Quenching Blocks Question

millejn3

Well-Known Member
Hello Everyone,

I will be ordering a heat treat oven very soon and I have friend that owns a scrap yard that has found me some aluminum plate for quench blocks. The plate is 1/2" thick. Heres my question; Everything I see that I can buy is 1". Would there be any issues with cutting the plate a little longer than needed and bolting it together? Of course I would be counter bore the bolt holes so that the heads/nuts of the bolts wouldnt interfer.
He also found some 3/4" thick plate for me as well. Would 3/4 be OK or does it need to be 1" ?
 
bolting a couple 1/2" plates will work if they are flat and will touch across the entire plate. The idea is to conduct the heat away quickly and a small air gap between the plates might be an issue. The idea is, the more mass of aluminum available, the more heat can be pulled away quickly. I'd bet the 3/4" plates will work and you won't have to mess with bolting the thinner plates together. Use compressed air and shoot in between the plates as you quench and it should work. Copper would actually work better but it is so expensive that no one uses it.
 
No need to cut them longer IMO... just drill and tap from the under side, and use some flush mounting screws/bolts.

I'd probably get a tube of heat sink compound (aka thermal paste) and spread some between the middle for a little added help in heat transfer. Probably not entirely necessarly, especially if you're using compressed air in addition to the plates, but it really couldn't hurt.
 
Thanx! As far as size of knives I would be quenching, I make hunting knives. The largest is 3/16 thick and about 9" max length.
 
make sure the plates are several inches larger around than the blades so you don't have any sticking out and burning you. I always wear heavy welding gloves. I've been burned enough to know I don't care for it.
 
I've been using 3/4" quench plates and they seem to be working just fine. As Tracy said, blow air thru plates to make cool faster. I mist a tad of water on outside of plates for really nice cooling - notice I did say "mist on outside" and with the 440C and Sandvik I've been using the Rockwell tests after show good results.

Ken
 
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