Annealing a solid copper head gasket (2015)

I just annealed a solid copper head gasket and found that after bringing it to temp and dull red color, it formed quite a bit of what I call copper oxide on both surfaces.
It is difficult to clean this rough surface of oxide off with scotch brite, steel wool, or even 600 wet/dry.
Propane was not effective enough to raise the temp.
The usual patter internet advice of dull red copper was reached with oxyacetylene #3 tip in a total blacked out shop.
After completing this task, and getting the results I achieved, I am beginning to feel like this annealing is something that is advised and discussed, but not actual ever practiced or accomplished by anyone describing the non specific generalities of this annealing process.

Is anyone annealing and has very specific, valuable, useful advice on how to accomplish this on a solid copper motorcycle head gasket?
Is this annealing only valid for short period of time? and how would you know this?

When I last annealed my copper head gasket I turned the electric hot plate to high and put one side central to the hot plate. When the copper was cherry red I quenched it in the sink then repeated the process (with overlap) for the other side. Annealed copper stays annealed until work hardened e.g. by bending. Work hardened copper is more rigid.
Ta.

Just blast it with propane until as hot as it can get then drop it into a bucket of cold water. You are getting rid of "memory ". Wipe clean then use a very thin layer of High - temp Permatex silicone to surfaces before dropping the head down . Thinnest application near the tiny oil drain hole . Run bike to full temp then re-torque head again. Never had that fail unlike flame ring etc. types.

Last time I rebuilt my motor I forgot to anneal the copper head gasket it wasn't till after I tensioned the head down that I remember, but after over 5 years now it hasn't leaked and the head only got retensioned after 700 miles (once only), it has done over 25,000 miles since, I nomaly annead the copper gasket over a open flame on the gas stove.

Ashley

Yeah, I burned up a perfectly good copper gasket with the oxy/acetylene. It's a fine point of redness. I don't think I'd try it again. I question the value of heating it that hot. The propane may have been good enough.

I do it regularly on copper head gaskets for Nortons, and occasionally for other copper gaskets. I routinely anneal new copper head gaskets before installing, as well as annealing old ones to re-use. I use an oxy-acetylene outfit with a rosebud tip. Heats them up rapidly.

If you heat it to red and let it cool in the air, it does form the oxide coating your describe. I cool it in water immediately after heating, and that removes the scale for me. Either technique brings the copper back to it's original soft state. I just use the water method because it is cleaner. You end up with the scale in the bottom of the water bucket, instead of on the gasket. I don't clean the gasket any further after annealing.

I've been doing this for 40 years now with copper gaskets, probably done it 100 times, at least, and can assure you that it works as described. It's a common procedure among engine builders who use copper gaskets.

Ken

I did mine on the kitchen table over wifey's cake pan, with the lights out, so much easier to see the dull red come on.

My metallurgy college courses are 50 years behind me, but my memory says only beryllium copper alloys age harden. These are the alloys that are used in making copper springs.

I would not expect a copper head gasket to be made of beryllium copper, therefore, there is no need to anneal a new head gasket, even one that has been lying on the shelf for many years. Copper alloys and pure copper will work harden, and would require annealing if a used gasket were to be used again. I find the cost of a new gasket is justified by the peace of mind that comes from using new over a recycled one.

Therefore, IMO, annealing a new gasket is a useless endeavor, and an old gasket, a frugal but foolish endeavor.

I will defer to someone with more knowledge of metallurgy on this.

Slick

I read that copper annealing should happen at 900'F. This is a very inconvenient temperature since it is hotter than a kitchen oven on "Hi" , but cooler than a torch.

Propane and (especially) acetyline are much hotter. Non-alloyed pure copper has a fairly distinct meting point (like aluminum) and (like aluminum) it oxidises when heated in the presence of oxygen. Even steel will burn (combine with oxygen and turn to iron oxide). Copper does, too.

Solution: the self cleaning oven. The operating temperature of a GE self cleaning oven is 900'F.... just perfect. You will need to perfect the "Honey, the oven is looking a bit skanky... I put it on "clean" " routine, then get up before her to remove the gasket the next morning. Tell her it's Mother's day in Slobovovnia so you go up early to make her a Cuppachino. Heck, if you have trained her with engine parts in the dishwasher, you can skip the coffee in bed.

I would forget about dunking red hot copper in water. I don't know anything about crystal structure in copper, but when you anneal steel, it is best to let it cool slowly. Dunking it hardens it, which annealing is trying to cure.

A big help around the shop is a digital infared thermometer, available from your friendly Home Depot. I use it for everything from telling which cylinder is misfiring or running lean (exhaust pipe temperature) to seeing if the pizza oven is hot enough. perfect for telling if your BBQ is hot enough to anneal your head gasket!

Manxman

I learned this way back when in shop class that sudden cold water "quenching " is the "stop all things now " and all molecules will be neutral and without memory. I spend a small fortune on spooled fishing line very regularly to eliminate memory. Copper goes neutral with heating and sudden cooling for re-use. Public school education. :roll:

A copper head gasket work hardens. It get's harder when they are rolled and cut. They do need to be annealed before use.

I use a big rose bud on acetylene and make it red all over. At this point is is completely annealed. Then I quench it in water to help remove the scale.

After that I lay it in the bottom of my solvent tank and remove any remaining scale with a wire brush.

Then I give it a coat of high temp aluminum paint and it's ready to use. Jim

Ya really can not get copper too hot as gets warm wax soft if orange/yellow heated but as propane is only hot enough to get bright red level that what most references quote as good enough and generally is. Can heat piecemeal no problem just as long as whole gasket covered by small heater to least bright red, Water dunk is just to save a racer event time as does nothing else but tend to undo some the heat softening by the thermal shock contractual internal work hardening. I have gotten to point of give me a real Flame Ring or go w/o head gasket if clearances can tolerate it. I would say each new copper kind is good for about 4 reuses then tends to get mashed down in areas no amount of annealing can compress whole gasket enough to seal well no matter how tight head fasteners torqued down. Its risky to try to mechanically clean oxidation scale off used copper gasket as can leave gasket thickness uneven and work hardens surface again, so think Tarnex if pressing luck to reuse. Btw you can not pick up a orange/yellow annealed gasket by a wire in a hole as will sag like Dalis melted clocks but if careful with horizontal support its the cats meow to seal to me.

manxman said:

...I would forget about dunking red hot copper in water. I don't know anything about crystal structure in copper, but when you anneal steel, it is best to let it cool slowly. Dunking it hardens it, which annealing is trying to cure... Manxman

Click to expand...

Heat treating steel is not the same as annealing copper.
You may care to read further on this regarding copper Propreties: "...Unlike ferrous metals—which must be cooled slowly to anneal—copper can be cooled slowly in air or quickly by quenching in water..."
https://en.wikipedia.org/wiki/Coppersmith

https://ia801407.us.archive.org/28/item ... llgoog.pdf
and:
"...Typical temperature to use is 400C or 700F. Annealing causes the structure to
create and grow new grains that are free of strain... http://materialseducation.org/educators ... Copper.pdf
Ta.

Might review this down and dirty scope on annealing copper and alu gaskets and washers with its note about orange hot is more than most need but me anymore. Again 4 x re-annealed plus clamp downs is my new found limit for now on. Ya all know to never use the taboo Norton Alu head gasket but alu washer for head oil banjo is the cats meow that long time venders put me on to buy and glad of it.

http://www.motorcycle.co.uk/reference/a ... um-washers

hobot said:

Might review this down and dirty scope on annealing copper and alu gaskets and washers with its note about orange hot is more than most need but me anymore. Again 4 x re-annealed plus clamp downs is my new found limit for now on. Ya all know to never use the taboo Norton Alu head gasket but alu washer for head oil banjo is the cats meow that long time venders put me on to buy and glad of it.

http://www.motorcycle.co.uk/reference/a ... um-washers

Click to expand...

Aluminium properties: "...Aluminum melts at 933K, 660C and annealing is done at about 200C..." You can easily put that one in a kitchen oven - furnace not required! Yes, it would be worthless as a head gasket.
http://materialseducation.org/educators ... Copper.pdf
Ta.

I use MAPP gas to anneal copper washers. It is much hotter than propane, thus speeding up the process. It has no trouble heating copper to the melting point, so don't take copper to white hot. :twisted:

I use a propane torch (bernzomatic} to anneal the copper head gasket, A butane torch will do the job as well. A member of our local NOC asked me how i get it hot enough as he was having problems trying to get it to red heat all over. I told him that if you 'chase' the heat around the gasket so that at some point in the heating cycle the whole gasket has been at red heat then it will be annealed. Using a DIY torch the flame isn't big enough to heat the whole gasket up at once. Thirty years ago I used to clean the scale off by quickly dunking it in water and then scrubbing the residue off. A easier (and safer way) is once the gasket is cool I pickle it by dunking it in a shallow container of citric acid (kettle scale remover crystals, available from your chemist etc) this removes all the scale and leaves a nice clean pink gasket

I was taught in copper smithing/beaten metalwork class at school in 1961. We had to use a coal gas/air provided by a foot bellows as the heat source. Worked a treat. How people can't anneal with propane I can't imagine. We were making bowls with a much higher thermal mass than a head gasket.
You do not have to have the piece uniformly hot all at the same time, once one area is hot enough, move on the the next. I've never tried under arc lamps, but that is the only likely way you would not be able to see *dull red*
Then drop it edge on into a bucket of water. The water shock will remove all or at least most of the black oxide. The black oxide is messy and will get everywhere. It's best in the quench bucket.
The edge thing will minimise distortion.
Red oxide can be removed by pickling in a convenient acid solution, but is not necessary for gaskets.
The important thing is not to bend the metal or it will work harden again (by trying to straighten out the distortion caused by not dropping it in edgewise).

http://www.nancylthamilton.com/wp-conte ... Metals.pdf
Sorry its a pdf which I can't edit, copper on the second page.

I did some research.

Manufacturers of copper sheet hot roll it and the Rockwell hardness of the product is F50 which is considered soft.

Sheet can also be obtained from the manufactures as 1/8, 1/4, 1/2 hard which is the soft R50 work hardened by cold rolling it further in stages.

Copper is annealed at 700 to 1200 deg F. The time at temperature is a factor .... lower temps should be held longer.

If a gasket mfgr uses the Rockwell F50 sheet, I do not believe the stamping of the gasket will significantly work harden the sheet, just the edges where the punch shears the material. If the gasket mfgr uses the 1/8, or 1/4 hard material, then I would agree the gasket should be annealed. IMO, a reputable manufacturer would not sell a product the customer has to modify to be suitable for intended use.

Furthermore, like Ashman, I have twice had the head off my Atlas, and both times replaced the head gaskets with copper straight out of the package. Buy a quality gasket, and this becomes much ado about nothing.

That said, what follows is an educated assessment:
It may be some hardness in a gasket, particularly a head gasket, is desirable to reduce the need to re- torque the assembly several times. A soft material will creep, or flow, under the clamp load, and will require re-torque after time. Perhaps, gasket mfgrs account for this, and use 1/8 or even 1/4 hard sheet. Thus, if one anneals the material, one sets himself up to be re-torquing the head 3 or 4 times after assembly.

Slick

Mapp gas does a fine job. No need to go crazy or risk popping a hole in it.