sodium bisulfate scale removal

[Tai Goo]

I had another thought about how the sen scraper and abrasives stones may be working. With the stones, I use a course stone with a small surface area of contact. There is some abrasion going on, but also the pressure on the scale with the small surface area sort of buckles the brittle scale and pops it off as well. With the sen something similar might be happening as well as getting under the scale.

 

[Greg Obach]

I started using it because vinegar was too weak to get things done like I wanted, muriatic fumes way too much and I don't like soaking my steel in hydrogen based acids, so I was using sulfuric acid for a while but didn't like the nasty stuff sitting around, so I gave the bisulfate a try for an effective yet tamer solution. I never did the blasting thing becasue I have a cabinet that I don't want to refill anytime soon and while doing my fine work I like to know I am using the silica bead media of a uniform grit, not the media mixed with assorted chunks of iron oxide and black glassy flux.

it works great with L6... the scale on that is pita to remove... why as if you forge with W1 or plain carb stuff...scale comes off easy with acetic


G

 

[Tai Goo]

Good to hear some talk about scale.

I think trying to minimize scale in general is a good practice, especially on alloys with sticky scale.

I usually de-scale once after the higher temperature rough forging, and when I go to the finishing and straightening, (lower temperature heats), I make an extra effort to run it very reducing. With propane I throw in some wood chunks or use wood splits to run it extra rich. It actually coats the blade with soot. This makes the final de-scaling and clean up much easier.

The initial de-scaling can be done with a simple die grinder and an abrasive stone bit or tungsten carbide which pops scale off. However, I usually do the final clean up with hand stones,... especially if I plan on leaving some hammer finishing and process marks... never cared much for machine marks on my blades though.