Gel coat repair gone wrong

[ratdude747]

Well, I'm having a fail of a time with gel coat repairs.

I had a pretty nasty chip in my Gel coat (along with a decent amount of dock rash) and made the mistake of using a generic "mix your own color" type gel coat kit.

The issues so far have been that I can't get an orange as vibrant as the original oxidized color, the compound turns severely yellow at the surface (seems to stop after 12 hours), and after 23 hours (24 hour cure) it's still very soft.

After 39 mins my orange turned to peanut butter:



(Yes, I'm using a wasted composite prop blade as a redneck mixing board)

Per a second batch this morning (filling low spots), covering with plastic doesn't help:



But, last night at 14 hours I cut the excess open, revealing the orange I originally had, which this morning (23 hours) still retained it's original color:



(It is porous down there )

Overall, I am very disappointed. But since my boat is too old for anybody to sell a premix for, at my scale I don't know what else I could have gotten....

 

[ratdude747]

Just got home from lunch... and the bit I cut open in the last pic above has since turned yellow as well.... So yep, this product is cosmetically a failure...

 

[DeepCMark58A]

weird that it turned a different color

 

[ratdude747]

It didn't even adhere well. A good 30 hours of cure and the older stuff was still rubberery and peeled off when worked. A bit better adhered than chewing gum but not by much. Maybe with a good plastic scraper it'll e easy to remove. Something very clearly went wrong...

 

[nnl1987]

What surface prep are you doing on the gelcoat repair?

 

[ratdude747]

What surface prep are you doing on the gelcoat repair?

Not much per the instructions with the kit. I did make sure everything was clean. All areas were either gel coat or (in a few locations) down to the fiberglass resin.

I wasn't expecting perfect results... but not this mess. I'll be doing good to be able wet sand the areas worked on so they don't completely look like trash (and to think I'm going to be showing the boat with my truck this coming weekend in a local show... ).

I didn't have the materials stored in a climate controlled area... so maybe that ruined something. I don't know. Seems like something chemically went terribly wrong.

 

[jbcurt00]

MEKP catalyst has a shelf life, more so then the resin...

 

[ratdude747]

MEKP catalyst has a shelf life, more so then the resin...

That would do it... who knows how long it sat in the warehouse before it was shipped. And it was ordered a couple months ago, as my original plan was to use it as part of a currently-postponed job removing some defunct pitot tube hardware from the transom (and filling/covering the associated screw and tube holes).

 

[MikeSchinlaub]

Not much per the instructions with the kit. I did make sure everything was clean. All areas were either gel coat or (in a few locations) down to the fiberglass resin.

Scuff with 80 for chips down to the glass, 320 for minor stuff in the gel, clean with wax remover and it's ready. For bigger chips you'll need to add a thickener to make a paste. Use a bondo spreader to work it in, and a razor blade can help smooth it out.

I'll be doing good to be able wet sand the areas

It sounds like it didn't set up fully, in which case it'll just gum up the sandpaper.

I didn't have the materials stored in a climate controlled area... so maybe that ruined something.

Did you store it there theough the winter? We had some mekp go bad once, and my theory is it got too cold. I've also had this curing issue when I tried to rush it with a heat gun, but if you just let it sit outside in the sun I doubt that's what caused it.

It sucks that this happened, and from the results I wouldn't recommend using the same materials again. I don't know of a better small batch kit I'm used to getting stuff out of 5 gallon buckets to match with.

 

[ratdude747]

Scuff with 80 for chips down to the glass, 320 for minor stuff in the gel, clean with wax remover and it's ready. For bigger chips you'll need to add a thickener to make a paste. Use a bondo spreader to work it in, and a razor blade can help smooth it out.

It sounds like it didn't set up fully, in which case it'll just gum up the sandpaper.

Did you store it there theough the winter? We had some mekp go bad once, and my theory is it got too cold. I've also had this curing issue when I tried to rush it with a heat gun, but if you just let it sit outside in the sun I doubt that's what caused it.

It sucks that this happened, and from the results I wouldn't recommend using the same materials again. I don't know of a better small batch kit I'm used to getting stuff out of 5 gallon buckets to match with.

It was ordered in the late winter/early spring, was stored in a box in the boat with a caulk gun and a tube of UV4000 (all ordered at the same time, the other items used to reseal my rubrail). Later on in covered outside storage... but before I got it, goodness knows.

 

[MikeSchinlaub]

It was ordered in the late winter/early spring, was stored in a box in the boat with a caulk gun and a tube of UV4000 (all ordered at the same time, the other items used to reseal my rubrail). Later on in covered outside storage... but before I got it, goodness knows.

I would guess the cold is the cause of this. Unfortunately, I would say all of it is no good anymore. Mix all of the gel together, catalyze it, and dispose when hard and cooled down. It can generate quite a bit of heat when a lot is mixed, so wait for it to cool first.