JB Weld
 

Anyone know what I can mix with JB Weld to make it very runny so it'll ooze better into some cracks I'm repairing? Alcohol? acetone? Thanks.

I assume you picked JBWeld for its strength... so mixing it with ANYthing is not a good idea.
Many glues have a minimum thickness at which they work properly.Superglues need really tight fit ups... Epoxies typically do better with some " substance" to their applications. Cleanlyness is very important with stuff like this and it might be better to increase the size of the crack rather than making the JDWeld thinner......

I'm in a "Mechanical Engineering Technology" program at school, and I am seriously :D thinking about making a project out of testing JB weld for tensile strenth, toughness, hardness and other physical properties :D ....just so we could compare to it more conventional metals...and make claims like "well, that JB weld is stronger than the low-grade aluminum that is it bonding together, so they aluminum should break first." :D

unless someone has already done this... :D

-John

JB Weld is just an epoxy ( I think). Rather than try to use it, I would just buy a less viscous epoxy. There are tons of different kinds available. I always keep at least four or five different kinds around from plumber's epoxy which is very thick to a kind that is very close to the viscosity of water. SuperMend is about in the middle of those extremes. My local hardware store must have about 10 or 15 different kinds.

An epoxy can be heated to thin it out. Use a hair drier of a heat gun. It's normal practice in the composite airplane building circles I run around in.

Heat it before you mix in the hardener or it will "go off" too quickly. (your workable time will be shortened).

Joe

jb weld vs. Marine Tex
 

John (Angel),

If you're into testing, I'd love to find out how MarineTex compares to JB Weld. It is a marine epoxy for use underwater, with oil/gas, and it hard as a rock (looks like cured bondo, but very impervious). I usually keep it around for misc. boat fixes - like the mounting tabs on the fender flares for my conversion van. Also used it to attach a metal lamp fitting to the ceramic pot of an oil "hurricane" lamp.

Never used JB Weld, would it be similar? Is it more metal specific?

Chuck

Don't use alcohol
 

Alcohol in epoxy is BAD. At least if you're interested in retaining structural strength. Chemically, it will act as a chain end, and thus reduce the polymerization. There are thinners out there designed for epoxies, and in fact the thinner epoxies you can find in your hardware store are generally the real thing mixed with one of these. One we use is made by a company called PTM&W. You could probably get a free sample if you call.

I concur with mplafleur that heating will make it quite thin (great way to smooth it), it didn't seem to cut much out the workable time for me though.

Years ago we used to fix surfboards for gas money and other stuff?? When the waves were good we did not want to spend any extra time waiting for the epoxy to set up and cure. We used hair dryers. The epoxy wasn't as strong due to the decreased curing time, however, boy did it get hot when accelerated. More than one surfboard went up in flames. AAAAHHH Twisted Youth!!!

Joe