Humidity question...


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RugerBob
January 20, 2010, 09:55 AM
Hey all, I have been reloading and casting for a few years now. My wife got me a temp and humidity gauge for the basement where I have all my stuff. I am not sure of the summer time temp down there, but this winter it averages 45 degrees w/44% humidity. When I heat the basement its 65degrees w/47% humidity. During the summer its cooler down there and I do run a de-humidafier. I have had no problems with primers or powder.
I am in Maine. I was wondering if there was a level of humidity that is a safe zone for powder and primers. I do also keep 2 1/2"x5" deccisant (sp?) blocks in all the areas of need. (free of charge). Kid works in a computer shop and gets a lot of them.
So, is there a safe # in both temp and humidity that are safe that should be aimed for?
Thanks Bob

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Kernel
January 20, 2010, 11:02 AM
If your primers and powders are kept in airtight sealed containers, then the humidity in the basement shouldn’t matter. Okay. That’s a BS reply, but you get the idea. I’d keep the RH in your basement between 40% and 60%. Higher RH in the summer, lower in the winter. Store your primers in an old .50 cal ammo can, or something similar. Since you have so many, throw a couple of those small desiccant pacts inside. Put some in your powder containers as well, can‘t hurt. As long as your basement temp stays below 100F it won't be a problem for longterm storage.

rcmodel
January 20, 2010, 12:44 PM
50% H / 70 F is Museum grade storage conditions.

Sounds like you are close enough for Goobermint work year round.

rc

RugerBob
January 20, 2010, 08:57 PM
Thanks. Guess I'm good to go on it then. Bob

snuffy
January 20, 2010, 09:51 PM
I flat out don't worry about humidity. Smokeless powder just does not absorb humidity. Neither do primers. The sealant they put on the primers is impervious to not only water, but most solvents.

I'd be much more worried about rust on steel dies and press parts.

Ateam-3
January 20, 2010, 10:26 PM
"I flat out don't worry about humidity. Smokeless powder just does not absorb humidity. Neither do primers."

I do not follow this. Powder is very hygroscopic and will absorb moisture from the air if left in an open container or uncovered. Some powders may do this quicker than others, but they do draw moisture. I'm in eastern North Carolina, where the avg. relative humidity exceeds 60% at least 9 months of the year. Several years ago, I saw some powder that had broken down due to moisture. My observations were a brownish-red cloud coming from the container when opened, a sulfur smell and some clumping.

As mentioned earlier, keep it stored in an airtight container and you will be fine. I also store primers in ammo cans even though they are less likely to be deteriorate via high relative humidity.

Quoheleth
January 20, 2010, 10:55 PM
I live in Houston and all my stuff is in a un-climate controlled garage. I'm still working through a pound of AA#5 from spring, 2007. No problems at all...

Q

snuffy
January 20, 2010, 11:04 PM
Powder is very hygroscopic and will absorb moisture from the air if left in an open container or uncovered.

Nope, sorry, it's not. In order to be hygroscopic, it would have to have some sort of salt in it. Smokeless powder is simply nitrated cellulose. The size, shape and the amount of retardant regulate how fast it burns. But nothing in that makeup makes it hygroscopic.

Powder left sitting around uncovered breaks down more rapidly because of exposure to LIGHT, especially sunlight. Ever notice how powder containers are opaque? They take special pains to keep out the light.

Powder kept in it's original container with the cap on tight, will last almost indefinitely.

Tests have been run with ammo loaded in different humidity levels. Same loads, just different amounts of water vapor in the air at the time the powder was charged. No difference in the accuracy or velocity. If the powder would have soaked up humidity, it would have showed up in the performance of the ammo.

The Hercules powder company,(now Alliant), took a quantity of unique powder out of the first run. They tested some of it with a standard load. Then they placed the rest UNDER WATER. That was when unique was first developed, many years ago. Occasionally they take that powder out of the water, dry it thoroughly, then test it again. Guess what, it still works the same as day one. If it absorbed water, it would dissolve!

RugerBob
January 22, 2010, 09:10 AM
Thanks for the replys all, some good info there for me to think about. I look forward to this summer to what the readings are. Maybe I won't have to run my de-humidifier as much as I was and will save some on the elec bill. Bob

SlamFire1
January 22, 2010, 12:07 PM
I do not follow this. Powder is very hygroscopic and will absorb moisture from the air if left in an open container or uncovered. Some powders may do this quicker than others, but they do draw moisture. I'm in eastern North Carolina, where the avg. relative humidity exceeds 60% at least 9 months of the year. Several years ago, I saw some powder that had broken down due to moisture. My observations were a brownish-red cloud coming from the container when opened, a sulfur smell and some clumping.

Heck yes, gun powder attracts water. Smokeless gunpowder won’t dissolve in water, but that does not mean water is not attracted to the Oxygen-No2 double bonds or the nitroglycerine in gunpowder.

A Navy Energetics expert informed me that water is bad for gunpowder. H2O is slightly ionic and is attracted to the complicated chemical surface of gunpowder*. Water, as it dries and condenses on the surface, will wick nitroglycerine towards the surface, changing the burn rate at the surface for one thing. If my recollection is correct, it also helps the redox reaction in which NO2 is liberated. Iron particles (rust) will do the same thing.


Gunpowder is not inert. Gunpowder is a high energy compound. It wants to break down and reach a lower energy state. It is deteriorating the day it leaves the factory.

I asked him about the Alliant Sharpshooter powder left under the water. I think he said that storage under water will absorb the NO2 gas, but if the powder is dried and left out for long, it will simply deteriorate faster than powders not in contact with water.

He told me that the Army scraps double based propellants at 20 years, single based at 45 years. These times have margin, to reduce the number of ammo dumps that go Kaboom, http://www.liveleak.com/view?i=13c_1205681217
but they are not ultra conservative. Scrapping ammunition is expensive.

My expert told me the best storage conditions are cold and dry. He actually said Arctic. Like unchanging arctic.

* Take a look at the complicated structure for smokeless propellants and their stabliziers:
www.dtic.mil/dticasd/sbir/sbir031/n154.doc

For 2NDPA stabilized propellants, the first nitration product is n-nitroso 2NDPA, which rearranges into dinitrated diphenylamines, mostly 2,4’-dintirodiphenyl amine.

Darn Dem ole dinitrated diphenylamines, ;)

:D:D:D

snuffy
January 22, 2010, 12:56 PM
Slam, that's a very interesting paper. I need to study it further, but it seems it doesn't matter whether the powder is single based or double based? I didn't see any differentiation between the two. Not all powder has nitroglycerin in it.

Also, I didn't see where water vapor came into the equation. It's been a while since I read of those tests done under different humidity conditions, so I don't know if they're still valid. After reading that, I became unconcerned about humidity in my loading room. I loaded in a damp, dank basement for years without any problems related to powder/primers. I had lots of trouble with rust on tooling, but none I could point to with the reloads.

SlamFire1
January 22, 2010, 03:18 PM
Not all powder has nitroglycerin in it.

Single based powders are nitrocellulose. Double based are nitrocellulose and nitroglycerine. The NG in the powder breaks down the nitrocellulose.

I am not an inhibitor expert in any way, but my understanding talking to the expert, is that inhibitor technology has changed over the years, but the same inhibitors are used in single based and double based powders.

After reading that, I became unconcerned about humidity in my loading room. I loaded in a damp, dank basement for years without any problems related to powder/primers. I had lots of trouble with rust on tooling, but none I could point to with the reloads

There is so much water vapor in the air, even loaded ammunition has water in the case. Still, from what I understand, water accelerates aging in powder.

Heat is the worst. Heat is very bad for powder.

That is why you always read the same recommendations to keep your powder cool and dry. But the reasons why have been forgotten.

Mags
January 22, 2010, 03:42 PM
Wow, maybe I need a humidifier from the responses here. The average humidity in my house right now is 29 percent. I often have to equalize electricity out of my body before entering my loading room.

gazzmann
January 24, 2010, 12:59 PM
Ruger Bob,
Down here in Florida humidity is usually 85% to 98%.
Components hold up fine. Don't loose any sleep over it.

RugerBob
January 24, 2010, 07:38 PM
Thanks, With the scarcity of supplies at times, I don't want to lose what I have on hand. Bob

Grump
January 24, 2010, 11:20 PM
Don't really know whether it's solvents or water, but I've deliberately left 5 charges of rifle powder--40-something grains--in the pan for up to a week at a time. More than once. When it's been dry, less than 30% RH, it will go light to the tune of about 0.1 grains per powder charge. When it's wet, it stays the same.

Don't think I've ever had a load get heavier. I lost interest in the exercise.

qajaq59
January 25, 2010, 08:22 AM
Maybe I won't have to run my de-humidifier as much as I was and will save some on the elec bill. Bob Here in Florida I don't worry much about the powder because it's in tightly sealed containers. But.... Keep an eye on you equipment! That's where you can get into grief real quickly with high humidity. Rust is not a friend.

flrfh213
January 25, 2010, 11:10 PM
i just shot 150 38 spl that had 3 year old primers stored in non-temp controled garage here in SW florida and about 1 year old bullseye powder and every one went bang and for what it is worth, i was sweating when reloading part of them they still went boom... i never considered temp and humidity but it is food for thought for long term storage

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