Rubbing Compound for Gelcoat Scratches?

J

Jazzmanic

New member
I've searched various threads and have an idea what I want to do but need some confirmation. After three boating seasons and numerous run-ins with docks and pilings etc, we've produced some unsightly scratches on the gelcoat, most notably on the green trim. These scratches are not gouges but have defintely scratched the gelcoat surface. The worst of which occurred after rubbing against a piling, which produced several scratches about a foot-long, like scraping a big sharp comb against the hull and leaving about eight uniform scratches across the surface. :cry

My question: Would rubbing compound get these surface scratches out? Or would I have to use wet/dry sandpaper and sand the affected areas first? I'm hoping that I could just use rubbing compound, buff it out, then wax the entire hull to make it look like new. What's the verdict?

Peter
C-Dancer
 
Peter-

It would be impossible to predict which method would work best without seeing the scratches up close, as so much depends on their depth. They might just buff out, rub out, wet sand out, or have to be filled with gel coat if you can see the light hull color underneath.

Best thing (IMHO), is to start by trying the simplest and then work up to the more aggressive methods.

FIRST, try a light POLISHING COMPOUND and see if you can rub them out by hand.

If not, then use a more aggressive RUBBING COMPOUND with a heavier abrasive.

If that doesn't remove them, try WET SANDING them with 400, then 600, then 1200 wet/dry emery paper.

Still got scratches or starting to see the white hull color below? Then it's time to FILL IN THE SCRATCHES WITH GEL COAT.

Of course, as soon as you get rid of the scratches, the work backwards through the list of methods above and FINISH OFF WITH A WAX JOB.

HOPE THIS WORKS OUT FOR YOU!

JOE. :teeth :thup
 
Joe, you da man. That's kinda what I had in mind and now it's confirmed by someone who knows something! :wink

I'll give it a shot, just as you stated. Of course it's difficult to answer these kind of questions without a visual but honestly, I don't know how to answer whether the scratches are deep or not. In some ways, I wish I had an old hull sitting around so I could try to replicate the condition and use that to experiment.

Thanks as always,

Peter
 
The vast majority of scratches can be removed with 3M Finessit. I agree with the above, but I would be very cautions about using any sandpaper with a grit courser than 1200. As Joe says, wet sand paper--keep it wet all of the time, and dunk it in the bucket every few seconds. Gelcoat is not all that thick--and if you wear it off, it will have to be eighter re-gelcoated or painted. (neither is cheap).

Even with the hurricane damaged boat which had fallen 30 feet, I was able to get the majority of scratches out with Finessit.
 
Peter, how did Finessit work for you?

Bob and all, I was reading the C-22 Owner's Manual in the archives here, and I was struck by the numerous warnings not to apply rubbing compound in sunlight. Admittedly, that would be a nice problem to have here :shock: , but what is the underlying issue and how concerned should I be?

Thanks,
Warren
 
I use 3M Finesse-It on my green hull for minor scratches and areas rubbed by the fenders with great results. I do it in the shade, inside the "boat house" garage. From the way it works I'd guess (but don't know for sure) the reason not to apply it in sun is to keep it from drying out too quickly.
 
Warren,

I did use Finesse-It and it did get out the light scratches. However, I had to go to the regular rubbing compound by 3M to get out the deeper scratches. It did a good job. However, some of the scratches went pretty deep and those are still visible, just not as obvious as before.

I did it last summer, I can't remember if it was sunny or not. I have a feeling it was but I didn't see any negative effects.

Richard, even with the sun, it seems to stay pretty cool around here. Maybe that's the reason for no negative effects. :wink

Peter
 
The Three M system is what most pros use . The "fiberglass cleaner restorer" is the next step up from "finessit " Less finesse, more true grit .
Marc
 
Wefings":3c2d6f4f said:
The Three M system is what most pros use . The "fiberglass cleaner restorer" is the next step up from "finessit " Less finesse, more true grit.
Click to expand...

Thanks, Marc -- so, what happens when you use any of these in sunlight?

Warren
 
Doryman":2cv434s3 said:
Wefings":2cv434s3 said:
The Three M system is what most pros use . The "fiberglass cleaner restorer" is the next step up from "finessit " Less finesse, more true grit.
Click to expand...

Thanks, Marc -- so, what happens when you use any of these in sunlight?

Warren
Click to expand...

You get a sun burn? :lol: Sorry Warren I couldn't resist. Too much Easter chocolate this morning. :) I haven't been keeping up. Have you made it home yet? Picked up the new boat?

Roger
 
Roger, I have been home for a little over a week. I go to Utah to pick up the 22 sometime at the end of May. Will make a road trip of it and go visit friends and family en route to Salt Lake.

Warren
 
I believe its a drying issue , they want to make sure you get even results with the solvents still being liquid while applying the compound. Think of suntan lotion and supermodels.See if you can still concentrate .
Marc
 
Marc is correct. The problem is drying out of the abrasive. When you are using any abrasive; compound or wet/dry sandpaper you need to use water. (Finesse-it is a mild abrasive compound). Water prevents the drying out of the compound as well as acting as a lubricant. This is especially true if you are using a buffing wheel or sandpaper to compound out the scratches. A handy way to apply and control the amount of water is to use a a spray bottle. Another suggestion that works very well is to add a few drops detergent to the water in a normal size spray bottle. This also helps to control the build up of residue on your wheel pad or sandpaper. I use this technique when I am either painting a car or cleaning up a gel coat problem. I hope this helps

Best regards,
 
C-batical":3lkw8djs said:
Marc is correct. The problem is drying out of the abrasive. When you are using any abrasive; compound or wet/dry sandpaper you need to use water. (Finesse-it is a mild abrasive compound). Water prevents the drying out of the compound as well as acting as a lubricant. This is especially true if you are using a buffing wheel or sandpaper to compound out the scratches. A handy way to apply and control the amount of water is to use a a spray bottle. Another suggestion that works very well is to add a few drops detergent to the water in a normal size spray bottle. This also helps to control the build up of residue on your wheel pad or sandpaper. I use this technique when I am either painting a car or cleaning up a gel coat problem. I hope this helps

Best regards,
Click to expand...

This is also why it's important to control the rpm of the buffing wheel- to limit the heat build up/drying out of the rubbing compound.

Rubbing compound should be used at a lower rpm than when buffing up applied wax. Always use separate buffing bonnets. The one with the rubbing compound will remove the wax if you use it to buff the wax out! :lol:

Joe. :teeth :thup
 
I wanted to bring this thread back to the top because I'm trying to repair fender rub damage on my green trim. I've polished, using the 3M fiberglass restorer, and waxed and waxed, but the dull scratches are still obvious:

photo2.jpg

I also have some scratches from meeting a dock pile (so a C-Dory and a pile go into a bar...). They also disappear when wet, but don't completely buff out:

photo3.jpg

I'm thinking of stepping it up to wetsanding -- but as my MO is to escalate when confronting a hurdle, I thought I'd seek some additional input.

I believe the scratches are repairable because they disappear when the boat is wet -- suggesting that there is gelcoat under them. But, I haven't been able to get them rubbed out with the 3M. Any thoughts on the wetsanding?

Thanks,

Matt
 
Matt-

Since they disappear when wet, you might try one of those "miracle" scratch removers they sell on TV or in auto stores that (I think) is actually a clear acrylic coating that fills in the roughness and picks up the coloring of the pigmented areas around it.

Ron, formerly of "Snoopy C", used an acrylic coating "wax" on his new boat a few months back with great results! See:

Tried a New Product

Joe. :teeth :thup
 
Use 600 wet/dry grit followed by 1000 wet/dry grit followed by rubbing compound. Doctor Bob is the absolute best authority on that so if he differs from my technique definitely follow his lead.

I would also consider starting out with 400 grit on the worse ones and working through to 1000 using PLENTY of water. I have several spots on the C-Brat that will be getting "the treatment" real soon now.

It doesn't take a lot of muscle so go slowly and use a rubber sandpaper block or something that's really flat. Pep boys sells a little sanding "kit" with a nice small block and various wet/dry grits 400-1000 I think. Cheap and works great in small areas. Look for it in their paint and sanding product area.

Don
 
Thanks for these suggestions -- I'm wary of the acrylics due to the difficulty in removing and a concern over discoloration or peeling over time in the sun. I'll try the wetsanding under the waterline to see how things go and report back. Thanks for the tips.

Matt
 
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