Gelcoat repair on a vertical surface?

Ian_Edwards

Ian_Edwards

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I need to repair the gelcoat on the port stern quarter, after it got battered on some exposed steel work on a pontoon.
It's cracked/chipped the gelcoat off the grp.
The boat, a Southerly has relatively thick gelcoat, 2 to 3 mm. I'd like to repair it with gelcoat, rather than filling it with epoxy filler and then painting on a thin layer of gelcoat.
I've bought a colour matched gelcoat repair kit from East Coast Fibreglass, and used it to successfully repair some dings on more or less horizontal surfaces, but it's much to runny to stay put on a vertical surface.
I could thickened it with microfibers or colloidal silica?
What would the experts do?
 
For vertical surfaces I use cling film.put the film on the area and mark with a felt tip pen. Then spread the gelcoat over the marked area and using the film to keep it in place.
This does have the advantage that pressure can be applied to get better adhesion with very little sag.
 
I wouldn't add anything. Paint it on pretty thinly and heat a bit with a hot air gun and wait 5 mins til it goes a bit tacky. Repeat several times til you have a pretty thick coating.You must be using gel and not flowcoat which has wax and means you cant overcoat.
Note, the colour match isn't really the trick. You need to sand about 10 cm around the damage with about 80 grit ( dont go crazy,just sand it back a tad),and cover with this new gelcoat. When you sand it back down, you " blend" the old colour gel with the new colour gel, and if you are very good, your eye can't see where they blend. Do not mask off or you will get a solid line that you will never get rid of. Edit..the 10 cm was assuming a modest area, obviously less if the repair area is more minor.
The new gel will be alot softer and so will sand/blend in alot more easily than the old, hard gelcoat. You can only colour match to some extent, so don't just put a blob on the repair area only or it will be visible from the next pontoon!!
If you aren't satisfied, just have another go.
I d leave for a couple of days for the gel to hardens b4 sanding.Maybe even a bit more if Spring doesn't arrive soon.
 
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Maybe worth trying Teroson gelcoat filler (formerly known as plastic padding). It's not a 100% match for my 1990s Moody but its very close. It goes on a bit yellow but once it is exposed to UV it blends in nicely. You might be similarly lucky.
 
gjgm said:
I wouldn't add anything. Paint it on pretty thinly and heat a bit with a hot air gun and wait 5 mins til it goes a bit tacky. Repeat several times til you have a pretty thick coating.You must be using gel and not flowcoat which has wax and means you cant overcoat.
Note, the colour match isn't really the trick. You need to sand about 10 cm around the damage with about 80 grit ( dont go crazy,just sand it back a tad),and cover with this new gelcoat. When you sand it back down, you " blend" the old colour gel with the new colour gel, and if you are very good, your eye can't see where they blend. Do not mask off or you will get a solid line that you will never get rid of. Edit..the 10 cm was assuming a modest area, obviously less if the repair area is more minor.
The new gel will be alot softer and so will sand/blend in alot more easily than the old, hard gelcoat. You can only colour match to some extent, so don't just put a blob on the repair area only or it will be visible from the next pontoon!!
If you aren't satisfied, just have another go.
I d leave for a couple of days for the gel to hardens b4 sanding.Maybe even a bit more if Spring doesn't arrive soon.
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Flowcoat has wax so that it cures in air and once degreased, can be painted. Gel remains tacky in air.
 
I tend to keep some bits of flat plastic sheet from the front of food packaging handy for covering small repairs.

If just slightly stiff plastic then it can keep the setting gelcot nicely in place with very little sanding needed afterwards..
 
PaulRainbow said:
2" Sellotape works. If you're using gelcoat, rather than flowcoat you need to cover it anyway.
Click to expand...
Well, sometimes. If you are going to be sanding back the new gel.which you are for the reasons I gave above, then just wipe it with acetone to stop it clogging the abrasive. Hardly matters if the top 0.1mm is a bit tacky to start with,.you are about to sand it off anyway. Alternatively,OP, use flowcoat ( ie gel with a tad of styrene wax).as your final brushed on gel, but that assumes your gel repair toolbox is getting a bit more complete!
Flowcoat is of course essential if no sanding or the gel will stay tacky.
 
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gjgm said:
Well, sometimes. If you are going to be sanding back the new gel.which you are for the reasons I gave above, then just wipe it with acetone to stop it clogging the abrasive. Hardly matters if the top 0.1mm is a bit tacky to start with,.you are about to sand it off anyway. Alternatively,OP, use flowcoat ( ie gel with a tad of styrene wax).as your final brushed on gel, but that assumes your gel repair toolbox is getting a bit more complete!
Flowcoat is of course essential if no sanding or the gel will stay tacky.
Click to expand...
Try reading the thread title.
 
I helped a friend to do this exact job yesterday. He had a colour matched kit from the same company. His kid came with plastic film sheets to put over the wet gelcoat. I mixed the gelcoat and hardener. Then filled the scratche. As soon as I put the gelcoat on, it was trying to sag. So I applied the plastic sheet and spread out the gelcoat. It’s worth masking the area you are going to work in and use a thin flexible spreader tool.
This method seals it from air and will make it cure and harden.
It also helps to smooth out the wet gelcoat but applying the film and gently rubbing it to spread it. Should make for less sanding too
 
ducked said:
"Gelcoat repair on a vertical surface?" doesnt seem definitive in the way you rather snippily imply..

It says you are repairing gelcoat, but does not necessarily specify what with.
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Fairly definitive. He wants to repair gelcoat on a vertical surface, like it says in the title. So he needs a way to stop the gelcoat running down the hull. He also says he's using gelcoat.

Someone else who seems unable to either read and/or comprehend.
 
PaulRainbow said:
Fairly definitive. He wants to repair gelcoat on a vertical surface, like it says in the title. So he needs a way to stop the gelcoat running down the hull. He also says he's using gelcoat.

Someone else who seems unable to either read and/or comprehend.
Click to expand...
Still untrue.

Maybe type it louder?
 
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