Vermiculite Annealing.

[kurtmm]

I have a bucket of vermiculite for annealing but am unsure of the application as I've never used it before.
Basically, At what temperature is the blank or rough blade put into the bucket of vermiculite?
Red, orange, or cooled to what temp?
Thank you all for any info.

 

[J. Doyle]

What steel are we talking about?

 

[kurtmm]

1095,15n2o and any hicarbon used in making knives.

 

[J. Doyle]

1095,15n2o and any hicarbon used in making knives.

You don't want to anneal or slow cool 1095 at all.

In fact with any simple high carbon steels, just heating to 1475 F. and air cooling once or twice will leave them in excellent condition for cutting/drilling/shaping/grinding. No anneal required.

 

[Alex Topfer]

look up the annealing temperature of the steel you're working with, it varies depending on alloy. i wouldn't be too concerned about getting it exact, you won't get a proper temperature controlled anneal out of vermiculite anyway, it's a bit of a rough process

 

[HSC ///]

As mentioned it depends on the steel. For example, Japanese high carbon simple steels do respond well to vermiculite or wood ash annealing.
For those steels, Heat to a dull cherry red, insert the blade into the media for one hour minimum

 

[Joseph Bandeko]

K kurtmm https://knifesteelnerds.com/2021/08/28/how-to-thermal-cycle-knife-steel/

 

[kurtmm]

You don't want to anneal or slow cool 1095 at all.

In fact with any simple high carbon steels, just heating to 1475 F. and air cooling once or twice will leave them in excellent condition for cutting/drilling/shaping/grinding. No anneal required.

Thanks.

 

[kurtmm]

K kurtmm https://knifesteelnerds.com/2021/08/28/how-to-thermal-cycle-knife-steel/

Thanks for the lead.

 

[kurtmm]

As mentioned it depends on the steel. For example, Japanese high carbon simple steels do respond well to vermiculite or wood ash annealing.
For those steels, Heat to a dull cherry red, insert the blade into the media for one hour minimum

Thanks, That is what I was looking for. A heat range for insertion.

 

[kurtmm]

look up the annealing temperature of the steel you're working with, it varies depending on alloy. i wouldn't be too concerned about getting it exact, you won't get a proper temperature controlled anneal out of vermiculite anyway, it's a bit of a rough process

Thanks.

 

[Ken H>]

From my understanding vermiculite is normally used to make a billet/blade easier to drill, machine, etc. For this I normally take a billet/blade up to around "red hot", clamp between two "red hot" iron blocks to make the billet/blade hold heat longer. Bury in vermiculite, and 12 hours or so later it's still warm indicating it's cooled slowly. The billet can then be drilled or machined nicely. This is NOT part of grain reduction or anything along the HT'ing process. Just make it easy to drill.

 

[HSC ///]

From my understanding vermiculite is normally used to make a billet/blade easier to drill, machine, etc. For this I normally take a billet/blade up to around "red hot", clamp between two "red hot" iron blocks to make the billet/blade hold heat longer. Bury in vermiculite, and 12 hours or so later it's still warm indicating it's cooled slowly. The billet can then be drilled or machined nicely. This is NOT part of grain reduction or anything along the HT'ing process. Just make it easy to drill.

annealing is a heat treat process to reduce hardness and make the steel softer so it is more workable. (Easier to drill, machine etc )

 

[12345678910]

If you don't like the dusty / asbestos nature of vermaculite, look at pearlite too.

 

[kurtmm]

If you don't like the dusty / asbestos nature of vermaculite, look at pearlite too.

Thanks, I haven't tried the vermiculite yet but I will keep it in mind. Also, Is the temp range the same as vermiculite?

 

[kurtmm]

annealing is a heat treat process to reduce hardness and make the steel softer so it is more workable. (Easier to drill, machine etc )

Thanks.

 

[A.McPherson]

Another thing you can do to increase the cool down time is to heat up the vermiculite/perlite.
Take a chunk of steel, heat it up to red/orange and toss it in, once you have your blade up to heat, stick it in next to the "heater" steel, then take the "heater" out and let it all cool down.
Certainly not as good as a timed, argon filled furnace, but it'll work well enough on simple steels.

 

[Stacy E. Apelt - Bladesmith]

Actually, the method using a heater block/bar is to leave the block/bar in as extra thermal mass. The vermiculite does not heat up much due to its very low coefficient of heat/thermal conductivity , but the block/bar will help the blade stay hot longer, thus slower cooling rate.

 

[CWendling]

You don't want to anneal or slow cool 1095 at all.

In fact with any simple high carbon steels, just heating to 1475 F. and air cooling once or twice will leave them in excellent condition for cutting/drilling/shaping/grinding. No anneal required.

What is wrong with annealing 1095 in this manner?

 

[Stacy E. Apelt - Bladesmith]

Too slow a cooling can produce fine pearlite, which can be pretty hard. Moderate cooling is all that is needed with hypereutectoid steels. This produces coarse pearlite, which machines much easier.