[NSRCA-discussion] 5 min expoxy

Tue Sep 13 12:16:32 AKDT 2011

I quit using 5 min epoxy altogether. Partly for the reasons mentioned (I have noticed it turns rubbery with age, etc) and also because I am not as fast at mixing and applying as I used to be. :-)  Whenever possible, I use slow-cure epoxy since I feel it does a better job wetting the surfaces and ultimately gives better adhesion. 

I used to be able to buy 2 hour epoxy but now the longest cure time I see in hobby shops is 30 minute, so I typically use either 15 min or 30 min epoxy.

I have also gotten into the habit of setting the assembly in a hot environment (like inside my car on a hot sunny day) to aid in the final curing. Seems to cure harder and be more resilient when I do that.

Bob R.

--- On Tue, 9/13/11, Phil S. <chuenkan at comcast.net> wrote:

From: Phil S. <chuenkan at comcast.net>
Subject: Re: [NSRCA-discussion] 5 min expoxy
To: "General pattern discussion" <nsrca-discussion at lists.nsrca.org>
Date: Tuesday, September 13, 2011, 3:53 PM

Mike, the laminate layer will not protect the 5-min from heat -- only sunlight/UV and chemicals -- maybe.  OTOH, you have the testimony of several who have used the 5-min with no problems.  Why not use 15-min if you have a question about the 5-min variety???

On 9/13/2011 1:23 PM, Michael S. Harrison wrote: 

Matt,
This is the critidcal info I needed.  100 ‘ deformation is a real concern since batteries,etc go to well over 100’, sometimes in the order of 140’.  Even sitting in the sun will go to 120 or more.  I believe the double layer, 5min/laminating will work.  It will be stronger and redundant.
Thanks
Mike 

From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of rcmaster199 at aol.com
Sent: Tuesday, September 13, 2011 11:26 AM
To: nsrca-discussion at lists.nsrca.org
Subject: Re: [NSRCA-discussion] 5 min expoxy

Mike,

Deformation temp of 5 minute is usually very low, on order of 100F. I no longer use 5 minute for anything load bearing.

You are correct on sunlight degradation for the amine cured epoxies (most of the stuff we use) but the process is fairly slow. Usually don't have to worry about that as RVP pointed out, unless you are like me and keep your planes for 8-10 years plus

For much better sunlight protection there are other curing systems (J Greer) available but these are slow curing and could be counteproductive for your purposes

MattK

-----Original Message-----
From: Michael S. Harrison <drmikedds at sbcglobal.net>
To: 'General pattern discussion' <nsrca-discussion at lists.nsrca.org>
Sent: Tue, Sep 13, 2011 11:52 am
Subject: Re: [NSRCA-discussion] 5 min expoxy

Thanks Ted and others.  This is all helpful, my concern is what I have witnessed over many years as the heat and fuel ruined the 5 min epoxy.  Since it is electric, fuel is not an issue but there is plenty of concern about heat.  I don’t know the deformation temp of the epoxy nor the exposure to normal environment so that is why I was asking.  I am going with the 5 min and doing a thin coating of laminating to have a seal and redundancy.  Sunlight will eventually ruin the epoxies but since it is inside the fuse, that is not an issue. 

Thanks

Mike 

From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Ted Sander
Sent: Tuesday, September 13, 2011 6:54 AM
To: 'General pattern discussion'
Subject: Re: [NSRCA-discussion] 5 min expoxy

I tend to use whatever the local shop carries – but do lean toward Z-poxy.  The current Pres. Of our local club spent his career formulating adhesives, so I trust his opinions, and in his view all hobby marketed expoxies are far stronger and longer lasting than we ever need, so go with price.  That said, longer curing is stronger than shorter curing (but once you are good enough, do you really need it stronger?) and using laminating is better than thinning with alcohol, acetone, or whatever if you need to coat an area…..(thinning does dramatically reduce strength).

If you are getting into whole plane fabrication with epoxies (glass/composite construction, etc.) then you need to do some more research for thin film strengths, viscosity, etc. , especially since weight becomes a big factor.  But for general gluing of firewalls, wing halves, or the like – go with what you can easily get/afford.

From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Michael S. Harrison
Sent: Monday, September 12, 2011 2:31 PM
To: 'General pattern discussion'
Subject: Re: [NSRCA-discussion] 5 min expoxy

Thanks,

Ted what was the brand you used?

Mike 

From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Ted Sander
Sent: Monday, September 12, 2011 1:51 PM
To: General pattern discussion
Subject: Re: [NSRCA-discussion] 5 min expoxy

You'd just be adding weight.  I have 20 yr old planes where the 5 min is still perfect.  Enough heat to be a problem with the epoxy will be a much bigger problem for everything else in the plane!

Ted Sander

On Sep 12, 2011, at 11:57 AM, "Michael S. Harrison" <drmikedds at sbcglobal.net> wrote:

Thanks Dwane,

Sorry, I was very ambiguous in my search for answers.  I am referring to the cured state.  I am using it for construction and I have decided to coat the cured 5 min epoxy with a high quality laminating epoxy to seal/insulate it from solvents, air, etc so that it is preserved-don’t know that it will work but gonna do it that way.

Mike  

From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Dwayne Brown
Sent: Monday, September 12, 2011 11:28 AM
To: 'General pattern discussion'
Subject: Re: [NSRCA-discussion] 5 min expoxy

Keep it in the freezer until needed and it will outlive all of us on the NSRCA group.  Dwayne

-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Michael S. Harrison
Sent: Saturday, September 10, 2011 1:59 PM
To: 'General pattern discussion'
Subject: [NSRCA-discussion] 5 min expoxy

Tech question.

What is the lifespan quality of 5 min epoxy.  How long does it last?  I am using in an electric for construction and I am concerned about degradation over time.  How does the heat affect it?  I am building to ca models fuse.  What is your choice of adhesive in this case?

Thanks

Mike Harrison

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