I think JB Weld is good stuff---many possibilities for quick and lasting "fixes" on our cars. One question: will the application of heat seperate a metal part that has been JB welded? Your experience appreciated and thanks, Paul
JB weld, when properly applied is a great fix for small freeze cracks. When I worked at an Oldsmobile dealership, we had a couple Oldsmobile Aurora's that had cracks in the block and were under warranty. General Motors didn't want to fork out the big bucks for a replacement engine, so they told the technician to fix it with JB-Weld. The procedure was to drill the crack on both ends, undercut with a dremel tool, and insure that everything was super clean before applying the JB Weld. I know of two cars that were fixed at that dealership under warranty and under the direction of General Motors by that method and as far as I know, the repair lasted and they never came back. I tried it myself on one T engine block in 2005 and it has proved to be a satisfactory repair. Bear in mind, that the block was surgically clean, like a new casting, and that the crack was vee'd out and undercut, and that the cracked area was not structural... If applied over surface rust, oil, paint, etc, I doubt it would work very well.
Agree with Adam and Paul,
JB Weld is a staple of any Model T'er, just like bailing wire and cotter pins!
The heat required to break a well bonded JB joint is about 500 degrees, so its fine for blocks and pans, and most anything other than the exhaust system.
I just used some to 'weld' a little chain link with a galvanic anode to dangle in the radiator, just a dab under the radiator cap and the chain is fixed.
Also, the newer JB Weld Quick is really nice for vertical surfaces, it bonds in less than 5 minutes, as the regular stuff takes longer and can droop on vertical surfaces.
When I worked at an Oldsmobile dealership, we had a couple Oldsmobile Aurora's that had cracks in the block and were under warranty. General Motors didn't want to fork out the big bucks for a replacement engine, so they told the technician to fix it with JB-Weld.
That Kwik stuff from JB Weld has an oddity - it has metallic particles in it that are attracted by magnet. I only found out after using it to afix a small rare earth magnet to my glass sediment bowl. The blob all pulled up on top of the magnet from around the surface.
I also used the stuff to mount a magnet back into the holding base on a trouble light. It also pulled up on top of the magnet and I had to shave it down after.
I once took a running[barely] '20 engine that had been on a buzz saw apart to tighten it up to put in one of my truck creations.When I lifted the crank out of the mains the upper center bearing came with it, in three pieces.I was standing at the work bench swearing when a friend showed up.When I showed him the reason for the profanity he said,pointing to my pegboard, 'hell,there's the JB Weld.' So,I glued and sculpted a center main.That cobble job repair lasted through several summers of trips to the neighborhood fishing hole.Then some guys showed up one day at my place looking for parts to build a chassis to run a jackshaft attachment for a T that their tractor club owned.I showed them that little truck,told them about all the JB Weld, the rolled oats and pepper in the radiator and showed them where the frame was nearly pitted through.$800.00.They groused a little about the tires so I threw in a couple more bald 21".That was about 1988,and I wonder what ever happened to them and that rough ol' T.
JB to repair a centre main, now thats inventive, one question , how do you get your gapping back ? file or scrape like a regular babbit ?
What do you mean when you say "undercut"? Is that taking a thin layer of metal off the top of the crack? I have never had to use JB Weld, but if the need did arise it is good to have some background on repairs with it. I understand the v-groove, drilling and cleansiness.
Paul, heat from a welding torch will break down JB Weld allowing for disassembly. I use JB Weld to set bushings eg king pin busings, front driveshaft bushings, rear cam bushing, repair of buggered out hole in rear axel backing plate to accept the brake cam bushing. Have also used it to seal pinholes in crankcases and repairing cracks in water pumps. Oil or water won't get hot enough to cause a problem. Wouldn't use it in high pressure applications eg to hold the race of a wheel bearing. In the right applications is a very good repair.
One thing is critical. If using to repair a crack, V out the crack really wide, say 1/8", thin applications don't hold up.
That's been my experience.
I was on a national tour with my TT and blew a manifold gasket on the front end of the manifold. Scraped it with a screw driver while it was still warm and sluffed J B weld in and it held for 3 years touring and pulling the HILL at Newport Indiana.
I used it to repair a honeycomb radiator a few years ago. Everyone, including the radiator shop who said the radiator was junk, said it would not work.
Guess what? That "junk" radiator is still holding water and doing a fine job of keeping those 20 horses under the hood cool.
Sounds interesting. What is the shelf-life of this stuff ? If you use some and put the caps back on the tubes how long will it stay pliable and useable ? Most things harden if left to themselves. Thanks.
Bill, I've had some that was still good after a couple years. The jb quick is good for a lot of things but seems to break down under exposure to oil and gas. the slow drying holds up very well. I've used it on every thing from truck oil pans,worn spindles and pump impellers. good luck, Keith B------by the way, I have no affiliation with JB co.
I imagine that you used the slow drying JB? I too have a honeycomb radiator with a very tiny leak and never thought of using JB as a fix. Did you apply it lightly or layer it on? How long does the slow drying take to cure? Is JB paintable when done so it is not noticable?
Paul and y'all,
JB Weld is pretty darn good, however, there is a product called Marine-Tex that I've used for many, many years repairing cast iron and cast aluminum, that I feel is even better.
I recently repaired a leak in a fuel tank (no new tank available, Brent) and it's holding well against the softening effect of gasoline that JB users experience. I use a lamp to assist in setting it off - it's a two-part epoxy-like stuff. It comes in white and gray. I'd recommend the gray - even the maker does.
Shelf life is many years.
Marine-Tex is found boat supply places. Comes in a bottle, not a tube.
Not as good as a new part perhaps, but it can sure save a part that is no longer available.
And ditto what Keith said - no affiliation with Marine-Tex here.
Yes, I did use the slow drying JB. I applied two "coats", but your small leak might not need that much. However, two applications is pretty cheap insurance.
I let the first coat dry twenty four hours before putting on #2. I painted it. I don't know if JB reccomends painting it or not. The paint is still there.
Prepping the surface is key here. This is what I did. I took an electric Dremmel Tool, with a small metal ball shaped grinder bit that was supplied with the tool, and ground the rad. surface. I made the surface as "clean" as I could without removing metal. I sprayed the area with brake cleaner (it evaporates leaving no residue) and blew it off with compressed air. Then applied JB. For #2, I took the same Dremmel tool and lightly "roughed up" the smooth, shiney surface of the hardened first coat. Just like sanding before paint, this would ensure a good bond.
I should add that it was'nt just leaks that I fixed on this rad. I also used it to "stick" one side of the mounting/support strap underneath the rad. back on one side because it was loose. I also repaired an area around the filler neck where the shroud had worn through the metal.
In answer to Daves' question as to how I got my bearing clearance.This was a long time ago but I'll give it a shot.First,I had everything as clean as I could get it.Then I glopped JB into the holes in the block that hold the bearing in.I stuck what pieces of the bearing that were left to the block.I smeared JB in the places where the babbit was not present.I then laid some fairly thick plastic,probably from a garbage bag,acroos the bearing so none of it would stick to the crank.Then I bolted the cap on tight. I may have let it sit a couple days.Then I took it apart,filed off the excess that oozed out,drilled out the oil hole and groove.I am sure I had to file all the caps in that engine.So basically it was by guess and by god.Or my other favorite method----T.L.A.R.-'That looks about right'.I never expected this 'repair' to last five minutes.The original reason I built up this really rough,pitted,just the near side of a safety hazard T was to loan it to my former high school ag teacher for his ag mechanics class. I still love to tech a kid basic mechanics using a T as a lab tool...But,at this time the school system hired a new superintendant that was fussy about liability and so forth and forbade students from working on anything self propelled.I would have bought a ticket to see the reaction of this same superintendant when he found out the FFA had a thing called a 'pest hunt'.And that the school owned 15 or so .22 rifles and .410 shotguns for boys that did not own their own guns to use during the pest hunt....
Touche ! bang bang ouch !
I've used JB weld to repair the cast aluminum timing cover of a Ford 302, where the water pump attaches. Clean and remove all corrosion, apply goop and let cure. I used stiff paper taped in place to act as sort of a mold to keep the JB from sagging, and to keep a decent water passage. I then filed the stuff back to the correct contour to accept the water pump and make a smooth sealing surface so as to not lose coolant. It held up for over 80K miles and was still fine when I sold the car. I also used JB to repair a minor crack in the block of my 8N tractor, it is still OK and I did the repair in 89 or so. I don't hesitate to use it, within it's limitations.
I used J B weld on a gas tank on an old car one time several times on the same leak actually. probably didn't have it prepped right.
By the way Jim, I use the "SWAG METHOD", scientific wild a## guess.
The U.S. Navy uses JB Weld on a regular basis to repair diesel engine main bearings. My neighbor just got out of the Navy and told me all about it... So, that said, if it's good enough for large ship engines, it's good enough for a T.
oh, and to answer the question. The temperature stated on the box says 600F which is probably half the real value.
I've used JB weld on eveything from the Model T, fixing patients glasses, and false teeth. It has never failed me yet. I have no affiliation with this stuff either.
I have used the stuff to glue brake lining onto the shoes. The brakes on my TT have been working for 3 or 4 years now.