Mixing Gel Coat and hardener for a small scratch

[Eric]

I have a small scratch in the bottom of my Mac 26X. With a Gel Coat to Hardener ratio of 50-100:1, how do I mix a small enough batch of Gel Coat/Hardener that I don't end up throwing away the vast majority of what I've mixed?I wouldn't bother except that, in one small spot, the scratch goes down to the underlying fiberglass.TIA.Eric

 

[Jim Willis]

You could use a PE syringe but..

I have used medical syringes for inflatable glue, but this is xylene/toluene based. Not use if the acetone in would damage the neooprine plunger. The PE should be OK since the mixing cups they sell are made from this.There may be problems in your area using "drug para". Otherwoise try using Polyethylene eye droppers glass eye droppersand mix by the number of drops.Otherwise mix up and thrwo excess!ThanksJim W

 

[mark v.]

this has worked for me.....[ long msg. ]

small mixing cups are great but if its just a small quick batch you can use a small piece of clean cardboard and a tounge depressor,[blunt one end with a razor blade first.] if you have an amount of gelcoat the size of a reeses peanut butter cup,[ sorry i could'nt quickley think of a better example] add no more than 4 drops of m e k catalyst. small batches are not rocket science. always add the catalyst 1st then mix into the gelcoat colloidal silica, west system#406 is one example and there are other brands ,mix it into the consistancy of mayo not p-butter as there will be some shrink as it cures and if its to thick it will crack,use a well placed heat lamp or just wait several hours, DON'T BE IN A HURRY! a bastard cut file will make quick work of roughly shaping the repair,block sand it flat,wet sand,polish.....your done!

 

[Eric]

Any way to mix a smaller batch?

The syringe/drops idea had occurred to me, but even this will produce a much larger batch than I require.Would it be feasible instead to simply mix up a bit of a good two-part epoxy and use it to cover the spot is question? The scratch isn't visible, so I'm not concerned with how it looks. I really just want to keep water from getting under the Gel Coat and causing blisters.Thanks.Eric

 

[Dave]

Gel Coat Repair

Where is your repair located on your boat? Since the material below the gelcoat is already a GRP (glass reinforced plastic) you should not expect blisters from its' exposure to water unless it is below the waterline. Gelcoat has been shown to be somewhat porous so repairing your scratch with gelcoat won't prevent that problem. The quick answer is yes you can use a two part epoxy and you can get coloring agents if you want to bother trying to match the color. From your description you might not need to do anything (invisible location and above water line).Dave

 

[Tom]

Epoxy and UV

If you use epoxy in a location above the waterline, you still should cover that with something, as epoxy breaks down from UV. Epoxy is not a "top coat". Paint it, or cover with gelcoat.

 

[Eric]

Scratch is on the very bottom

The scratch is on the very bottom of the boat, just to port of the center line. The scratch begins about 18 inches from the rear trailer bunk. The boat became rather intimate with a rock.My primary concern is that I don't want to give water any kind of an opportunity to seep beneath the Gel Coat. Color isn't really important given the location of the scratch.Thanks for all of your help.