Are all epoxy glues equal?

[JDarvall]

why was Cruzi's post erased ?......I have a copy of it here in my outlook express. He made a good point......things don't always have to be just 'roses' around here does it. Like a big brown nosing convention.

[bitingmidge]

There are epoxies and epoxies all designed to do different things, but virtually any form will do for the purposes most woodworkers need, providing the mix is thick enough to do the job.

Basic laminating resins like boatcote and west make very good glues when mixed with their various thickening compounds, and to a lesser extent, even wood dust (although not if you want a high load joint!).

Epoxies as a class are NOT fragile particularly. That is why they are used in things like turbine blades, but they are designed to be part of a COMPOSITE structure.

Epoxies also don't have a shelf life, PROVIDED they arent' exposed to humidity. Keep the lid on the bottle and you'll have an indefinite shelf life. Our PDRacers are-half built from stock I had for 15 years.

There is plenty of info on the web, check the manufacturer's sites!

Cheers,

P

[Marc]

On the subject of epoxy manufacturing. I once had to get a roof on a shed and the roofer liked to yarn a lot. One of the stories he told me was that one of his customers had an epoxy glue factory. THis factory was in a very isolated area of the countryside an he had to go there to replace the roof over the reactor often.
His instructions were to make the roof as light as possible. The reactor's walls were very thick. The reactor apparently blew up at regular intervals, the roof would usually fly up and end tangled in a mess some 200 meters away.

As for strength, slow curing epoxy, the old 24 hours one, is generally speaking stronger than the 5 minutes one. To get the resin to cure in 5 minutes the amount of accelerant and catalyst necessary compromise the strength of the product. However to glue up the leg of a chair, you will probably never know the difference. This things mean something when building structural stuff like a plane or a boat.

[AlexS]

Epoxies also don't have a shelf life, PROVIDED they arent' exposed to humidity. Keep the lid on the bottle and you'll have an indefinite shelf life. Our PDRacers are-half built from stock I had for 15 years.

Yep. I'm still using 10 year old casting resin Kept cool & airtight, still works as well as new.

[Master Splinter]

Check the boatbuilding threads, there's one from August 2006 - basically WEST and Boatcoat are the standout winners. From another thread, the epoxies that have uneven mixing ratios (5:1 not 1:1) tend to be stronger.

I buy the WEST stuff because I like reading their site and seeing pics of test rigs they have made up to keep insurance underwriters happy with with the strength of a proposed boat glue detail, but I also use Techniglue as it is available from the same store as the WEST stuff.

Price wise, WEST and co. are considerably cheaper than buying Araldite from Bunnies.

[bitingmidge]

Also check out Michael Storer's FAQ pages for a heap of info on various epoxy methods etc:

http://www.storerboatplans.com/Faq/faqindex.html

Cheers,

P

[graemet]

I've used WEST system quite a lot in boat building and the beauty of it is in the versatility.
That is, unthickened for laminating glass fibre, thickened with silica fibres for glueing and with microballoons for filling and fairing. Only one system. The individual components tend to have a shelf life of about 10 years, although WEST won't tell you that.
Cheers
Graeme

[JDarvall]

Yep. I'm still using 10 year old casting resin Kept cool & airtight, still works as well as new.

excellent. So I can save money. buy in bulk and not get caught out.

[AlexS]

excellent. So I can save money. buy in bulk and not get caught out.

The stuff I'm using is called Araldite M, which is an epoxy. Some casting resins are polyurethane - I'm not sure how long they last.

[hansp77]

another vote for West System here.
I've gone through liters of the stuff on my boat- and now use it for a ton of stuff with my home woodwork.
as mentioned, gluing, fairing, straight coating- or even as I do, thinning it down for penetration (either with thinners, or as I often do for a partial penetration yet not crispy cure for sealing drilled holes that are about to be screwed- thinning it with actual penetrating epoxy).


its good stuff- definately worth buying a decent amount of it IMHO.

[JDarvall]

The stuff I'm using is called Araldite M, which is an epoxy. Some casting resins are polyurethane - I'm not sure how long they last.

right. Araldite M. ta.... I feel like I'm stumbling into a minefield with this purchase.