Heat Treat scale question

R. Mark Lee

R. Mark Lee

Joined
Oct 21, 2002
Messages
232
Hello Everybody,

I've heard of placing a piece of paper in the SS foil when wrapping a blade prior to heat treat to reduce oxidation, but I was wondering if you sprayed the SS foil with something combustable (WD40, pam, etc) would this work as well? Has anyone tried this? Just thought I'd ask before trying it myself. I thought this would make for a tighter seal/wrap. Thanks.
 
Mark

I can't help you with your question but does this mean your getting ready to HT some blades? I've got two possibly three ready depending on when your ready. Hope the offer is still open.

Darren
 
The problem with most combustibles is that, while they will probably use up the oxygen in the packet, they'll also make as much of a mess where they contact the blade and burn as the oxygen will. Also, most combustibles will also cause your packets to balloon up and possibly break your seal.

I used to put a small piece of paper or tissue in the packet with the knife on the handle end until I had a few packets balloon up pretty big (at least I know I had started with a air tight seam). I since just wrap the blade up well in a snug packet, and don't worry much about the minimal scale (more like discoloration than scale) I get after heat treating stainless steels. It pretty much just sands right off in finishing.

I do know that a good number of makers use a combustible in the packet, I'm just not sure what works best in a sealed packet.

--nathan
 
We too use combustibles (brown paper) in the foil pack and have not had an envelope blow in a LONG time. We do get a small square 'stain' where the paper was. I too have wondered about using some other combustible and will be following this thread with interest. I haven't done any of my own knives for a while and I'm certainly not going to risk a customer knife on the experiment. I would think that the ideal combustible would be a pure hydrocarbon - yeilding only CO2 and H2O in combustion, and preferably not too volatile so it burns early (< 500 degrees) and not explosively. I would be concerned about WD40 (though many consider it omnipotent) because of it's silicon component. I have considered BBQ charcoal powder as well as :eek: old gunpowder - (I have lots of that) - and even things such as lighter fluid or kerosene.

The experiments would be pretty easy, but I just plain don't have the time right now especially with very good results already. Watching............

Rob!
 
I guess my other problem is I start with a heat soaked oven, so the oven is 1400 F or more when I put the packet in. In other words, whatever combustible I use burns FAST. Maybe if I started with a propane torch or something to burn the combustible prior to putting it in the furnace I would have better results.

I too will be following the suggestions with interest.

--nathan
 
Thanks for the feed back everybody. I was also wondering about the residual mess left behind by some of the different products available off the shelf (for example the miracle liquid WD40). I might try a side by side test with just tightly wrapped foil and the same tightly wrapped foil with perhaps a combustible of choice from this thread.

Darren, I haven't fired up the oven yet just thinking ahead to what I want to do. I have a buddy in Ohio that sent me two blanks to heat treat, one O1 and the other 1095 plus a couple I'm working on. Shoot me an email or give me a call and we can figure out when I might be doing when to do your blades.
 
powdered wood charcoal is almost pure carbon, it will go pretty much entirely to CO
when I am heat treating I throw a couple of chunks of homemade wood charcoal in my electric kiln to produce a reducing atmosphere. I should play with some stainless and look at it under a microscope. but it would seem to me that wood charcoal powder inside the SS foil would be slightly better than brown paper

-Page
 
My experience is to place a stamp size brown piece of paper from a grocery sack inside the SS foil packets. The blade come out looking great with the silver and rainbow color finish. My son when he was a toddler called them rainbow knives because of the blue, purple and red color from the initial heat treat.
 
Degrease your blades. Crimp the foil packets well and fold over 3 times on each end.....they will come out scale free. No combustibles required.
 
I agree, Being a Tool and Die maker for 15 yrs. I have even seen people put cigarette butts in the foil. Think about it this way, anything you put in there can create an air pocket. Cleanliness and proper packaging is the key to being scale free.I make most of my blades from D-2 and never have scale issues.
 
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