Author Topic: problems welding aluminium  (Read 2672 times)

Offline dawesy

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problems welding aluminium
« on: June 09, 2014, 03:59:02 PM »
can anyone give me some advice.
doing some modifications on my car and i needed to cap off an alloy mount for the standard oil to water oil cooler which i have removed.
i cut a cap from some 1mm alloy sheet and set to tig welding it ( i cleaned with acetone first and dressed the face to clean metal) when i started welding i noticed that it did not weld very easily it became porous (the same as mig welding steel with poor gas coverage).
now i have heard that toyota used magnesium/ aluminium mix for some of its alloy casting and wondered if that is what this could be?
i know that the oil can seep into the casting but unsure if this would cause the 'aero' effect i have.
ive decided to turn a new mount out of alloy and fit that, just interested in what could have caused the problems i experienced.
thanks in advance.
Lee.
wishing my workshop was larger :(

Offline awemawson

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Re: problems welding aluminium
« Reply #1 on: June 09, 2014, 04:35:36 PM »
Send me a suitable sample and I'll use my Analoy alloy analyser on it for you
Andrew Mawson
East Sussex

Offline ieezitin

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Re: problems welding aluminium
« Reply #2 on: June 09, 2014, 05:44:29 PM »
Hello..

you sound to me you have a clue about welding but i will go over a little basics.

Especially Tig process needs to be clean and for aluminum super clean, the tungsten, cup, gas even the surrounding atmosphere should all be looked at, that's just to get the right environment, next the alloys in a simple world should have to match, i used to make copies of exotic racing motorcycle tanks from scratch all from 16 gage plate and i cut from the plate the wire to weld them to over come this problem tig or gas welding.

Its why you cant really weld a cast iron engine block, the block is made from pig iron and you dont know what the mixture is, its achievable but just makes your life so bloody hard.

Try it with a 50/50 mix of argon/helium Its cleaner....... back yonder thats all they welded with thats why they call it Heliarc... Try The 2% thoriated electrodes Pure tungsten dont cut it. Ball it up on the stone slightly nature will do the rest.

Syncrowave with a AC fine tune on your rig, if you dont have one get one there cheap now.

Stand next to a microwave for 3 minutes and you will get more radiation than using thoriated electrodes, so dont worry about it.

I think you will stand a chance if you do what i suggested.

Hope this helps and let us know how you get on...

All the best.   Anthony.

If you cant fix it, get another hobby.

Offline PekkaNF

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Re: problems welding aluminium
« Reply #3 on: June 10, 2014, 02:16:16 AM »
All previous sounds very good.

Just one more anecdote, which I'm not sure if this relevant here, but this har worked few times:

My brother had problem welding together aluminium audi gear box and ford coupling bell, it lookked very porous with grey froth and all. Then he preheated the parts well over 100C, probably closer to 200C and cleaned all weldable seams just seconds before welding one more go with new cleaned stainless steel wire brush. It worked out really well.

Pekka

Offline dawesy

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Re: problems welding aluminium
« Reply #4 on: June 10, 2014, 02:18:34 PM »
Thanks for the replies guys.
Andrew I might take you up on that offer.
Anthony yeah I know my way around welding, just a little new to alloy. I'm using thoriated electrodes and the parts were very clean. Welded a few cast alloy parts and this is the first time I've had this issue.
Pekka that's a useful tip I'll remember that one ;)
Lee.
wishing my workshop was larger :(

Offline awemawson

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Re: problems welding aluminium
« Reply #5 on: June 10, 2014, 03:06:10 PM »
Lee,

I've PM'd you my address

Andrew
Andrew Mawson
East Sussex

Offline dawesy

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Re: problems welding aluminium
« Reply #6 on: June 11, 2014, 02:57:51 AM »
Cheers Andrew. I'll get it off to you when I've take the measurements i need to make the replacement ;)
Lee.
wishing my workshop was larger :(