HT Foil Wrap

Michael J. Spangler

Michael J. Spangler

Joined
Oct 8, 2003
Messages
2,181
ok so i scored some for an amazing price, now how exactly does one go about using such a thing, well moreso how does one go from the oven to the quenchant if using it for a oil or water hardening blade? or would using it on anything less than stainless and air hardening just be foolish?
 
I have recently done numerous testings on RWL-34 and some of those involved oil quenching 'in the foil packet' and also taking the time to remove from the packet before quenching. My conclusions were that neither were as good as air quenching in the packet (for air quench steels) or oil quenching without using a packet at all and that oil quenching is over all best. I do not use foil for carbon steels or simple steels but do for high alloy steels and air quench them while in the packet. I have decided, for myself at least, that an oil quench is best and that using a packet prevents me from getting the steel into quench fast enough.

Roger
 
You have a good disposition about this. Look at the foil as your first tool purchase toward gearing up for heat treating the supers. Now, as you are pinching pennies for the Parogon, also start looking out the corner of your eye for a good dewar.

RL
 
dewar? definition please. i'm very new to the whole air hardening steel techniques, but i'm willing to experiment to make them work thats for sure! well i think the tax retun this year won't make it to pay bills but will make it to pay for a furnace:D
 
Dewar, A phrase often used by drunken sailors whilst eyeballing the local female populace.

Or a container for holding liquid Nitrogen
 
thanks.... now where could i find one of those? i assume its for te cryo, and uhhhh where to i buy liquid nitrogen? and can someone give me a brief detailed explination of cryo, i've heard a few but would like a better one
 
I wasn't aware of that first definition but I think I've done a lot of that.

Cryogenic treatment transforms retained austenite into un-tempered martensite. That IS IT and the steel needs to be tempered after freezing. There is an argument about the minimum and maximum optimum temperatures. liquid nitrogen is below -300 F.. Dry ice is about -109 F.. We use one or the other. Check a local welding supply store as to where in your area is best to find liquid nitrogen. Dewars are used to store liquid nitrogen and may be bought there new or used and if not Ebay is another source and they are normally expensive, several hundred dollars.

RL
 
how about pricing on cry ice and liquid nitrogen? i would imagine nitrogen costs more, but what do you mix with the dry ice before the quench? and how do you store the dry ice during the cryo process?
 
Pricing seems to vary within different parts of the country. For me, once I got the dewar, LN is much less expensive and I only have to make a trip to the vendor once every 5 months. I doubt there is a home method of storing dry ice over a long period. I used to get it for each individual knife and it would cost me 7 to 10 bucks. I tryed mixing with kerosine but you need to line a styrofoam cooler because the kerosine will eat it up. I have also used the dry ice without any medium. I like using LN much better.

RL
 
rlinger, I know that eventually I'm going to have to get a dewar and do LN. How much does it cost on the average for you and how long does it last? I'm sure length varies with use but just a wild ballpark so I have some kind of idea.
thanks
 
Tracy, I pay about 70 bucks (something like that) to fill my 20 liter dewar. That is expensive for some areas of the country and maybe inexpensive for others. I have what I believe to be an excellent dewar. If not used much it will last me about 5 1/2 months. This last refill I have been doing a lot of heat treat testings on sample pieces of steel and am doing more blades so it has seen much more use and I do not expect it to last much past the four month mark. It may go 4 1/2 months if I am real lucky. The biggest expenditure is a good dewar. The price of LN is much less over time than having to purchase dry ice on a as need basis.

Here is the dewar I have and I got it from this very Ebayer: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2587973188&category=7321

RL
 
I ended up with a lab dewar off from E-bay.
it's a shot term transportation container

when I need the LN I go the the bottled gas company
it holds 9 LB's and it cost me $10.00 but
I have a cylinder account with them also but you can pay
$2.00 or more a pound depending
how much they want to rip you for.

this dewar I can put 7-8 blades in and
let it do it's thing
until it completely gone, about 24hours
and this lets it warm
slowly with out touching it, it's been
working right for me.
I don't have to store it while not a use for it.. :)
 
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