Gelcoat repair problems

[freshwaterski]

Hello, I'm new to repairing and gel coating process. I had damage to my gelcoat on my seadoo about the size of a Dollar. I sanded it Down and cleaned the area with acetone. I ordered my gelcoat from gelcote international wich has perfect matching colors for my pwc .
Once I put the gelcoat on and let it dry and sanded it Down to smooth it out I can see the fiberglass showing through the gelcoat. I've done 3 coats now with same result. What am I doing wrong?

 

[Scott Danforth]

Re: Gelcoat repair problems

you are not putting it on thick enough and you keep sanding thru the gelcoat. gelcoat is only about 0.020" thick (1/2 mm). so there is not much there if you keep sanding.

 

[freshwaterski]

Re: Gelcoat repair problems

you are not putting it on thick enough and you keep sanding thru the gelcoat. gelcoat is only about 0.020" thick (1/2 mm). so there is not much there if you keep sanding.

alright, thanks. Are there any other tricks to smoothing the gelcoat besides putting a piece of plastic over the gelcoat?

 

[gm280]

Re: Gelcoat repair problems

alright, thanks. Are there any other tricks to smoothing the gelcoat besides putting a piece of plastic over the gelcoat?

Never having worked with gelcoat myself, but have worked similar issues with many types primers, fillers, base coats and clear coats, maybe you could sand the area a little deeper before applying the finish gelcoat. Then apply a few coats of the gelcoat and sand that areas for the final finish. It would have a thicker gelcoat coverage and the fiberglass would not reappear. Just a thought! :watermelon:

 

[DeepBlue2010]

Re: Gelcoat repair problems

After sanding/grinding the fiberglass, you should be able to to insert the thickness of about 5 sheet of paper under a straight edge that spans the repaire area. This tells you that about 20 mils to fill with gelcoat. make sure you apply it a little more thicker to account for sanding

 

[Scott Danforth]

Re: Gelcoat repair problems

alright, thanks. Are there any other tricks to smoothing the gelcoat besides putting a piece of plastic over the gelcoat?

I use PVA in a preval sprayer vs plastic to get it to set.

for small areas, I use a brush, for large areas, I spray the gel, or roll it on.

I usually hit the area with a DA with 320 grit to knock down the gel until I am close, then wet sand till smooth, then buff.

 

[Woodonglass]

Re: Gelcoat repair problems

As Deep Blue says, you need the repair area a bit "Hollow" so you can lay the gelcoat in Thick. How are you applying it? How many coats? I'd recommend using a PreVal Sprayer and then applying 5-6 coats in order to have the thickness required to do the final sanding and fairing.

 

[freshwaterski]

Re: Gelcoat repair problems

As Deep Blue says, you need the repair area a bit "Hollow" so you can lay the gelcoat in Thick. How are you applying it? How many coats? I'd recommend using a PreVal Sprayer and then applying 5-6 coats in order to have the thickness required to do the final sanding and fairing.

I have been applying it with a putty knife. I uploaded some pictures to give a better idea. I guess I'll buy a gun and try spraying it.

 

[gm280]

Re: Gelcoat repair problems

I have been applying it with a putty knife. I uploaded some pictures to give a better idea. I guess I'll buy a gun and try spraying it.

The should be a piece of cake to repair. Sand down the area so that it is lower then the surrounding area and then use the gelcoat and put on a number of coats until it is a little higher then the surround area. Then use a long straight flat sanding block and using a diagonal chris-cross sanding pattern, sand the finish until it is almost blended in with the surround area. Don't use only you hand to sand. It will never blend in straight or flat. Then using some 1000, 1500 or even 2000 grit wet/dry sand-paper, wet sand the area until it blends into the surround area and it will look perfect. You can take a low speed buffer and some polishing compound and make it shine like a new penny...

 

[Scott Danforth]

Re: Gelcoat repair problems

I would use a small disposable brush or roller for that small area. 2 or 3 coats, block sand, wet sand and buff.

 

[freshwaterski]

Re: Gelcoat repair problems

thanks all for all your help. I sand it back down and build it up a few layers.