Properly bonding composites and what your government doesn't want you to know.

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Grog6

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There is some reason isopropanol is better than acetone; something about it leaving the epoxy in the fg degraded and less strong. Yes! this is it; it destroys acrylic and polyesters. Don't use acetone, use alcohol.
200 proof Ethanol is best, but expensive.
 

MJW

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Why is Everclear better than Isopropyl electronics cleaner? Clearly rubbing alcohol can have contaminates added, but 99.9% pure anhydrous IA is a pretty clean solvent. Is ethanol just a more compatible molecule?
 

6inchmonster

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There is some reason isopropanol is better than acetone; something about it leaving the epoxy in the fg degraded and less strong. Yes! this is it; it destroys acrylic and polyesters. Don't use acetone, use alcohol.
200 proof Ethanol is best, but expensive.
Personally I think it is better because it does not get me drunk/high thru osmosis :-/
 

Grog6

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If you pour anhydrous ethanol to the brim in a shot glass, it will overflow in a few minutes. :)
It sucks up moisture out of the air.
86% is the best you can get without chemically dehydroxifying it.

Let's remember how bad acetone is for us; I'd hate to have my liver fall out. :)
I remember the buzzwords now, coffee is wonderful. :)
Ethanol leaves a" low surface energy surface"
I worked with PCB's and RTV a lot. :)
 

BDB

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I'm guessing ethanol is preferred because it evaporates better than isopropyl alcohol, so you don't have to worry about residual solvent getting trapped in the epoxy. But the pure stuff is difficult to get. I'm an organic chemist, so we have plenty of 200 proof ethanol in my lab. There is way more paperwork to sign to buy it than there is to buy cyanide.
 

prfesser

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If you pour anhydrous ethanol to the brim in a shot glass, it will overflow in a few minutes. :)
It sucks up moisture out of the air.
86% is the best you can get without chemically dehydroxifying it.
Correction: 95% ethanol is the maximum that can be obtained by distillation. That concentration makes the mixture an azeotrope, that is, distilling 95% ethanol gives a product that is still 95% ethanol. When 100% ethanol is needed, one way to remove the last 5% is by adding calcium oxide (CaO, "quicklime") to the distilling pot; it reacts with any residual water.
 

Homer_S

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I'm guessing ethanol is preferred because it evaporates better than isopropyl alcohol, so you don't have to worry about residual solvent getting trapped in the epoxy. But the pure stuff is difficult to get. I'm an organic chemist, so we have plenty of 200 proof ethanol in my lab. There is way more paperwork to sign to buy it than there is to buy cyanide.
On account of the revenuer's need to get paid. When we use it in the lab, it doesn't get sold where ethanol is normally taxed.

Homer
 

kramer714

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So we’ve got lacquer thinner, acetone and denatured alcohol available in the rocket barn.

Looking for the best prep solvent for an “R” powered G-12 fiberglass rocket that we’re just starting to build. Read the entire thread twice it’s so chock full of great info.

For the maximum cleaning of the G-12 what’s the consensus on which of the above is the best to use?

Thanks!

Chuck C.
Acetone is best, it will help remove the mold releases used when the fiberglass is made, wipe then sand then wipe. If you prep ahead of time, a quick wipe with with alcohol works to 'dust' the surface.

Use clean oil free wipes, Kim Wipes or some generic knock off work best.

Mike (actual aerospace composite engineer) K
 
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