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welding stainless to mild steel

11-04-2008, 06:56 AM
Ok wizards

:D I'm new to this and need to weld mild steel to stainless steel What is the best process ( Mig, Tig, or stick) and what is needed RE: rods tips, filler etc.
This is for a stainless flue liner project that my neighbr is doing and he needs to secure the long flexible flu pipe to a steel plate that replaces the damper that was in the chimney. i suggested just using stainless for the plate but I guess he is too cheap :roll:
joe :P

11-04-2008, 07:40 AM
Any of the processe will join the materials together. Thickness, fit of material, accesability would all play a factor in which process to use.

Using a wire feed process (GMAW or FCAW) will require a spool of wire be purchased BUT may be mnore suitable for thinner sheets. In addition, less skill is required.

SMAW requires more skill but takes less equipment and user access.

GTAW can be used but cleanliness is a must and welding times can be longer. Joining poorly fit pieces that are thin can be a pain for GTAW

11-05-2008, 10:06 PM
If the pieces of metal that are welded together are light guage (<14Ga) then use TIG or wire, the filler or wire must be SS
If the pieces are geavy guage (10Ga or higher) then use stick weld, the rod must be SS
From this the grey area (14 to 10) you can use either process.


11-05-2008, 10:25 PM
When stainless is welded to mild steel the weld will rust rather easily. You might want to consider a covering (paint).

12-22-2008, 11:11 AM
When stainless is welded to mild steel the weld will rust rather easily. You might want to consider a covering (paint).

.....or bronze it by brazing the joint after welding, has a nice appearance if you want that metal look

12-22-2008, 12:20 PM
What type of flux do you use to braze weld over the 300 Series stainless weld? Does regular borax and bronze rods work?

Since it is attached to a piece of CS I would think rust is not an issue. If its the case with overlaying carbon steel with SS then plug welding would rok. If this is inside a heater or furnace, rust on the surface would not be an issue.

04-12-2009, 06:14 AM
I haven't been able to master TIG on thinner material, I keep blowing holes. Brazing works easier for me on carbon steel.