Removing rust and cutting sheet steel, best options?

[BikerDad]

I picked up a remnant of 1/8" (approx) steel (12" x 79") for my bench rebuild. The sheet is a bit oversized, so I will need to cut it down sightly. It also has a pretty robust case of surface rusties. My experience working with metal, other than drilling, is very limited.

I have the following tools available to me for the cutting:

Jigsaw, hacksaw, Sawzall, 4.5" angle grinder and 7" angle grinder. I suspect that my best option will be either the jigsaw or one of the grinders. I do not have any cutoff disks for the grinders at this time, so suggestions on 'em would be appreciated if that's the best option.

For the rust removal, I have the grinders, plus belt sanders and random orbit sanders. I'd like to use whatever options I can that will have quick, effective results and minimal consumables cost, while also not tearing up my equipment.

For the grinder (4.5") I have some flap grinding discs, and can get some of these wierd spongy stripper things. I have gobs of discs/belts for the sanders.

 

[Thumper68]

I would use one of the grinders with a cut off disk, as for cleaning off the surface rust a paint stripping disk for the 4 1/2 inch grinder works real well as do twisted or knotted cup brushes.

 

[softailgarage]

You might want some earplugs too. My experience with cutting metal is it's loud as hell.

 

[bad_idea]

First thing: Face shield. Don't overlook safety.

Handful of cutting wheels (you don't need that many, but those are the style and brand I prefer) for the 4.5" grinder and a wire wheel (the twisted wheel type get into tight spots and last better than the none twisted. The wire wheel will throw wires everywhere. You will be picking them out of your fore arms and thighs, even through denim. Definitely wear a face shield.

 

[racingtadpole]

I'm not a fan of something rotating at 13k rpm throwing small steel spikes at me. I'd run your belt sander over it to clean the rust off, a coarse then medium belt should do the trick.
The thin cutting discs or a metal blade in your jigsaw will trim it to size for you.

 

[AndrewDouglasBird]

Cut with the 4.5" grinder and a cut off wheel, then sand with either the belt sander or the 7" grinder and a sanding disk.

Wire wheel would also work, but sanding will give you a nice flat surface, where as the wire wheel will just remove the rust and leave any pits.

 

[spongerich]

Chemistry is your friend.

You can get rid of most (or all) of the rust in 1 of 2 ways.

Evaporust - Buy a gallon for about $25. Get some plastic painters' drop cloths and some old thin blankets, sheets etc. Lay the steel on the plastic, cover the steel with your blanket and soak with Evaporust and then seal up the plastic so it doesn't evaporate. Leave it for 24 hours or so. You can treat a section at a time if that's easier.

Electrolysis is also a decent option. You can also do that with some electrolyte soaked towels, but it works much better if you can submerge the whole sheet. Get an old kiddie pool from CL, or just dig a small pit, line it with some plastic sheeting and have at it.

 

[BD1]

You'll get a cleaner cut using a circular saw with a metal cutting blade rated for your saw. Clamp a straight edge down and cut.

 

[scooz14]

i like cutting big sheets with a jigsaw or a metal cutting circular saw.

 

[jimgood]

For rust and scale removal, I like using the discs similar to the one you have linked on Amazon but I get them from a cheaper source. http://www.lehighvalleyabrasives.co...d-t27-clean-strip-disc-black-coarse-cs4-5-crs

These things work like a charm.

 

[rvieceli]

Are you cutting across the short 12 inch section of the sheet or down the full length?

If the short section then cutting to a marked line with a cutting wheel in an angle grinder is not too bad. Eye and ear protection a MUST.

that way you only have to buy some cutting wheels.

Depending on the level of rust, you might want to try the sanders you already have with some sandpaper to see how they work. If they work you don't have to spend any extra money. If they don't do the job you can always try something in an angle grinder.

 

[zkling]

How long is the cut you need to make? 12" a jig saw or sawzall with fence guide will be great.

Get rid of the rust with a cup wire brush on the 4.5" grinder for starters.

 

[MoonRise]

#1 - Safety first.

OK, that out of the way, although you can remove 'surface' rust with wire wheels and abrasives (BTDT, more than once ), it takes time and effort.

If you can, chemical removal methods usually take less effort.

Simple (relatively) way to remove surface rust is just to use a relatively strong acid.

Naval Jelly (phosphoric acid), or some other phosphoric acid metal prep can work.

Or CAREFULLY use some muriatic acid (aka hydrochloric acid).

Or the electrolysis method (look it up).

Like I said, abrasives can work. But that approach usually takes more time and effort. If you want to turn one of your belt sanders into a 'for metal use' machine, you can go that route too.

Cutting that plate? Jig saw or recip saw with the appropriate blades can work. So can some cut-off wheels (aka zip disks).

If you have a 7-1/4" circular saw, you can buy a 'special' saw blade that has carbide tips that is made to cut plain mild steel. About $30-$40 or so, works great to make nice straight cuts through 1/8" steel sheet. BTDT. Waaaay faster and 'easier' than a jig saw or recip saw or cut-off wheels. Watch out for the cut edges though, they are sharp.

http://www.amazon.com/dp/B00008WQ3B/?tag=atomicindus08-20

http://www.amazon.com/dp/B001CZJ56M/?tag=atomicindus08-20

http://www.diablotools.com//products?c=Saw_Blade&material=Metal_Cutting

http://www.metaldevil.com/

or similar blades. (I've personally used Morse and Freud versions, both worked well. About 10,000% faster, easier, and 'better' than using an abrasive blade approach IMNSHO. )

Or torch cut it. Oxy-fuel or plasma.

 

[Farrier]

Dust masks are your friends OP

 

[ZRX61]

Simple (relatively) way to remove surface rust is just to use a relatively strong acid.

Naval Jelly (phosphoric acid), or some other phosphoric acid metal prep can work.

Or CAREFULLY use some muriatic acid (aka hydrochloric acid).

or use Ospho.

 

[kazlx]

Just disc or belt sand it, especially since you have them. 36-80 grit depending on how bad it is. I prep pretty much all my metal that way. Don't waste your time with acids, you will have a problem with more rust afterwards if you don't paint it.

Jigsaw with the right blade, clamped down tight with a guide will go super quick. Then, just deburr the edge when you're done with the sander.

 

[BikerDad]

Thanks for the inputs. For the rust removal, I think I'll pick up some of the stripper spongies, and then simply experiment. I now have an abundance of sanders (and media), so I'll use the ROS, the belt sander, and the grinders. There's no hurry, and I enjoy messing around with tools (if I didn't, why would I hang around here??). I'm going to pass on the electrolysis and Evaporust, I don't really have the room to set up properly for either one. If the piece were smaller..... And I'll skip on the wire brushes. The responses here have simply reinforced the idea that too many of those wires seem to escape. I'd prefer to avoid myself or my surroundings being pincushioned, whether it happens immediately or I find a wire embedded in one of my motorcycle tires later....

The cutting is still on the fence. I know I will need to do a cut across the 12" side, don't know if I'll have to do a rip cut yet. The circular saw blades linked by MoonRise are definitely an option, although the cost is a bit more than I expected. I must admit I'm a bit surprised they would sell those, given the much higher RPM's that a 7 1/4" circular saw runs compared to the smaller "metal cutting saws". More than twice the Surface Feet Per minute. They do sell them though, and it's not like Freud is a fly by night operation lacking socks to be sued.

With regards to safety equipment, oh yeah. I wear ear plugs very frequently in my shop. Routing, tablesaw, shop vac, running the jointer/planer w/ dust collection, often even when using my impact drivers. Also if I'm using the oil free compressors. And I was planning on using eye protection for any of the cutting/rust removal operations that go beyond a random orbit sander. Dust mask for all... Still, the reminder is appreciated.

All of this activity will take place outside, where it's highly unlikely any hot sparkies will land in piles of plane shavings or sawdust.

I'll report back on my impressions of the different methods of rust removal after next weekend.

 

[Crusarius]

if you use sawzall or any other type of saw blade do not try to cut it at full throttle. That is the quickest way to destroy the blade. Cut it slow and steady. Don't force it.

I also prefer the knotted wire wheel on the angle grinder for rust cleanup. The other thing that works real nice depending on the finish you want is a worn out flapdisk. I have a ton of these and I can get a mirror finish on the plate with them. No swirl marks since they are essentially a piece of canvas spinning at high RPM's

 

[jimgood]

Unless it's deeply pitted, I can almost guarantee that the stripper discs will remove the rust on that sheet in under 15 minutes.

 

[BD1]

Might consider calling a local sheetmetal shop on shearing the piece. It may be the easiest.

 

[kazlx]

That's another good option. It would be cheap, clean and perfectly to size. I'm also kind of curious about the amount of rust. 1/8" isn't that expensive to buy (4x10 sheer around here is ~$80) and if you really need to clean up that much of it, you might be better off getting new material or buying a pre-sheared piece that you need from a sheet metal place. I wouldn't go out of your way to clean up a rusty piece of 1/8" unless you just have abrasive to burn.

 

[MoonRise]

The cutting is still on the fence. I know I will need to do a cut across the 12" side, don't know if I'll have to do a rip cut yet. The circular saw blades linked by MoonRise are definitely an option, although the cost is a bit more than I expected. I must admit I'm a bit surprised they would sell those, given the much higher RPM's that a 7 1/4" circular saw runs compared to the smaller "metal cutting saws". More than twice the Surface Feet Per minute. They do sell them though, and it's not like Freud is a fly by night operation lacking socks to be sued.

I was skeptical at first too (cut steel plate with a 5000 rpm woodworker's circular saw with a carbide tipped blade? WTF?). But they work, and work well.

Not necessarily the most cost-effective way to cut steel, but waaay faster than abrasive cutting methods (abrasive blade in same saw, or zip disks on a grinder), no dust (but sharp swarf ), and a rather nice cut quality (it is a machine-cut edge, after all).

For a straight line cut, clamp a cutting guide to the steel and make that cut.

Only way faster (at home) would be a torch cut.

Or get a shop to shear it to your desired size.

All of this activity will take place outside, where it's highly unlikely any hot sparkies will land in piles of plane shavings or sawdust.

Famous last words there. I've set my lawn on fire with an abrasive cut-off saw (aka 'chop saw') cutting steel angle iron. And there was green grass there.

 

[sberry]

I would sand off some rust to clean it what I could and sawzall, safe, fast and leaved a decent finish.

 

[jeepinerdeep]

Cutting- A 12inch cut across 1/8, pretty much anything you have listed will work.

Cleaning- If its pretty flat and you have a 3x21 belt sander. A pack of 50 or 80 grit 3M Purple Regalite belts is about 13 bucks on Amazon. 5 to a pack, you'll have leftovers, and you can even use it to clean up any rough edges from cutting.

 

[sberry]

I am gong to agree, if there was anywhere friendly to get a new piece of steel its something to consider. I use old **** but use it where its on other old **** and doesn't need to be wholesale cleaned.

 

[tarbellb]

Belt sander and jig saw with straight edge. 30mins.

Clean up with orbital sander and 4.5" for burrs.

Kazlx has the most useful insight imo.

 

[kazlx]

IMO, liquids are out of the question on something that size and it's a waste of time and money. If you can't clean it up with a quick belt sand or DA sander, also wasting your time. Jigsaw will cut it extremely easily. Either that or pay for it to get sheared to size. Otherwise, save it for another project and just pay to get the correct piece cut. I know at my local shop, you could buy new material, have it sheared to your exact size and still get to keep the rems and probably be a little bit over the $100 mark.

You could also find a sheet metal shop and have them shear something they have to size for you for less than that, especially since you are just using as a top and don't necessarily need 1/8".

Don't buy a bunch of extra **** you don't need, unless you really think you'll be doing more stuff in the future. No need for a metal saw blade that costs more than the top you're trying to build unless you really have repeated use for it.

 

[kkroger]

In my shop I could use the Plasma, Milwaukee 8" metal saw, Sawzall, Cutoff wheel on the /4.5" or 9" grinders, Take it to my steel supplier and have him shear it...

Knotted Cup or Wheel on a 4.5 Inch Grinder... Flapper on the 7/9" Grinder, Flapper on the 4.5", Phosphoric Acid, Muriatic Acid 50% with Water in a Hudson Sprayer, keep it wet then rinse with water when rust is gone... Or Take to shop and have it abrasive blasted... Granted by the time you did any of this you could probably just get a new piece from the steel yard. Shear Cut and Clean...

 

[BikerDad]

In my shop I could use the Plasma, Milwaukee 8" metal saw, Sawzall, Cutoff wheel on the /4.5" or 9" grinders, Take it to my steel supplier and have him shear it...

Knotted Cup or Wheel on a 4.5 Inch Grinder... Flapper on the 7/9" Grinder, Flapper on the 4.5", Phosphoric Acid, Muriatic Acid 50% with Water in a Hudson Sprayer, keep it wet then rinse with water when rust is gone... Or Take to shop and have it abrasive blasted... Granted by the time you did any of this you could probably just get a new piece from the steel yard. Shear Cut and Clean...

yes, well, my shop is primarily a woodworking shop. So no welders, oxy-acetylene torches, plasma cutters or metal saws. (Yet... ) I did see a YouTube video recently that included a plasma cutter and by gosh by golly I WANT one. Just because they're epically awesome. That, however, is not enough justification for me to drop the coin on one, so ...

One of the problems for me with the steel yard is their location and hours. When I first moved up here, neither would have been an issue, because I worked a block away from them. Now, however, I work 15 miles in the other direction and they have bankers' hours. Actually, my bank has better hours! Since I've decided that this is a very forgiving "project" that's as much about me exploring different methods of doing some things, just getting a better hunka steel is not exactly the direction I'd like to go.

 

[62blue]

Here is a thought that you can save for future use. If the parts aren't to big you can use regular vinegar form the grocery store. Around here you can get it for about $1.49 to $1.69 a gallon. I use the white stuff just let it soak and keep a eye on it as if you leave it to long it will eat into the good metal. I have used this stuff for sheet metal auto parts. It does a really decent job. Just use it over and over until it gets to rank to use. Oh just rinse it off with water and metal prep it.
62blue

 

[TheEquineFencer]

That's another good option. It would be cheap, clean and perfectly to size. I'm also kind of curious about the amount of rust. 1/8" isn't that expensive to buy (4x10 sheer around here is ~$80) and if you really need to clean up that much of it, you might be better off getting new material or buying a pre-sheared piece that you need from a sheet metal place. I wouldn't go out of your way to clean up a rusty piece of 1/8" unless you just have abrasive to burn.

I was wondering when someone would say what I was thinking, toss it, write it off as experience, you'll probably spend more time money and energy cutting and cleaning than it's worth. Buy a whole sheet and have it cut to size, it hurts one time.

Then again, I've done almost the same thing. I've had a whole sheet of .120 gauge sheet that sat outside and got rusty, sort of heavy scale and I didn't have anything else to do at the time, so I wore out a 4-1/2 inch wire wheel cleaning it to reuse. I was VERY dirty when I finished. A fan, gloves and safety glasses are a good idea.

 

[yhprum]

If you have w welding shop nearby their plasma cutter will make quick work of it for a few dollars.

 

[steel 35]

And I go out of my way to make things rust

 

[ilovevocs]

I have had good results on larger areas using evaporust. I lay down a sheet of 3 mil poly, put the plate down, lay rags over the area, soak them with the evaporust, and then wrap the poly over the top like wrapping a big present.