P B C non scaling compound

P

Pete Allan

Joined
Oct 29, 2003
Messages
220
Being somewhat new to knife making but not to metal working I tend to follow the ways I have been doing things for the past 60 + years. I have used Boric Acid as a coating for heat treating for as long as I remember. My results have been from almost good to almost bad but never like using no coating at all.
About a week ago I broke down and called Brownells and ordered their P B C non scale compound and used it on 4 blades this morning. Now you must understand I am Scotch and find rather hard to spend money but this is one of the BEST items I ever bought. All 4 blades came through heat treat as smooth and shinny as before I started and not a single speck of decarb. I was using 1084 carbon steel and I would say I saved myself at least 2 hours of finish sanding because of using the P B C.
Thank you Mr. Primos for your wonderfull show and tell on heat treating.
 
It is good stuff. It took me longer to go up the learning curve of how to use PBC from Brownell's than it has you. I also want to alert those that do stainless foil wrap of a disaster waiting to happen to you after using PBC in the same oven. Here is my experience: I did a blade coated with PBC. All was well. I neglected to clean the residue off the refactory brick that I place my blades upon while in the oven. The next blade I did was a S30V foil wrapped. At the S30V austenitizing temperature, well above PBC rating, the PBC residue on the brick that contacted the foil attacked the foil and eat through it. It was a long 2 inches of exposure. Pretty nasty but not enough to not be able to save the blade but plenty bad enough to have learned a good leason. I would also advise keeping the PBC coating away from thermocouples because if its residue contacts it the next time you go high on your oven you may loose the themocouple termination.

RL
 
Pete,
Thank you for the mention. I really appreciate it. I'm glad you found the information useful.

Roger,
Cut a piece of your stainless steel HT foil and put it in the bottom of your oven when you are going to be doing the carbon steels. It will catch any of the run off.

When you do stainless steels, just remove the protective sheet. It keeps the bottom of the oven clean. I use the sheets for months before I have to replace them. I don't cover the entire bottom of the oven -- just enough to accomdate the largest knife I make.

Also, I don't put blades coated with PBC directly on the bottom of the oven (on the stainless steel sheet). I have some little ceramic "fingers" to rest the blade in. So the blade is suspended above the stainless steel sheet. Any excess PBC will drip onto the protective sheet.

Am I making sense?
 
Terry, I neglected to mention that I learned to do that (almost too late). I place stainless foil on the floor and on the refactory brick I place upon the floor when I use the PBC.

Thanks Terry for that good advise.

RL
 
Hmmm I just learned something. Thanks Guys. Its a good thing I dont do stainless blades very often. I just send them to Roger. Maybe I should check my oven floor.
 
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