A question about anealing?

[sturner]

The stick or paint which one works best

 

[nksmfamjp]

I have only used the paint. I heard bad things about the stick when it comes to annealing brass. I think that is because the stick gets touched to the hot surface during heating.

 

[tim_w]

Tim, curious how you decided on 1500f. Studies have shown brass can be annealed at 600 for an hour (ugh) or 800f for 5-8 seconds. Definitely not linear, as you stated. What not try 900-1000 for a quick dip of 3-5 seconds? curious to see your results!

Becuase it take way longer than we can leave it in salt to reach the temp. We need higher salt temp so that with the neck actually gets up to that 800f range. Consider the study from University of Illinois using molten lead @ 1000°F it took a piece of 70/30 brass the thickness of a case neck fully submerged 19 seconds to reach the same temp. With 3/4 of the case out acting as a heat sink and the fact we can not leave it in more than 5-8 sec or the body gets too hot we need much higher temp.

Consider that propane torch flame outer tip os close to 2000°F

To answer another question asked. Tempilaq can only work where its not in the salt. It can be put on the body using 400 to ensure they do not get too hit. But on the neck in the salt will not work as its measuring the temp of the salt touching it not the internal core of the brass. I hope that all makes sense.

Its all counter intuitive on its face.

 

[sturner]

Well dang the luck just ordered 800 from amazon

 

[tim_w]

Well dang the luck just ordered 800 from amazon

If you use it for propane I would try putting it inside the case neck as you need to ensure full thickness heat and not direct flame temp. Then some low temp like 400 on the outside case surface body below shoulder junc. Set a real timer while you do heating to be precise.


.

 

[sturner]

I'm using a salt bath

 

[tim_w]

I'm using a salt bath

Oh then not sure tempilaq is helpful other than the lower temp to put above the salt line. Anything that touchs the salt is reading the temp of the salt and as its a liquid its inside and out Still be interesting to see the results. You could put it on the case neck and then try it on a different piece if metal like steel sheet metal and see if the time to burn changes significantly. Give an idea if the thermal conductivity difference has any effect on the tempilaq reading.

 

[bushmotornv]

To avoid dripping salt, I started tapping the cases on the case holder after pulling them from the bath. The extra goes back into the pot and less filling it with extra salt. Nothing cosmic, but it seems to work well for me. Great to hear other guys experiences with SBA. It sure is noticeable on the comparator. Easily .003" difference between twice fired RUM and annealing each time. MUCH more repeatable when I compare each case after FL sizing.

I started doing the same thing myself. I think the tendency is to rush the case to the quech tank. If you just slow up a touch,and let the salt run off of the case,you're good to go. I did find that tapping the case seemed to dribble more on to the top of the case holder.

 

[Mram10us]

Becuase it take way longer than we can leave it in salt to reach the temp. We need higher salt temp so that with the neck actually gets up to that 800f range. Consider the study from University of Illinois using molten lead @ 1000°F it took a piece of 70/30 brass the thickness of a case neck fully submerged 19 seconds to reach the same temp. With 3/4 of the case out acting as a heat sink and the fact we can not leave it in more than 5-8 sec or the body gets too hot we need much higher temp.

Consider that propane torch flame outer tip os close to 2000°F

To answer another question asked. Tempilaq can only work where its not in the salt. It can be put on the body using 400 to ensure they do not get too hit. But on the neck in the salt will not work as its measuring the temp of the salt touching it not the internal core of the brass. I hope that all makes sense.

Its all counter intuitive on its face.

Instead of using other people's numbers, I did the calculations but back me up to make sure I didn't mess something up.
Q=mc(deltaT)
M=1gram of brass
C=.380
deltaT= 500c
1x.380x500= 190c
then,
T=190c/250watts=.76seconds

According to my gibberish, it should take less than a second (.76) to heat the neck (1gram of brass) up to 500c. That makes sense to me since the neck is .015" thick and the volume of salt will not lose heat quickly when heating that much.
Again, please re run the numbers and critique this because I want this right.