What is the safest way to cut up an old steel water tank in my loft?

September 11, 2009 5:21 AM

What is the safest way to cut up an old steel water tank in my loft?

The tank is large and too big to get through my loft hatch but it takes up so much room. I'd like to get shot of it. I have an angle grinder but I'm nervous to use it in the loft as there are wooden joists everywhere and the noise would be tremendous.
Does anyone have any better ideas please?

posted by mccartrey to home & garden (24 comments total)

Sawzall, fine-toothed blade. Hearing protectors.
posted by jon1270 at 5:29 AM on September 11 [3 favorites has favorites]

I think a hacksaw and a bunch of blades, is your best bet. You can drill a few holes to get you started, and it would help to have someone else to bend the metal so that the blade does not catch. There's a good chance the wall of the tank is not too thick so it should go fairly quickly.
posted by a womble is an active kind of sloth at 5:31 AM on September 11

Sawzall, fine-toothed blade. Hearing protectors.

That's what I'd use, and I'd add that eye protection is at least as mandatory as the ear plugs. Cutting metal can be loud, and catching a sharp sliver in your eye will put a kink in your plans for the day. Buy plenty of spare blades, don't cut yourself on a sharp edge, and work carefully.
posted by Forktine at 5:32 AM on September 11

Nthing sawzall. If you don't want to buy one, I'd bet you can rent from either the local big-box home improvement store or a local rental agency. Make sure you get blades designed for cutting metal. Also, is this thing still plumbed into your water system? Be sure you know how and where to shut off water and how removing this will effect your plumbing.
posted by cosmicbandito at 5:45 AM on September 11

They used a sawsall to take cut up our old oil tank in the basement. I worked really well.
posted by bonobothegreat at 5:54 AM on September 11

oh, and do make sure it - and its connecting pipework - are entirely empty of water. A tidal wave of rusty water will do delightful things to your decor. Draining and plugging will enhance domestic harmony.
posted by scruss at 5:59 AM on September 11

How big is it? How thick are the walls? You might need something more like a circular saw. (And eye and ear protection.) A circular saw with a metal-cutting blade is going to cut through it a lot faster than a reciprocating saw.
posted by musofire at 6:02 AM on September 11

I want to reinforce all of the safety-related remarks made above, and add two more:
1) fire extinguisher (yes, really)
2) work gloves
posted by aramaic at 6:04 AM on September 11

I've cut literally tons of cast iron indoors with a sawzall. I'd also add a pair of good quality gloves if you have absolutely any hand sensitivity (to ear/eye protection and a few extra blades). If you have a side-grinder, you can use that to start it. I personally think that using a circular saw is a more advanced option for someone who has experience. Sawzall's kick pretty hard if they hit something but you can get a very tight grip on them. Circular saws will also kick but you don't get such a good grip.
posted by mrmojoflying at 6:11 AM on September 11

Seconding the fire extinguisher.
It may also be possible to rent fireproof blankets from your local welding supply store that you can lay near where your cutting.
posted by Confess, Fletch at 6:29 AM on September 11

Agreement with the above. Sawzall, ear protection, eye protection, hand protection. A supply of fresh blades, because working with a dull one is a drag. Return unopened packages for a refund.

If you get tired, stop and rest. Accidents and injuries are more common when you are tired out.
posted by Midnight Skulker at 6:32 AM on September 11

N'thing the 'protect yourself' advice. Eye protection/face mask (a hat too; filings in your hair is uncomfortable), leather work gloves, a boilersuit. A leather apron works well as a local fire blanket, you are unlikely to be liberally spraying hot filings around.

Sawing it up is probably the most effective but if noise/discomfort/very-small-risk-of-fire is unacceptable then you might be able to use a heavy duty set of cutters. It'll take longer, and it'd be more awkward but it'll be clean and quiet.
posted by BadMiker at 6:50 AM on September 11

I would NOT use a circular saw outside a controlled environment. An accident with a sawzall and a metal cutting blade would lead to an ugly gash. A circular saw could easily take off a finger or worse. They're an order of magnitude more dangerous because there's a ton of momentum behind that spinning blade, the blades tend to be more jagged, and it doesn't stop instantly when you take your finger off the trigger.

Counter-intuitively, metal cutting tools are a lot safer than cutting wood. An abrasive cutting wheel on an angle grinder will nip you, but a table saw will grab you and bite off large pieces.

Wear goggles for this sort of thing, not safety glasses. Metal goes all over and believe me...a sliver of steel getting under an eyelid can be so shockingly painful that it drops you to the floor, blind, screaming and crawling on your hands and knees to someone who can rush you to the ER. I've had quite a few slip ups in industrial environments. I cut the pad of a finger off with a knife, had my hand get hit by a 20lb chuck rotating at 5,000 rpm, got zapped with 240v 3-phase power, got my entire arm splashed with 180F molten wax, etc. The pain from getting a .5mm sliver in my eye blew all those things away.

A cheap paper face mask would also be a good idea for extended cutting sessions in small spaces.

Go slow and take brakes to avoid heating the blade. They stay sharp a long time if you don't overheat 'em.
posted by paanta at 7:11 AM on September 11 [2 favorites has favorites]

I would NOT use a circular saw outside a controlled environment.

Yes, this is what I meant to say in case it was unclear and anyone think that it is a good idea. Do not use a circular saw for this unless you work with your saw every day.
posted by mrmojoflying at 7:55 AM on September 11

I'd go with the angle grinder. It'll definitely be noisy, but it's a lot faster than using the sawzall. I imagine your neighbors would prefer 20 minutes of fairly intense noise over a couple hours of moderate noise punctuated by swearing and banging.

We took down a shed built of angle iron and corrugated roofing with an angle grinder. They can cut through sheet metal (and angle) like butter. Wear a face shield and gloves and you should be ok.

If you do go for the sawzall, keep in mind that the tank will start losing its stiffness as you cut and start flopping around, at which point it will be really handy and a lot safer to have someone to hold it in place while you cut. It's really easy to have the blade seize once that starts happening.
posted by electroboy at 8:13 AM on September 11

With regards to reciprocating saws - you may look at rental fees and decide to buy a lower end model. From taking off an addition on a house with a lower-end saw (DeWalt) as well as a rental (Milwaukee). There is a HUGE difference between them. Apples and oranges, maybe, but the DeWalt I bought kicked like a mule and had a blade guard held on with what I referred to as "the stupidest screw in the universe" when I wrote my subsequent nastygram to DeWalt - in short, the saw kicks which works out the screw, which cause the blade guard to fall into the chuck, seizing the saw and tearing out all the teeth on the gearing. Game over.
posted by plinth at 8:28 AM on September 11

You may wonder how to start a cut in the side of a tank with a Sawzall if there are no penetrations to allow the blade to stick into the tank. One way is to drill a line of a half a dozen 1/4" holes slightly more than 1/4" center to center and then taking a cold chisel and hammer and wacking a slot through the material separating the holes. This will give you a roughly rectangular hole in which to insert the Sawzall blade.
posted by digsrus at 9:27 AM on September 11

3Lb sledge and a nice sharp chisel cuts rolled steel like butter.
posted by hortense at 9:35 AM on September 11

You are absolutely sure this is a water and not a gas/oil tank, right? Because that would be bad.
posted by sully75 at 11:01 AM on September 11

Just to keep piling on the safety recommendations, you don't want ear plugs, you want ear protection earmuffs, which will do an outstanding job of protecting your ears. I use them all the time for metal work and they make a huge difference.

Also, seconding the recommendation that if you do use a reciprocating saw, the Milwaukee saws (like all Milwaukee power tools) are really, really good, and will give you many years of reliable service. If you decide you'd like to own one, they are also available reconditioned, at a decent discount.
posted by mosk at 12:38 PM on September 11

This is a really interesting question. I think that everything mentioned so far is pretty good info. I'd suggest a couple things -

1: having a helper on-hand who can assist/hold the tank/call for help. Someone who's there the whole time, not just someone in the other room who you'd have to yell for if you were getting in trouble. If I'm working on a project with a high risk factor, I like having another set of eyes to look out for problems.

2: Where is this water tank? is it suspended in some way? electroboy's comment about the tank losing rigidity as it's cut up is an important one. if this tank is a cylinder, once you cut the end off, you're going to turn the rest into a big floppy noisy resonator for your sawzall to vibrate. something like a 2x4 wedged inside the open end could make the tank rigid enough to keep working on it.

If it were me, i'd start the project something like this: day before - warn the neighbors you're gonna be making some noise. day of: drill a hole in the lowermost part of the tank. Helper holds a bucket underneath while you do this. let the last of the (potential) sludge drain out while you measure loft hatch or whatever exit you're using to get this stuff out. figure out your maximum piece size based on what you can comfortably lug out the door. Smell around the area you drilled a hole and make sure there's no odor of volatile chemicals. I know you said it's a water tank, but cutting any metal container that could ignite is baaaaaad news, so i'm being paranoid on your behalf.

And, more specifically to the original question, I'd suggest the angle-grinder, assuming you're okay with sparks shooting everywhere.
posted by dubold at 3:16 PM on September 11

Plasma cutter! No, seriously, reciprocating saw and safety gear (Sawzall being a trademark of the Milwaukee Corp.) Also, a helper or several.
posted by fixedgear at 3:31 PM on September 11 [1 favorite has favorites]

Partner Saw with a Steel cutting blade is what I would use, I would find it frustrating to muck around with a Sawzall. A photo of the tank would be helpful.
posted by MLIS at 8:11 PM on September 11

Just to keep piling on the safety recommendations, you don't want ear plugs, you want ear protection earmuffs

This ain't necessarily so. I've worked in the metal fabrication industry for over thirty years. My company has only used foam style ear plugs ( but used them religiously ). I've recently had my hearing checked and the doctor was shocked by how good my hearing was considering the industry I was involved with. I find the foam style plugs much more convenient and their noise reducing properties are as good if not better than ear muff style protectors.
posted by digsrus at 6:27 AM on September 12