Cleaning Steel - Surface Rust / Mill Scale

[bp71k5]

Well a complete longbed truck frame is a little bigger than a trans tunnel...

Ah, I somehow missed the truck frame and only saw the crossmember part. Makes more sense now.

 

[Billyworld]

Roll cage tubing shouldn't have any mill scale on it anyways. Any of your mount plates that do have scale, I'd hit with a sandblaster. Hell, price out having the cage professionally stripped and primed. You might be surprised...

tRustyK5. Name checks out. Lol. I'm getting a cheap sandblaster today

 

[Billyworld]

Some powder coating ships will sand blast everything you give them to coat. Might be an option that wouldn’t cost all that much extra. I’d like to get my cage powder coated sometime as the rattle can paint gets hammered by the sun.

Speaking of hammered and rattle can, i painted my cage with Rust-Oleum rattle can, hammered black. It's finish is forgiving, and touch ups are invisible. I really like the way it looks. So easy!

 

[CGT80]

mil scale.. good luck with that! only way I know to get it off is mechanically... the DA with 80 to 150 will work thru it... i do like to remove it whenever possible, but you can just sand it and prime/paint too.. I've never tried a nasty acid like muriatic on it, but I'd bet it won't budge it...

Muriatic acid eats mill scale like candy!

After cnc plasma cutting parts, I soak them in a tank of 50/50 acid and water, for a couple hours. They come out with no millscale, most of the dross gone, and they look white like they were blasted. They do flash rust easily after being rinsed. Sometimes I will hit them with crushed glass in the blast cabinet after they dry. It beats grinding slag on thin sheet metal parts that warp easily and does less damage than a flap disc on heavier plate. The only drawback is that it could be possible to get hydrogen embritlement after welding parts that have been acid dipped, but most of my stuff isn't structural in a way that a failure would be a major deal.

The acid is nasty and my tank is just a large plastic tote that is kept away from people and pets.

 

[KirsL]

Muriatic acid eats mill scale like candy!

After cnc plasma cutting parts, I soak them in a tank of 50/50 acid and water, for a couple hours. They come out with no millscale, most of the dross gone, and they look white like they were blasted. They do flash rust easily after being rinsed. Sometimes I will hit them with crushed glass in the blast cabinet after they dry. It beats grinding slag on thin sheet metal parts that warp easily and does less damage than a flap disc on heavier plate. The only drawback is that it could be possible to get hydrogen embritlement after welding parts that have been acid dipped, but most of my stuff isn't structural in a way that a failure would be a major deal.

The acid is nasty and my tank is just a large plastic tote that is kept away from people and pets.

Be careful welding on parts that have been chemically dipped. You want to make sure it's all clean off before welding. It can make some nasty fumes if you're not careful.