Rubbery 2-part epoxy

[Don Fry]

No, it disintegrates, or more accurately, degrades.

It works for Two stoke exaust, but is challenged, or copes.

For Four stroke exhaust, it might cope. Perhaps for a time. 
Pushing your luck.
 

[Nigel R]

JBWeld copes with over 250deg C I think?

 

How hot does a four stroke get?

[Martin McIntosh]

Plus one for JB weld which easily copes with temperatures of four stroke exhausts. I used some when the silencer strap on a Laser 155 broke during a show and the hole in the head got considerably enlarged due to the loose silencer rattling about. Fixed it a treat.

[Christopher Wolfe]

After using various epoxy adhesives over many years my observations are that 5 minute epoxy 'dries' to a rubbery compound that slowly deteriorates to a crumbly yellow mess. Quite useless for building a model aircraft unless one predicts a short life expectancy.

 

Traditional slow cure epoxies are are another matter. I still have models built over 25 years ago using 24 hour Araldite to secure the engine bearers and bulkheads and the bond is just as good as the day that I built them.

 

Sometimes it pays to be patient and wait for the glue to cure Araldite

 

Chris

[Allan Bennett]

1 hour ago, Christopher Wolfe said:

After using various epoxy adhesives over many years my observations are that 5 minute epoxy 'dries' to a rubbery compound that slowly deteriorates to a crumbly yellow mess. Quite useless for building a model aircraft unless one predicts a short life expectancy.. . . 

 

Well, there's certainly a lot of different experiences in this thread.  Up until a few years ago I used individual tubes of 5- or 10-minute epoxy (can't remember which) of a well known brand (also can't remember which!), and I've got models up to 20 years old which show no deterioration of the epoxy, which I normally used only for firewall and wing joiner/main spar joints.

 

About three years ago I started using an own-brand twin-syringe 5-minute epoxy from our local model shop, and never had any problem with it -- the residue on the mixing tray was always hard/brittle.  It's only during lockdown, using mail-order supplies of Devcon, and then Gorilla, that I've come across this rubbery issue.

[conrad taggart]

Horses for courses = some excellent testing done here ?

 

[George P.]

I decided to epoxy some horns into control surfaces today but did not have space on the building board to fit a wing panel. It was 13 degrees in the garden and it had felt very mild in my shirt top when I painted the shed earlier in the morning and so I set up a table and began the process. A horn was glued into position using Devcon 30 minute  but I was surprised to find it had not set when I returned over an hour later. I had mixed it correctly. Nearly four hours later I lost my nerve and decided to pull the horn out while I still could and clean up so I could try again another time. 

 

Was it too cold for the Epoxy? I have read many accounts of people working in sheds in the midst of winter with no problems. Do you think it would have cured if I had taken it inside and left it?

 

OR

 

Is it just an unlucky batch of POXY Epoxy?

 

 

[Martin McIntosh]

Not unusual. I have some 30 min of unknown brand which I only use on horns and gives the same problem; even in a warm shed I can be looking at 2 or 3 hours. Gentle heating during mixing helps.

[George P.]

2 hours ago, Martin McIntosh said:

Not unusual. I have some 30 min of unknown brand which I only use on horns and gives the same problem; even in a warm shed I can be looking at 2 or 3 hours. Gentle heating during mixing helps.

Thanks, Martin. Given your experience, I probably could have just left it to set. I will probably send off for some new epoxy anyway to be on the safe side and, now I know it is not unusual, I will give it longer to set next time.