Aluminium braizing

[myne]

I dont suppose anyone knows where to get the alloy braizing gear (adelaide preferably)

Has anyone got any experience with it?

I plan to braize 3mm plate, I have a little experience a long long time ago braizing steel and I plan to practice a bit, but any tips?

[Ben Wilson]

Never tried brazing aluminium, but your problem is going to be the same as welding it with an oxy. The stuff sinks heat really well, you basically need to get the whole lot up to temperature before you start. It also doesn't get that nice colour change going on like steel.

I'm sure it can be done though, with practice.

[merc-blue]

i have some special alloy brazing/soldering stuff, is that what you plan on using instead of traditional "brazing rod"
it works with just a LP torch although easyer with oxy,
deffently can be done with practice, infact have done some quick patch up jobs with a jet lighter

[Zerko]

Funny, I was about to attempt this too.

Attempting to make an air filter adapter with sheet alum.

This is what the GFs dad says (he has fixed his boat and done other small jobs):
- Make sure the surfaces are really clean. Use emery cloth to clean up the join areas.
- Get the surfaces hot and even with a torch. As said before, you wont see a colour change, like with steel.
- Use the proper aluminum/alloy brazing rods. These will set harder than the alum you are working with. No need for flux if the surfaces are clean enough. It will just flow.

Good luck with it. Pics when done??

[Ben Wilson]

To clean alow prior to welding or brazing, us a stainless wire brush and acetone, emery cloth will leave deposits on the surface which would contaminate the weld/braze.

[takai]

Hm, i might have to give this a go sometime, sounds interesting.
Common places to source the brazing rods?

[merc-blue]

i got mine from a boating show for repairing tinnys, worked fine on sheet, although one hard grade (cant remember what it was but it was damn tough ally) didnt like it very much, it worked but wasnt as strong as others

[SL666]

ally brazing isn't particularly strong, and generally doesn't look that good..

[Ben Wilson]

Why would it be any weaker than any other brazing? Assuming it can get inside the granular structure - I can't remember my metallurgy well enough..

[Zerko]

To clean alow prior to welding or brazing, us a stainless wire brush and acetone, emery cloth will leave deposits on the surface which would contaminate the weld/braze.

Yes, good point. GF's dad didn't say to do this, I just added it, but yeah, at least clean it with acetone.

[TA22 GT]

The bst option is to use a TIG welder. Brazing will not only look average it won't be too strong either.

TIG welding aluminum takes a bit of practice as it takes alot of heat and can easily collapse if your not careful, its much harder than welding stainless or mild steel.

Hope this hleps,
Simon

[ReQuieM]

Screw brazing just weld it. Acetone is a must. If you weld flux is a must. otherwise you just end up with a oxidised skin that wont allow pooling. It'll deform before it pools. Heat first with the torch then whipe on the flux. Also aways sit/clamp it on metal, I'l found anyway. If you haven't done it before get lots of scrap! It takes a bit to master. I'm going to do a mini write up on how to 'lip' aluminum piping for intercooling probably at the end of the week end, if your interested.

[ReQuieM]

BTW I'm using a LPG gas welding kit that I got off ebay. Not bad quality but you can get one from 'supagas' for similar price, maybe $50 MORE, and from what i've seen they look pretty good. oxy only tho.

[merc-blue]

gassless welding is a joke, only in emergency will i ever use a gasless mig or tig welder after using the gassed style im never going back

[30psi 4agte]

yeah i have a couple of them rods .

They are designed for thin alloy and only need a small amount of heat to use them. ( great for fixing factory thin IC tubes )

They can hold a 1000 psi or something crazy like that !
Sorry but cant remember where i got em.