Welding stainless steel questions.

Firewoodjoe · March 28, 2015, 09:07:54 PM

Ok I've done a little searching on here and have found some info but i was hoping somone could tell me what rod to use for the stainless steel. I bought a owb that has the problematic stainless firebox and the top has been welded a few time and just continues to crack. I want to cut it out and put a new patch in. I read also that you can weld carbon steel to it? Is this something I could consider being I have that? Or should I buy the stainless?

coxy · March 28, 2015, 10:08:37 PM

don't know anything about how to weld it ;D did you get it new a few people here that had them and nothing but trouble like you say your always chasing a/the crack do they still make them good luck with your patch

Magicman · March 28, 2015, 10:19:38 PM

I would Google "welding stainless steel". There are at least a half dozen different metal alloys that are classified as SS. Some can be welded and some, not so well.

sandhills · March 28, 2015, 10:37:38 PM

Only experience I've ever had was watching an older very good welder putting in a milking parlor between milkings (very limited time) and hearing him complain about how "this @$%# is like trying to weld toilet paper together". Sorry I have no advice but I'll never forget his thoughts on it.

beenthere · March 28, 2015, 10:53:37 PM

From what I've heard, there are good welders and there are stainless steel welders. Not necessarily equal the same.

sandhills · March 28, 2015, 11:03:30 PM

Probably like diesel mechanics and Detroit diesel mechanics eh ;)? He is a very good welder just don't like the SS stuff.

Don_Papenburg · March 28, 2015, 11:40:13 PM

Stainless is as easy to weld as carbon steel if you have a tig outfit. Use filler rod as close to the same alloy as you intend to weld . Use 75/25 co2 / argon gas mix. Weld in a well vented area , chromium is bad for the breathing system . Clean the area that needs welding with clean grinders and SSwire brushes that have not been used on carbon steel. 308 rod will work on 304 ss . and it will weld 409 ss that has less chromium and more carbon. You can weld ss with carbon steel rods and carbon steel to ss but you will have a corrosion zone there. There are rods for regular arc welding ss but I have never used them . Talk to the guys at your local welding supply shop for them. SS can also be mig welded

justallan1 · March 29, 2015, 08:22:09 AM

Something I do on fixing cracks is to start at each end of it and work towards the center. I've heard (whether it's right or not) that for whatever reason the end of your weld is the weakest and offers a better chance for the crack to start again. Something else I do is if I can see where the crack is heading I start my weld well before the crack and weld into it. I have to believe that if you can see 2" of crack that there is more and you just can't see it yet.
I weld on trucks, tractors and farm equipment, amongst other things and it seems to work well.

Firewoodjoe · March 29, 2015, 08:37:41 AM

Thanks for the response guys. I just bought it. Used and leaking. $400. It been welded a few times and u can see the cracks like old leather! About a 12x12 area maybe right on top where the flames would hit. I've googled and you just get so many differant answeres. I'm a decent welder with my old miller just never welded stainless. Would I be better off buy some type of stainless as I have no idea what this one is or be just as good using carbon steel. I'm not worried about corrosion. The other thought is to use what I can from this stove and continue building my own. I already have the firebox welded and sealed but doubt I could get the stainless firebox out and mine in without destroying and creating more work then just starting fresh.

21incher · March 29, 2015, 09:08:09 AM

I have welded steel to stainless with steel wire in my mig in the past and had good results but I don't think it is recommended. In a OWB you may have problems with heat cycling of the different metals or fillers that causes cracks later.

pabst79 · March 29, 2015, 10:39:43 AM

Quote from: justallan1 on March 29, 2015, 08:22:09 AM
Something I do on fixing cracks is to start at each end of it and work towards the center. I've heard (whether it's right or not) that for whatever reason the end of your weld is the weakest and offers a better chance for the crack to start again. Something else I do is if I can see where the crack is heading I start my weld well before the crack and weld into it. I have to believe that if you can see 2" of crack that there is more and you just can't see it yet.
I weld on trucks, tractors and farm equipment, amongst other things and it seems to work well.

The end of your weld bead is weakest because the heat is lower than in the middle of your weld. Welding from each end of a crack is IMO a stronger weld as Justallan suggests. If you don't have access to a TIG welder, the almost lost art of Oxy welding can be done to fix stainless. When I went through my apprenticeship, we had to Oxy weld 304 ss pipe, with just our torch, solar flux b and 308 filler. If you know anyone including yourself with a good torch welding kit, its a viable option. It will help immensely if you can narrow down what type of SS your dealing with, Good Luck!

Josh

millwright · March 29, 2015, 12:26:38 PM

You can weld ss with mild steel wire which is not too hard to do, trying to weld overhead or vertical with stick is much harder

LAZERDAN · March 29, 2015, 12:50:07 PM

https://www.youtube.com/watch?v=0GowaLg_yBM&feature=player_detailpage

I've seen these cobra's at the farm shows, If you can weld already it should be no problem. I was thinking you could weld up the cracks, and then weld a patch over the whole thing. I learned from a pro welder you don't always use big patches, use pieces the size of playing cards, and weld one over laping the other and you will have a much better patch. Lazerdan

magicmikey · March 29, 2015, 03:24:20 PM

The best repair would be to replace the damaged section with the same type ss and rod/wire.
To alleviate the overheating a mild steel plate about the same size on short standoffs inside the firebox to prevent flame impingement might buy some added life. The ss to mild steel rod is 409 in most applications.
Good luck
mike

dean herring · March 29, 2015, 03:40:16 PM

Can you post some pics. I am not sure what you have. Might have some ideas.
How thick is the original material? I

Don_Papenburg · March 29, 2015, 03:46:55 PM

Do you know the type of ss that the stove has in the fire box.
Lot of good info here .
Stainless is going to move a lot more than mild in a heating and cooling situation. That might be a problem in the place you indicated.
What brand is your OWB?

Qweaver · March 29, 2015, 04:39:07 PM

With a crack you must make the weld 100% ! SS is very easy to weld but very hard to put a good root pass in unless you TIG weld it and have shielding gas on the back side. Do not weld SS with a carbon steel rod!...use the same type of SS or better. 309 is used to weld carbon steel to SS.
Biggest thing... MAKE SURE the crack is completely gone. The easiest way is to put a pass on the inside, grind the outside until the crack is gone and then weld the outside. If you can not get to the inside then a full penetration root pass with back shielding must be put in from the outside. Now welding skill will be tested. Good luck.
Quinton

Firewoodjoe · March 29, 2015, 05:05:57 PM

I haven't picked the stove up but will sometime this week. They already cut the water jacket out to access the top of the firebox and agin they have welded it a few times. And there are a half dozen or so cracks that are visible. I'm not just welding each crack it will either get cut out or weld then patch over top. Should be easy welding do to its virtually flat. And it's a Canada cold killer owb. I have no idea what material it is. But stainless. But I'm getting good stuff here😊

Corley5 · March 29, 2015, 07:59:11 PM

The first OWB I had was a Crown Royal. It was built for Northland Distributing in International Falls by Turf Master in Winnipeg. They built the stove to ND's specs of welding the SS with carbon steel wire. The end of the first season my stove's chimney corroded at the seem where it went through the water jacket and began to leak

:( >:( Northland was rude about it and Turf Master did pay for the repair, although grudgingly :

which required cutting a hole to access the chimney. Halfway through the next winter it began to leak where the ash pan trough was welded to the water jacket >:( >:( >:( >:( >:( >:( They agreed to pay to fix it again but after the welder started to clean it up it was more of a mess than it was worth. The carbon steel weld was completely corroding everywhere on the boiler. I had the choice if trading my old one even up for one they'd taken back, cut apart and welded back together with the proper wire or pay half the cost of new one and trade mine back but with no warranty at all on either the rebuilt or new one. I went with the new one as I was warned about re-welding stainless and it's tendency to craze after repeated welding. My new stove has been in service for quite a few years now with no issues. It's a Heat Master SS built by the people in Winnipeg. I won't promote them as they blame Northland and Northland blames them and I feel they should have known and did know that welding stainless with carbon steel wire was wrong. That's my experience with stainless welding in an OWB. I surely wouldn't use carbon steel to weld it and would be concerned about repairing the stainless even with stainless materials. Good Luck with it

dean herring · March 29, 2015, 10:27:45 PM

You will never see all the cracks with your naked eye. You will have to use some dye penetrant. Its a 3 step process ,can get it at most welding supply houses. You must use all stainless . I think you can use 304 ss if you are not sure exactly what kind you have. 309 ss is used for carbon to stainless.
What thickness? Imho anything less than 1/8" you will need to TIG. 1/8" and 3/32 stick rod. Can you post some pics would help answering questions

magicmikey · March 30, 2015, 04:09:48 AM

Qweaver and dean, thanks for correcting my mistake :-[, it is 309.

Firewoodjoe, do you have an age and repair history on the OWB?
mike

Firewoodjoe · March 30, 2015, 09:16:26 PM

I have no history. I will post pics soon as I get it home. I will not just weld the cracks it will most likely be cut out and new welded in. I have a friend taking a welding class and the instructor told him to use 508 stainless rod and it would be no problem welding carbon steel in. Why does it corrode? It shouldn't rust with a fire on one side and no oxygen filled water on the other. Or is it the two metal types have some reaction?

Corley5 · March 30, 2015, 09:21:28 PM

Quote from: Firewoodjoe on March 30, 2015, 09:16:26 PM
Why does it corrode? It shouldn't rust with a fire on one side and no oxygen filled water on the other. Or is it the two metal types have some reaction?

I have no idea why but mine and many others like it most surely did.

dean herring · March 30, 2015, 10:00:45 PM

Will a magnet stick to the original firebox or the attempted repairs?

pine · March 31, 2015, 03:10:19 AM

Quote from: Don_Papenburg on March 28, 2015, 11:40:13 PM
Stainless is as easy to weld as carbon steel if you have a tig outfit. Use filler rod as close to the same alloy as you intend to weld . Use 75/25 co2 / argon gas mix.

Are you thinking Mig with the 75/25 mix? Not a normal Tig gas mix.
I use straight Argon for Tig. A little helium can be thrown into the mix or go old school and go straight helium but it is not cheap anymore.