Using a angle grinder what are the better cut off blades to use to cut these propane tanks?

Soon as I can get this 500 gal tank I bought home I will be starting to trim her up a bit and plan to use an angle grinder to do most of the cutting on it.

Man... having been thru a little bit of tank cutting...VERY little... see if you can rent a plasma cutter for a day or two. POOF- done.

the cheapest blades you can get... i don;t care what you get, the blades will eventually be ground away and you need to install a new one. that's the nature of abrasive blades. lol.

one tip to make them last longer, let the blade do the work for you. don't push it too hard. after you get the feel for it, you will know where the "sweet spot" is for pressure. not too hard, not to soft... juuuuuust right.

now, for the more pressing matter... be careful with that tank. propane has a nasty habit of soaking into the metal. this being said, even after a year or more of a tank sitting empty, it can still have a high enough LEL worth of propane in there to make things go boom and level your garage. one spark and your BBQ budget may be going towards hospital bills and/or a funeral or two.

i'm not trying to scare you away from doing it... just be careful. fill the tank with water and a bottle of dish soap, let it sit for a week or two, then drain it and cut, while the inside of the tank is still wet. after you get your initial door cut out, you should be fine... but if you smell ANY vapors, or have any doubts, just walk away and don't chance it. i've heard too many stories to tell you otherwise.

Later,
Andy

Man... having been thru a little bit of tank cutting...VERY little... see if you can rent a plasma cutter for a day or two. POOF- done.

i concur. figure $1.50-$2 blades/disks... you can easily go through a few dozen per day. let's just say 20 disks for some even numbers.

20 disks @ $2 each = $40.
if you look around you can probably rent/borrow a plasma cutter for something in the neighborhood of $40-$50.

the main drawback is that you need an air compressor with a dryer to run it. sometimes the PC's will come with a dryer on/in them, but i try not to assume too much when it comes to rental houses. and no, a little pancake compressor probably won;t handle it... figure 4-6 CFM @ 90 psi, depending on what size cutter you get.

www.millerwelds.com will give you a better idea about what you will need/want.

Later,
Andy

see if you can rent a plasma cutter for a day or two. POOF- done.

I agree. If you can rent a plasma for a day, man, POOF, Done LOL, so much quicker. Plus, you can tack down strips of flat iron to use as a guide to make straight cuts.
Those tanks are minimum 1/4" and the one I looked at the other day was 3/8th wall thickness. But if you gotta go with blades, the cheaper the better cuz your gonna go thru a few of em.

I will check the rental places out to see what they have, a friend can help me and he has a plasma and all that stuff but just trying to minimumize the costs on my end so if I can do some or most of the cuts I might be better off, but maybe not if I go through 40 - 50 bucks in blades.

I have 2 tanks to cut on. The other is a 120 gal propane tank that is going to be a "patio" smoker on a cart and I am hoping to do all of the cuts on that myself and just have my friend weld the cart up, doors, RF plate and fire box so we will see how things go as this will be the first one I start with (its smaller and I can move it around by myself - kind of) This tank has had the valves removed for a couple months now and I will fill it with water and dawn soap and let sit a few days before I start and when I do start it I will add some dry Ice to it and some water to utilize the carbon monoxide properties to eliminate the chance of explosion....

What about the 3x blade they are a 1/4" thick blade, are they worth the price? they will have to cut tripple the amount of steel as a standard blade as they are so thick.

What about the 3x blade they are a 1/4" thick blade, are they worth the price? they will have to cut tripple the amount of steel as a standard blade as they are so thick.

not gonna happen. the only time a blade lasts longer is if it's a stronger material or it's larger in DIAMETER. the thicker, 1/4" dimension only means that it will cut slower and you will have a larger gap/kerf in your cut. if anything, that 1/4" dimension will make it cut less linear feet of metal, rather than more. I am assuming that you have a 4 1/2" angle grinder. this being said, the most you will be able to put on there SAFELY is a 5" disk, and even then, you will need to take off the spark guard. without starting a thread hijack, i prefer to run without a guard, but that's a whole other story.

if your buddy has a plasma cutter, use it. the "consumables" last a LOT longer, are relatively cheap, and if he is letting you use it, he is either confident that you won't hurt the machine, or he is there to help you with it. after using them in the past, they are worth their weight in gold, platinum, salt, and every other material known to man. clean cuts, easier to get straight if you use a straight edge, and are a LOT faster.

let's use my real-life example for a basis of your decision. when I made my 2'x2'x2' fire box for my fridge smoker, I cut (along with my brother in law) about 14 linear feet of 1/8" plate steel. this relatively small amount of metal was cut in about an hour, including the time to change blades, move cords, etc. that was with 2 guys cutting. granted, i'm a bit more experienced then he was, so i would say that I probably cut about 8 or 9 feet in that hour. that time also includes layout and prep. I also went through about 4 or 5 disks, IIRC. besides the beers, it is also absolutely imperative that you wear eye and ear protection. gloves are an "optional accessory" as far as I'm concerned, but probably wouldn't be a bad idea. also, anyone around you after the grinding/cutting has been done will insist that you smell like a fried electrical device... that's the smell of "working man". lol

now keep in mind, this was only 1/8" steel. with my experience with larger tanks such as this, and what others have said, i would expect your tank to be in the 1/4"-3/8" range for wall thickness. this being said, you can easily assume that you will spend at LEAST 75% more time getting through your tank, as well as about twice as many disks.

bottom line, get the plasma. lol. it's not a requirement, but take an hour or so and try cutting with disks, then you will know what we are talking about. lol.

I have a feeling that if I ever get a contract that would require anything over about 3/16" steel and a significant amount of cutting, a plasma will be charged to the welding account. lol. I have wanted one since the day I used one, and have thought of hundreds of projects that I can use one for... the only thing a torch set can do over a plasma is heating. other than that and draining your account on gas cylinders, there are no benefits to going with any other method of cutting as far as i'm concerned.

Later,
Andy

http://www.sears.com/shc/s/p_10153_12605_00925864000P?prdNo=6&blockNo=6&blockType=G6

http://www.sears.com/shc/s/p_10153_12605_00982835000P?mv=rr



This is what I have to cut metal, used it to build my smoker. I cut up to 1/4" pipe and plate with no problems and hardly any sparks.

Thanks guys I get the idea...Plasma. My friend will do the cutting with it, i will suck a few beers down while this gets done:)
Just not sure what he will charge, trying to keep all costs down (my economy is, well not much of an economy).

Just not sure what he will charge, trying to keep all costs down

There's gonna be LOTS of "tuning sessions" in your future... Hmm what to do with all that meat... :noidea: :thumb:

BESIDES filling the tank with water and soap afterwards depending on your welding equipment i also will purge the tank with mix or straight argon gas just plug the holes with rags purge with argon for about a solid 5min. i just did a 5oo gal. lp tank over the week end. plasma cutter is the only way to go for straight thin cuts.

Sounds like you are getting good advice. If you don't get the plasma cutter, next best thing is a skil saw with a metal cutting blade. Beats an angle grinder hands down for straight easy cuts. And the blades are realitively cheap. Good luck and take pics. And stick with the dry ice. Cheap insurance there.

Sounds like you are getting good advice. If you don't get the plasma cutter, next best thing is a skil saw with a metal cutting blade. Beats an angle grinder hands down for straight easy cuts. And the blades are realitively cheap. Good luck and take pics. And stick with the dry ice. Cheap insurance there.

I have used these carbide tipped skil saw blades to cut though 3/8 steel plate on top of a couple of taconite dump tanks and they work great for making a straight cut,and like whisky said there are very few sparks, if you use this method you need GOOD hearing and eye protection.good luck cant wait for some pics :thumb:


Oh and one other thing to rember is to always start your cut at the bottom so the cut piece dosnt drop on you

The metal saw blades work great and a good one is around $70. But you will be able to cut a lot of the other metal you'll need for your smoker. Just check the RPM on the blade and the RPM on you saw. Most cheaper saws have to high of a RPM, you need something like a skill worm-drive saw.

I differ from others here about the cut off wheels. At my last job I would go through between 10-20 wheels a day. They would buy what ever they could buy cheap. The window installers would buy Hilti and Metabo, I would pickup the used one they would throw out (once the wheel was a little over half gone it wouldn't cut what they needed and would go to a new one). That half wheel would last longer than 2 or 3 of the ones we would get. Your mileage may vary. Just remember the thing the kills them is binding them left and right of the cut.

Todd

I know this thread has run it's course, but I'd like to offer up some thoughts anyway.
I wish I had a plasma cutter back when I built mine. I have one now, but too little, too late for my smoker.
A couple things you can do on the cheap is:

1) Jig Saw - Time consuming yes, but it's cheap and cuts are thin and straight. If you are cutting along and through a weld, like cutting the dome ends off, forget it. Even a plasma cutter will have a problem here, unless you're spending righteous bucks on one.

2) Oxy acetylene torch - I have used this the most. If you spot weld strips of mild steel as a guide, you can make cuts that are as nice as a plasma cutter but with a lot of slag. But you can chip and grind that off.

3) Sawzall - Works, but two hands on it at all times sucks, and just because of their anatomy, they're hard to work with for long cuts.

i have to add this: for the OA torch... if you don't have the setup, have access to one, or have never had the experience in setting it up/running it/tuning it, don't bother... you will go through a couple hundred bucks QUICK, and that's with a used setup. granted, i would recommend one anyway, if you are building a full trailer (OA works great for heating and bending large pieces... that little dinky propane/MAPP torch won't get anywhere NEAR where an OA kit temps), but for cutting, it'd be difficult to work with. if you had the scrap metal and cash to get going, it would be cheaper than running plasma (especially on a single job like this), but if you are looking at OA, you might as well look at disks.

if you go with the jigsaw and/or sawzall, take a spray bottle and fill it 50/50 with anti-freeze and water. spray just a little bit and keep the blade wet and your blades will last longer. it's a redneck trick to keeping the blades cool, similar to the large, industrial sized bandsaws. don't soak it down, but keep it wet and cool and you'll save some cash pretty quick. i do the same thing on my bandsaw at home (horizontal metal bandsaw) and never had any problems with it.

I also agree with the comment that the twisting/side motion will decrease life... i've had a couple of them explode on me due to the metal binding up. on 1/4" plate steel, i doubt it would happen, but on thin stuff like 20 gauge and smaller, it can happen pretty quick. just be careful. remember... them there blades are spinning at 11,000 RPM+. that translates into a helluvalotta MPH. lol. i have seen pics on welding forums of the disks getting lodged in drywall after exploding. this is what one did to my sweatshirt in less than a blink of a eye. if it was tight up against my fat gut, i'd probably be dead, or a hell of a lot less pretty than i currently am. lol...

http://i219.photobucket.com/albums/cc228/aczeller/67fbb35c.jpg?t=1286762756

http://i219.photobucket.com/albums/cc228/aczeller/67fbb35c.jpg?t=1286762756

Later,
Andy

Andy, you jacket shows the importance of a guard on an angle grinder. And I'm usually not a big guard fan. On a lot of tools I think guards are more dangerous, than safe, like on a table-saw.

I have a Harbor Freight grinder that the guard vibrated off and I lost the screws. When using a cut-off wheel I kept nipping my gloves with the wheel. I ruined a good pair of welding gloves because or not having a guard. Luckily it was the gloves and not my hands. Now I just use that grinder for a cup wire wheel since a guard really doesn't do much good.

Oh, ear and eye protection makes for a better day of grinding.

Todd

Andy, you jacket shows the importance of a guard on an angle grinder. And I'm usually not a big guard fan. On a lot of tools I think guards are more dangerous, than safe, like on a table-saw.


in my experience, I do not use guards on my grinders when cutting/grinding metal. call it luck, call it stupidity, call it what you want... if I had a guard on the grinder when I ruined that shirt, i probably wouldn't be here today. the grinder caught the metal, popped off the metal, and landed in my shirt, instantly being wrapped up and bogging down the disk. if the guard had been on there, i am confident in saying that there probably would not have been enough resistance on the disk to stop it.

do with that information as you may... trust me, i've been in many heated debates on the use of guards on angle grinders. every one of those discussions to date have ended in a draw... no one seems to budge from their viewpoint. I can see how many people think that guards are important and need to be used on grinders at all times. accidents happen and certain things are just out of our control. i do still have my guards for all my grinders... i only use mine though when I am cutting concrete/bricks/tile, etc., especially when using water to cool the blade. metal is always cut guard-free.

like I am trying to say, i respect others' views and do not wish to attempt to change their minds. bottom line, everyone does as they wish. I can merely tell my side of the story.

Later,
Andy