Tempering

[etp777]

I can always find a question to annoy y'all till I get my books.

Ok, have an old craftsman file, which I'm guessing is W2, as a rough guess. Either way, I think it'll turn into a decent knife with a good heat treat, though not up to real steel(ordering my real steel on monday, so have to keep grinding the old files I have until then).

Anwyays, as it's going with a tactical style thing, got 1200deg. flat black header paint for it. Wanted to try a park finish, but oculdn't track down the stuff I needed for that.

So anyways, I normally(on the whole two knives I've done so far ), temper arou nd 425 for a half hour and then up to 450deg for a few minutes. Comes out a nice dark straw color, and seems to have turned out very strong without being brittle, which was my goal.

I would like to achieve about the same temper/strength on this knife, but it suggests curing the paint at 1.5 hours at 400(there are also directions at 600 and 300deg, but figured these temps were too far off my "target" range for tempering). So what kind of performance difference on the temper will I get with the longer, but cooler temper? And are there any other options on this?

 

[Terry McMaster]

Straw brown color on the steel you described will probably be just fine. It should occur at 400-425. If you are trying to get the Park finish at the same time (wise) I would shoot for 410 on both and see what you get. LOL Terry

 

[Guy Thomas]

I'm with Terry, split the difference at around 410 degrees F and see how it comes out. I doubt the 10 degrees difference would matter much in curing the paint. I'd try a second or even third tempering cycle as well. I've gotten good results from 1084 tempered at 410 degrees on a convex ground tactical knife I made using a triple temper sequence for an hour each cycle. (Previous questions I asked various makers on tempering 1084 ranged from 375 degrees to 425 degrees).

File steel shouldn't be much different in it's heat treating regimen from 1084 but the type of grind needs to be taken into account. A heavy convex grind has more beef behind the edge and can take a lower tempering temperature without risking chipping. Thinner blades of course need a higher temperature. I was looking for a happy medium as I was tempering four knives at the same time all made from 1084, but with radically different blade sizes and grinds.

Make sure you use oven thermometers!

 

[Greg Covington]

Wanted to try a park finish, but oculdn't track down the stuff I needed for that.

Go to www.brownells.com and look at Amerlene Parkerizing solution. I really like the stuff, it is cheap and easy to use.


Greg Covington

 

[Scott Fulford]

etp777,
Here`s what I do.....
grind drill and finish the blade to 220 grit,harden it,sandblast it and blast it with brake parts cleaner to remove any imbedded sand and any trace of oil(the BPC will cool the blade to the point where condensation gathers on it so let it dry),paint it with a light coat of header paint,bake it at 400 degrees for 1 hour.Let it cool,spray on another light coat,bake it another hour at 400.let it cool,and bake a third time at 400.
Youre tempering the blade and baking on the finish at the same time,
I`ve found that 400 degrees works fine for the 1084 I`m using,as shown by the brass rod test but you might want to do some testing to get the temp just right for your oven,(400 indicated in my oven might be 425 in yours or vice versa)1084 and W-2 are forgiving steels when it comes to the heat treat,dont be afraid to experiment,try different quenching oils,multiple quenches,multiple temper cycles at different temps,or wear different shoes each time you quench,break a few blades that you`ve treated and notice how far they flex before breaking,and try edge quenching too,it`s the way I do it,why harden parts of the blade that need not be hardened?

As far as the paint goes,it`s not picky about temp.
Scott