Gelcoat repair issues

[cdlong]

I have started gelcoat repairs on SeaCracker and am having issues. i started by opening the cracks with a church key, but that wasn't working out. I went to a dremel with various shaped stones and am taking the cracks & nicks down to fiberglass. I'm using Evercoat Marine match & patch. My issues are: pin holes in the gelcoat after sanding with 220 grit. I assume I'll have to add anothe layer and repeat the sanding process? I have several areas where I'l sanded thru to the fiberglass upon sandind with the 220 grit? I'm not so much worried about the color as I know a really good match will come with continued repairs. 1st batch was a little to reddish, second batch was closer. My sandpaper ranges from 80 to 800 grit & I'm using rubbing compound & Mother's carnauba wax. I tried several marine waxes, but Mother's has the best shine.

[cdlong]

More pictures. I haven't finished opening up the last 2 pictures yet. Just giving you an idea of what I'm doing. Any advise, different tools, etc. will be greatly appreciated!

[Bikecop1]

Following with interest.

[cdlong]

The bow was in worse shape than I thought. Had to extend the repair area due to a yellow substance that was used for repairs. As soon as it was touched, it turned to dust. PO musta smacked something pretty good. Have ordered the items Wildfire recommended. As soon as the bow repair is completed, it's gelcoat repairs again.

[cdlong]

I feel I finally have a system. I grind out the cracks with a dremel tool, using an angled stone. Then sand w/ 220 grit paper. I wash the area with TSP to remove any remaining wax, then wipe with Acetone using a microfiber rag. Wear gloves. I mix one ounce of gel coat with 12 drops of wax sol, ( shake Wax Sol before mixing), after I have the color mixed. Then add 2 drops of hardener. Dab it in the repair area, I don't use a putty knife, only the black mixing stick. Adding Wax Sol has eliminated the air bubbles caused by the heat while curing. Once cured, I dry sand by hand with 220 grit wet/ dry paper for metal. I stopped using electric & air sanders as I feel this also lead to exposing the primer under the gel coat. This paper seems to last longer than regular wet/ dry paper. I wrap the paper around the flex sponge as it seems to hold the contours of the boat better and I don't sand thru to the primer as much. I have tried Starbrite compound for heavy oxidation, didn't like the results. I'm not happy with the Starbrite Polish either. The Starbrite mildew stain remover is excellent. Make sure you wear gloves. This stuff will take the hide off. Worked well on the access covers. Spray on a microfiber rag and wipe the covers. DO NOT spray and get it on the gel coat. Made the fenders, seat covers and throwable like preserver look new. I applied 2 coats of compound and used the Harbor Freight 7 inch polisher. Not crazy how this starts out slow & comes up to speed, but the price was tight. Tried the compounding pad, but got better results with the wool bonnets. Hand buffed after the compound did it's job. Applied the Mother's wax by hand, dabbing it on with a pad, then worked the wax using a terry cloth pad on the buffer, then polished with a microfiber towel over the terry cloth bonnet using the HF 10 inch buffer. Once the repais are completed, I'll be spraying the gel coat on areas using Wildfire's instructions.

[cdlong]

Forgot about the gelcoat thickener. Very helpful on radiuses, curvers & vertical surfaces. The photo of the port side stress crack is a 50-50 mix of gelcoat & duragloss. The pin hole sanded out nicely. Once sanded, I discovered with a straight edge that the fiberglass repair was too low so I had to grind out the gelcoat & build it up more with fiberglass.

[cdlong]

Sprayed the starboard side today using Wildfire's recipe. Looks good so far. Been 1 hour and the gel coat is already set up. Mixed 2 ozs and 5 drops of hardener. Had plenty of time to spray. Actually sprayed all the gel coat, then lacquer thinner. I didn't realize I missed so many small holes. Anyone tell me what I can use to fill them in, (fairing compound?), and respray or do I grind them out again and start over? They are hard to see in the fiberglass, but jump right out at ya when the light color hits em. It's a lot of work, but I do like the spray gel coat. I used the small HF gun @ 35 psi. Very good spray pattern. I probably when overboard on the masking.

[cdlong]

Update, It took 3 batches to get the color very close. Now I have to grind out all the previous repairs and redo them. Buy the large tubes of tint, they are much easier to get uniform drops from. I save the cardboard I mix the hardner into the gelcoat on to check the color. Only do one repair until you get the color right. I have purchased a palm polisher from Harbor Freight to compound, polish & wax the top sides of the cuddy. I also am using an electric palm sander for the 500 & 800 grit wet/ dry paper. Yes, I have a GFI, but I'm using a hand spray bottle. I use the Mouse & triangle sanders dry, then wet sand by hand with 220 or 320 depending how thick I put the gelcoat on, I realy like the Evercoat gelcoat, it doesn't run. There were 3 holes in the last picture which was the 3rd batch of gelcoat. They need need a cover, (thin) coat, then final sanding using 500 wet/dry, then 800. Fololowed by the rubbing & polishing compounds, then wax.

[cdlong]

Found a guy in VA Beach. He told me the "burn thru" is actually the primer that was applied to the fiberglass before the gelcoat was shot. Dark primer helped show the coverage depth of the gelcoat while it was being applied.

My son, the painter, said Dad toss the plastic spreaders and get some flex puddy knives. I got a 1 1/2 & 3 inch knife. Seems to be helping a lot getting the air out of the gelcoat. I'm going to try a foam brush to apply the gelcoat over the spots where the primer shows thru. If this doesn't work, I'll have some Rustoleum paint tinted and apply it with a foam brush, Then wet sand just enough to get it smooth.

[Wildfire]

I am not familiar with the Evercoat Patch system you are using but it sounds like it is thickened gel coat. If it is then the pin holes you are getting is from the gassing produced by the heat created by a relatively thick liquid. We do these repairs all the time. This is our method. Use regular white gel coat
(not thickened with no wax added). You can use the tints you already have to get your color match. Once you have your match you mix your gel coat one to one ratio with Duratec High Gloss Additive. Both the gel coat and Duratec can be purchased at any good fiberglass supplier. Thicken the gel coat into a paste by adding some cabosil., add your hardener and apply like body filler. It will shrink a little. After sanding with 100 grit repeat the process. If you are satisfied with the finish, final sand with 220 grit going out a few inches past your repair. Harbor Freight sells a little 4 oz gravity feed paint gun for about 13 dollars on sale. If you plan on continuing to do your own touch up work this gun is the best 13 bucks you'll ever spend. Mix another batch of gel coat and Duratec the same ratio. If your base repairs are a pretty close color match then you can reduce your gel coat with lacquer thinner another 10%, ( thinner also cuts down the hiding ability of the gel coat) add your MEKP and paint over your repairs out to the edge of where you sanded. Get rid of the excess gel coat and put some more lacquer thinner in the gun. Spray a little out to clear most of the remaining gel coat from the gun, then spray over the outer overspray ring to help melt it in and reduce the amount of sanding later. After curing sand the remaining overspray down with 400 and then 800 grit and finally with 1200 for light colors, 1500 for darker. Buff out with the compound of your choice. We use 3M Perfect-it extra cut, it is a bit pricey and only available at automotive paint suppliers. Because of the line edge on most gel repairs, unless you get a perfect color match you will always be able to see the repair. By spraying your final coat even slight mismatches will usually blend in enough so that the casual observer won't see it.
Good luck