Tiny question

Thin, weld, and stainless = Tig Not cheap.

Cheap would be > I want to weld stainless tube and sheet, about 0.25mm thick/wall

I'm looking for a diamond in the two to three carat range. Cheap, if possible, but it should work at least okay. Well, with this chick, I'd say it would work at "least" okay. Could even be life threatening.

Steve

Silver Brazing also know as silver soldering is a good way to join thin stainless. Especially .25 mm thick material. That is only .010 inch. The problem with silver soldering in that you need lap joints. It does not work well with butt joints.

But the equipment is cheap. I would recommend getting a couple of insulating firebrick so the heat does not get sucked away. And then even a propane torch will work.

Look at the Lucas Milhaupt website. THey have a Brazing Book on line with lots of good info. Regular silver solder will work, but there are some alloys with a bit of nickel in them that wet the stainless better.

=20 Dan

The preferred equipment is TIG. You will need a power source, Argon bottle and regulator, appropriate rod, torch and Helmut and gloves and all that.

Again, depending on use, you can buy a cheap power source, DC only, which will restrict you to non-aluminum welding, as part of a kit which includes the torch and regulator. the bottles.

I do not know U.S. prices but the local stainless guys all use a small (maybe 150 amp) Chinese made power supplies and seem to do their field welding successfully. In the local welding shop one of these will set you back, for the kit, about 150 - 200 dollars. Perhaps more in the U.S.

One point, this IS the rock bottom, basic, cheap, limited capability, type of system, but is all you are doing is 0.25 MM stuff it will be satisfactory.

Now here is a secret :-) To weld your thin stuff the rod size is a bit critical and the usual 1/16" rod is going to be too big. You will have to use more then the usual amount of heat and you are going to get more penetration then you want, dingle berries all over the back side. Instead of the normal 1/16" TIG welding rod get some 0.010" MIG wire and try that. I think you will be pleasantly surprised.

Cheers,

John D. (jdslocombatgmail)

Eh?

Why do you think so?

I have propane, butane, propane/butane, methane, hydrogen, MAPP, acetylene (and argon, nitrogen) and oxygen, all on tap. Bit nerdy, or something, but there it is.

I seem to have inadvertently misled you, and I apologise - I'm not a newbie, the cheap thing is I'm not looking for a £250,000 system, just to hand weld thin stainless at a reasonable, hobbyist, price.

I've done a whole lot of brazing, but thank you anyway.

Don't know the book you mention - is it any good

(eg would the old curmudgeon who has been brazing whatever comes at him every working day (with no sick days) for 40 years who taught me to braze learn from it)?

:)

-- Peter

Because silver solder has great strength if the joint has about .0015 inch clearance. That is about .04mm. But if the strength of the silver solder is 100,000 lbs / square inch and you are making a .25mm by 10 mm butt joint, you end up with a joint that will only hold 400 lb. with the pull even. If you put a load on it so that one end of the joint is in tension and the other end is in compression, you can pull the joint apart with you bare hands.

You did not mislead me. I just assumed you were looking at doing one or two things and wanted to keep the cost to the absolute minimum.

If you do buy a TIG welder, be sure to look at the minimum current. The cheap machines have a minumum current of about 15 to 20 amps. To weld .25mm stainless you will need to go at least as low as 5 amps, maybe lower. If possible try the machine before buying or at least have the vendor show you some .25mm material that has been welded by the machine you are buying. A pulser would help.

The old curmudgeon may not learn much from it, but he would still like to have a copy ( unless he has memorized all the silver solder alloys along with their melting points and recommendations on when to use them.). He would certainly use it for illustrations when teaching someone else how to silver solder.

Just looked at the site. It is

As I remember it is about forty pages. To access it you have to register but then you can request a CD copy of it.

Dan

Well said and if a butt joint is needed - it can be backed with a strip that makes two lap joints in the back, a butt joint in the front. You will want to try to match the color if it is to vaporize to the eyes or have the thought of strength and pick a strong alloy.

Mart> >> Thin, weld, and stainless = Tig Not cheap.

Correction. I'm not a Migger so I know little about the sizes of wire that they use. I find now that they don't seem to use 0.010 wire as I suggested. But they do use wire smaller then the 0.0635 1/16" welding rod.

Cheers,

John D. (jdslocombatgmail)

a bit high, but for the sake of argument ..

Most things which are 10mm by 0,25 mm, I can pull apart with my bare hands. Why does this make butt joints badder?

[...]

he wouldn't need any of that sort of stuff - or at least he'd think so, and mostly he'd be right.

I'll - do something.

Thanks,

-- Peter Fairbrother

The first one you show is one of the high priced type (it's got a gauge) the second is probably the one I see all over the place - every "Stainless Guy" has one to weld stainless rails on boats, etc. Carry them around, run 'em off long extensions cords, I don't know how efficient they are but they get the job done and the Thais are pragmatic - if it works, be happy.

Cheers,

John D. (jdslocombatgmail)

Example: Tee-joint in stainless tube.

Straight part is: 20mm long, OD 3mm, ID 2.5 mm wall 0,25 mm.

Tee is: 12 mm long, 2.5mm OD, 2mm ID, 0.25mm wall.

Welded, not brazed.

-- Peter F

Geez, I step away for a day and all hell breaks loose.

The best tool to weld thin stainless tube will be a TIG machine capable of running at as little as 5 amps. You only need DC so if you can find a stick welding power source that can go down very low, you could just hook up a valve-body TIG torch and scratch start your welds.

You need to make sure the Stick welding source has no "hot start' feature, or that you can turn it off. The hot start will blow holes in your piece.

You will be running DC Electrode Negative with a sharp tungsten.

At 0.25 mm (0.010") you will need to be under 15 amps output. You will need some very small filler wire that matches your base metal. The smallest filler wire readily available is 0.024" (0.6 mm). It can be purchased in small spools for spoolguns.

Tube this thin will take quite a deft hand.

The equipment doesn't have to be expensive as long as it has the right features.

Miller used to make some really low powered Maxstar DC TIG machines just for electronics assembly. They would be very good for what you are doing. I have seen them sell for under $500.

A Miller Maxstar 150 might work for you, if it goes low enough.

Also Thermal Arc has a new tiny TIG machine for under $500 total

Another > I want to weld stainless tube and sheet, about 0.25mm thick/wall

Your problem is going to be the diameter. Nothing else is difficult. But welding around your 3mm tube is going to be tedious, to say the least.

Is this some sort of welding qualification? Or a part. and if a part does it actually need a fillet weld or can you just bodge it?

Cheers,

John D. (jdslocombatgmail)