need advice about how to cut 36" metal pipe

[Rob-D]

I'm not sure about the Sawzall, if you have 1/4" pipe (isn't that what he said the thickness was close to?) it won't rip through it very fast especially if you have several feet to go through. If it was less than an 1/8" maybe but once you start getting up in thickness things slow down very fast.I've cut a lot of metal in my life and 1/4" with a Sawzall wouldn't be my first choice.
Also if you're going the Sawzall route remember when you select blades that the rule is 2 to 2-1/2 teeth in the metal at all times. So a 1/4" pipe would mean using a blade with no less than 8 teeth per inch and 10 to 12 is probably better.Any less and you'll be breaking teeth.

As far as the cheapest solution I look at it like this. If I buy a good tool I'll have it the rest of my life. If I hire someone I get one repair. If I rent a tool I get a fee everytime I have another similar problem.

Bottom line is I have alot of tools I've built up over the years and there aren't many emergency situations I can't handle.

It's the old adage about teaching someone to fish as opposed to giving them fish. If you give them fish they'll always need you, if you teach them to fish they only need your help once.

 

[Car Doc]

I use the same line of reasoning Rob does and I never borrow anything or loan either. I also wouldn't use a sawzall there may be better mechanical methods to cut steel but that would not be my choice.

IMO a torch with a large tip will do the fastest job but fixing it where it will work as good as it did afterwards will require an arc welder.

I also would have a piece of pipe ready to fit into place when I had the hoe on site and have him back fill the culvert after the top half of the pipe is welded back on but thats me. good luck however you do it

 

[Rob-D]

One other thing, that pipe is probably hot rolled and hot rolled can go through blades pretty fast even high Rockwell hardened ones.

 

[Car Doc]

I cut steel with cutoff wheels in hand grinders but that gets expensive its slow and may be prettier than a torch cut it wouldn't make a difference in a repair like this at least it wouldn't to me. Id want to get in get it done as fast as possible with the least effort and get back to something else.

 

[Buckgnarly]

If you plan on Sawzalling a few feet of 1/4, you may want to bring a tent.....if you are planning on doing it with a cordless, you might want to build a house! Seriously though, I agree with the above!

 

[rbtjr]

Well, guys, here is the report--probably the final report for a while. First, I want to thank everyone for their suggestions and their feedback. As usual, I have learned a lot from posting. We uncovered about the last 4' to 5' of the 20' pipe with the backhoe. Then we tried to open the end of the pipe some by putting the backhoe bucket teeth in the crushed end of the pipe and applying lift force, dipping force--every combination of force that the hoe could deliver. It's a 7' Woods PTO-pump-driven hoe. It moved the pipe and we actually got it opened up maybe another 2" ro 3", but that's all. Then we tried hooking a crowbar under the lip of the pipe, wrapping a chain around the crowbar so that the chain wouldn't slip, hooking the chain in the hooks welded on my neighbor's loader bucket, and applying max lift with the FEL bucket. No permanment movement of the pipe. In this process, when we used the hoe to uncover the pipe, I learned that the bend in the pipe starts farther back in the pipe than I thought. Contrary to what it looks like when you look through the upstream end of the pipe, the bend in the pipe is not linear. In other words, instead of the top of the bent pipe sloping in a somewhat straight line from where the bend starts to the end of the pipe, the bend in the pipe goes down pretty quickly from the place the bend starts. This means that to accomplish any significant additional water flow by cutting out the end of the pipe, I would have to go back up the pipe at least 5' and probably 6'. Since the pipe is only 20' long and the dirt on top of the pipe needs a sloped shoulder to stay intact, I can't cut the pipe that far back without excessively narrowing the top of the bridge. As a result, I decided to cover back up the part of the pipe we had exposed. I am going to wait and see what happens with the water flow. If the water flow is such that the one good 36" pipe and the crushed pipe can't handle the flow, then I think my practical choices are (a) let the overflow occur and run around the top of the bridge like I have the bridge contoured to occur, and then dig out maybe 1' to 1.5', or a little more gradually, where the overflow occurs, put in the geotek fabric and the rip rap on top in that section of the road to prevent erosion, and live with it, or (b) get an excavator in and replace the entire pipe. I just don't see any practical way to uncover the pipe all the way back to where the bend starts, cut off the pipe at that point or near that point, and install what would be a 6' or longer extension of the cut-off pipe. Too many things having to be done at the same time. Disappointing. But I really do appreciate all of the good advice and good ideas I got. Like I said, I learned a lot.