DIY brass annealing setup?
- Thread starter bigHUN
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BattleRife
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No, not really, it's not something I ever considered.
If it does, I'm not sure it really matters. As discussed below, ammonia and related nitrogen compounds are so common it doesn't matter much if you get rid of them today, they will be back tomorrow.
No, it's do-able for some people, but it would be tough to have certainty, so it now just makes sense to me to make sure my bottlenecked rounds are annealed.
The basic idea is that stress-corrosion cracking (SCC) depends on the trio of material, corrosive environment, and stress. Take any one of these away and you will not get cracking.
As long as we are talking brass cases, the material is fixed. So the variables we have to try to control are the environment, or the stress. The problem with tackling the environment is just how common the culpable compounds are. People associate cracking of brass with ammonia, but the fact is a large range of similar nitrogen compounds will also cause cracking. Ammonia is present in the urine of many animals, but in the article by Moor, Beckinsale and Mallinson that Ex3dy referenced above it was found to be coming from a wood stove burning green wood in a warehouse. In fact, many early reports of cracked drawn brass were linked to the products of combusting fuels in air.
My own experience with this was when I bought the house I live in now. When I moved in in the fall, I decided that the best place to put my ammo cabinet was in my utility room. I was astonished next spring when the first time I went to the range with an AR15 and bunch of 5.56mm reloads I had neck cracks in over half of the rounds fired. But as spring turned to summer the problem went away and I could load and shoot a case a half dozen times with no problem. I figured that brass must have used quite a lot more than I had thought. But then winter came, and ammo once again sat in the cabinet for a while, and when spring came they all cracked again. It was only several years later, when I was doing serious reading and experiments with case cracking and annealing, that I put it all together: the ammo cabinet sits in the utility room right beside a natural gas furnace that runs frequently all winter. Trace combustion products of natural gas in air, probably NO2, were sufficient to cause cracking in stressed case necks after a period of months.
So, is it possible to mitigate cracking by limiting the environment? Sure, maybe, and this I'm sure is why I see some people claiming to have never had a cracked neck in years of reloading despite never annealing. But for many people living near animals or industrialized environments it would not be a realistic option. Annealing is a much more reliable bet.
Just looked at my coil for 6.5x55. It has six wraps not four. There is no formula for the diameter of the coil. I make it wide enough so my shaky hands don’t have the coil touch the brass when heating. If you use a bigger diameter coil, it will take a little longer to heat the brass to annealer it. No big deal. As for the spacing between the coils, I separate the coils so they aren’t touching. You may have to adjust from time to time as you use the coils. I make my coils from 10 gauge electrical wire. It does not have the white wrap. It is bare wire.
Watch the second video and follow the instructions. You will be fine. If you mess it up the worst that will happen is you ruin a piece of brass or you burn up one of your coils.
Watch the second video and follow the instructions. You will be fine. If you mess it up the worst that will happen is you ruin a piece of brass or you burn up one of your coils.
Really appreciate the insight; my thought process was along the lines of burnt powder residues, barrel solvents and brass cleaning medium being impregnated or entrained into the brass during the sizing process rather than purely atmospheric environmental conditions. My theory is that the abrasive nature of sizing both breaks any factory applied passivation layer and any abrasive debris may cause localized stresses. The type of brass cleaning ritual used by the reloader would have varying influence on what substances may be present during the sizing process. Being that Moor, Beckinsale and Mallinson were dealing with new production ammunition this was likely not a significant consideration for them.
If I had one tip for the annealer it would be that right after annealing your cases will be very dry, try to keep the cases dry because moisture is a major catalyst for corrosion.
There are a lot of variables that go into winding the correct coil. Any coil could work, but if you do the math you will have one that works really efficiently. I have no problem helping you spec it out once your ZVS board arrives and we can get the specs off the capacitors. You have a 3D printer right? You can print a jig, makes winding the tube super easy and fool proof.
