speaking only from a "wood worker's perspective", a person can wetsand pretty aggressively with 1000grit before getting close to a sand through.