best way to remove unset epoxy

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DrBryanJ
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best way to remove unset epoxy

Post by DrBryanJ » Tue Jul 23, 2013 10:28 am

I am using system 3 epoxy to encapsulate. I mixed a 2-1 ratio using a scale to measure, Mixed for over 1 minute, and coated my stringers. It has been 2 weeks and is still sticky. I have resigned myself that I have to remove it and start again. What is the best way to remove the old epoxy? ( by the way, I didn't mix enough in my first batch and had to mix a second batch. That area has hardened in 1 day)

Bryan
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red
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Re: best way to remove unset epoxy

Post by red » Tue Jul 23, 2013 10:44 am

could be it just blushed real bad if so soap and warm water will clean it if not acetone will remove it and if you don't want to use a chemical you can use vinegar

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DrBryanJ
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Re: best way to remove unset epoxy

Post by DrBryanJ » Tue Jul 23, 2013 11:45 am

Thanks, I will try the vinegar. But why would 1 batch blush and the other not?

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Bill Edmundson
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Re: best way to remove unset epoxy

Post by Bill Edmundson » Tue Jul 23, 2013 12:28 pm

Blush changes a lot with temperature and humidity.

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DrBryanJ
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Re: best way to remove unset epoxy

Post by DrBryanJ » Tue Jul 23, 2013 12:31 pm

The two areas were done at the same time. About 5 minutes apart. So wouldn't be different humidity.

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Bill Edmundson
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Re: best way to remove unset epoxy

Post by Bill Edmundson » Tue Jul 23, 2013 12:42 pm

Bryan

Got me :?

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DrBryanJ
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Re: best way to remove unset epoxy

Post by DrBryanJ » Tue Jul 23, 2013 12:56 pm

That's why I am thinking i may no just be blush. I mus have done something wrong with mixing. Maybe I mixed up the a and b parts in the first batch and had my ratios off. I will try to clean blush with vinegar, but if that doesn't work, I am back to my first question. What is the best way to remove the uncured epoxy?
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Bill Edmundson
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Re: best way to remove unset epoxy

Post by Bill Edmundson » Tue Jul 23, 2013 1:06 pm

Bryan

Use scraper to get as much as you can. I hope this isn't the glass coat. If it is then a heat gun may help. Lauren helped with my glass. She messed up on the ratios. But, most of it finally went off. That my story and I'm sticking to it (In the interest of domestic tranquility!) :!:

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rbrandenstein
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Re: best way to remove unset epoxy

Post by rbrandenstein » Tue Jul 23, 2013 6:19 pm

I'm not 100% sure about this, but I think you should measure by volume, not weight. The densities are probably very close so it may not matter.
Anyway, like Bill suggested, I get a carbide scraper (Harbor Freight sells a cheap one) and scrape as much as possible. Then use Acetone to wipe as much off as you can. It will eventually harden/dry so you can recoat.
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Re: best way to remove unset epoxy

Post by fredt » Wed Jul 24, 2013 4:32 am

Bryan ,

I had a similar thing happen on my a final bottom coat of clear epoxy . I mixed everything the same, but the final coat was applied during heavy humidity, which hadn't affected me before so I got
a little too confident I think. Anyway, thinking it was blush, went through all the removal techniques, soap and water, ammonia, etc, to no avail. Sanding paper gummed immediately.

I waited a few days with plenty of air circulation, but think somehow the humidity mixed with the epoxy, so my patience ran out.

Took a paint scraper and found it relatively easy to remove the entire layer . Then cleaned and re sanded to 80 grit, and put another coat on. Worked fine.

Hope this helps. I am no chemist, other than humidity, have no idea how the batch went bad.

I also changed my beer brand to see if that helped for future mixing :D

Good luck.

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DrBryanJ
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Re: best way to remove unset epoxy

Post by DrBryanJ » Wed Jul 24, 2013 10:21 am

This morning I cleaned one area with vinegar and a scotch brite pad. Then cleaned with warm soap and water. Finally sanded with 100 grit. Seems to have come off fine. Will attack remaining areas the same way. Then I will wait for less humid day to reapply.

Thanks everyone for your help.

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Bill CNC
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Re: best way to remove unset epoxy

Post by Bill CNC » Wed Jul 24, 2013 12:47 pm

With the time it has been trying to cure, ... it has nothing to do with the humidity especially in this weather, ... your mixture was wrong.

If your using pumps, ... sometimes your pump will allow air to get into the pump and it will vent the pump allowing some of what was in the pump to drain back into the can resulting in an "bad mix ratio". NOTE: This can happen with BRAND NEW pumps, ... I have had this happen more than once in the past.

Now, ... When mixing from pumps, The first pumps "resin and Hardener" are tossed. If I have to wait 2 hours till the next mix, ... Again, the first pumps are tossed.

I have NEVER had a bad mix from new or old pumps since then.

Just make sure you get all the uncured epoxy out from the wood grain, ... Your joint is only going to be as good as your prep, ... nothing more, ... nothing less.

Bill
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DrBryanJ
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Re: best way to remove unset epoxy

Post by DrBryanJ » Wed Jul 24, 2013 2:52 pm

Thanks for the heads up Bill.

I measured the two parts by weight because I don't trust the accuracy of the pumps. I think what happened is I mixed up components and mixed 2 parts B to 1 part A instead of 2 parts A to 1 part B. :oops: The areas effected will not have any joints. I was encapsulating the wood, and this was the second coat of epoxy.

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tsmitherman
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Re: best way to remove unset epoxy

Post by tsmitherman » Thu Jul 25, 2013 7:40 am

When I mixed a batch using all resin from 2 containers rather than resin and hardener, I used the following method to remove it from the boat:

With leather gloves, I scrubbed the area with handfuls of sawdust. This go all the resin from the surface and left it feeling dry to the touch.

I followed that with several scrubbings with a rag soaked in vinegar.

I'm not sure if this method would work for half-cured epoxy or not, but it worked great for my "all resin" goof-up.
Tom
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pauloman
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Re: best way to remove unset epoxy

Post by pauloman » Fri Jul 26, 2013 8:14 am

you mixed a volume mix ratio using a weight mix ratio which is different

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