Problem Welding Damaged Fireplace Insert
Posted: Fri Nov 16, 2018 12:27 am
Approximately 15 years ago I built a fireplace insert out of 1/4" steel diamond plate which formed a shell around the inside of the fireplace. It had a fan which circulated air through the chambers and heated the whole house. Two years ago I was low on wood and mixed coal with the wood which made a much hotter fire and damaged the back plate of the insert making it wavy even though it was reinforced with 1" angle iron on the inside. This fall I noticed a crack forming and cut out all of the damaged metal and went to replace it with new diamond plate. The weld will not form on the old metal. It just burns in and falls off much like trying to weld an aluminum crankcase that has been saturated with oil. The only way that I have formed any weld is by starting on the new metal and pulling the molten metal into the old which I'm sure is not a strong weld and looks like Fido's butt as Jody would say. I started using stick (7018 DCEP, 6010,6011) then switched to the mig (ER70S-6 CO2/ARGON) both giving similar results where the weld would just blob and fall out.. I don't think the metal has too much carbon in it as I was able to bend the old metal with a pipe wrench. Is there any special rod that would deal with this problem? It is apparent that there is some sort of chemical change in the old metal as the filler just refuses to weld to the old metal. The apparent solution is to build a new insert but for now I'd like to just repair this one.
http://s32.photobucket.com/user/Starduster_/library/
https://www.castolin.com/sites/default/ ... de-680.pdf
MANY THANKS to all who answered this plea for advice. I would have posted pictures beforehand but this was my first post. The pictures show the massive damage to the heat shell with the distortion and the crack which finally developed. I tested many rods with different settings and and the metal would burn through on vertical runs even running below recommended voltages and amps. I ended up mainly using Forney .035 flux wire and running the gas also as it seemed to reduce spatter which seemed important as I lay inside the fireplace on my back or stomach. Best results were made running hot and fast passes (3) then just throwing metal at it on top. Vertical weave was an impossibility for me but there's enough metal blobbed on it to make it through another season or two. If you look at the test weld on pictures 4&5 it shows that even though the test weld material appeared somewhat weldable on the front, the backside showed the metal was completely rotten with slag/carbon/coke residues. Grinding to a clean surface and using acetone made no difference. The metal was just plain porous and saturated. The Eutectrode 680 rods were in my junk container of old rods which I bought over 30 years ago. I was surprised that they worked so well as I'm sure they needed to be put in a rod oven (the flux had turned from BLUE to Grey on some of the rods).
The FLAME STRAIGHTENING video from TUNGSTENDIPPER shows some of the design flaws i made on this one (my second). The outer shell was welded up tight against the fireplace bricks making it too rigid to expand like the inner one did. The backside needs a baffle spaced in between the fire and plate to absorb the direct radiation from the fire which is just too close. The two cores need to be spaced closer to 2" instead of 1 1/2"with more angle irons to help heat transfer. Standoffs need to be placed inside between the two plates and welded like rosettes. Finally a curved baffle plate needs to placed on the upper part of the chamber to help recirculate the hot exhaust gasses and smoke which will provide a somewhat catalytic action and more uniform temperatures within. I have a CEMI II insert in the basement fireplace and it has most of these features. I just always liked the large glass doors (dangerous) rather than the small Mica windows for the living room. I almost did not post these pictures out of shame but hopefully they will help someone in the future know what to expect and how to avoid similar problems. Hopefully Jody won't make a video showing how easy it is to weld material like this if you're a master welder and know what to do.
http://s32.photobucket.com/user/Starduster_/library/
https://www.castolin.com/sites/default/ ... de-680.pdf
MANY THANKS to all who answered this plea for advice. I would have posted pictures beforehand but this was my first post. The pictures show the massive damage to the heat shell with the distortion and the crack which finally developed. I tested many rods with different settings and and the metal would burn through on vertical runs even running below recommended voltages and amps. I ended up mainly using Forney .035 flux wire and running the gas also as it seemed to reduce spatter which seemed important as I lay inside the fireplace on my back or stomach. Best results were made running hot and fast passes (3) then just throwing metal at it on top. Vertical weave was an impossibility for me but there's enough metal blobbed on it to make it through another season or two. If you look at the test weld on pictures 4&5 it shows that even though the test weld material appeared somewhat weldable on the front, the backside showed the metal was completely rotten with slag/carbon/coke residues. Grinding to a clean surface and using acetone made no difference. The metal was just plain porous and saturated. The Eutectrode 680 rods were in my junk container of old rods which I bought over 30 years ago. I was surprised that they worked so well as I'm sure they needed to be put in a rod oven (the flux had turned from BLUE to Grey on some of the rods).
The FLAME STRAIGHTENING video from TUNGSTENDIPPER shows some of the design flaws i made on this one (my second). The outer shell was welded up tight against the fireplace bricks making it too rigid to expand like the inner one did. The backside needs a baffle spaced in between the fire and plate to absorb the direct radiation from the fire which is just too close. The two cores need to be spaced closer to 2" instead of 1 1/2"with more angle irons to help heat transfer. Standoffs need to be placed inside between the two plates and welded like rosettes. Finally a curved baffle plate needs to placed on the upper part of the chamber to help recirculate the hot exhaust gasses and smoke which will provide a somewhat catalytic action and more uniform temperatures within. I have a CEMI II insert in the basement fireplace and it has most of these features. I just always liked the large glass doors (dangerous) rather than the small Mica windows for the living room. I almost did not post these pictures out of shame but hopefully they will help someone in the future know what to expect and how to avoid similar problems. Hopefully Jody won't make a video showing how easy it is to weld material like this if you're a master welder and know what to do.
