Is welding of thin stainless steel tubing (wall thickness 0.01" - 0.02") possible ?

[H80N]

Your engine choice is delightful .... looks like a miniature Franklin 2A-120 (O-120) Twin..... Guess they do not make miniature O-320 clones....

Wonderful project

some additional thoughts.... if that hinge is to be laid on top of other joints that have already been silver soldered then you will have precluded Tig Welding on that spot... as you will draw out the solder from the previously soldered ones.... you could however solder them using jewelry practice of using the next softer grade of silver solder

Hard
Medium
Soft

each softer grade melts at a lower temp allowing you to layer several items in steps without damaging the one done before....

please keep us posted... if you like PM me and I can probably help you with some sources....

for hard solders... this stuff is 80percent silver...

http://www.riogrande.com/Product/Sil...d/101730?pos=6

These guys at Rio have more hard solder options... plus their site is fun to look through...

http://www.riogrande.com/Search/hard-solder

[d_adams]

I've used this STL150 for .015" thick tags welded on to the stuff I make. I bought a syncro 180 to replace it and still weld the same tags with the 180.



I didn't weld any more than the corners to hold it in place, but with patience, it can be done.

[pilotarix]

Hi all,

many thanks for your input !

@H80N
good idea, never thought about that, will definetely get some solder with a lower amount of silver for the critical areas where a lot of parts comming together.

@d_adams
thanks for the pictures !


Chris

[H80N]

Please keep us posted on how this works out on the present Super Cub project..... and particularly interested in how construction techniques evolve on the next one......

[d_adams]

I've been using 1/16th filler wire on mine, you probably want to hunt down something a bit smaller in diameter. I know there's .035" filler available, we had some at the last job I worked at. They may have had even smaller stuff, might have been .020" wire. That was at an aircraft manufacturing machine shop though. I never realized there were so many different types of filler metals until I worked there for a few years. Mostly Ti and inconel, but they did have several (8 or 9 at least) grades of stainless. Lots of other stuff that I had absolutely no clue what it was for, they just had numbers on it.

Those guys made my welds look like a pre-schooler scribbling with a crayon as opposed to a fine painting when compared to theirs.

[popspipes]

I tig .022 steel parts .57 mm, these are done at about 10 amps for a butt joint, this is the thinnest material I work with. There are pics in my profile, click on album.

I never knew they made 80% silver solder, good to know.

I use a Dynasty 200 dx machine, wp9 torch and a gas lens but my work isnt as small as your compound joints.

For filler wire I use .023 steel mig wire inside a small diameter piece of copper tube to hold it straight. I have a roll of .030 stainless 304 that I have used on stainless parts. This wire may come in smaller diameters.

The thin gage materials are purge welded too, as the atmospheric oxygen can attack the material from the backside as well.

[H80N]

Pop
for what it is worth.... you could use sterling silver wire as "silver solder" on anything that has a higher melting point.... 92.5 percent silver, melting temperature of 1475°F (802°C) and a liquidus flow point of 1650°F (899°C)

so for stainless steel it would work fine as a top tier ultra hard silver solder...

[popspipes]

Pop
for what it is worth.... you could use sterling silver wire as "silver solder" on anything that has a higher melting point.... 92.5 percent silver, melting temperature of 1475°F (802°C) and a liquidus flow point of 1650°F (899°C)

so for stainless steel it would work fine as a top tier ultra hard silver solder...

Thanks for the info, I dont do much silver soldering, I use 45% for most of it as its noncritical things.

[Keith_J]

Joint fit is crucial. I would imagine a jig with file/burr tooling is available. Like chainsaw sharpening files.

The next issue is jigging to hold joint while welding. But seeing how you have silver soldered, that should be a given.

Micro torch is also a must for most joints. I would stick with 0.040" electrodes with a good inverter type machine that has adjustable arc starting parameters, like a Dynasty. These also have an automatic spot mode which might be handy for tack welding. 0.020" tungstens are fragile. WP125 is a good choice here since the glass/fused quartz nozzles in 45, 90 and 180 degree heads make for great visibility.

Shade 8 with suitable magnification is a good starting point, I weld up to 50 amperes with shade 8 with my Dynasty on the small stuff (0.040" tungsten).

With good fit and practice, this can be done. If you could find a few feet of ER309L in 0.023", you would be set for life.