OzFclass

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?

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

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

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

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.

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.

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

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

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

Peterla wrote: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

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

3.5 seconds per case, does an awesome job.

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.

aaronraad wrote: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

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

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.