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Originally posted by earlfor
Yep Scotty, have a lot of experience with that sort of thing. :-)
J B Weld is a two part high temp epoxy filler, and will work just fine for that problem. There are a couple of things to consider. J B Weld normally takes about 6 hours to primary cure. Epoxies are absolutely intolerant of oil, or any greasy contamination. Not even a fingerprint is acceptable. The joint will have to be cleaned spotless and it cannot weep any oil for at least 6 hours while the epoxy is curing. Any oil that weeps after the compound is applied will form a microscopic barrier between the surface of the metal and the epoxy and it will not seal. The characteristics of epoxies in general can be modified by the ratio of catalyst to base. J B Weld is a 1:1 mix. That yields a very hard/brittle filler. With epoxies, INCREASING the amount of catalyst will produce a filler that is softer and more flexible. With engine vibration, an extremely hard filler would be susceptable to developing cracks. I would mix the J B Weld in the ratio of 2 parts of catalyst to 1 part of base so as to have a filler that is more flexible and less prone to cracking. For a neat "patch", I usually mask off the seam line and remove the tape before the filler has started to set. You can clip a shop light to shine on the repair and the heat will hasten then curing process.
You only want the filler surface to be slightly warm...not hot.
Acetone will usually draw excess oil out of a gasket edge if that is needed. Just prior to applying the filler, I scrub the area with comet cleanser and water to remove any acetone or other residue, then rinse with clean water and dry the surface with a heat gun or hair dryer.
Earl
J B Weld is a two part high temp epoxy filler, and will work just fine for that problem. There are a couple of things to consider. J B Weld normally takes about 6 hours to primary cure. Epoxies are absolutely intolerant of oil, or any greasy contamination. Not even a fingerprint is acceptable. The joint will have to be cleaned spotless and it cannot weep any oil for at least 6 hours while the epoxy is curing. Any oil that weeps after the compound is applied will form a microscopic barrier between the surface of the metal and the epoxy and it will not seal. The characteristics of epoxies in general can be modified by the ratio of catalyst to base. J B Weld is a 1:1 mix. That yields a very hard/brittle filler. With epoxies, INCREASING the amount of catalyst will produce a filler that is softer and more flexible. With engine vibration, an extremely hard filler would be susceptable to developing cracks. I would mix the J B Weld in the ratio of 2 parts of catalyst to 1 part of base so as to have a filler that is more flexible and less prone to cracking. For a neat "patch", I usually mask off the seam line and remove the tape before the filler has started to set. You can clip a shop light to shine on the repair and the heat will hasten then curing process.
You only want the filler surface to be slightly warm...not hot.
Acetone will usually draw excess oil out of a gasket edge if that is needed. Just prior to applying the filler, I scrub the area with comet cleanser and water to remove any acetone or other residue, then rinse with clean water and dry the surface with a heat gun or hair dryer.
Earl
Originally posted by slopoke
While we are on this subject. I have developed a leak in one spot on the front of my engine where the barrels meet the lower cases. I really dont want to take her apart yet. My friend told me that and old trick was to use a quality 2 part epoxy just in the area over the leak. Any comments suggestions warnings--anything. Has any one ever done this
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Thanks
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