Aluminium welding table

[Pilgrim22]

Ive just been given an Ally plate 1m x1m x10mm with a grid of M6 holes every 50mm. Any reason why i shouldn't use this as the top of a welding table? The hole grid is appealing for clamping etc.

I have a Stealth 200 AC/ DC and weld steels as well as ally.

 

[Morrisman]

6mm holes aren’t of much use really, unless you are doing some very small work. And being ally it will be easy to burr over or damage the threads, or destroy with an errant arc. Might be good for delicate Tig assembly welding though.

 

[Pilgrim22]

Most of my stuff is small steel TIG. The fact it was an ally plate will be in 'the loop' was my concern really

 

[Dr.Al]

I'm not sure I'd want to use it as a main welding bench: it'll probably get damaged quite quickly and those little threads could get damaged (although they'd be easy enough to clean up with a tap I guess). I've got a small aluminium plate (about 20 mm thick and with a grid of 8 mm reamed holes and M8 tapped holes on a 20 mm pitch) that I use as a fixture plate for tacking stuff together; I then take the parts off the plate and complete the welding elsewhere. Your plate would probably work very well for that sort of purpose (especially if the holes are on an accurate grid). You can see some pictures of my little plate being used here.

Aluminium is a good conductor (better than steel), so it won't have any effect on the welding current path. If you don't have a good connection between the part being welded and the aluminium plate then any sparking is likely to damage the plate quite quickly.

 

[Morrisman]

Most of my stuff is small steel TIG. The fact it was an ally plate will be in 'the loop' was my concern really

I’m sure it would work quite happily as your earth link for anything clamped to it. Ally is a better conductor than copper, it’s used in them big overhead power-lines I believe.

 

[Dr.Al]

Ally is a better conductor than copper.

Not true. Aluminium is a very good conductor, but not as good as copper. Aluminium's resistivity is about 26 μΩm; copper's is about 17 μΩm; steel's is about 100 μΩm and silver's is about 16 μΩm. So silver is the best, copper is very very good, aluminium is good and steel is pretty awful by comparison.

Having said that, with the cross-sectional area of your aluminium plate, the resistivity is largely academic.

 

[Pilgrim22]

thanks for the information guys.

 

[JMS1972]

Ive just been given an Ally plate 1m x1m x10mm with a grid of M6 holes every 50mm. Any reason why i shouldn't use this as the top of a welding table? The hole grid is appealing for clamping etc.

I have a Stealth 200 AC/ DC and weld steels as well as ally.

Sounds like it would make a number brilliant sub-table or fixture table for machining (pallet?)

You could cut it up and flog it on eBay...

Pardon our interruption...

 

[tom2207]

be very nice sitting on top of a steel bench for fine work though.

 

[Dr.Al]

Sounds like it would make a number brilliant sub-table or fixture table for machining (pallet?)

You could cut it up and flog it on eBay...

Pardon our interruption...

Eep that's expensive! Mine is quite a bit smaller (about 300 mm × 200 mm × 20 mm at a complete guess) and came out of a skip (I drilled the holes myself).

 

[JMS1972]

Eep that's expensive! Mine is quite a bit smaller (about 300 mm × 200 mm × 20 mm at a complete guess) and came out of a skip (I drilled the holes myself).

I think its the holes that cost the money

 

[fizzy]

Not true. Aluminium is a very good conductor, but not as good as copper. Aluminium's resistivity is about 26 μΩm; copper's is about 17 μΩm; steel's is about 100 μΩm and silver's is about 16 μΩm. So silver is the best, copper is very very good, aluminium is good and steel is pretty awful by comparison.

Having said that, with the cross-sectional area of your aluminium plate, the resistivity is largely academic.

Indeed so.
You forgot to mention Gold! Surprisingly not as good as copper and silver but better than aluminium. Of course it never tarnishes so after time it will be the best conductor.
The ultimate welding table

 

[Kram]

Id be tempted to re drill and tap to fit helicoils as then it would take some abuse without damaging the threads, probably chose M8 as thats what I use most. Its big enough unlikely to over cook it.

Ally is a better conductor than copper, it’s used in them big overhead power-lines I believe.

Alu is far cheaper, so it is probably the best conductor per £ and per gram. Used in the USA for house wiring and I was told its caused a lot of fires (could have been poor fitting or bad standards rather than the wire). Im not sure if alu wiring is allowed over here?

 

[Paul.]

Whilst aluminium is a good electrical conductor the residual oxide (al203) that is always on the surface of it is not, so if using ally plate as a welding bench its best to connect the return to the job, or clamp it down, a small arc between the bench and the job can make a big mess if not careful.

 

[Shox Dr]

I'd put a thin sheet of steel on top, to save the surface. Easy enough to take off when you need to fixture

 

[Pilgrim22]

I'd put a thin sheet of steel on top, to save the surface. Easy enough to take off when you need to fixture

Hmmm that is a good idea. A 2mm sheet with a bolt in each corner....

 

[bricol]

Id be tempted to re drill and tap to fit helicoils as then it would take some abuse without damaging the threads, probably chose M8 as thats what I use most. Its big enough unlikely to over cook it.


Alu is far cheaper, so it is probably the best conductor per £ and per gram. Used in the USA for house wiring and I was told its caused a lot of fires (could have been poor fitting or bad standards rather than the wire). Im not sure if alu wiring is allowed over here?

IT was used here for a time when there was either a copper supply problem or it was stupidly expensive. Problem is it needs the proper fittings for it - it relaxes under pressure, so the clamp screws become loose - bad contacts, overheating/sparks . .. burnt down house. It also seems to be more fragile and suffers more breaks - again, leading to overheating. Friend of mine recently had their house rewired to get rid of it.

As it complied with regs at the time, I don't think you can be forced to get rid if it all works though.

 

[JMS1972]

Indeed so.
You forgot to mention Gold! Surprisingly not as good as copper and silver but better than aluminium. Of course it never tarnishes so after time it will be the best conductor.
The ultimate welding table

Sorry, not sorry

 

[Shox Dr]

Does no body wet sand any more?
(Im surprised it isnt mandatory H&S)