best ever use of JB Weld ????

phillyskip said:

I have used it to repair a leaking seam on an alloy fuel tank.....worked great.

Click to expand...

Seems unbelievable! Where was the seam? :shock:

I built a racing 500 Daytona engine, I took the ports out to 34mm (running 34mm smoothbores) and splayed the head a lot so the ports could be kept straight and miss the centre studs.

Doing this made the ports break though into the fins on the rer of the head a lot. I used it to fill inbetween the fins. Worked perfectly and lasted forever, well, so far at least!

hobot said:

No good to remake threads with it as fails to adhere or very brittle in thin layer but by golly if ya roughly clean out the hole and JBW fill then just drill-tap new threads and use some wits on thermal and torque applied.

-

Click to expand...

It seems to me a thread repair that does not require high torque could be made by drilling and tapping the hole to next larger size, then filling with JBW and re tapping original size. The JBW should hold in the larger sized threads. Of course, if one can drill and tap to next larger size, why not just insert next larger size screw? Only if appearance is important, and one wishes to match other screws in the assembly. A helicoil insert would be better, but JBW would be a poor man's fix.

Slick

My Trixie Combat had a TS cover screw sheared off below the ign. cover and I buggered the hole trying to drill/extract it successfully so tried the special epoxy thread repair kit and it worked a treat with some care nipping down and getting it close to seated as hole a bit skewed from the others but stayed sealed through several engine blow ups going easy 50's mph from old piston let go then old rod bolt let go. The cover screw in that area ain't got much surround to hog out for helicoil nor am I set up to do that right yet cover has been on/off half dozen times and off again now to reseal whole engine before fall arrives. My poor multiple animal crashed SuVee is mostly JBW in bikini fairing, head lamp mount, instrument panel, mirrors, gas tank, rear seat fairing pillion seat lock and shift linkage into new lever that threads didn't match up. I may end up using JBW to get tubeless spokes to stay sealed on Peel. Look up JBW dental repair but can't fix a broken heart with it.

I had a stripped brake bleeder valve and bought a HD repair replacement, drilled out the hole and JB welded the HD bleeder repair kit. Been that way for years.

comnoz said:

xbacksideslider said:

I used it, per Gordon Jennings' recommendations in Cycle Magazine way back when to raise the intake port on my Yamaha SR500. I dunno, maybe 30 years later, it still holds tight to the intake port floor with help from the thicket of small aluminum machine screws that it is embedded in. They stick up into the port from the underside and through holes drilled and tapped from the underside.

Click to expand...

Yeah I did that once on my Norton racebike -intake and exhaust. The Jb weld in the exhaust was gone the first weekend.

I only had three screws into the floor of the intake port and it lasted most of one season before a big enough piece broke off to keep the intake valve open enough to get hit by the exhaust valve and end my race day.

I have used it in the intake on cast iron car heads and had it last for years. Jim

Click to expand...

Didn't use it on the exhaust side. Trick might be many small screws, maybe fact that they were all aluminum helped too, although expansion rate of JB Weld likely differs from aluminum.