Advice on Heating with a Stick Welder

[Bootheal]

I have a few of these concrete covered foam blocks that were the walkway at a marina. The original install used wire rope strung through the blocks to keep the dock ‘together’. I would like to remove the old cable as I probably need this to reassemble in another fashion.

I’m thinking of hooking a welder to the old cable in an attempt to heat the cable fairly hot.

Questions:
Will it damage the welder?

What amperage?

Time limit?

I know some welders have 20% duty cycles. Not sure what this one is but will find out. It’s an old Forney that you plug the leads in for different amperage.

thanks, Mike.

 

[TVA]

My uncle used to heat up very long tapered bolts in the machine tools that was was stubborn to get out.
I need to call him on procedure, but as far as I remember the main thing was to control the current so the bolt will get heated and it would not start arc or melt at contact point.
Don’t know about damage to the welder, but I think you better use 100% duty cycle transformer one for that job.
Copper beaded strap is the best for making a contact with the piece being heated.

 

[DB2]

We had an old Lincoln SAE400 set up to thaw pipe. It had a fuse box installed in the positive cable. Not sure what settings they used.

 

[skyking1]

My tombstone lincoln has a circle around 75 amps. that was the pipe heating setting.

 

[Bootheal]

Thanks for all your input. Sounds like 75 amps after I find the duty rating.

Thanks again to all and Merry Christmas.

 

[1693TA]

I've thawed a lot of mobile home water lines using my Hobart Bros. engine drive using between 30, and 60 amps in years gone by. First one I did as a test as I thought the guy with me at the time was nuts attempting this on a mobile home which burn easily anyway it's looked at. Not only did it work, it worked well and the new tenants moved in the next day after new heat tape was installed.

 

[Willie B]

I have a 1974 Twentieth Century 295 Amp, 100% duty cycle I've thawed many underground galvanized steel pipes with. My goal was to warm them to 40 degrees F. At 75 amps it took only a few minutes to warm it enough for a tiny bit of water to flow. I'd get a drip or two, it was time to disconnect. The flow of water conducts heat very effectively. Water coming from the main line was always over 40 degrees, that is enough heat to thaw the ice.

I would be very nervous about heating 5? feet of steel cable to 400? degrees

 

[Bootheal]

I would be very nervous about heating 5? feet of steel cable to 400? degrees


Is this because of potential overheating the welder?

I’m pretty sure the cables are not coming out without some assistance and heat was the go to method.

To make it slightly worse, they are 8’ long!

 

[Willie B]

I would be very nervous about heating 5? feet of steel cable to 400? degrees


Is this because of potential overheating the welder?

I’m pretty sure the cables are not coming out without some assistance and heat was the go to method.

To make it slightly worse, they are 8’ long!

Yes, Heating a 3/32 electrode to melt it is a Hell of a strain on a welder. Heating a cable with several multiples of its cross section, I doubt it'll handle.

 

[Bootheal]

Not helping here Willie B

 

[Delmer]

It's also several times the length of an electrode. Those old forneys are heavy copper, and worth more as scrap so you don't have much to lose. Try it on one of the lower middle settings with heavy short leads, and see how it works. I don't think you're going to need more than ten minutes to know if it's going to work or not. Maybe ten minutes at a time to do several heat and cool cycles on the cable. If anything, put a fan blowing air over the transformer, I think those didn't have a fan originally.

I'm torn between putting some pull on one end of the cable while heating, and waiting until it's cooled to pull?

 

[Bootheal]

Excellent suggestions Delmer.

That’s going to be the first try.

 

[Willie B]

Could you single out one strand of cable? A whole lot easier on the welder to heat.
The goal is to have more resistance in the expendable material, It'll heat, welder innards won't.

 

[Bootheal]

Yes, I think I can. Another good idea. Thanks.

 

[JLarson]

What's the plan? Heat the cable then pull it out?

 

[Bootheal]

Hopefully! It might be a pipe dream but need to try something.

now, I’m thinking, there’s no way to heat just one strand…but if I single out one strand, it might still be easier on the welder. Just thinking.

 

[JLarson]

Why not just chip out around the cable and take the torch and wack it off it then pack a handful of non shrink over the crater.

 

[Bootheal]

I want to reuse the pipe after the old cable is removed.

Hopefully, tie three ‘blocks’ together and make a floating, fishing pier for some grandkids.

 

[63 caveman]

How about putting expandable anchors with eyes and shackle them together?

 

[Delmer]

How about knocking the rust off the cable and pipe (steel pipe channel for the cable?) and welding a chain link to the end of the whole mess? Then coupling the floats together with two vertical 6x6's and a piece of plywood with beveled and sealed edges for the top?