Who is annealing in sand?

[dolomite_supafly]

I think finding the right media size is going to be the key to success. It needs to be bigger than what I used but still small enough to get good contact and fast heat transfer.

When I used to do a lot of casting I tried to use the molten lead to anneal cases. The problem was that it would sometimes leave lead in/on the neck. It was nearly impossible to remove.

I made a case holder to help me safely anneal using a torch. It makes it nearly impossible for heat to migrate past the shoulder. It is like using a socket but mine are made out of aluminum and has a series of fins to dissipate heat transferred from the case to the holder.

 

[birdiemc]

I think finding the right media size is going to be the key to success. It needs to be bigger than what I used but still small enough to get good contact and fast heat transfer.

When I used to do a lot of casting I tried to use the molten lead to anneal cases. The problem was that it would sometimes leave lead in/on the neck. It was nearly impossible to remove.

I made a case holder to help me safely anneal using a torch. It makes it nearly impossible for heat to migrate past the shoulder. It is like using a socket but mine are made out of aluminum and has a series of fins to dissipate heat transferred from the case to the holder.

The stuff you used, is that the stuff for mixing with epoxy to make pretty decorations, or is it the stuff for melting down to make casts?
Wondering if the stuff for epoxy is something other than just copper.

 

[birdiemc]

Just spent the past hour searching the web for a possible medium and came across HBN, hexagonal boron nitride. I know some folks are using this for coating bullets, but what I read it's close to copper on thermal conductivity and has high heat capacity, keep it under 1000deg C and should be ok.
More expensive than the copper powder, bit added perk that if you air dry your case necks come out already lubed up.
Gonna look more at graphite powder tomorrow and see how it stacks up.
Anybody out there with actual knowledge on these above what I found on google????

 

[Greasegun]

Just spent the past hour searching the web for a possible medium and came across HBN, hexagonal boron nitride. I know some folks are using this for coating bullets, but what I read it's close to copper on thermal conductivity and has high heat capacity, keep it under 1000deg C and should be ok.
More expensive than the copper powder, bit added perk that if you air dry your case necks come out already lubed up.
Gonna look more at graphite powder tomorrow and see how it stacks up.
Anybody out there with actual knowledge on these above what I found on google????

This sounds promising. How much would it cost to halfway fill a lee pot?

 

[375ultramag]

I definitely stay away from the graphite powder. According to the MSDS graphite powder has an autoignition temp of 700-730°C

 

[birdiemc]

I definitely stay away from the graphite powder. According to the MSDS graphite powder has an autoignition temp of 700-730°C

Saves me from looking further into that.

 

[dolomite_supafly]

The stuff you used, is that the stuff for mixing with epoxy to make pretty decorations, or is it the stuff for melting down to make casts?
Wondering if the stuff for epoxy is something other than just copper.

The copper is pure and was for a bullet powder coating project a few years ago. Initially we were concerned with the durability of the powder coat so we mixed copper powder in for testing. It is very fine and hangs in the air like smoke.

The aluminum was for DIY a tannerite.

 

[Carsyn.22]

Try putting a deep socket on a drill instead of burning your fingers

That works too, however if I burn my fingers then I have waaaaayyy over annealed that particular piece of brass and should discard it. I barely feel the case head getting warm when I see the first colour change in the neck and immediately pitch it in the bowl of water.

 

[birdiemc]

Yesterday I used my new temp probe to get the sand stable at 850 degrees then tried a few cases for 12 seconds and dumped them in the water. I saw no sign of color change on the neck so i cranked up the temp to setting 9, then once temp was stable i removed temp probe and let it cool to room temp, then put it in my bucket of water to get down to the same temp as my cases. then I timed how long it took for the probe to reach 850 degrees...35 seconds.
Then pulled a case out of my bucket of water, shook off as much water as possible then stuck it in the sand for 35 seconds. At about 28 seconds the little drop of water sitting in the primer pocket vaporized indicating the case head reached 212degrees. The neck was colored perfectly at 35 seconds.

 

[Greasegun]

Yesterday I used my new temp probe to get the sand stable at 850 degrees then tried a few cases for 12 seconds and dumped them in the water. I saw no sign of color change on the neck so i cranked up the temp to setting 9, then once temp was stable i removed temp probe and let it cool to room temp, then put it in my bucket of water to get down to the same temp as my cases. then I timed how long it took for the probe to reach 850 degrees...35 seconds.
Then pulled a case out of my bucket of water, shook off as much water as possible then stuck it in the sand for 35 seconds. At about 28 seconds the little drop of water sitting in the primer pocket vaporized indicating the case head reached 212degrees. The neck was colored perfectly at 35 seconds.

Sounds to me like the sand is not transferring the heat nearly fast enough. How much hotter can you get the sand?

How long would it take the probe to heat up in salt bath?

 

[birdiemc]

Sounds to me like the sand is not transferring the heat nearly fast enough. How much hotter can you get the sand?

How long would it take the probe to heat up in salt bath?

Sounds like Mikecr was correct doesnt it?
However heating the case head to 212 shouldn't have any negative effect, I dont know the exact temp off the top of my but I know we want to stay under 500 something....but the problem is knowing what temp is at what location on the case body.
Doesnt help that my brass started at 57degrees either

 

[cape cove]

Like I posted earlier this guy knows what he is talking about. If @Mikecr reads this maybe he can chime in as to a possible substute for salt, if there is any.

 

[Dirtrax]

Verifying temperature is what I'm struggling with in my mind right now. Forgot to pick up some sand today, so I'll grab some from the masons at work tomorrow. I have some trash brass that I have been saving for just such an occasion so I'm gonna give it a go with the method Watson suggested, just crank it up and dip them in. But I am trying to find somebody with some temp measuring equipment that I could borrow just to test it out. Thought about tempilaq, but kinda seems like a bad idea since it will be out of the sand in order to be visible, so by the time it starts working the heat will be too far down the case body. So it's got to be a sensor in the sand sensing I would think. Also as Mikecr mentioned early on the thermal coupling in sand is horrible compared to liquid, so stirring the sand will be necessary to keep the temp somewhat even throughout the depth.But hopefully tomorrow I wont get stuck at work late and will have some very crude preliminary results to share.

Get some 450* Tempilaq and place it above the sand to determine temperature at the point where it can begin to do harm. I guess below that an infrared temp gun could be used to measure temps at the neck/shoulder.

 

[FatOldMIHunter]

I tested today with medium grit sand using very thick Norma brass. I didn't get a good temperature change on them until I had them in at 750 degF for 45 secs. I picked the cases up with pliers and quenched them. I made a stand in the sand with copper wire to keep the case from tipping. That wire turned black and when it cooled it shed a coating of oxide and returned to copper color.