5 min epoxy

[Paul Allen]

Have noticed that high humidity has a drastic
effect on 5 min epoxy, seems to stay in a rubbery
state,has anyone else found this.
Different brands tried,equal amounts mixed?
Still the same result. 

[Ron King]

Paul,

I stopped using five minute epoxy many years ago because of this and one other problem: It gets brittle with age.

My ex-wife (the chemist) told me the chemical makeup was a compromise with the fast-setting epoxy and I would be better off if I used slower setting epoxy and just learned to be patient. 

Ron

[Glen Wearden]

I quit using 5 minute epoxy because it dries faster than I can think.    Glen

[phil c]

Five minute epoxy takes thorough mixing, just like any other epoxy.  It really takes a couple of minutes of mixing to get it uniform, then apply and hang on tight.  You have a lot less leeway in the proportions and mixing than with longer cure stuff.  Like any other epoxy, warming it during the cure to speed the reaction and doing a post-cure by heating it again after it is hard will help it get the maximum strength.  You're looking for 240 deg. or so during a post cure and hot enough so it gets runny just before it kicks off.

[Shultzie]

Five minute epoxy takes thorough mixing, just like any other epoxy.  It really takes a couple of minutes of mixing to get it uniform, then apply and hang on tight.  You have a lot less leeway in the proportions and mixing than with longer cure stuff.  Like any other epoxy, warming it during the cure to speed the reaction and doing a post-cure by heating it again after it is hard will help it get the maximum strength.  You're looking for 240 deg. or so during a post cure and hot enough so it gets runny just before it kicks off.

---------------------------GREAT INFO-----------------------------------------------
BOTTOM LINE:
The major error in mixing expoxy and fast drying two part bonding agents...
IS BEING TOO STINGY IN MIXING a large enough portions.

The smaller the portions.....IT IS BOTTOM LINE JOB NUMBER ONE...TO MIX BOTH A & B PORTIONS EXACTLY AS STATED!

So many model builders just don't understand the principle that just because one mixes the exact parts onto a mixing surface before mixing...REALLY DOESN'T MEAN A THING UNLESS

you factor in what you are using to mix that batch of goo together with, be it a popsic-stick , a Q tip..etc. 
Also remember that on some of these two equal part formulas are not created equally...Often the B part hardner and the A part have really major vicosity thickness differences...and especially when mixing teenie-tiny amounts--TRUST THIS!!! WILL ASSURE YOU THAT YOUR MIX WILL NEVER BE ACCURATE ENOUGH TO MAKE THE RIGHT MIXED PORTIONS.

BE MEAN!! KEEP IT CLEAN!!!!
DUST, GREASY FINGER PRINTS, AND MOISTURE, ARE REAL EXPOXY JOINT KILLERS.
Due to the fast set up times...this adds to the errors in mixing plus gives virtually little time for the mixture to be absorbed into the materials to be bonded.
Parts such as plywood, metal, non-pouris' surfaces should alway be roughed up or scored, then carefully chem cleaned (naptha-whatever) and kept free from dust etc. before bonding with fast setting expoxy glues.
MIXED CORRECTLY, CLEAN PROPERLY, MIXED CAREFULLY WITH CONSISTANT BATCHS AND WITH MATCHING MIXING TOOLS..will assure that these fast drying expoxy's will be produce a beautiful long lasting and stress crack free model that will last years and years.

Attached is a photo of one flutter stress-test models that was built with the very fasted setting glues...that endured the most rigorous stress flight testing that I ever had the pleasure of being a part of their build and test team. Balsa to bals...(Vigor brand super goo' CE-480 ) and Devcon 5minute on other fiberglass-metal to balsa joints...
That model endured amazing stress testing..
(check the rudder!!)
. It was bumped into by mistake by our test director...and during the next model run... that rudder part, broke off and blew down the tunnel during the yaw damper testing faze.
Our model build team....and me were put into over-drive and had a bare balsa rudder  remade in less than 70 minutes.
Without fast drying expoxy or super goo' that test would have been toast. 

[Paul Allen]

Thanks guys for replying,have never used it
in model construction,but since wrapping line
ends ,I used it to seal the wrap.Now if the lines
were made in the cooler months with low humidity
even mixed in small amounts no problem,go figure.

[Clancy Arnold]

I used 5 minute Epoxy ONE time.  I mounted the bellcrank mount in a model with 5 minute epoxy.  During the first flight the bellcrank pulled loose in the wing.  Looking at the remains there was a perfect mold of the bellcrank mount.  Absolutely no strength.    It had been pull tested to AMA specs but that does not include vibration.
Clancy

[Shultzie]

I used 5 minute Epoxy ONE time.  I mounted the bellcrank mount in a model with 5 minute epoxy.  During the first flight the bellcrank pulled loose in the wing.  Looking at the remains there was a perfect mold of the bellcrank mount.  Absolutely no strength.    It had been pull tested to AMA specs but that does not include vibration.
Clancy

-------------------see what I mean???---------------------------------------------------
NO MISTAKES...JUST LESSONS TO BE LEARNED?
"ABSOLUTELY NO STRENGTH...HUMM? GET A CLUE and review your building techniques before nailing the blame to the expoxy?

[dennis lipsett]

I've used 5 minute epoxy since the 60's when it was introduced by Hobbypoxy  and can honestly say that I've had extremely good results with it.
As has been nopter 5 minute is only for very small areas that can be done fast and accurately. I usually score the items and in some cases dimple drill the parts to be joined and mix only enough to do the job. Mix it really well and get it into position and clamp and forget it.
 Oh and never try and mix any epoxy when it's cold, get out your heat gun and warm the tubes before you start, You need the glue to flow not sit like a gell on the parts.
I've never had a part fail including motor mounts for a rather large gas motor or 2.
Dennis

[Bob Reeves]

Like Dennis I don't understand the problem. I use it quite a bit and have never had an issue strength or otherwise..  I do make sure it's mixed well, when I think it's mixed good enough I always mix it some more just to be sure.

[john e. holliday]

I beleive what brand you buy will have an effect.  Mine came from local hardware as hobby shop was closed.  I will wait on hobby shop next time.  Now I think of it, I have been to the hobby shop and stocked up.   DOC Holliday

[Shultzie]

Actually...at the wind tunnel, it was standard policy that ALL PAINT AND GLUE PRODUCTS had to be date checked and stamped..before we recieved them at the shop for not only freshness..but for safety reasons. All paint products were check on a weekly basis to assure that no pre-mixed or outdated glue or paint products remained on the shelves.

It broke my heart to see perfectly good paint, glue etc. products being sent to collection stations...SIMPLY BECAUSE THEY WERE SHORT DATED.
Before picky picky rules went into effect....I WOULD STOP BY WEEKLY TO BOEING SURPLUS TO REAP IN THE WIND-FALL GOODIES that modelers from all over the world would droooooooool or covet thy stunt-grunt neighbors over these gleaned expensive and rare short dated materials to die for.
Humm? "to die for.....just might have serious meaning....since many of those beautiful space age materials proved to be....more than just TOXIC...but down right deadly.
As for proof of this...try reading this post for an example. An illustration of what "sniffing dope" (the stunt-grunt kind) has demented my noggin'?