aluminium welding

[Paranoid Dave]

Can anyone tell me if anodised ali will make a difference when welding it?
I want to get a couple of bits welded, no problem they say, but I have to find out if they can do it to a bit that's been anodised or should I sand, file the top layer off.

I thought as its a chemical process to change the colour of the metal and not a coating then it won't make a difference.

Anyone give me a yes or no answer?

Thanks
PD

[claicerrig]

Dave

Cleaner the weld the better for alumimium .We weld Aluminium all the time that has been Anodised and we find the cleaner the two surfaces are the better the weld apperance and less likly to fail

Hope this helps

Clai

[Paranoid Dave]

thanks for that, but just clarify when you say clean..

do you mean so long as its washed and degreased type clean or I'm better to file back beyond the anodising to a clean bit of ali?

Sorry to be a pain. :confused:

[Didge]

Dave, I know bog-all about welding, but anodising is the process where the aluminium's oxidised surface is dyed, and not the metal itself, therefore I would imagine he means bare metal surface.
I'm sure he'll correct me on that if I'm wrong, and I'd be interested to know this for sure.
So come on claicerrig, you aluminium welding Gog git....what's the answer.

[BoozyBOB]

you need the joint to be as clean as pos...
if the Aly has a coloured anodise it just turns black and is not a very strong joint...(as it will contain impurities)...
Bob the welder....enough of work...its the weekend....the pub is open!!!

[claicerrig]

Sorry for the slight delay folks :o :o

Hi Didge !!!! :D :D

The Ans is :-

CLEAN BRIGHT BARE METAL

As Bob says with Aluminium any impurites/ paint/ oil`s/ grease or oxides (Rust to you Didge) left on the joint surface will result in a very poor fragile weld

My advice is get it clean and shiny on both faces using files/wire wool etc and dont even use your finger to touch the area because you will leave a film that can impeade the weld (Aluminium is very sensative to stuff like that)

This advice should really be used on all surfaces to be welded stainless/steel/iron and things like soldering etc any one who has welded rust car bodies or painted sections of steel will know how hard it is next to two clean unmarked plates of steel

Hope this helps everyone

Clai

[DesmoDom]

My two penneth,

You had best make sure that the edges to be welded are filed/ground to an angle (V) to give the biggest possible surface area for the filling metal, which should be of the same type as the original part, to prevent heat stress cracks, as they will melt at the same temperature.
Another reason to have the edges to be welded clean, is that Aluminium oxidization has a melting point of around 2000 Deg C, where as the Aluminium itself, only has a melting point of 659 Deg C. (think about it)
So I should imagine any surface treatment like an anodised finish, would have a similar effect as oxidisation.

Errrr I think ???? :confused: :confused: :D

Baz

[A Yerbury]

he's a regular rhubarb...or custard. the one with the shed. what are you up to now p diddley?

[claicerrig]

Correct Baz :D :D

We weld Anodised Aluminium (I know this sounds crazy Aluminum Casting Moulds ) all the time so i get to see the effects of poor weld preparation coz the moulds are Annodised to prevent oxidisation during casting

I used to work in the mould repair shop in an Aluminium Smelter before i got moved up stairs :(

[DesmoDom]

Wey Hey !!!!!, I got something right for a change, I must have been listening that day at college, when I was doing my apprenticeship :D :D :D

Baz

[Nonnie]

he's a regular rhubarb...or custard. the one with the shed. what are you up to now p diddley?
You wouldn't believe it but I've been measuring the angle of the rear of the frame using baked beans and a piece of cardboard this evening for him. Is there no let up?

[A Yerbury]

I hope it is worth it, he needs a bigger engine but there is no telling the lad. he knows his onions though, or is it beans?
toodle pippins.
your long lost uncle cortnelius.

[Paranoid Dave]

Alex - all in good time, you'll just have to wait and see. :D

[Fodder]

Wey Hey !!!!!, I got something right for a change, I must have been listening that day at college, when I was doing my apprenticeship :D :D :D

Baz



Oooooh did they make you weld two ally plates together with an oxy acetylene torch, that was a skill that very few mastered. It's all shielded electric now sir, still tricky but much easier. :D

[DesmoDom]

Yeah Simon, I was one of those who never mastered gas welding aluminium, it usually ended up with either clouds of ali flakes floating around the workshop, or a pool of ali on the floor. :D :D :D
TIG welding, tricky but a million times easier than gas, I can braze stuff though ;) ;) :D

Baz

[claicerrig]

Baz its all about getting the flame right :eek: :eek:
I can do it but not very well (gas Weld Ali):(
We have some artists in the TIG welding Dept :cool:
They welded up a primary drive cover from sratch for a (sorry for swearing HD :o ) last week
When it went to get machined the machinists said there was no warping at alll !!!