What cuts the "crust" off steel

I made my ch***is out of 2x4 box. I'm going to clean it up for paint this week, the steel has a hard crust on it that is hard to cut with sandpaper or silicon carbide disk on a rotary sander. Tiger Paws are the closest thing I can get to work, but they burn up pretty fast.
ANY SECRETS?
I have a lot of real estate to sand.

 

It is called mill scale and the only solutions I have seen involve soaking it in acid, which is obviously out of the question for you. AFAIK, lots of discs is the only solution. You did remove the scale before welding, right?

 

Sandblasting? Might be quicker and easier than wearing yourself out with a disc grinder and 36 grit.

 

I'm working with an older aftermarket frame.Previous owner had primed it for protection.As it was sat for a few years some patches of rust have developed.Once I've finished working on the frame,I plan on getting it sand blasted.Probably not the cheapest way but,it'll get all the **** off in all those hard to get to places.And you'll still have finger prints at the end of it!
Mark

 

If you want to cut the scale quick and rough, I'd use a flap disc on a 4" grinder. otherwise, some 36g sanding discs on an angle grinder will do.

 

Yes, I ground and beveled everything. It's hard to even scuff, if I get and etching prime I guess it'll be okay.

 

Sandblasting works nicely.

 

Thanks for your help, I guess the frame needs to go with the tub to the blaster.

 

i use the gl*** bead machine for smaller items i'm fabbing. takes it right off.

 

Yeah sandblasting is the way to go
later on... years from now if not blasted - the paint will blister from that mill scale popping up

 

flap disk on a side grinder as was already mentioned. I love the ones from Lehigh valley abrasives (online sales also) I get the Z40 4 1/2" version which is priced very right and lasts better than anything else I've tried.

OC

 

Go to Harbor Freight, buy a cheap pressurized blaster and do it yourself in the back yard.

 

Nah - been there, done that. For about $100, it's not worth the mess outside in the cold.

 

This.

I tried sandblasting a crusty pickup bed with a HF pressure pot. Took me several days and about 5 or 6 80lb bags of sand. Made a huge mess and the results weren't that great. For about what I paid for the sand I coulda had somebody else do the work in less than a day.

 

blasting is best, don't use any type of plastic media (gl*** bead) it leaves behind microscopic streaks that will eventually cause coating failure.

aluminum oxide is the way to go.
I would recommend going to a professional blaster, we blast new model A frames for a local builder usually about 1 hour ($60 pr hr at our shop)
definitely worth $100 or less to have someone else do it

 

Mine works good but I've never done anything as big as a frame either. I plan to throw up a booth out of tarps and reuse my abrasive when I do my frame in the spring.

 

for my money, I'd sand blast it....faster , cheaper, best results.

 

Yeah for what it costs take it to a sandblaster. I had my frame done for $100.00 and I own a pressure pot sand blaster. By the time you pay for the sand, buy a respirator so you don't kill yourself, spend time setting up, blasting it and then cleaning up the mess it is nowhere near worth not taking it somewhere to get it done IMO. Small stuff I can see but not a frame.

 

Sand blast

 

I've had success with a product called "Pickle X".

"Must for Rust" is a product I get from Ace hardware also works good.

Spray or wipe it on, use a Scotchbrite pad or wire wheel and it comes out nice and clean.

Both products claim they will prevent rust from coming back.

 

Thanks for your help guys. Sandblasting was the way to go, it cleaned up a lot of spatter, etc. Epoxy prime and paint/clear:

 

blasting is best, don't use any type of plastic media (gl*** bead) it leaves behind microscopic streaks that will eventually cause coating failure.


Plastic gl*** beads ?

 

SANDBLAST IT. Get some one to blast it for you,not worth the mess doing it your self.

 

I have a similar problem on a round tube frame of a lakester we are building. I had good luck with a product called Rust Blast made by KBS. I soaked pieces of terry towel in the Rust Blast and wrapped them around the tubing. Waited about 1/2 hour and unwrapped . Scale removed and tubing has a mild etch.Don't let towels dry on tubing. Yo7u can use over again as long as cloth is wet.

 

I used a twisted wire wheel from HF on my 56 frame and It worked great.I'm doing all the inner fenders and supports.I used it on a 4" grinder.

 

You mentioned that the previous owner had used primer to protect the frame. I learned the hard way long ago....primer is for giving paint a surface to bind to...it does not protect against oxidation well at all.

 

Its the carbon coating from the processing. Its easier to blast it clean. You can grind it but it only takes a few minutes(60 or so) under the deadmans valve to be rid of it all.....Dave