OT: JB Weld Question

"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

Been a while since I last used it but I don't recall it being runny. If you can let it sit for a while before applying - towards the end of its working time - and then apply, that might be better. Some epoxies get weaker if you don't mix in the specified ratio. Depends on the chemistry.

I'll try that... could be because it's _warm_ here ;-)

Yep. ...Jim Thompson

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Never deviate from the corect ratio with epoxies. Its a misnomer to call one fo the tubes hardener anyway.

NT

Which flavor of the stuff were you using? I used the 'regular' and don't recall it being runny.

JB Weld is pretty thick. We use it on vertical oriented parts. There's a 5-minute version of JB Weld if that will help.

Don't you mess with the epoxy chemistry, Jim. You're an IC designer, not an industrial chemist.

As pointed out, "hardener" is a misnomer. It's not quite "the other half of the glue when finished", but it's pretty close. The Wikipedia entry on epoxy is pretty educational.

Epoxies tend to be runny. They just aren't thixotropic by nature. Since you want a thin glue layer anyway, the best way to deal with this issue is to not use too much glue.

That doesn't sound right... should be the consistency of putty.

-- Les Cargill

He bought the enema compatible version.

Dont change the ratio, adding more harderner will make it more brittle. The faster it cures the weaker the bond. Unless its a 5min type.

Cheers

I was Leary of strength when I hardened a puddle, then easily snapped it when hard.

Greg

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You might also try:

Used it once on a very difficult vertical repair of a hinge that was under high stress. Worked amazingly well, actually. For all I know, it might be the same stuff as JB Weld. ?

They have a quickset version that may be less runny. Never tried it, but have the suspicion that it is not quite as spiffy in strength.

Well, yes, but..it flows quite a but during the "set" time, and so seems to be runny; all relative (aunts, uncles, einstiens, etc).

Epoxies do not tend to be runny; there is a brand called CantSag if i remember correctly, and that is but one of three i found without looking too hard.

Wikipedia the source of all ignorance has the same strength figures for JB-kwik and JB-weld.

Jim Thompson wrote in news: snipped-for-privacy@4ax.com:

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adding more hardener does not make epoxy cure faster or thicker. it actually makes things worse. Every epoxy is designed for a specifc resin:hardener ratio. Epoxy actually takes a week or more to FULLY cure and reach full strength.

You need thixotropic fillers to do make it thicker. Like fumed silica. Glass or plastic fibers will add strength. JB Weld already has fillers in it.

Jim Thompson wrote in news: snipped-for-privacy@4ax.com:

it gets runny because of it's thermal reaction in hardening. heat makes it cure faster,but makes it thinner and more runny.

Tim Wescott wrote in news:1vSdnRYZI8kRGIHSnZ2dnUVZ snipped-for-privacy@web-ster.com:

actually,too thin a glue joint is not good for epoxies,unlike wood glues. but too much,and the excess does run.

Robert Baer wrote in news:_e2dnR7LeqHmc4HSnZ2dnUVZ snipped-for-privacy@posted.localnet:

you've never seen a boat-building epoxy then. most epoxies -used as glues- have fillers added,and some of those fillers make it less runny. But temperature is a big factor.