Gel coat superficial scratches -not too deep not too superficial

[circa1971la]

Hi I have a dark blue gel coat on my sailboat. The inflatable dinghy tied up alongside left scratches. They are too deep to remove with rubbing compound but seem to superficial still to have to do a major Gelcoat repair I’m not handy with this stuff but is wet sanding alone an option? Scared to do this and really appreciate any suggestions ..

 

[Will1073]

You can likely wet sand these out. USE A SANDING BLOCK starting at 400 grit. At 400 grit you don’t want the scratches to be completely gone because 600 and 800 will both remove material, just more slowly. Finish with 1000 and compound.

This will be a “thin” spot in the gel coat afterwards, so just be aware of that.

 

[circa1971la]

Thank you so much for the reply.. I know this is a dumb question but since it’s not a discrete area that can be masked off what happens to the adjacent good Gelcoat as I’m sanding this? Also do I do an x-pattern and what do you advise to use for wax and polish after I’ve sanded this? I’ve never done DIY so really appreciate your insight

 

[SloopJonB]

Always use an X pattern when sanding or otherwise abrading a compound curved surface.

Anything else will flatten it.

 

[phill_nz]

i would use a 7" polisher and cutting compound then a polish as a first attempt

you are only going for a cosmetic fix
rounding off the scratch edges then polishing them should hide them enough to not be eye catching

if you are not happy with that finish then try the sanding approach but you are always gamboling on did the gelcoater leave a thin area here or not .. the chances are very very low they did but the consequences are not

 

[Crash]

As has been stated, depending on the depth of the original gelcoat and the depth of the scratches, there is a risk of sanding either a shallow spot in the gelcoat, or even maybe sanding thru the gelcoat. So as phill_nz suggests, I would start with the most gentle abrasion product you think might do the job (I'd start with cutting compound as he recommnends) and work you way "up" to more aggressive abrasion (1000 grit, 800 grit, etc) until you either get the results you want, or start to sand "thru" the gelcoat.

As SloopJon says, sand in an x pattern. Essentially, you want to sand only the areas of scratches with the most aggressive (lets say 600), then a little larger area with next less aggressive (800), then little larger with 1000, then little larger with compound, the finally little larger with polish. Then wax over all of it....

 

[Quickstep192]

It depends on your skill level. If you have skills like will_1073 or SJB you can sand, but if you don’t, or you’re impatient like me, you could accidentally sand through.

phill_nz has the idea. Start with cutting compound until the scratches are almost gone, then switch to polish. It might take longer but it will decrease the likelihood of going through or making a thin spot.

 

[blurocketsmate]

When you're done, you may feel the need to buff out the rest of the hull to match!

 

[Marty Gingras]

I’m not handy with this stuff but is wet sanding alone an option?

Everything has been covered above, except to say that if you started with wet 600 on a hand block then (1) it's extremely unlikely --- as in, nearly impossible to imagine --- you have the patience or the inexperience to do damage and (2) you'd be able to get good at sanding technique.

 

[Grrr...]

You can likely wet sand these out. USE A SANDING BLOCK starting at 400 grit. At 400 grit you don’t want the scratches to be completely gone because 600 and 800 will both remove material, just more slowly. Finish with 1000 and compound.

This will be a “thin” spot in the gel coat afterwards, so just be aware of that.

Unless that's a flexible hand block you're going to make flats. Get a flexible sanding block and adhesive strip of sand paper to do it.