TIG welding Cast Iron

[Shark Bait]

I have a three ring cast iron burner where each ring has 32 “Ports” about .100” in diameter. I want to fill in the “Ports” in one and maybe two rings to reduce the burners output. Even at the lowest setting the burner puts out too many Btus. Strength is not an issue - the “Ports” just need filling in.

I normally braze cast iron pieces but since I am concerned with the finished appearance I would prefer to use my Dynasty 200DX, but I have never welded cast iron with TIG and any recommendations would be appreciated.

200DX settings, filler rod – type and size, tungsten (I normally use 1.5% Lanthanated), cup, gas, other? I would assume I should preheat the piece to about 400F to 500F before starting.

Thanks

[H80N]

For that application you might consider drilling and tapping those holes.... then threading in machine screws.... followed by grinding them flush.....

that would be quick and easy... plus have the additional benefit of NOT inducing any un needed welding stresses into the cast iron....

I try to avoid welding cast iron if at all possible.... it sure can be fraught with headaches and timebombs...

[turbo38t]

Drilling/tapping cast iron? I don't think that works very well. I'd just preheat it a bit, use some stainless filler and ur Dynasty and then wrap in a blanket or put in some black beauty/sand to let it cool slowly...

For that application you might consider drilling and tapping those holes.... then threading in machine screws.... followed by grinding them flush.....

that would be quick and easy... plus have the additional benefit of NOT inducing any un needed welding stresses into the cast iron....

I try to avoid welding cast iron if at all possible.... it sure can be fraught with headaches and timebombs...

[H80N]

Drilling/tapping cast iron? I don't think that works very well.

why would it not work very well??

engine blocks, machine tools and all manner of cast iron devices are routinely drilled and tapped without problem... what have I missed??

[BD1]

Can you plug the manifold for each burner instead ?? What type of device is it ?

[aametalmaster]

That would be a perfect job for a mig. Drill each hole to clean them out and zap zap...Bob

[Shark Bait]

Can you plug the manifold for each burner instead ?? What type of device is it ?

I wish it were that easy. After the NG goes thru the orifice & air shutter it goes down a cast iron runner to the lower part of the burner assembly. Then it travels up to the upper part of the burner assembly which is essentially a heavy cast iron cap 5 1/2" in diameter with the three rings of "Ports".

The only way to reduce the output is to pug some of the holes by welding, brazing, threading and putting plugs in or to use a high temperature epoxy material like muffler putty.

[aametalmaster]

That looks simple enough. 1/2 hour tops...Bob

[Shark Bait]

That would be a perfect job for a mig. Drill each hole to clean them out and zap zap...Bob

Bob: So you are saying just plug the holes with a normal MIG unit set up for steel? What wire and gas? Never tried cast iron with my MIG unit - I have heard it does not work very well but that may be in high temp/high stress applications.

[SundownIII]

Seems to me you're going to also have to change the size of the orifice.

If turning the gas down now still still outputs too many btu's, plugging a few (or even a row of holes) is only going to result in more gas flow thru the remaining holes that haven't been plugged.

Plugging holes hasn't changed the volume of gas that passes thru the orifice. All it's going to do is increase the velocity thru the remaining holes.

[aametalmaster]

Bob: So you are saying just plug the holes with a normal MIG unit set up for steel? What wire and gas? Never tried cast iron with my MIG unit - I have heard it does not work very well but that may be in high temp/high stress applications.

No sorry with cast iron mig wire. It has the same properties of stick rod drawn out for mig wire. I love it and thats why i bought it for odd jobs just like yours. Seems like i get some every now and then...Bob
http://www.crownalloys.com/TechSheet...ew_Warning.pdf

[turbo38t]

Guess I wasn't thinkin. I just remember breaking a lot of bits trying to drill cast.....too slow and they snag and snap.....too fast and u burn em up. ....I have definitely welded more cast than tapped it though.....haha

why would it not work very well??

engine blocks, machine tools and all manner of cast iron devices are routinely drilled and tapped without problem... what have I missed??

[H80N]

Seems to me you're going to also have to change the size of the orifice.

If turning the gas down now still still outputs too many btu's, plugging a few (or even a row of holes) is only going to result in more gas flow thru the remaining holes that haven't been plugged.

Plugging holes hasn't changed the volume of gas that passes thru the orifice. All it's going to do is increase the velocity thru the remaining holes.

YEP....Unless.............. it has a control valve like on the burners of a gas range or gas grill....

[Shark Bait]

Seems to me you're going to also have to change the size of the orifice.

If turning the gas down now still still outputs too many btu's, plugging a few (or even a row of holes) is only going to result in more gas flow thru the remaining holes that haven't been plugged.

Plugging holes hasn't changed the volume of gas that passes thru the orifice. All it's going to do is increase the velocity thru the remaining holes.

Sundown: You are absolutely correct - any change in the number of "Ports" will drive a reduction in the size of the orifice and a corresponding change in the air shutter adjustment. I have researched this aspect of the project and know exactly what size orifice will be needed based on the number of "Ports" I block.

Thanks for bringing this up - some folks may not understand the importance of the orifice & air shutter .

[aametalmaster]

Seems to me you're going to also have to change the size of the orifice.

If turning the gas down now still still outputs too many btu's, plugging a few (or even a row of holes) is only going to result in more gas flow thru the remaining holes that haven't been plugged.

Plugging holes hasn't changed the volume of gas that passes thru the orifice. All it's going to do is increase the velocity thru the remaining holes.

Sounds like he needs a globe valve installed before the burners to regulate the flow of gas...Bob