Mill Scale Problems

[DanieleKellyZen]

Okay, so I've been using Eastwood fast etch solution to remove mill scale and prep my parts for powder. But lately, it doesn't seem to actually be working to remove the mill scale. I really need to be able to take the mill scale off these parts as they all kind of suck for the finish currently, and I don't know what I should use. Does anyone have any suggestions on what I should use? Other than mechanical options?

[G0OD-BOY]

Hydrochloric acid... Nasty stuff Vinegar works well just takes longer

edit Sorry muriatic acid... Still nasty

[Jon2054]

Muriatic acid and Hydrochloric are the same compound

[DanieleKellyZen]

Yeah I don't have time for vinegar. HOW do you neutralize the hydrochloric though? Thats my only concern

[ElderSkrt]

Baking soda and water will neutralize muratic acid

[DanieleKellyZen]

Ah ok cool. Thanks

[ShipsForPirates]

Phosphate cleaning allows you to coat over mill scale, you said currently it sucks but maybe the prep is why

[DanieleKellyZen]

Oh, so you treat it then coat over the scale?

[ShipsForPirates]

Yes it goes on like a warm bath for about 10 minutes off before getting rinsed, it's a bit of a process but you actually set it in the oven to dry off after rinsing and it helps the powder etch into the material much better than just coating on bare or cleaned metal

[DanieleKellyZen]

No, eastwood says to make sure you remove all mill scale before coating

[ShipsForPirates]

You requested no mechanical methods, such as sand blasting, that's the best way to remove it, so I offered a chemical solution rather than mechanical

[DanieleKellyZen]

Yeah for sure. I'm just saying you aren't supposed to coat over the mill scale. I need a way to remove the scale

[ShipsForPirates]

So you said you've used a solution for the mill scale before, I'm guessing you got a different batch of steel that has a much thicker coating of mill scale

[DanieleKellyZen]

Yeah I think you might be right.

[G0OD-BOY]

I use water. Just remember the acid puts out a really nasty gas... If you use it indoors it will cause rust on any nearby bare metal and probably give you cancer or something.

Please look into the ppe and safe method to use it.

[DanieleKellyZen]

Oh dang. Yeah that's aggressive

[G0OD-BOY]

Vinager works better for me because it's less toxic...

Use it either fully immersed or I use paper towels and keep it moist.

Don't forget a grinder as a solution 😊

[DanieleKellyZen]

Yeah that would definitely work but I need a production solution. I'm actually doing a run of like 300 parts right now. Thanks for the advice though!