posted 07-22-2009 11:06 PM ET (US)        

So now how do I get rid of this stuff and start anew?

What is a good solvent for uncured gel coat that won;t eat cured gelcoat?

posted 07-23-2009 12:57 AM ET (US)            

Lacquer Thinner (which is a mixture of solvents) typically contains acetone.

I have never applied acetone to the gel coat finish of a Whaler manufactured after 1989, though I know those who have, with no ill effect.

posted 07-23-2009 11:53 AM ET (US)            

Applying oil to any hard object will make it shinier...for a period of time. Go ahead, wipe some olive oil on your topsides; it will look great.

But the notion that gel coat has "oils" that need to be replenished is not accurate.

For the record: wiping the gel coat of a Whaler (built before 1989 and perhaps later) will not dull the shine, not one iota.

posted 07-23-2009 11:29 PM ET (US)            

I don;t remember the brand gelcoat I used, the container is at my office. It was not spectrum however.

I've waited two days for the gel coat to cure, it is hard as nails everywhere but directly over the epoxy. I've parked it in the sun, and applied heat to it to try to coax a little more action, but nothing so far. Tomorrow morning is the removal and retry.

I'm thinking of going with interlux brightside polyurethane paint. Thoughts?

posted 07-24-2009 02:46 PM ET (US)            

As for why they recommend against it, it's simple. Gelcoat is basically just colored resin. Resin is a petrochemical product. That is, it's made out of oil. Acetone, by it's nature, breaks down hydrocarbons (the building blocks of oil). Given enough time, acetone will eventually eat away ANY oil based material, including gelcoat. But, hard-cured resins like gelcoat take a lot longer to break down. Acetone has a funny habit of evaporating very quickly. Quickly enough, in fact, that it evaporates off gelcoat before it can do any noticable harm. Acetone is more commonly used in an immersion technique. Fiberglass shops use it to clean resin off tools, buy dunking them in a bucket filled with the stuff, or by scrubbing with a rag soaked in it.

posted 07-24-2009 06:05 PM ET (US)            

The patch itself is just a temporary thing, and even a crapy job will look better than the hugh patches of fiber glass that were there.

The epoxy was put there to fill in two gashes that were on either side of the boat. It looked as though there was a footing for something there and it was just ripped from the boat. So like I said above, even shoddy work looks better than that.

Thanks for all the help...

posted 07-27-2009 02:38 PM ET (US)            

In layman's terms, the catalyst creates heat, and that heat causes the resin to harden. The heat dissipates out of the mix, and so, the cooler the ambient temperature, the more catalyst required to maintain the proper temperature. If you do not use enough catalyst, you will usually end up with the core or bottom layer that has catalyzed, because it reached temperature, but the surface and extremeties will not, becuase they were kept cool by the surrounding air. This is a common mistake, and can usually be fixed if caught quickly. If, after about 10 minutes, you notice that it's not setting up, hit it with a heat gun and apply some extra heat to the surface. This will usually get it to set up, assuming the chemical reaction in the material has not completely fizzled out already. Also, cranking up the temperature in the facility, and simply giving it more time often works as well. But, if the surface is vertical, this sometimes won't work, as the resin may "run" downhill somewhat before it hardens, leaving you a bunch of material that must be ground off.

Improperly mixing in the catalyst would result in some areas that are over catalyzed, and others that are under catalyzed. Over catalyzed resin can do one of two things. At best, it can cure before you have fully worked it into position. At worst (and this is more common), it can catch on fire while curing. So, improperly mixed gelcoat would have portions that burn and smolder, and other portions that never set up. If you improperly mix AND don't use enough catalyst, you could end up with sections that don't harden, but with no regard to depth or coverage. This, of course, is all hypothetical. Improperly mixing the catalyst is almost never done. I've never done it, and I've never seen it done. But then, I was taught by professionals with decades of experience, and only worked around the same. It never ceases to amaze me how amateurs can screw something up. As a general rule, mix it up as though you were adding an egg to pancake batter...the catalyst should be completely mixed in. It really isn't that hard, and, in my opinion, most amateurs over-work the resin prior to application.