Okay, let me explain my feelings and why I poo-poo on epoxy repairs to the newbie. Especially when they are told to 'pack the crankcase' or to make engine repairs using JB or any plastic material.
The product, 'IF USED AS DIRECTED' by the manufacturer might work in certain applications. The key words here is 'IF USED AS DIRECTED' and that means proper surface preparation. Trying to get any epoxy based material to adhere to oil impregnated metal will not work.
It doesn't take a lot of reading to realize the limited mechanical knowledge we often see here with new builders. These are the ones who overtighten fasteners, etc. All too often they might not understand the importance of cleaning the surface before applying the epoxy. Failure of the repair is almost certain in that case. They are told to use JB Weld to make a repair and then try to glob on the stuff without any prep. It won't work.
In Greg's case there is no doubt that he made sure there was no oil, grease, moisture or other contaminents on the metal before he applied the JB. And, it might hold until he gets his new parts. I hope it does. I've been where he's at.
I too have used epoxy based material for critical repairs in the past and had excellant results. Devcon products are an example. Of course they cost ten times what JB does. I was involved with a repair of a steam boiler supply flange where the flange cracked and it wasn't feasable to have it welded. The boiler was to be replaced soon and the cost of dissassembly was prohibitive. Devcon Liquid Titanium was used and it held for five years under steam pressure and temperature before the boiler was replaced. However, the repair was done according to the product makers exact instructions. The broken parts were thoroughly cleaned and properly clamped into position for the prescribed time before the machine was put back into operation.
Imagine a new builder with limited mechanical experience, knowledge or appitude trying to glue a cylinder stud or engine mount fastener back in with the threads coated with 2 cycle oil, grease, dirt and whatever. All too often the advice to use JB doesn't include the warning to follow the manufacturer's instructions precisely and that will usually result in a failed attempt at a repair.
That said, I did try to repair an engine with Devcon. I did exactly as Devcon said to do and the stud pulled out of the threads long before the torque value was reached. I used a heli-coil and that engine is still running strong today.
I've said this before and I'll repeat it here. JB has its uses but it isn't a silver bullet and it won't work for every repair. It will not work to repair stripped threads in an engine case, cylinder or other areas of high stress. It is a inexpensive alternative for some things but not everything.
Tom
