Wood furnace cracked. Break out the welder?

[Mustang71]

So I have a daka wood furnace and I've never been very fond of it since I do hvac for a living and take out 50 year old systems that are more advanced than this thing. I found a Crack by the door today that started from one of their welds. It's 3 years old but the warranty says I have to pay freight to ship it back. I'm gonna call them tomorrow but I'm sure that's worthless. So do I weld it for this year and get something new over the summer if so what's an economical furnace since I only use it when I'm home and burn about 7 face chords a year?

 

[jo191145]

I welded the light plate steel firebox on my Jensen furnace about 6 years ago. Still holding. Had never used a welder before.
Chances are whatever you do will be better than what they did

 

[chucker]

just be sure to drill a 3/16" or a 1/4" hole on "both ends of the crack"---- "ahead of it" to prevent it from expanding from the welding!! once metal has a fracture or stress crack it's like glass and only continues to expand....

 

[Mustang71]

Alright I've been using my welder for over 10 years and I have a couple of them so hopefully I can get it fixed. I really think it was a bad weld on their part since that's where it cracked. I'd like a different furnace but figured this one would last at least 10 years. It heats the house even if half the heat goes out the flue lol

 

[bigmoose]

Does the crack run im the existing weld metal itself?

 

[Mustang71]

 

[Mustang71]

It starts right in the weld

 

[buzz sawyer]

Looks like maybe a small defect when the opening was cut and it happened to be under the area to be welded. As the metal expands and contracts from heating and cooling, the defect results in a stress point and starts a crack. I have two similar cracks on my Squire wood stove. It was repaired once and cracked again but the cracks haven't changed in close to 30 years. What is behind the cracks? Is there a chance for CO or smoke leakage? If the concern is only appearance, I would drill a hole to stop the crack as Chucker said and watch it. The metal IS going to move as it heats and cools. If it is caused by a stress point, it may crack again.

 

[bigmoose]

Like chucker said drill a hole at the very end of it so the crack can run out in it to prevent it from running any more. If u have a torch i would apply some heat to make it show just how long it is and to show any more deffects. Dont get carried away.... just a little to make it show up. I wouod take a grinder and use the edge of the rock and grind a v in the crack.... and fill it in with the rod. Not reall deep just enough to give u more space for more weld metal.

 

[chucker]

View attachment 533489

looks to be the same as mine .. thinking mostly of the cause beginning from a heavy door let go with a bang to help the problem along !

 

[Mustang71]

Yeah I'm sure slamming the door didn't help. I'm only concerned cause I don't want it to get bigger I don't think there is any co problems since the chimney drafts good. So am I better using the torch and brazing it up or using the mig welder? I can't get the stick welder near the furnace

 

[chucker]

mig weld! drill, grind the crack(groved, not through) and fill ... if needed you can also use a piece of metal behind the crack to support the weld, again using the 2 end drilled holes to hold the backing metal in place(bolted momentarily) to weld by adding a few extra drill holes along the crack! bolts in the surrounding metal for added strength... ! an ounce of prevention, is worth a pound of cure.

 

[bigmoose]

Is it cast iorn or plate steel?

 

[chucker]

it's welded not brazed ..... plate steel will hold a weld as cast will crystalize with a weld ! possible?? nickel weld would hold for cast.....

 

[bigmoose]

If its plate steel i would stick weld it....

 

[Mustang71]

It's 3/16 plate steel I believe. It should weld up great hopefully it holds up

 

[blades]

Weld it up then take torch and anneal weld and adjacent area.

 

[Mustang71]

I welded it up tonight. I did a few passes on it since my mig is a 120v Hobart auto arc. I couldn't get the Lincoln 225 stick welder by the furnace. I loaded it up its running hot and looks good so far