Lab Metal for filling block rot

[DMC02766]

While I was cleaning up the engine valley getting it prepped for paint I noticed some slight block rot in deep slots. Have any of you used a product called "lab metal" for filling in the "rotted" spots? They claim it can handle up to 350 degrees and is self leveling. They also make a high temp lab metal but you have to heat cure it at 400 degrees so that one is pretty well out for this task.

Here is a link to the site that makes it:
http://www.alvinproducts.com/Products/Products.asp?id=1

[Bitsyncmaster]

Don't see how thick you can fill it and have it harden. I guess you could try it on a test sample and then cut it open to see.

[eagle-co94]

How much pressure can that stuff hold and how much pressure is there where you have your rot?

[Jason]

I tried using Lab Metal to patch a very small and slow coolant leak in my engine block that was caused by corrosion. The instructions say that you should apply Lab Metal in thin layers and let it dry before applying the next layer.

In my case it didn't work well at all, but I think that's because I was trying to do the patch with coolant still in the engine, and as the Lab Metal started to dry coolant would seep through the Lab Metal and mess up the drying process. The end result was porous and crumbly. Because of where the leak was, I wouldn't be able to get it clear of coolant without pulling the cylinder head off. I was hoping the putty like consistency of Lab Metal would keep the coolant from seeping out while it was drying.

I tried again with Belzona 1111 instead of Lab Metal. That worked a little better, but still had hardening problems that appeared to be caused by seeping coolant. I tried a third time, again with Belzona but this time while applying the stuff and letting it harden I pulled a vacuum on the cooling system. I also heat cured it with a hair dryer for 6 hours. That seems to have worked. The stuff bonded well and no more leak. I've only driven the car for about an hour since the patch, but so far its holding.