So one squash, one work cycle, under a banjo bolt is enough to harden a washer?
Standard procedure in aircraft Mtx and when removed you canât bend the washers in your fingers ,after heat treatment you can easily
The proper Jag washers have a crushable ring in them itâs just not worth fooling with
Cheers
I used the âproperâ ones, and they didnât leak. I recall there was some issue with the length of the bolts, which may not be an issue if they were never changed. I donât recall the issue, but likely it involved incorrect replacements and the location of the hole. In any event, why not use the ones designed for that purpose? Copper should work, but perhaps it may be too thick, etc. Also, the Cu alloy on âbox of rocksâ selections of Cu washers may be suspect.
Enough so to minimize its sealing capabilities, yes.
Iâm glad I stumbled across this thread as I also have a leak at the oil feed pipes. I thought I had the correct copper washers, but the ones I got were not thin. Now I see a different p/n than what I bought:
C4146XX from Terryâs thanks to @Jagjim1.
Is this the correct washer?
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Yup order some extras for a rainy day
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Yep: order a double supply!
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Yup, whenever I bought gaskets like for the cam covers, T-stat housing and oil breather, and sealing washers I always bought spares. Youâll probably need them in the future and when you do youâll have them on hand.
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Thatâs exactly what I did â I needed 6; ordered (and received the other day) 12 if them
Craig
Series III
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Iâve given up doing this as if the future need is more than 1/2 a day away I will have forgotten where I put the spares by the time I need themâŚ
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I donât believe that is correct, copper does not need to be âquenchedâ to anneal it. Dipping in water does help to remove some of the scale from heating.
Cheers,
Lynn
Ref: Annealing copper - Toolbox - Mirai Forum
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Annealing has worked for my cam feeds (4 times, 18 washers?) and I still use the original, reused copper washers. They donât need the âcrushâ. I had one failure which was my fault entirely.
Those who say it is not possible simply didnât get it leak free when they attempted it - it is possible.
I anneal all of my copper washers until they are really flat from reusing.
I did not know the answer for rate of cooling - quench or air cool - when annealing copper, so I turned to the ASM Intâl (the engineering materials society) that led to a reprintable excerpt:
**Copyright Edmonds Community College 2007; Permission granted for use and reproduction for educational purposes only. **
**Annealing the copper requires a high temperature. Copper melts at 1357Kelvin and annealing generally occurs at greater than half the melting point in degrees K; even higher temperature causes faster annealing (but not past the melting temperature, of course). Typical temperature to use is 400C or 700F. [Itâll glow reddish.] Annealing causes the structure to create and grow new grains that are free of strain. The new grains remove all dislocations and other defects caused by the deformation, thus leaving the material in its original soft condition, although NOT in its original shapeâit will still be the same shape as after deformation, but can be easily bent again. Annealing takes time and temperature, so that this part of the experiment can only be done with a high enough temperature annealing furnace or in a propane torch. **
Cooling rate after annealing does not matter (except at 10 million degrees per second the material would get harder again)
So it seems a valid process to heat the washers with a propane torch for a while (?) and drop in in H20 of let air cool (makes no difference). Copper has the same type of crystalline structure as gold and silver and they act the same way upon annealing. [? = 30 sec or so for these washers and a few minutes for something much thicker.]
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Thanks Scot. That sounds like the last word on the subject.
I think what I quoted above is important. If the washer is distorted, not uniform in thickness due to a previous installation, annealing wonât correct that distortion.
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Iâm sorry⌠But this is pretty ludicrous! New washers are cheap, and almost always a sure thing.
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I agree Paul, I just found it interesting to seek the truth on copper annealing. For me, Iâm buying new washers. 
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A soft washer will seal again because tightening pushes the distortion away. Because itâs soft. It will only work so many times because eventually it becomes too thinâŚ
Quenching gets rid of the scale, otherwise no real world difference.
The fact that it will seal just fine when annealed might help someone who does not have the time to wait a week for a replacement, or has difficulty obtaining a spare, and it hopefully gets rid of the misconception that an annealed banjo washer will not seal again. They do seal.
Donât be upset if you bought new washers, if they seal all is well?!
Maybe, I guess that would depend on the extent of the distortion. Applying enough force to do that could also compromise the threads the banjo bolt is screwed into. Iâm specifically thinking about the threads in the head for the cam feed lines. Iâd still just buy new. The hassle and effort to replace a leaky washer far exceeds the cost of buying new. Iâve read some folks advocate annealing new washers just as a belt and suspenders measure âjust to be sureâ in case the new oneâs werenât annealed.
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They are a weak point.
I wonder how much distortion you can get. I would say the worst case would be a raised ridge on the mating surface that leaves a channel for the oil in the washer, or a deep scratch from handling. That should be obvious when looking at the washer, and would probably not close up reliably from tightening.
Annealing also takes time and effort but it works in a pinch or if you like doing it that way.
Just thinking out loud. The sealing surfaces on each of the components that touch the two sides of the washer are likely not perfectly parallel to each other (if they were, would you, in theory, even need a sealing washer?). So, the copper washer would form itself to fill the space between the two parts, and wind up slightly thicker in some spots, slightly thinner in others. Obviously, we are talking about very small differences. Enough of a difference to cause a leak? Maybe, maybe not. Being a lazy person my first preference is to buy new which I think decreases the opportunity for leaks and redos.
That said, I have tried annealing used washers in the past and have had mixed results.
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