Experimental Flash Steam and others

[william_b_noble]

not also that I have read several accident reports, some with death and very serious injuries when the sanding dust from aluminum and iron are mixed in a pile and some sparks ignite the mixture, which is basically thermite. I'd agree that mixing metals from sanding/grinding is best avoided, or at least clean up the pile from time to time.

 

[Steamchick]

Hi Byron. You mention TIG welding aluminimum. Have you TIG welded copper?
K2

 

[william_b_noble]

why would you want to TIG weld copper? silver solder is very strong and faster and invisible when done right (well "nearly invisible"). you can also weld copper by putting a current directly through it and bonding it that way.

 

[Steamchick]

Hi William. For "boiler work". There is a limit (according to USA ASME Regulations) of 100psi for "silver soldered copper boilers".
But in the UK there are some boiler makers who make Copper boilers that are TIG welded. I think they go to 120psi NWP (TBC?). - Beyond that the permissible stress for copper (due to the elevated temperature yield stress "drop-off") makes it "uneconomic".
But for Superheaters in Copper, thick walled tubing can permit higher temperatures due to the extra copper cross-section compensating for the yield stress drop-off... I think? Or am I just in need of Stainless Steel TIG welded superheaters?
Of course, if I didn't care about the Factors of Safety in the current Regulations, I could "cheat"... but those risks are not in my book of rules.
I worked in an industry that used Copper and Aluminium (for electrical reasons), so I saw copper fabrications, and we MIG welded aluminium onto aluminium plates that had been "explosion bonded" onto copper plates that were a part of the fabrications. I have also heard of full-sized loco boilers in copper being repaired by welding where they have had cracks... Maybe that used Oxy-acetylene? I really don't know?
There seems to be little literature about this, just an odd U-tube demo that doesn't explain TIG current versus material thickness, etc.
TIG just seems a neater and "stronger" process - to me at least. Am I in "cloud-cuckoo land"?
Cheers!
K2

 

[Bentwings]

not also that I have read several accident reports, some with death and very serious injuries when the sanding dust from aluminum and iron are mixed in a pile and some sparks ignite the mixture, which is basically thermite. I'd agree that mixing metals from sanding/grinding is best avoided, or at least clean up the pile from time to time.

We are pretty careful about cleaning up grinding. Years ago some magnesium got sanded on a belt sander then one of of the guys sanded some steel. The machine caughtfirebrilliantly . Huge mess after fire extinguishers were usd. Melted some ofvthe heavy parts. Ironically it was almost brand new so it entered the dumpster un glamorously . I saw one other magnesium fire as an apprentice in the tool shop. Same deal magnesium and hot steel . Melted a hole in the chip pan on a big lathe There nearly was a disaster in the shop if it had spread. Lots of flammable oils and piles of magnesium aircraft parts. Glad I close to the exit.