Best way to anneal aluminium?

[Monrovian]

Hello,

I want a decent torch for annealing aluminium. I have no real need for a full oxy / acet other than for this purpose. I have seen the build off guys blacking the alu and then burning off to make it pliable for bending. Can i get anough heat in from a propane set up or something similar.

I would also use it for heating larger jobs before welding.

Also how would i know when the temperature was correct and should i quench or leave to cool naturally. I have used old soap bars smearen on in the past and heated until they turned black. But not exactly that accurate i wouldnt think!!!

Any help appreciated.

 

[English Steve]

Oxy-Propane should give plenty enough heat for that application. Don't quench - that will harden the material again.

I'm a bit out of date here, but patches were available which you stick on the metal, and which change colour when a set temperature is reached. I seem to remember that crayons which do the same thing used to be available. Your welding supplier should be able to point you in the right direction, but you will need to know what temperature you require.

Anyone got more up-to-date info?

Steve

 

[Monrovian]

Cheers - anyone know where crayons are available?

Also where can i get oxy propane and do m/mart do a torch that is suitable?

 

[rtbcomp]

I've heard of the soap thing too. It's quite common so it will probably be accurate enough.

Wouldn't propane on its own be hot enough? Machine Mart do a nice little propane torch kit for about £16.00 - include torch, several nozzles and a regulator.

 

[^neo^]

If it's only thin stuff, you'll get it hot enough with a blow lamp.
As above, if you rub soap on it before you start (cheapest stuff you can find) when it goes black it's annealed.

 

[Unclefista]

I've annealed sheet alu (just parts not the whole sheet) using a B&Q butane torch and soap, I was quite dubious about it, but worked well.

 

[English Steve]

I would also use it for heating larger jobs before welding.

is why I suggested oxy-propane. If only aluminium is involved, then I would agree with the blowlamp suggestion.

Steve

 

[runnach]

Apart from soap, you can also use a simple piece of wood, you look for the same result as soap, heat the ali up, rub with wood, turns black, tis annealed temp, simple really!

These crayons, are we talking about templesticks?

 

[snowcat]

These crayons, are we talking about templesticks?

like this perchance??

 

[rusty69bus]

washing up liquid as shown on tv 'build a 4x4 by vet'

 

[Monrovian]

thanks for the info - where can i get a templestick?

rust69bus - how does the washing up liquid thing work?

 

[Monrovian]

Also what temperature stick do you need to anneal aluminium?

And does anyone know whether to quench or leave to air cool?

 

[^neo^]

don't quench it, just leave it to cool on it's own

 

[Monrovian]

just found templesticks on uk welder site £10.50 each - just need to know temp required now?

 

[English Steve]

Looked through the Machinery's Handbook and Kempes Engineers Yearbook for annealing temperatures during lunch, no luck i'm afraid.

Steve

 

[snowcat]

just found templesticks on uk welder site £10.50 each - just need to know temp required now?

just a question what are you annealing it for???

Also you need to know the grade of material for the correct temprtures, acording to an old AWS book I have....

 

[Monrovian]

Looked through the Machinery's Handbook and Kempes Engineers Yearbook for annealing temperatures during lunch, no luck i'm afraid.

Steve

Well you always have tomorrow lunch!

Only kidding - appreciate you dedicated your lunch to my cause.

 

[Monrovian]

just a question what are you annealing it for???

Also you need to know the grade of material for the correct temprtures, acording to an old AWS book I have....

I anneal alu sheet before bending to avoid cracking.

 

[runnach]

like this perchance??


View attachment 3292

Yep thats the ones Snowie, not used to them being referred to as crayons tho! I had a rake of them, chucked them out as I no longer had a use for them.

Cheers......

 

[runnach]

I anneal alu sheet before bending to avoid cracking.

Only time I ever had cause to anneal al/al was when folding marine grade al/al, 7000 series I think? Folding with the grain it did cause cracks, annealing sorted this out. What grade are you folding and thickness, also perhaps you do not have the appropriate size Vee and blade?