Copper Tube

[fry61]

Hi all, I have made several parts of my cooling pipework from standard copper tube--I have brazed(welded) all joints with 93/7 copper/phosporous rods as ordinary solder goes pasty at 100'C + & silver solder is SO expensive. Question is due to very high heat required in jointing the resultant job is very soft even when allowed to cool normally in still air; now comes the Q.? if you're still awake--- how do I restore the copper to "normal" hardness---or don't you?

Awaiting your wisdom, regards Bob.

[Guest salty_monk]

With Steel you would get it hot & "quench" it... no idea with copper, might be the same... get it hot & dunk it in cold water (used engine oil is better for steel, not sure about copper).

 

Dan

[Guest robin]

if i remember rightly that is correct. anneal by heating until cherry red then dunk in cold water. watch you dont rewet the joints though.

robin

[Guest robin]

doesn't your login name suggest you should know this?!

robin

[Longboarder]

ordinary solder goes pasty at 100'C

Are you sure? I thought it was just over 200C. My cooling system consists of part mondeo rubber and part B&Q's finest copper with several 90 degree bends and one T-piece all held together with the same flux cored solder I used to do the wiring loom. I don't think it's having any pasty moments. I hope it's not! There are many kitcar builds with ordinary solder joining copper pipes and I haven't heard of problems.

 

Nigel

[Graham B]

Maybe the "plumber" will respond ..

 

Sorry Graham

 

 

Graham B

[Bob Tucker]

My original Pinto engine was plumbed with several ingenious soldered copper joints.

It got pretty hot at LeMans over several years, and actually boiled up

at a Brands track day when I got a bit carried away (30 laps, B*&*s out, just over 35minutes).

Luckily it did it when I parked up in the pits garage.

But never any problems with the copper soldered pipes.

HTH Bob

[Guest peter2b2002]

just done a quick google, soft solder melts @ 190deg or there abouts so you should be OK

peter2b

[Guest Tweedy]

Hi,the only way to harden copper (and most non-ferrous metals )is by work hardening,typically rolling or drawing.Quenching softens it which is the opposite effect from alloy steels.

[miikae]

I have read somewhere that viberation hardends copper , like bead blasting or even hanging in front of a speaker as that is supposed to work also , if thats the case then a good talking/shouting at it should do it !

 

Mike

[Redspec]

I have read somewhere that viberation hardends copper , like bead blasting or even hanging in front of a speaker as that is supposed to work also , if thats the case then a good talking/shouting at it should do it !

 

Mike

 

 

Or put it in the hood and take it for a spin with the shocks set at max

[Guest gdc]

copper pipes and joints will work in cooling systems for cars . the temps are well whithin the limits for the tube and soldired joints .

dont use copper for the exhaugst it emitts a toxic gas when overly heated .

if using tube , and to joint to rubber , soldier an olive to the tube and put the rubber over it to stop the rubber tube blowing off . plain tube is ok when cold but when hot the rubber will blow off if no olive is fitted. ch plate copper clean off the ch plate first then soldier the olive on then jublie the rubber to it .

 

graham

[fry61]

Thanks for all the replies; it is more than likely this old fool got his Farenhiet & Centigrade scales & memories of solder melt temps mixed---so don't rely on it as you age!! Florin Metal Works is a hobby name used by me & a mate-- also Bob =built by 2 Bobs AKA 2 shillings=Florin for those too young for pounds,shillings & pence. So my brazed copper joints are probably OTT but I still need to know if I should (or can) re-harden the copper.Earlier posts saying quench in water are wrong--copper is annealled when cooled rapidly & I don't know what frequency sound or engine vibration would cause the required "hardening" So more posts please; even the silly ones may help pass the evening. Regards Bob.

[Guest Jaffer]

A bit late now to respond I guess, but I would have thought copper items on a car would be better for being annealled, rather than too hard which may tend to form stress cracks.... most plumbing copper these days is know as 'half hard' anyway.... I believe because its more of a copper based alloy rather than the proper copper pipe you used to get. It certainly doesn't spring bend as well as the old stuff!

 

Jaff

[fry61]

Thanks Jaffa, takes a while for news to reach those far-off places I suppose---was looking to return the copper to half-hard--as per "new" tube 'cause after cooking to braizing temp its very soft--you can almost leave finger-prints in it--I have tried to use older (2nd hand) stock where poss. as it's thicker wall--not the bend it & create a razor-blade stuff you get to-day.