Gel Coat Restoration, Still Scratches after 3000?

[Taylor_T]

I'm trying to bring the gelcoat on my old 1985 Chris Craft back to life. The majority of the gelcoat is black, so the oxidation build up over the years makes it look not-so-great.

My plan was to wet-sand 400, 600, 1000, 1500, 2000, 3000, then buff with rubbing compound and finish off with wax.

I did a little test section and after wet-sanding up to 3000 grit, I still see visible scratches from the 3000 grit (pics attached). I used varying motions to sand each grit, so I could make sure I removed the previous scratches. So, I'm sure these scratches are from the 3000, not from a previous grit.

Is this expected, will it come out with the rubbing compound, or am I doing something wrong? Any advice is appreciated!

 

[jbcurt00]

I suspect a random orbital might have helped, but I think a good bit of the 'problem' is that its black.

Doesnt look like it'll buff out w rubbing compound, but you could try. Not much to loose before going thru several more finer grit sanding stages before wax..

 

[Taylor_T]

Thanks for the tips. I used some rubbing compound on it tonight and it came out surprisingly well, but you can still see a good amount of the scratches in the right lighting.

I ordered some high grit sanding discs for my orbital sander (hard to find locally), so I’m going to try again this weekend with that and see how it comes out.

 

[chevymaher]

It looks like the coarser grits showing. After 3000 it should be a haze but shiney.

 

[Taylor_T]

I think it was a combination of the coarser grits showing and the fact that it’s black gel coat... everything shows! I also found out I was only going up to 2500. It looks waaay better after rubbing compound than I thought it would, though. I haven’t been able to work on it much this weekend, it’s been snowing... I did try it with the orbital sander, but ended up getting swirl marks no matter what I did. I’m suspecting maybe it’s due to low quality sanding discs that I got from Amazon. Where do you get high quality sanding discs in the higher grits? I found a 3000 sanding pad from autozone, and it works GREAT! But I can’t seem to find anything in the 1000-2500 range.

 

[GSPLures]

Using a wheel for compound on black will leave swirl marks unless you are extremely good at it. The body shop I worked at only 2 people were allowed to compound a black car with a wheel

 

[Meames1]

Just use swirl remover as the last step before polish. I like to use it by hand with a microfiber cloth on black or very dark colors. But, it can be used with a soft foam pad. Rub into a haze kinda like you would wax, then polish off with a very clean or new microfiber towel. All swirls gone. Of course, this is after all your sand scratches are buffed out.

https://www.amazon.com/Meguiars-G17616-SwirlX-Swirl-Remover/dp/B001O7I7H6/ref=sr_1_9?dchild=1&keywords=3m+swirl+remover&qid=1616506420&sr=8-9

3M used to make one that was awesome and easy to do by hand, they discontinued it and I have not tried the replacement ($$), but I have used the Maguire's I linked above and it works good.

 

[Lectro88]

You mentioned "Rubbing" compound.
Have you tried Polishing compound.
I don't claim to be a finish guru... But rubbing compound is more gritty or abrasive to me than the polishing compound.
and you may already be using polishing compound(difference in wording)
Just a thought.
(but yes as mentioned., Black is about the most unforgiving for showing anything)

 

[San_Diego_SeaRay]

I think it was a combination of the coarser grits showing and the fact that it’s black gel coat... everything shows! I also found out I was only going up to 2500. It looks waaay better after rubbing compound than I thought it would, though. I haven’t been able to work on it much this weekend, it’s been snowing... I did try it with the orbital sander, but ended up getting swirl marks no matter what I did. I’m suspecting maybe it’s due to low quality sanding discs that I got from Amazon. Where do you get high quality sanding discs in the higher grits? I found a 3000 sanding pad from autozone, and it works GREAT! But I can’t seem to find anything in the 1000-2500 range.

Rubbing compound PUTS scratches (swirls) into your gelcoat. It's the polishing w. the random orbit polisher that takes them out. You mentioned an "orbital" polisher. Do you mean a random orbit polisher? My guess is that's what you need at this point (random orbit). With polishing compound (not rubbing compound) applied with a "polishing" and/or "finishing" foam pad (two different types).

I'm in the process of doing the same with my boat right now, after many years of neglect and heavy oxidation. I'm having good results using the method above. Personally, I'd move away from sanding once you've removed the oxidation haze.

 

[San_Diego_SeaRay]

Doh. I guess I'm just repeating what others have already said. :-(