Which gas?

[scott/r]

In most of the videos I've seen of annealers , the gas being used is propane (blue bottle). Just wandering why you wouldn't use mapp gas (yellow bottle)? It's a lot more efficient gas to use. But is it too hot or is it because it's a bit dearer and the propane does the job anyway?

[Tiger]

Hi mate,
I got my machinist mate to knock me up an adaptor to go from my primus torch to an unregulated line from my 9kg LPG bottle.

That's what I use with my annealer, and it works fine. I think that mapp gas would be too hot, I achieve annealing easily with LPG.

Cheers.

Dave

[Peterla]

I have used propane on all the annealer I built.
I did try a lpg conversion but the heat output was much less and added about 40% to the heat time
This might be ok on large flame setups but as I use a pencil flame to get the heat in the right spot the lpg was not a option for my setup

I have a mapgas torch but have not tested that
If it get time I will do a comparison

This is not a rule it's just what I found works on my setup

Pete

[scott/r]

That would be cool Pete. I have a suspicion that you might have to speed up your machine a bit with the mapp gas.

[shooter mcreid]

Hey Scott,
Mapp burn temp is close to 3000 degrees C as apposed to butane which is around 2000 from memory. It would be far easier to over anneal with the mapp as your "window" would be far smaller. I have been using the old bbq gas bottle with a pencil torch attachment and it only takes about 4 seconds, this time also allows the case to rotate several times in my home made annealed. In summary I think mapp is too hot for annealing brass.

[scott/r]

I found some old cases and cleaned them up and give em a blast with the mapp gas. End result is that I don't believe that I will do that again with my setup. In a good machine turned up a bit faster than normal you might be lucky. But all I did was burnt the necks on probably half of the cases I tried.
Thanks for your input guys.

[johnk]

It's good to have blue sky probabilities resolved by proxy.

[Peterla]

Hi Scott
I did some testing on my annelaer and here is what I found

308 case with 750 tempilaq in the neck watching this melt for the timing
My motor runs a 25rpm and the sped controller is a % of this time

LPG took 22%
Propane took 34%
Map gas 55%

The map gas was fast but a bit broader flame so the heat traveled down the case a bit further
The pencil flame on the LPG and Propane gives me better control of where I want the heat to go.

Pete

[aaronraad]

I use one of the Bernzomatic Trigger-Start torches on a MAPP bottle without any issues. It just becomes a very quick process. I spin them in a cordless drill at 1500 - 2000 rpm using a 1/2" socket to hold 308W cases, then flip them out into a bucket of water...and then a bucket of acetone some distance away.

Might take 1/2 dozen to find my rhythm so I keep a few dud cases on hand to warm up.

Just have to remember where buckets are when you're flipping cases in the dark and to avoid using the MAPP torch as a light source to find the acetone bucket

[RonM]

Hi Scott
I did some testing on my annelaer and here is what I found

308 case with 750 tempilaq in the neck watching this melt for the timing
My motor runs a 25rpm and the sped controller is a % of this time

LPG took 22%
Propane took 34%
Map gas 55%

The map gas was fast but a bit broader flame so the heat traveled down the case a bit further
The pencil flame on the LPG and Propane gives me better control of where I want the heat to go.

Pete

FWIW - I use one of Peter's machines with a Tradeflame pin point burner head and propane cartridge kit from Bunnings - .308 Lapua cases, 750 Tempilaq, the speed controller on 025 readout gives me correct time. I presume this means 25% v Peter's 34% (Peter?). The difference I guess is in the torch. I have a bunch of Winchester cases to anneal at some stage as well; it will be interesting to see if there is any difference in the time required to anneal them.
I've used the cordless drill with adapter and count method - the machine is better IMHO.
Cheers,
Ron

[Josh Cox]

I use a single pencil width Mapp torch with a bench source annealler.

3.5 seconds per case, does an awesome job.

[6.5x55ai]

Haven't bothered with MAPP as I bought a lot of bottles of standard propane when I got the annealer. On my Bench Source I run 2 torches for quick with good results/short heating times.
Still experimenting but have already found I have to run very slightly different times for 308W brass from Lapua, ADI and Norma. All neck turned to similar dimensions.

[scott/r]

I use one of the Bernzomatic Trigger-Start torches on a MAPP bottle without any issues. It just becomes a very quick process. I spin them in a cordless drill at 1500 - 2000 rpm using a 1/2" socket to hold 308W cases, then flip them out into a bucket of water...and then a bucket of acetone some distance away.

Might take 1/2 dozen to find my rhythm so I keep a few dud cases on hand to warm up.

Just have to remember where buckets are when you're flipping cases in the dark and to avoid using the MAPP torch as a light source to find the acetone bucket

That's exactly what I have been doing as well, but I haven't been putting themin the water. Just standing them upright on the bench. Do you guys think it makes a difference to squelch cool them? I wouldn't of thought it would have, but I am very new to this part of case prep. I've normally blown out the primer pocket by this stage

[Longranger]

Makes little or no difference whether they are allowed to cool naturally or quenched.

[scott/r]

That's what I thought. And with my track record it's probably a lot safer if I don't have a bucket of flammable liquid and a gas flame in the same area.

Thanks for your time in checking the difference in the three gasses, Pete. Much appreciated.