The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: Minto on 29.05. 2020 23:03

Title: Annealing copper head gaskets
Post by: Minto on 29.05. 2020 23:03
Hi all,
I have 3 copper head gaskets to choose from, the one that was on the bike before I stripped it, one that came with the gasket set from SRM, and one that I bought last year which claims to be pre-annealed.
I first attempted to anneal the old gasket, with my plumbing blow torch, which now feels harder than before. Then I tried the same with the SRM gasket, same result. I am struggling to get enough heat in to the metal. Can I bring these two back to life by reheating them?
The other gasket I have feels loads softer than either the old gasket or the SRM one (before m attempt with the blow torch). Should I just go with that as it is?
Cheers y'all
Jase
Title: Re: Annealing copper head gaskets
Post by: berger on 29.05. 2020 23:10
have got a gas cooker? if so hold it over full flame gently moving it about until it glows at you and throw it in the sink provided you have water in the sink. when you take it out of the water you should be able to eat it, if your into that kinda thing *whistle*
Title: Re: Annealing copper head gaskets
Post by: RichardL on 30.05. 2020 00:59
have got a gas cooker? if so hold it over full flame gently moving it about until it glows at you and throw it in the sink provided you have water in the sink. when you take it out of the water you should be able to eat it, if your into that kinda thing *whistle*

Not sure if Berger means an outdoor gas cooker. I do mine by laying it across the hottest gas burner of our kitchen range and hitting it with two propane torches (bottle type) at the same time. Keep at it until every zone has had a chance to glow. I let it cool naturally, but with copper I don't believe it matters. Probably shouldn't bend it to see if it's soft, because that will work-harden it. If all your gaskets were of the same material, they should all he able to be annealed to the same hardness (by which I mean, "softness").

I've also, for laughs, tried annealing in our fireplace.
https://m.youtube.com/watch?v=cOul-aIO_lg&feature=youtu.be


Richard L.
Title: Re: Annealing copper head gaskets
Post by: Minto on 30.05. 2020 02:39
Berger,
If I try eating it, won't  I be visiting the bovine dentist again?
Title: Re: Annealing copper head gaskets
Post by: Minto on 30.05. 2020 02:44
Richard, I came across your bid on YouTube as while ago, nice one. Did I see on some other post that you're in Chicago? What a fantastic city, we visited last year and I was blown away. Just a brilliant time
Jase
Title: Re: Annealing copper head gaskets
Post by: Greybeard on 30.05. 2020 08:21
I bring mine into the kitchen. We have a gas hob. I lay the gasket over the hottest burner and also apply heat from a plumbers gas torch. The gasket doesn't need to be uniformaly cherry red but try to get all areas to that colour during the heating. I then pick the gasket up with a pair of long-nosed pliers and drop it into cold water. The last part is not essential but it shocks off most of the oxide. I finish cleaning it in the sink, with a Brillo pad or wire-wool.
Title: Re: Annealing copper head gaskets
Post by: Minto on 30.05. 2020 09:18
Right, looks like I'm cooking today then.
Ill try the SRM one first.
Jase
Title: Re: Annealing copper head gaskets
Post by: ianbsa on 28.06. 2020 12:06
I know I'm new around here and last thing I want to do is sound like a show off..but.
To anneal means to cool slowly, if u chuck it in water it'll just harden up again.
 I make a little kiln from any old bits of brick stone etc then heat to cherry red then keep the flame on it gradually backing off...it can take a few minutes but the trick is to let it cool very slowly, leaves it soft as butter.
Title: Re: Annealing copper head gaskets
Post by: chaterlea25 on 28.06. 2020 12:58
Hi Ian,
Yes and no!
With copper quenching will leave it dead soft, different to  most other metals
This was taught to me as an apprentice and is in the text books
It has worked for me for the last 45 years
Quenching in heavily salted water (brine) should also remove the scale, I have tried it  But maybe not enough salt as it was only partly succesful

John
Title: Re: Annealing copper head gaskets
Post by: ianbsa on 28.06. 2020 13:14
Well I've learnt something new. Just googled it, thks John...tho I still don't understand how cooling it quickly in water softens it....It kind of goes against everything I thought I knew, kind of the opposite of case hardening steel with a quick dunk in oil/water.
Title: Re: Annealing copper head gaskets
Post by: berger on 28.06. 2020 16:14
mmmmm when do the pubs open *beer* *beer* steel , copper etc etc different metalaly bits or moleculeeeey things , I have always used water, might try some horrible beer someone left me *bright idea* *beer*
Title: Re: Annealing copper head gaskets
Post by: BSA_54A10 on 29.06. 2020 03:41
Well I've learnt something new. Just googled it, thks John...tho I still don't understand how cooling it quickly in water softens it....It kind of goes against everything I thought I knew, kind of the opposite of case hardening steel with a quick dunk in oil/water.

Quenching does not make any difference because there is no phase change occuring as there is in iron, steel or martensitic brasses.
It will definately clean the oxides from the surface.
Failed attempts at annealing generally happen when using lpg or oxy gear because you have held it at temperature for too long
Pure copper adsorbs carbon, oxygen & hydrogen quite readily and the higher the temperature the more it will adsorb
Title: Re: Annealing copper head gaskets
Post by: UKlittleguns on 29.06. 2020 15:00
Hi Everybody,

This might help.  A direct quote from Newnes Engineers Reference Book 1960 edition.

Heat treatment of copper and copper alloys page 1282.

"For commercial copper, anneal at 500C or 600C for massive sections.  Cool down slowly or water quench.  Water quenching is quicker and gives a rather softer copper".

Best Regards
Title: Re: Annealing copper head gaskets
Post by: Jules on 11.07. 2020 02:54
I just read this post, because I'm still focused on the frame and gearbox rebuild right now, however, I'm intrigued - it seems (from this post), that annealing the head gasket is "required" prior to refitting, which I can understand after years of use then reusing, but why would you anneal a brand new one??
AND, on the topic of head gaskets I read a post some time back that made reference to a co. that made various thickness copper head gaskets, I've tried searching but cant find it, can somebody put me onto that please?? The reason I ask is that I rebuilt the Golden Flash engine many (many!) years ago and its been sitting ever since, and back then the only new pistons I could find were HC, which I didn't want but had no choice. Then recently I read a post about various thickness head gaskets to reduce CR, hence the question....thanks
Title: Re: Annealing copper head gaskets
Post by: KiwiGF on 11.07. 2020 07:13
I just read this post, because I'm still focused on the frame and gearbox rebuild right now, however, I'm intrigued - it seems (from this post), that annealing the head gasket is "required" prior to refitting, which I can understand after years of use then reusing, but why would you anneal a brand new one??
AND, on the topic of head gaskets I read a post some time back that made reference to a co. that made various thickness copper head gaskets, I've tried searching but cant find it, can somebody put me onto that please?? The reason I ask is that I rebuilt the Golden Flash engine many (many!) years ago and its been sitting ever since, and back then the only new pistons I could find were HC, which I didn't want but had no choice. Then recently I read a post about various thickness head gaskets to reduce CR, hence the question....thanks

A used solid gasket will have been work hardened by the action of being compressed by head bolts. They can be re-used multiple times as I guess they (permanently) compress very little each time they get used.

A new solid gasket may be soft but more likely will be supplied work hardened by the action of the raw material its made from being rolled to thickness, or maybe when its stamped out, I’ve only bought a few solid copper gaskets and they were all supplied in a hardened or semi hardened state.

A properly annealed gasket can be easily bent between two fingers and has no “springinesss” in it at all, it stays bent without any spring back.
Title: Re: Annealing copper head gaskets
Post by: Swarfcut on 11.07. 2020 08:08
  Jules. Cylinder base compression plates are available, but whether raising the barrel affects the valve timing to any detrimental effect is probably academic for now. Just nice to get it running without too much hassle.

 Swarfy.
Title: Re: Annealing copper head gaskets
Post by: Jules on 11.07. 2020 12:40
Hi Swarfy, raising the barrels is an interesting alternative, I hadn't thought of that - probably because all my life has been spent on cars, which only has the block/head interface. Probably need to be a bit careful though because the barrels on the old models (mine) were a bit prone to failure due to the small thickness flange, if I remember correctly....
The barrel plates could be steel too which would be good down there, any idea who would sell them, did they have a part no. or were they just aftermarket?? cheers
Title: Re: Annealing copper head gaskets
Post by: JulianS on 11.07. 2020 13:35
Ebor motorcycle sell compression plates;

https://eborbikes.com/index.php?route=product/product&path=62&product_id=60

If you use one just make sure that the exhaust cam followers still actual touch the cam base circle. The slot in some pattern followers is not quite as long as the original BSA part.
Title: Re: Annealing copper head gaskets
Post by: Swarfcut on 11.07. 2020 13:43
 Jules. A Google search will bring up numerous suppliers, generally specialist solid gasket  guys knocking them out with modern laser cutters.  The snag with raising the barrel is that it alters the cam/follower relationship, also too thick will have the followers knocking on the follower retainers rather than following the back of the cam, as mentioned by Julian.

 The forum has details of how other folks approached the problem, and some of the pitfalls to what should be a simple exercise. The favoured alternative being a thicker custom head gasket. Plenty of posts and actual experiences of what works best. Your part of the world seems well served for custom stuff, and  recommended  suppliers are mentioned.

 Swarfy.
Title: Re: Annealing copper head gaskets
Post by: muskrat on 11.07. 2020 20:31
G'day Jules.
At 0.9mm the Ebor plates would be safe if everything is standard (cases/barrel flange not decked). I found anything over 1.5mm and you get the problem Swarfy describes.
Lani at Copper Gaskets Unlimited https://coppergaskets.us/ make gaskets in varying thickness 0.016" to 0.125". He even has a template for my special gaskets for my through bolted head/barrels. Reminds me to order more.
The beauty of a compression plate is the pushrod/rocker angles remain the same. With a thicker head gasket (especially if going extreme) the pushrods should be longer by the same amount.
Cheers
Title: Re: Annealing copper head gaskets
Post by: Jules on 12.07. 2020 02:36
thanks all, I think the Ebor plate will do the job, just need to find my old CR calcs  from years back when I did the engine build (I think its around 8.5 ish) *eek*..
I remember at the time that I changed the cam too because my std cam was well worn and a friend offered me a lesser worn RR or SR cam (don't know which, if they are different?), lesser worn meaning the peak lift was a bit down, but rest of lobe/bearings were good.
What are your thoughts on how best to setup timing etc since the rest of the engine is stock, iron head '56 Flash??
PS I know that all this is far from ideal but as long as it starts easily and runs smoothly, performance is what it is, its only for comfortable cruising really.....cheers
Title: Re: Annealing copper head gaskets
Post by: Colsbeeza on 12.07. 2020 23:29
A fault I noticed after dismantling my Flash was that the old copper head gasket had punch overflow (for want of a better description). I dremelled it off before annealing.
This fault must have affected the head seal.
Col
Title: Re: Annealing copper head gaskets
Post by: bikerboy on 26.09. 2020 14:41
Firstly in my experience the thin flange barrels are fine provided the head steady is fitted properly and provided you are not going up to 10.5 to 1 compression ratio.

Secondly (ok I was young and foolish then) I had a similar issue when I was young and just fitted 2 head gaskets. They were both solid copper and properly annealed and that bike was on the road and used daily for about 15 years without any problems.

Before you all tell me what a cowboy I was  *smiley4* let us remember that this was back in the 70's, I had no money and even if I had of compression plates were not even in existence, well not in my part of the world anyway.

In those days you just got the damned bike running so that you could tear about like a lunatic with your mates :)
Title: Re: Annealing copper head gaskets
Post by: BSA_54A10 on 02.10. 2020 11:53
You do not want a mixture of metals at any joint face if possible, paticularly a hard metal like steel .
That way you have 3 different expansion & contraction rates to try and seal to prevent leaking at the crank case mouth.
So either use a soft thick copper gasket which will deform to keep a good seal or an aluminium spacer which will deform a little less but expand at a very close rate to the casting.