[NSRCA-discussion] Epoxy Question

[Matthew Frederick]

It oughtta be a crime to "denature" alcohol...
----- Original Message ----- 
From: <patterndude at tx.rr.com>
To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
Cc: "Atwood, Mark" <atwoodm at paragon-inc.com>
Sent: Tuesday, November 20, 2007 3:48 PM
Subject: Re: [NSRCA-discussion] Epoxy Question


> Mr Fowler is out saving the world through explosives, but as a foot 
> soldier in the cause, here's my understanding (and experience):
> Alcohol and acetone both mix into the resin/hardener solution.  This makes 
> is harder for crosslinking to occur and it separates the epoxy molecules 
> trapping the alcohol.  THe resulting solid will be a bit rubbery because 
> of the trapped alcohol.  Acetone is a more powerful solvent than alchohol 
> and is beter for cleaning and thinning, but is also better for making 
> rubber.
>  The answer to the original question is really somewhat obvious.  Alcohol 
> is volatile and will evaporate from the surface of the liquid in your 
> mixing cup.  As the epoxy cures, it exotherms (heats up) and this will 
> also increase the evaporation.   However, not all will evaporate. 
> Whatever doesn't will be bound into the final rubbery solid.  THe amount 
> left behind is a variable affected by the size of the cup, heat in the 
> room, amount of epoxy mixed, speed of cure, etc.
>  The one time alcohol is OK to leave in the mix is when glassing.  The 
> very thin layer allows virtually all the alcohol to evaporate.
>
> Also, Mike says he is using 91% alcohol.  That means 9% water. Water is 
> never good.  He should go to home depot and buy a gallon of Denatured 
> Alcohol.  This is pretty close to 100% pure and it is less than half the 
> price.
>
> --Lance
>
> ---- "Atwood wrote:
>
> =============
> Actually...my thought goes the other direction.  That if indeed the
> alcohol actually MIXES with the epoxy, then it would truly bind and in
> some way harden as part of the overall mixture.   Epoxy "cures"...rather
> than flashing, so my guess...and it's truly a guess...is that it would
> be much closer to the original total weight of 2 oz.
>
>
>
> Still waiting patiently for our resident epoxy deity, previously
> referred to as Master Fowler to take away the mystery and lead us oh so
> graciously to the light...
>
>
>
> From: nsrca-discussion-bounces at lists.nsrca.org
> [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of wgalligan
> Sent: Tuesday, November 20, 2007 9:52 AM
> To: Don Ramsey; NSRCA Mailing List
> Subject: Re: [NSRCA-discussion] Epoxy Question
>
>
>
> OK,  I'll take a stab.  After the alcohol evaporates you would have the
> same mass or weight of epoxy that you started with.  AND to reiterate
> what I learned from the Master Fowler, thinning epoxy, if I remember
> right, changes the molecular structure weakening the mixture.  It will
> also cause the epoxy to shrink over time. BTDT.
>
>
>
> Wayne Galligan
>
>
>
> waiting for Master to speak
>
> ----- Original Message ----- 
>
> From: Don Ramsey <mailto:don.ramsey at suddenlink.net>
>
> To: NSRCA Mailing List <mailto:nsrca-discussion at lists.nsrca.org>
>
>
> Sent: Tuesday, November 20, 2007 8:53 AM
>
> Subject: [NSRCA-discussion] Epoxy Question
>
>
>
> Breaking news.  Here's something from Mike Harrison that will be
> of interest to the list.
>
> Don
>
>
>
>
>
> Ok, think about this, take 1 oz epoxy and thin with 1 oz alcohol
> (91%).?  After curing how much do you think it weighs and tell me why.
>
>
>
> Mike
>
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