liquid steel gunk stuff

Has anyone used that stuff at hard ware stores that say it can patch a hole in a muffler. And its as stronge as steel and heat can't melt it and all that other wonderful miracle stuff? Is this stuff for real or is it

i used the stuff from lawson it's like a roll of tape but it's putty, it's not cheap like 27$ a roll but ut hardens like concrete worked on my exaust pipe

are you talking about JB Weld or another product.. ive used the JB weld for some stuff.. and it held up well.. we carried some in the pluging and patching kit on the cutter i was on... if the coast guard is counting on it to work.. id say its got a good reputation... some of the other stuff.. who knows.. might work.. might not...
there is also a plumbing putty ive used on some old steam lines.. that stuff worked great.. hardened up even while it was wet.. and hasnt leaked since.. on a steam boiler line!! ill try to find the package later this week.. so i can get the name..

Yeah I bought some cheap smelly gunk stuff that advertised to hold like steel. It stated it could resiste temperatures of up to 500'F. However I put some on a hole on my muffler and after I let it sit for a couple hours, and after only 3 miles of driving it was melting off the muffler and smoke was belowoing from underneath. So when I really got frustrated I had a good friend with a welding torch seal the holes for me. And in the end good triumphed over evil.