need advice about how to cut 36" metal pipe

Rob-D · Nov 13, 2012

radioman said:
like others suggested - a battery operated sawzall will work. buy a pack of 5 blades or so and use cutting oil. have several batteries ready and charged. You should be able to cut with at least 1 or 2 blades and 3 batteries to cut a foot or two worth long in 1/4 inch thick metal. Be prepared to recharge all the batteries and try again.
My C3 sears sawzall can do this. If I were you - I'd use sawzall over torch due to galvanized coating on the pipe- its no fun feeling sick at night or next day when breathing the fumes even in well ventilated area.
If worse comes to worse, and you are set on renting something to get the job done in no time- I'd go rent the gas powered saw with a metal cutting blade on it. less fumes to breathe in.

I never weld anything without a mask. Period!

rbtjr · Nov 13, 2012

I really appreciate all of the feedback. Looks like I have some really good excuses to buy some stuff. :licking: I think my cut will be more like 8' to 9' when all is done. It looks like the cave-in of the pipe starts about 4' or so from the end of the pipe. I might not go that far back with my cutting, but the farther I go the more I will alleviate the obstruction. If I go 3', let's say, from the lower end of the pipe, that's a cut of 2 X 3' = 6' if I were going straight back and not over. If I were going straight back on the sides of the pipe half way up and then over the top of the pipe, that would be another 3.14 X 3' / 2 = 4.71'. But since the cut would be angled from say the midpoint of the pipe on the end to the top of the pipe 3' back, the total length of the cut would probably be about 8' to 9'. Pretty significant, at least to me. That's why I wanted the advice.

CNC Dan · Nov 13, 2012

you might be able to just cut a few inches here and there, and then bend it up. Or heat the creases while using the jacks. that will take the spring out. then jack some more and heat again, repeat as needed.

If you cut the whole piece out you will have a hard time getting the edges lined to to weld them back.

as far as jacking goes, you need to keep jacking past the point of spring back. but your jack has limited travel. thats why you need two jacks. The second one continues the progress the first one has started.

rbtjr · Nov 14, 2012

Agreed, Dan. I am thinking that I can get a neighbor with a backhoe to uncover the last 3' to 4' of pipe. I will get a 2d jack. I will probably try heating first to help the reshaping along. I will probably have to make at least one cut, and I would be happy if I could get back to something like a 30" opening with one cut. That would get me back to about 70% of the original water flow compared to the original 36" diameter. If one cut or a couple of cuts don't work, then I can cut out the entire section of the pipe on the top. If I were to do that, I would try to find a short section of 36" pipe (or 30") and make the cut on the existing pipe a little below the midpoint, so that I could lay the new short section of pipe down into the cut section of the existing pipe. Then I would hope to cover the new section and be back where I started. All of that sounds good in theory, but the first issue would be to find a short piece of 36"pipe. And I would have to remove a lot of dirt in order to be able to make the cut below the midpoint of the existing pipe. Probably best to just heat and cut as necessary, and use two jacks to get the best outcome I can. Thanks for the feedback.

Cigar Face · Nov 14, 2012

Rent a gas powered circular saw with a metal cutting wheel at your local rental store. Looks like a chain saw with a large grinder wheel. I use this for this type of job and fortunate to have a brother that has one for work.

Fifelaker · Nov 14, 2012

If you have a friend with a backhoe hook the bucket under the lip and pull.

joshuabardwell · Nov 14, 2012

Fifelaker said:
If you have a friend with a backhoe hook the bucket under the lip and pull.

We have a winner!

Rob-D · Nov 14, 2012

Fifelaker said:
If you have a friend with a backhoe hook the bucket under the lip and pull.

My thought too the moment he said it, get that bucket under there and pry it up!

Gary Fowler · Nov 14, 2012

Fifelaker said:
If you have a friend with a backhoe hook the bucket under the lip and pull.

That is exactly what I was going to suggest. A backhoe should have no problem straightening that lip.
As for oxyacetylene torches, I just bought a new one (Harris brand) last week from my local welding supply. I was in asking about repairing my Victor brand gauges as they were all not working properly. For the price to fix them, I just bought an new torch kit for a tad over $200 which also had a #5 brazing tip. I had bought a #1 tip last year ($68 for a Victor brand) so this was a pretty good deal for the whole torch set. WS guy said he quit stocking Victor because they got too expensive and all the HARRIS brand parts are interchangeable with Victor.
Bottles are extra but can be rented on a monthy basis. I own my bottles and just pay for refills which to me is best because I dont use them enough. Everyone needs a oxyfuel torch on a farm. Guys with plasma rigs swear by them about how great they cut, but lets see them load it up and go out in the back 40 and cut something with them. Have to have one heck of a long extension cord and for about half of what they invested in a heavy duty plasma that can cut more than 1/4" thick material, you can have a complete torch set up with bottles and bottle buggy and can change the tip size to cut everything from thinnest sections to over 2" thick even with smallest torch. Limitations are that it only cuts steel where plasma will cut anything that an electric current will flow thru.

Buckgnarly · Nov 14, 2012

Gary Fowler said:
That is exactly what I was going to suggest. A backhoe should have no problem straightening that lip.
As for oxyacetylene torches, I just bought a new one (Harris brand) last week from my local welding supply. I was in asking about repairing my Victor brand gauges as they were all not working properly. For the price to fix them, I just bought an new torch kit for a tad over $200 which also had a #5 brazing tip. I had bought a #1 tip last year ($68 for a Victor brand) so this was a pretty good deal for the whole torch set. WS guy said he quit stocking Victor because they got too expensive and all the HARRIS brand parts are interchangeable with Victor.
Bottles are extra but can be rented on a monthy basis. I own my bottles and just pay for refills which to me is best because I dont use them enough. Everyone needs a oxyfuel torch on a farm. Guys with plasma rigs swear by them about how great they cut, but lets see them load it up and go out in the back 40 and cut something with them. Have to have one heck of a long extension cord and for about half of what they invested in a heavy duty plasma that can cut more than 1/4" thick material, you can have a complete torch set up with bottles and bottle buggy and can change the tip size to cut everything from thinnest sections to over 2" thick even with smallest torch. Limitations are that it only cuts steel where plasma will cut anything that an electric current will flow thru.

Cannot heat things with a plasma either.....but I own both, so the proper answer is to buy both!