JB weld question...

[Cody Carey]

A while back... I suggested using the wonderful J.B. weld as a perminant solution, and The team thought that it wasn't the best Idea, because we thought that it was more of a "fix it" product than a production product.I was just wondering weather or not anybody on this forum has any experience with the stuff and if your results were good. I have used it before... and it held allright, plus the user reviews all seem to be astounding... But if you've had any bad experiences with it, please post them here


Thanx in advance
-CodyC

[KenWittlief]

epoxy is stronger than the resin used in fiberglass construction (boat hulls, car bodies...)

it is definately a production quality material, and JB weld is one of the best epoxy products on the market.

the storys about it are true. I fixed a leak in the oil pan (small hole on the side) on my Fiero, and it lasted 3 years at least (I sold the car)

[DonRotolo]

Originally Posted by KenWittlief

I fixed a leak in the oil pan (small hole on the side) on my Fiero, and it lasted 3 years at least (I sold the car)

Funny, I used JB Weld for the same purpose, reinforcing the hole with a screw. Held up great.

JB Weld is a fairly good adhesive and an excellent filler. It has a lot of compressive strength, moderate shear, and poor tensile strength. It adheres well under poor conditions (heat, oil, chemicals) but isn't as good underwater. I knew a fellow who repaired a crackled engine block with it, that's where I first heard of it (over 20 years ago!!)

There are far stronger adhesives, like the clear stuff in a doiuble-tube syringe from Radio Shack (and others), but these are poor fillers. I recommend buying a small package and playing with it, you;'ll learn what it can and cannot do.

Hope that helps.

Don

[Tristan Lall]

I've seen a FIRST robot with its drive gearboxes held together by a similar product (it was titanium-filled, instead of steel-filled like J.B. Weld). It worked...but wasn't pretty.* I'd advise against that particular application.

When using it, watch out for the fact that it slumps as it dries, so it can be tricky to apply precisely to oddly-shaped surfaces. (I've also used a Devcon-brand aluminum-filled epoxy that is of a thicker consistency, which is more easily applied to complex shapes.) Also, though it's stronger than fibreglass resin, if you're using significant quantities of it as a structural reinforcement, it should itself be reinforced with something like a fibreglass mesh.

*The team was 919, Harbord C.I., in 2002.

[KenWittlief]

What Tristan said - I recently was suprized to learn that while epoxy is curing at first it gets more runny, then it gets thicker as it hardens.