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

in

=A0 =A0 =A0...Jim Thompson

you

ing

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.

=A0 =A0 ...Jim Thompson

=A0 =A0| =A0 =A0mens =A0 =A0 |

=A0 | =A0 =A0 et =A0 =A0 =A0|

=A0|

=A0 =A0 =A0 |

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.

I think it depends entirely on the specifics of the epoxy... the resins and hardeners used, and any fillers or additives.

TAP Plastics makes a nice range of "marine-grade" epoxies... one resin, three different hardeners. The mixed epoxies have significantly different viscosities, wetting abilities, and hardening times. The one I prefer as my "general utility infielder" bulk-mix epoxy is the low-viscosity variety, and if I don't add any fillers it's *quite* runny.

TAP sells a number of fillers that can be added to their epoxies, to modify the characteristics. One which might be of interest is "Cab-o-Sil", a very fine "fumed" silica that can make a liquid epoxy into a non-runny thixotropic gel, or a peanut-butter or petroleum- jelly-like paste.

Possibly, adding a few percent of a filler like this to JB Weld might reduce its tendency to be runny during cure, without affecting its strength and ruggedness. I would certainly want to try this experimentally before depending on the result!

See

Here's a nice, concise, page on the MasterBond epoxy range with a common frame of reference. (I.E. the table showing viscosity for common things).

Their epoxy range is 200 cps to 1,500,000 cps.