Which is best, perlite or vermiculite?

[Rolf]

To aneal springstock, which is best? Perlite or vermiculite


Best regards
Rolf

[Metalshaper]

Rolf,

 I use lime for all my annealing!

 I have a bucket of garden lime in my shop.. I put a preheated  scrap bar in to warm it, while I heat up the true part. Then slip the 'part' in as I pull the scrap piece out of the way.
a lil tap with the toe of my shoe and the lime seals over it and I let it sit.  never used either of the other materials..

Respect Always
Metalshaper/Jonathan

[Buffaload]

I keep a can of wood ash under the bench.
Ed

[Majorjoel]

I have read that bone meal is used for heat treating steel but have no experience with it.

[PPatch]

I use warm sand, used pretty much as Metalshaper describes with his lime. I believe vermiculite would work if that is what you have on hand. Apparently, from the above replies, anything that retards the cooling time would work.

dave

[jerrywh]

 Just plain wood ashes.

[SingleMalt]

Bill Brockway used vermiculite.  His work on doubles was magnificent.

[Hungry Horse]

Wood ash works fine for everything I do on a muzzleloader. I figure if it’s good enough for Hershel House, my guns probably won’t suffer from it.

  Hungry Horse

[D. Taylor Sapergia]

I tried ashes and sand to anneal a tumbler  and didn't gain an inch.  then I built a little birch wood fire in the yard, until I have nice coals, heater the piece good and re in my portable oxy/act torch, and dropped the part into the coals.  When the fire was dead, I fished out the tumbler and it was dead soft.  Nothing else worked at all.

[bob in the woods]

Some parts are more difficult to anneal than others. I have had the same experience as Taylor re a frizzen.  Now I just toss the part/s in a tuna can and put it in the shop wood stove at the end of the day. Take it out in the morning before I re stoke the fire, and it's soft. So far, I haven't had a problem re losing carbon in the steel, and the parts re harden nicely. The last piece  I did was a Chambers colonial frizzen.

[Mark Elliott]

I have used lime and perlite.   The perlite works better than the lime, but for small parts,  I still have to use my heat treat oven. 

[Jim Kibler]

One technique which sometimes works with small parts is to heat with a torch, hold at temp a few minutes and then just gradually over several minutes pull the part further and further from the flame until is below 1000F or so.

Jim

[jerrywh]

 One good thing about wood ashes is it is a carbon and will keep the carbon in the steel whereas some others can partially deplete some. When you put a part in the fire to anneal it as Taylor stated it is in wood ashes, It just cools a lot slower.  There is one thing about wood ashes that can be bad.  Do not let your parts remain in wood ashes if they are damp.  They will corrode the metal and make it pitted.