plug weld

[The Buddah]

Hello,

Has anybody tried plug welding two pieces of steel with an ali plate between?

Ie, drill holes in a steel section then drill the same size hole in a ali section, put the ali between the two steel sections then plug weld.

Does this work?

 

[Wozzaaah]

The ali will most likely spit and fart and contaminate the weld but if you drill the hole in the ali bigger than the one in the steel you may get away with it.
Worth a try on some scrap to see what happens.

 

[Windy Miller]

What's this for? Do you have a specific requirement for an ally sandwich like this? Sounds like a perfect situation for some galvanitic (sp?) action.

You would need to make the hole on the ally much larger, and then hammer the steel down through the ally hole so it touches the other steel sheet then plug weld it.

Still wondering why you would want to do this though?

Edit:
Woz beat me to it. Damn slow iPhones!

 

[The Buddah]

I was thinking of way to fix ali panel to a steel panel and the sandwich could be where they meet.

 

[cecotto479]

Sounds like a recipe for electrolytic corrosion that would do Land Rover proud.

 

[The Buddah]

mmm doesn't sound to good.

 

[pedrobedro]

Can't you use rivets or put a couple of plastic washers either side of the aluminium and bolt it ? You're going to destroy the aluminium welding steel through it. The problem is galvanic reaction and heating it is going to accelerate the process most likely.

 

[The Buddah]

I need to repair the outer wing on my discovery as its loose, at some point there will be ali touching metal. Trying to secure the ali outer wing to a inner wing or metal wheel arch......rrrrr, i think i have it!

Use rubber washers between the ali and the steel, that way the outer wing should be ok to secure with a steel bracket to the wheel arch.

But there will still be contact of ali and steel where the rivets meet either the ali body or the steel bracket....

Im going round in circles here.

 

[the snooper]

if you are going to do this make the holes in the ally bigger and insert a washer of the same thickness so the weld will only encounter steel

 

[The Buddah]

I'm learning from your remarks which is good new for the old newbieeeee....lol

Thank you all for help and comments.

 

[ibrooks]

Steel in electrical contact with ally is a recipe for the ally turning into white powder. Where you need a fastening the only real solution is to make sure the steel is painted first to avoid it touching the ally directly and where any fastener is likely to cut through or otherwise disturb the paint dunk the fastener in paint or similar before you apply it (still wet) and then slap more paint over the top afterwards to try to keep any electrolyte (water) out. Ideally you also need to account for the parts moving against each other in an automotive situation so a final application of some sort of flexible sealer over the joint is necessary (a water repellant with a creeping action would also do but these tend to be oily so make painting at a later date difficult).

Iain

 

[zx9]

Steel in electrical contact with ally is a recipe for the ally turning into white powder. Where you need a fastening the only real solution is to make sure the steel is painted first to avoid it touching the ally directly and where any fastener is likely to cut through or otherwise disturb the paint dunk the fastener in paint or similar before you apply it (still wet) and then slap more paint over the top afterwards to try to keep any electrolyte (water) out. Ideally you also need to account for the parts moving against each other in an automotive situation so a final application of some sort of flexible sealer over the joint is necessary (a water repellant with a creeping action would also do but these tend to be oily so make painting at a later date difficult).

Iain

Iain has described how Landrover fitted the wings to my early classic, painted both sides to seal the alloy and sitting on a bead of non setting sealer. The bolts are through oversize holes to allow for positioning a side effect would be to reduce the tendency for the bolt threads to cut into the alloy wing. My near side wing had almost undamaged original paint (under the carp respray) and is in much better condition than the off side which has had some bad repair work done and is now a mess of fluffy white corrosion around the mounting bolts.

 

[norsa]

if you are going to do this make the holes in the ally bigger and insert a washer of the same thickness so the weld will only encounter steel

I take my hat off to you. Pure class through experience.

 

[Wozzaaah]

Another issue I see with this is that you normally drill or punch holes in one sheet, push that sheet tightly onto the other and weld it.
Now you have two holes to line up, you have to hold both pieces tightly to the 'parent' one then fill the hole. Once you've done the first weld you've no way of adjusting the ali sheet if it moves....which it will.

 

[The Buddah]

I think i'll go for "L" shaped bracket with a piece of rubber between, drill some holes in the ali then brush holes with pain and fix together with rivets. Cover the rivets on the outer side of the body with some chequered plate.

 

[the snooper]

I take my hat off to you. Pure class through experience.

there is more then one way to skin a cat

 

[The Buddah]

well,

This is where i'm at:

Ali repair for rear wing return with ali cleats made from scrap and riveted.

I will put a small rubber barrier between the new ali section and the box section rock sliders when they are welded on