Soldering Very Hard Stainless and very Small Parts

beside TIG welding it .... there are rods available that can be applied with a soldering method...... you heat the metal with a propane torch and allow the filler rod to melt on the surface. .... my question is, would an epoxy do the job? - does this answer your question?

It goes onto a commercial sewing machine. On occasion , the needle will strike the outside of the piece. I do not know if epoxy would hold firm enough.

The piece I have looks bronze colored at the weld.

What type rod would I ask for? There are many welding suppliers down here?

Thank you.

You can see the hits where the needle flexes when it gets hung on the raschel netting.

You can also see a line of something that appears to hold the two pieces together.

THIS IS A TOP VIEW of the two pieces.

Dear Net Maker, you will need to TIG weld this piece, in order to get it to the strength you need. (the needle will be striking against it)

You do not mention the material of your component #2. I assume that it is metallic and can withstand the heat of welding or brazing. Silver brazing is the best method, especially if you have dissimilar metals. If you want high volume production, I would suggest resistance welding. SS is one of the best materials for this process because of its high electrical resistance and low thermal conductivity.

Looking at the original piece, can either of you determine what was used...TIG or soldering? This is the BACKSIDE...it goes against the Dogs ( gears) that move the raschel along as it gets sewn.

Looks like silver braze to me.

If it is Silver brazing it has withstood tremendous punishment for the past 4 years.

How does one Silver braze it ???

What do i ask for in a welding shop as far as rods go?

Thank you.

This website for SilFos has a lot of useful information:

http://www.silfos.com/

Thank you.

This site shows a lot of How To and that is what I need.

You will need an oxy-acetylene torch with a very small tip, to keep the heat localized and careful surface prep/fluxing. If possible purchase a refractory brick to work on.

Practice on some scrap, it is fairly easy, once you get the hang of it.

http://www.northerntool.com/shop/tools/product_200413934_200413934?cm_ite=171742&cm_pla=Welding>Cutting%2C%20Heating%20%2B%20Welding%20Torches&cm_cat=Nextag&cm_ven=Aggregates

http://www.starbrickstoves.com/acatalog/Firebrick.html?gclid=CPL27v-o8aMCFYLt7QodDCdo4A

Will these get me where I want to go?

For the torch, here is a less expensive rig: http://www.bernzomatic.com/PRODUCTS/KITS/TORCHKITS/tabid/215/ctl/Detail/mid/1147/xmid/6954/xmfid/3/Default.aspx

Unless you plan to do a lot of brazing and have a source for refilling the Nothern Tool cylinders.

The brick is fine.

By the way, do they call it "Southern Tool" down there?

Thank you. I do have a source to refill but I am NOT looking forward to any welding or soldering more than I need to for my own equipment.

I use this commercial sewing machine for the really small raschel nets we build 2mm>12mm mesh. The rest of the larger gear we sew by hand.

My Plate is wearing out and this thing is so modified the sewing machine guy in town just laughs when I ask for parts.

......and NO! The Yankees won't let us change the name.

That is Ok, because I heard one of their CEO's is a dang Colts fan anyway ......ha ha ha!!!!

Who Dat?

I worked on Union Special Machines and they came new with extra critical parts because they were hand built and no two machines were the same, so even fitting the extra part required hand work.

This is a Juki MO 6704-S

They tell me Juki bought out Union Special a few years ago.

This is as large as I can enlarge it without losing the clearity.

Netmaker -- This looks like a terrible project to do with TIG. I'd lean toward silver solder. But I wouldn't give you 2 cents for one of those Bernzomatic Torch setups. This is a job for an oxy-acetylene or possibly oxy-propane setup. You'll need a very small torch like the Smith Little Torch: Oxypropane is a bit cooler and easier to control on small jobs. That plus you can use a regular propane cylinder and save money there once you work out the adaptation of the tiny Smith hose fittings to a small propane needle valve. The tank valve is way too big to give the level of control needed

http://www.littletorch.com/

By the time you'd buy the torch and cylinders you'd be $300 plus into it.

I've had come success silver brazing 304 stainless. But it's tricky. Overheating the joint results in a very difficult oxide coat that most of the fluxes won't touch. So you have to stop, grind the oxide off (it's dark color makes it easy to see) and start over. On your repair job you won't have very many chances before the part is ruined. So a lot of preliminary practice is probably called for.

Also, if the stainless steel part is actually heat treated 400 series stainless you will lose the temper wherever you raise the part above about 600F. This may not be of consequence where the repair is taking place. A product called "Heat Fence can be applied to the part to keep heat from traveling where you don't want it. Comes in a jar from welding supply stores. About the consistency of soft modelling clay. Also pieces of copper clamped on will make local heat sinks.

BTW, for practicing on 400 series stainless go find some cheap stainless steel kitchen knives at the flea market or Goodwill store. To cut them into small pieces either anneal them first or get one of those cheap Harbor Freight 4-1/2" angle grinders and some thin cutoff wheels. I love this tool. Wonderful for a myriad of shop metal cutting tasks. Throws sparks like a 4th of July sparkler and howls on sheet metal like a screaming banshee.

Ed Weldon

Hi,

to the left of 1 or 2 the metal looks more yellowish then at 1 or 2.

If this is true color then this is silver-alloy brazed.

I do this conveniently with a propane torch and AgCu28In

The Indium content will let the braze flow easily. The AgCu28 has the lowest melting point in Ag-Cu.

But: you need a specialised flux for brazing stainless steel else the oxide will spoil everything. Usually I used DEGUSSA H and H-Special for brazing SS and some Nickel-alloys. (Vapors and fumes are poisonous!)

But if you have access to a welding shop that has a "micro-plasma-welder" and uses this with inert-gas then this would be better (stronger).

We used micro-plasma for welding SS-membranes (90mm diameter) 0.1 and 0.2 mm thick onto rings much thicker to get elastic structures.

RHABE

Defiantly a silver solder job. Use stainless steel silver solder paste do not use pre fluxed silver solder.

Silver solder grade 40% would be best. use a oxy propane torch small jet this will give you a needle point flame for small precision work. do not use a fierce oxy rich flame if you go to far over the melting point temperature you will screw up the stainless surface and it will not braze. Surfaces will then need cleaning in nitric acid[ drop parts into acid when they are hot,wear safety gear].

Practice with some stainless bits till you can-judge correct temperatures don't braze in bright lights it is easier to do it in the shade.

Rhabe and Garth -- GA's!! This is info I can use too.

Rhabe -- that Degussa flux may be hard to find in the USA. An initial internet search didn't turn up any real looking souces. Can anyone else here suggest a comparable flux they know works with 18-8 stainless steels?

Ed Weldon

Uhh Ohh ....just when I thought it was safe to get back in the water........... I see there are even more ways to do this.

After having studied this tiny add on part, I sent a message to an on-line supply place for a new Plate, minus the No.2 part. I'll get some odd pieces of SS and cut me a little flap.

I'll practice on this one.

Thank you all again.

Until the next crisis.........

netmaker

Hello,

for some reason I do not see the picture,

TIG can weld most metals, but in some cases it is difficult or impossible to weld dissimilar materials with TIG - ie. stainless steel to Carbide.

Silver solder and flux likely is the answer.

You could explore getting a new piece made (1 piece) stemming from the 2 pc design.

perhaps the only reason it was made from 2 pieces is due to the fact that it was complicated or expensive to make as a single piece. Of course I am not familiar with the function, perhaps the materials have certain properties for a reason rather than just the final shape requirement.