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View Full Version : Cut 25mm steel - no sparks.



Peter.
10-14-2011, 04:00 PM
I have a job to cut some 25mm steel plate, but I can't make any sparks. Current method is to use a reciprocating saw (which doesn't really fullfil the 'no sparks' rule but comes the closest) and a lot of effort - not to mention blades. Hand/portable tools only so waterjetting is out. Portable cold-cut saw not allowed either.

Got about 60 metres of it to cut. Any ideas folks?

isaac338
10-14-2011, 04:14 PM
Port-a-band sounds like it fits the bill!

The Artful Bodger
10-14-2011, 04:27 PM
Hydraulic nibbler? Although I am not sure I have ever seen one that can handle 25mm.

Peter.
10-14-2011, 05:01 PM
Port-a-band sounds like it fits the bill!

Forgot to say - I only have access to one side :(

winchman
10-14-2011, 05:14 PM
How many years to you have to get it done? :D

Is there a restriction on sparking because of what's on the other side, or because of what's on your side? Perhaps you could make a partial cut with some tool/blade that makes sparks and goes much faster, then finish the cut with a non-sparking method.

Can you use flood coolant to kill the sparks?

What in the world is it you're cutting up? An old ship's hull or storage tank?

kevindsingleton
10-14-2011, 05:21 PM
Yeah, this is starting to sound like some sort of riddle.

Unless you're trying to steal a bridge, and can't afford to make any sparks that might be seen by the police, I'd just pass on this job; too many restrictions, already.

http://www.wkbn.com/content/news/local/story/Two-Arrested-in-Steel-Bridge-Theft/2ze861b0_k2KHbZzsMUPSg.cspx

Peter.
10-14-2011, 05:36 PM
It's a large diameter flue in a facility which has a site-wide prohibition on spark-producing-methods. Haven't been there yet but as I understand it they have a good amount of ethanol being piped about the place.

winchman
10-14-2011, 05:44 PM
A pox on you if you're going to do anything that facilitates the production of ethanol that'll be added to gasoline. :D

Arcane
10-14-2011, 06:01 PM
Use a hydraulic or pneumatic powered magnetic drill and chain drill it.

aboard_epsilon
10-14-2011, 06:15 PM
diamond wire saw

http://www.youtube.com/watch?v=S2hR75HmD6M&feature=related

Peter.
10-14-2011, 06:24 PM
Diamond wire sawing is my trade :D

macona
10-14-2011, 06:31 PM
One of the evolution saws ought to cut it. They run slow and they, for the most part, dont make sparks.

http://www.youtube.com/v/j6Evk3mxy-8

Peter.
10-14-2011, 06:57 PM
One of the evolution saws ought to cut it. They run slow and they, for the most part, dont make sparks.

I do believe they have tried one of those. I'll find out tomorrow why they aren't using that, perhaps the 25mm is too much for it?

macona
10-14-2011, 07:10 PM
I bet it goes through blades pretty fast. Bet its pretty slow too.

wierdscience
10-14-2011, 07:22 PM
Another vote for chain drilling.

winchman
10-14-2011, 07:36 PM
I doubt you could put enough pressure on a hand-held cold saw to do much cutting with so much of the blade in contact with the work. Even a big Doringer with its 18" handle takes a lot of muscle under those conditions.

Is there a portable cold saw with a strong magnetic base and coolant?

Gravy
10-14-2011, 07:50 PM
With access only from one side and no sparks allowed, I'd think you are looking for something that takes large slow bites. How about hydraulic demolition shears?

boslab
10-14-2011, 08:16 PM
hydraulic circular saw in an aqua box [open top tank will do, mastic down]
or;
http://www.aquaairind.com/Index/Cutting-Welding/Oxylance.htm
good cut rates, relativly cheap, water box on the back side so the whole job is done under water
mark

tmc_31
10-14-2011, 08:48 PM
Rigid Tubing cutter on steroids?

Tim

danlb
10-14-2011, 08:53 PM
Most electric powered tools will be ruled out because of the sparks at switches, motor brushes, etc. There are some that a re certified for flammable environments.

Dan

pressurerelief
10-14-2011, 09:07 PM
I have used one of these in a refinery before to cut out sections of pipe. The pneumatic model with the air cylinder feed cuts well for all of the restrictions placed on you. I have no idea on your OD but these saws are limited to 24 or 30" OD i believe.


http://www.csunitec.com/saws/airhack.html

P/R

Evan
10-14-2011, 11:06 PM
What is the minimum feet per workday that you need to cut to make the job feasible?

john b
10-14-2011, 11:18 PM
Peter can you use a Wachs trav-l-cutter. john b.

tmc_31
10-14-2011, 11:25 PM
I was only partly kidding about the rigid pipe cutter on steroids, check this out.

http://www.reedmfgco.com/index.html?screen=universal_pipe_cutters

This comes in a pneumatic version.

Unfortunately, it does say that sparks can and are expected to be generated at the cutting wheel. I wonder if you could get by with shielding the area around the cutting wheel with a wet rag?

Tim

2ManyHobbies
10-14-2011, 11:28 PM
Split a 4" piece of 20' PVC lengthwise.
Glue/caulk/clay over a run of det-cord.
Fill with water.
Push button.

The only other thought I've got is that I'm not sure what you are being punished for.

Safety Tools Allmet?

LKeithR
10-14-2011, 11:50 PM
I have used one of these in a refinery before to cut out sections of pipe. The pneumatic model with the air cylinder feed cuts well for all of the restrictions placed on you. I have no idea on your OD but these saws are limited to 24 or 30" OD i believe.

With that saw it looks like you would be able to cut through the wall of the flue once you had a starter hole in it. Use a longer chain to clamp it down and move around the flue in steps. A big honkin' magnet might be enough to hold it in place...

Chris S.
10-15-2011, 12:33 AM
A pox on you if you're going to do anything that facilitates the production of ethanol that'll be added to gasoline. :D
May I second that?

lakeside53
10-15-2011, 12:46 AM
Hold on.... Maybe it's made into the "low cost" generic Vodka, Gin, ....:D

JoeCB
10-15-2011, 12:56 AM
Still not clear on the configuration of this piece of steel... but, Have you considered the wire saw/abrasive technique they use to saw marble slabs from the quary, I believe in Italy? slow but sure?
Joe B

Evan
10-15-2011, 01:24 AM
Wire sawing is what Peter does for a living.

Duffy
10-15-2011, 12:09 PM
Peter, from the limited info, I am assuming this is a "scrapping" job, and that it involves vertical curved surfaces, the material is "mild steel" and because of the prohibitions, cost and hence time, is not a major problem. While you said that you cant PRODUCE sparks from cutting, you implied that you could use electrical tools. This also can involve more than one worker.
If these are indeed accurate assuptions, then chain drilling COULD be a winner. IF you, (or someone,) cobbled up a magnetic holder for an 18 volt Li ion drill, (or corded, your choice,) with cobalt 6mm bits, it should be possible to drill about 30 holes per hour, with 1mm or 2mm gaps. (If this is standing, you cant possibly cut continuously to an open face.) If my arithmetic is close, one person can cut about 1.7 meters in a seven-hour day. For four workers, it is a bit less than a two-week job.
Any MAGIC BULLETS?

Evan
10-15-2011, 03:05 PM
Sounds like an interesting place to work. The lower explosive limit of pure ethanol is 3.3% in air. If there is anything near that amount in the atmosphere everybody should be stone drunk. Also, the flash point is 14C. On a nice chilly day the only hazard will be from puddles of liquid on the ground.

wierdscience
10-15-2011, 03:20 PM
Hold on.... Maybe it's made into the "low cost" generic Vodka, Gin, ....:D
You mean the kind that comes in Aluminum cans:D

Guido
10-15-2011, 03:34 PM
We've hours and hours erosion perforating, also cutting off 24 inch heavy wall casing below the mudline, etc., etc. Rockwell 80 stuff. Takes about 30 minutes max to cut off any oilfield tubular, submerged, and would make a nice fresh water mess inside a refinery, or factory-------

http://www.halliburton.com/public/bc/contents/Data%20Sheets/H03491.pdf

--G

Peter.
10-15-2011, 03:40 PM
Ok guys here's an update. Sorry it's took so long but I set off at 2am this morning for a 5 hour drive and went stright to work. Can't take any photos either which is a bummer:

Firtly thanks for all the good ideas and feedback. As soon as I saw the job I was resigned to using the recip saw because they forgot to mention some internal features inside the flue which meant the cut had to be steered up and down/around them. Obviously not possible with a circular blade.

Oh and it was Ethylene - not Ethanol.

Duffy has pretty-much dead-nailed the conditions, vertical curved surface and whilst there are some 'intrinsically safe' areas this isn't one of them so electric tools allowed but no showers of sparks etc. They ruled out the cold-cut saw after a trial on the ground.

Mild steel flue 25mm thick wall, 7 meter circumference and three of us cut around it in about 2.5hrs with a recip saw each which I was very surprised at. 14tpi blades lasted about 100-150mm of cutting if I used the adjustable foot to make use of as much tooth as possible. I also used cutting fluid to try to keep the heat down in the blade and it worked quite well.

Got another to do tomorrow then a long drive home. Once again thanks a lot - this is what makes HSM such a great place!

lynnl
10-15-2011, 06:48 PM
Uh.., just out of curiosity, would a diamond coated wire saw (in steel) be an absolutely, for sure non-sparking process?

That sounds to me much like the flint/steel fire starting process. (??)

I've seen TV segments showing that process in cutting marble and stone, where it's running in a wet slurry. But with steel I'd think sparks would certainly be possible, or even probable.

RussZHC
10-15-2011, 06:58 PM
Curious, what "support" has the part removed got?

Maybe complete out to lunch here, but I just envision a crane putting slight tension on some sort of sling set-up which then lifts once the cut is complete?

Peter.
10-16-2011, 03:26 AM
Uh.., just out of curiosity, would a diamond coated wire saw (in steel) be an absolutely, for sure non-sparking process?

That sounds to me much like the flint/steel fire starting process. (??)

I've seen TV segments showing that process in cutting marble and stone, where it's running in a wet slurry. But with steel I'd think sparks would certainly be possible, or even probable.

You do get sparks with a wire saw run either wet or dry when cutting bare steel. The biggest difficulty with cutting large diameter tube is that the wire cuts one side so when you are part-way through the cut you are pulling the wire through a very acute angle on the entry-turn - as sharp as 45 degrees - and this tends to strip the diamonds off the leading edge of the bead. Towards the end of the cut it is very prone to jamming too as the steel bends and if the holding load on the crane is too much less than the actual load it wrinkles the tube at the cut and the wire is permanently stuck

RussZHC: Yes the piece being cut is held by a large mobile crane - a thousand-tonner actually.