# Spotwelding aluminum



## ome (Dec 10, 2013)

Hi Guys,
i was experimenting with my 220 joyal benchtop spotwelder with some 1/16 aluminum. 
I got the best welds when i took 2 pieces of 1/16 " steel and put one one each side of the aluminum under the electrode. 
Works like a charm, only spotwelds the aluminum together and not the steel to aluminum. 
Jon


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## xalky (Dec 10, 2013)

Interesting...What happened when you tried spotting the aluminum direct? I've never tried spot welding aluminum, so I'm curious. When cleaning the aluminum to spot weld, use only a stainless steel wire brush and mark it for "for aluminum only", so as not to contaminate the weld area with other crap. Then wipe the weld area with acetone for a real good clean, this will remove the oxidation and oils that might be on the weld area. Aluminum oxidizes fairly quickly, so clean as much as you can spot weld at one sitting. Anything left overnight should be cleaned again. The methods given are for tig welding aluminum, but should also work well for spot welding.


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## ome (Dec 10, 2013)

Nothing happened at all.  It was wierd, and unexpected, but until I put those 2 pieces of steel, worked like a charm.

Jon


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## Rbeckett (Dec 10, 2013)

Are the welds truly fused?  I would love to see a sample of the result because I tend to think that the metal is probably not completely fused and would yield a weak weld that will fail if placed in sheer.  Ive actually never even heard of spot welding alli like your doing either.  Most of the time Alli is tigged with AC and high frequency. Could you possibly cut through the middle of a weld and get a good close up?  Very interesting concept though.

Bob


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## ome (Dec 10, 2013)

I will try to cut it, but have limited cutting tools , but i tried to bend it and pull it apart with no success, seems strong. 
Jon


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## legacyiron101 (Jan 26, 2014)

may want to use a couple scraps of stainless instead of reg steel for the same reasons that you use a stainless brush when doing tig....the spotwelds themselves will be plenty strong but theres no reason to risk iron or iron oxide inclusions and be sure and use more spot welds then you would for an identical steel peice..aluminum is far more prone to cracking around the HAZ then steel especially if its 6061 which seems to be the most common aluminum sheet found in most shops.One of the reasons that a lot of body shops and custom sheet metal places that do a lot of work with aluminum have started to go back to the old school way of welding it with flux and an oxy/acetylene rig...it takes more skill and more time but it leaves the joint and the surrounding metal less prone to cracking then a tig torch especialy if the area is to be further worked.


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## TOOLMASTER (Jan 26, 2014)

the aluminum absorbs all the heat from the steel


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## David Kirtley (Jan 26, 2014)

There is a demo of this on youtube. 

[video=youtube_share;gcgC3V3mkcw]http://youtu.be/gcgC3V3mkcw[/video]


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## TOOLMASTER (Jan 26, 2014)

you can see the thin steel band run through the machine every weld here.
https://www.youtube.com/watch?v=-amPG_FxUXo


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## SE18 (Jan 29, 2014)

A couple weeks ago, a neighbor down the street built a spot welder very similar to the one I built (from a microwave transformer). It runs on 125v normal US current, not 220V like they say you need in the video. He did some experiments with sandwiching aluminum between ferrous and said he could spot weld. If I have time this weekend I might try it, but my spot welder needs some tuning up first.


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## george wilson (Jan 29, 2014)

Aluminum  oxidizes instantly. But,the oxide is transparent,and protects the metal under it, so it SEEMS to resist oxidation.


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## SE18 (Feb 6, 2014)

my experiment with alum didn't work. I think what George says that alum oxidizes instantly is the reason.

BTW, I got my spot welder to work a lot better by putting a new copper connector on it. Also, I think it's important to clean off any coatings. I tried spot welding coat hangers and nails and found that some of them need to be sanded because they have nasty gooey coatings


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## SE18 (Feb 11, 2014)

I'm back! I added a handle from a second microwave I got and dismantled for another project
	

		
			
		

		
	






I wondered if it would do resistance soldering of brass and copper so I took a 4ga copper wire and a brass housekey and in just 1 or 2 seconds it created enough heat to solder the 2 parts fast


I got a switch on back of the unit and added a foot pedal today. The pedal, from Horrible freight, is the worst kind to get IMO. I thought it stops power when foot removed (fail-safe), but it doesn't. You have to tap it again. Another HF model is the fail safe kind. I got it on impulse buy without realizing and it would take several hours driving to return it so it stays




(warning about microwaves: short the capacitor as it could carry a lethal charge. Also ensure it's not plugged in. Also, the magnetron has 2 nice magnets in it but breaking the fluids surrounding them could kill. Also, in making the wood parts, if you slip and fall into the table saw, that could be lethal, as could slipping on the ice outside)


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## Marco Bernardini (May 4, 2014)

SE18 said:


> A couple weeks ago, a neighbor down the street built a spot welder very similar to the one I built (from a microwave transformer). It runs on 125v normal US current, not 220V like they say you need in the video.



In Europe household power is 220V/50Hz (actually 230V) single phase instead of 110v/60Hz.
In the video Lazze told about the trick coming from an old Italian guy, so probably he intended 220V as "normal household power".
BTW, our three phase is 400V, even if almost everybody still call it "380V" according to the old value.


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