Advice on welding stainless steel

[mattbridges]

Hello welding experts.

I work as a cabinet maker, mostly making expensive complicated multi material pieces for the disgustingly rich. I have always subbed out most of my metalwork (except basic brass work), but I would love to learn how to do it myself.

Some of my current work uses stainless steel box section (50 x 50 square) that needs to be welded together with mitred, 90 degree joints. The joints must always be invisible and the metal either brightly polished or brushed finish.

I would be very grateful if anybody could tell me what type of welding would be best for this work (tig/mig), if there are any good books for the novice stainless steel welder, or any good courses available in the Bristol area - I am not interested in a qualification, I would rather a day of one to one private tuition from an expert.

Sorry for the long rambling message, any advice would be greatly appreciated.

Matt

 

[Hitch]

If you want neat and tidy..... Tig is the best option. If you have a steady hand, its not all that hard to pickup.

 

[dannyweld]

but if your going to grind the welds down and polish or brush mig would be better.

 

[mattbridges]

An invisible joint is my main priority at the moment, I imagine that would involve a raised joint which I grind flush afterwards?

 

[craigthewelder]

Pretty much. Weld it yourself and let a good polisher sort the rest out.

 

[dannyweld]

a little trick is after grinding the weld down to the surface, clamp a thin bit of sheet across where the weld was, eg outside corner to inside corner, one section covered the other not, and polish, then visa versa. polishing up stainless is just like cleaning a pot, its all about elbow greese.

 

[Angusdog]

^^^ Nice tip and one I will put into practice soon.

I notice 'pickling paste' mentioned for removing the bluing from the welding process. How effective is it? I was planning on just using a flap disk and so on for polishing the heat marks out of the joins.

 

[dannyweld]

yeah, you need to use a bit of pickle before you polish up the metal. the heat from welding f@#ks up the metal a bit and the pickle will help bring the stainless back towards its original state. believe me i have learnt the hard way on this one on an industrial scale. i had cleaned up my welds with a stainless wire brush on a polishing machine, a proper 350kg machine, but only a year later the welds were brown. its a pickle job and then wire and polish for optimum finish really.

 

[Hitch]

Fettle away until flush with a fibre disc, then surface conditioning pad, then polish as required.
If you Tig it up, theres virtually no extra material to grind away.

 

[mattbridges]

What would you recommend I use to give the stainless steel a brushed finish? I can't afford to spend too much on new kit, but already have most woodworking tools if they could be adapted. I would need to get into a couple of internal corners on 50 x 50 box steel, but keep the grain direction along the length.

I feel a lot of elbow grease will be required. Maybe I should have a crack at tig to keep the mess down?

 

[Paul.]

I do a lot of finishing on stainless steel, I use a combination of pickling paste, stainless steel wire brushes, standard Flap wheels, and scotchbrite flap wheels, and ordinary green scotchbrite cloth with soapy water, for getting into corners garyflex blocks are particularly useful, they are useful for reinstating brushed finish on faces too, a flexible drive or an air die grinder is handy for running the flap wheels,

 

[Welderpaul]

a little trick is after grinding the weld down to the surface, clamp a thin bit of sheet across where the weld was, eg outside corner to inside corner, one section covered the other not, and polish, then visa versa. polishing up stainless is just like cleaning a pot, its all about elbow greese.

Interested in why you would use this method Danny?

 

[Paul.]

I do it as well Paul, use a piece of thin sheet as a polishing mask to get a straight line where the grain changes direction, it makes a nice mitred corner, like the woodgrain effect on a mitred picture frame,

 

[Welderpaul]

I do it as well Paul, use a piece of thin sheet as a polishing mask to get a straight line where the grain changes direction, it makes a nice mitred corner, like the woodgrain effect on a mitred picture frame,

Ah i see. Thanks

 

[dannyweld]

What would you recommend I use to give the stainless steel a brushed finish? I can't afford to spend too much on new kit, but already have most woodworking tools if they could be adapted. I would need to get into a couple of internal corners on 50 x 50 box steel, but keep the grain direction along the length.

I feel a lot of elbow grease will be required. Maybe I should have a crack at tig to keep the mess down?

for an inside corner on box is where i go and turn on my TIG, and get up near as possible the finish before welding and flash across no bead just fast and steady across with plenty of filler, i have a little pad that i can stick scotch onto and make sure your nails are clipped!! for brushed finish i do as much as i can on my linisher and then back to the scotch, maybe you have some sort of belt sander although if its a light weight can make a dogs dinner of the job.