Powder storage temperature?

[rskent]

After going through the search function the best answer I could find is "keep it cool and dry and it will last forever". Well here in beautiful sunny Florida, cool and dry is a bit of a problem in the summer. It’s starting to get hot, and the humidity is fast approaching 90%. Currently the temperature in my workshop is running around 85 degrees at night, and about 100 in the afternoon. In a few months the afternoon temperature will be around 110 degrees. The humidity, well this is Florida, so 95% or better is the norm.
The question is, under these conditions, what would be the life expectancy of powder and primers? Right now, I just store it on the shelf in the original plastic jugs. Of course, under these conditions the powder isn’t going to last forever. The question is, how fast will it deteriorate? Any guesses?

Thanks
Steve

 

[rcmodel]

It will last probably as long as you will living in those conditions!

Don't you have A/C in the house?

If so, put the powder in a steel GI ammo can and bring it in out of the heat!
Even if that is not possible, an ammo can or even an old beer cooler will provide an extra mosture barrier and insulation from day/night temperature swings out in the shop.

rc

 

[MikeS.]

A second vote for storing it in the house.

I keep my in use bottle in the garage, the rest resides in a bedroom closet.

 

[MutinousDoug]

Seems like someone asks a question like this every about 12 months so I wrote this up on WORD in answer:

I worked for 20 some years in engineering for an aerospace ordnance company that specialized in pyrotechnic devices for military aircraft and space vehicles. Some of these used common reloading powders such as Bullseye or Unique as gas generants for piston driven, single use devices, for instance; pin pullers and latch operators in escape or ordnance arming systems.
Commonly these devices had a 5 year operational (on aircraft) or 10 year shelf life after which these would be returned to us for refurbishment or disposal. Upon return, we would perform “lot verification” tests on approximately 10% by firing these at the extremes of their operational environment (normally -60f to 140f IIRC) and this data compared to the data collected when the devices were originally qualified. Then, to refurbish the remainder, the original lot of propellant was used if possible as a replacement. Using the original propellant lot allowed us to use a smaller acceptance test group and abbreviated test regimen-PROVIDED: no statistically significant difference in performance was exhibited in any of our test samples; original, return or refurbished. I know of no case where we witnessed a change in performance due to propellant degradation.
When deployed, these devices (and aircraft) were subject to conditions that ranged from the Sandbox to Siberia. Our replacement propellant was stored in their original containers in un-insulated steel magazines about the size of a conex box or semi trailer, painted dark red. These were placed on the back of the company property here on the Colorado prairie. Not an extreme environment but -10f to -20f in the winter and 90f to 100f in the summer. The magazines were stifling in the summer: easily 20 degrees hotter inside than ambient. The propellants cycled through these extremes for 10-20 years with no measured ill effect.
If you keep oil away from them, primers are nearly indestructible in my experience. Percussion caps? Not so much.
HTH

 

[Slamfire]

The question is, how fast will it deteriorate? Any guesses?

I have read threads where people have had 80's vintage IMR 4895 go bad in the can.

I don't know and I do not have access to any sort of data base that predicts the deterioration rate of smokeless powders based on temperature. I am sure they exist.

I was informed that the rate of deterioration in double base powders follows the Arrhenius equation. The higher the temperature, the faster the powder deterioration.

From an expert in this area, I was told the Army scraps double based ammo after 20 years, and single based after 45 years.

Since I learned of this, I am making sure that I am using my older powders first.

I have had half of the surplus IMR 4895 powder go back within five years of purchase. Perhaps they were 25 years old at the point.

Keep your powders out of the heat. That is the best guidance I can provide.

 

[Slamfire]

I worked for 20 some years in engineering for an aerospace ordnance company that specialized in pyrotechnic devices for military aircraft and space vehicles. Some of these used common reloading powders such as Bullseye or Unique as gas generants for piston driven, single use devices, for instance; pin pullers and latch operators in escape or ordnance arming systems.
Commonly these devices had a 5 year operational (on aircraft) or 10 year shelf life after which these would be returned to us for refurbishment or disposal. Upon return, we would perform “lot verification” tests on approximately 10% by firing these at the extremes of their operational environment (normally -60f to 140f IIRC) and this data compared to the data collected when the devices were originally qualified. Then, to refurbish the remainder, the original lot of propellant was used if possible as a replacement. Using the original propellant lot allowed us to use a smaller acceptance test group and abbreviated test regimen-PROVIDED: no statistically significant difference in performance was exhibited in any of our test samples; original, return or refurbished. I know of no case where we witnessed a change in performance due to propellant degradation.
When deployed, these devices (and aircraft) were subject to conditions that ranged from the Sandbox to Siberia. Our replacement propellant was stored in their original containers in un-insulated steel magazines about the size of a conex box or semi trailer, painted dark red. These were placed on the back of the company property here on the Colorado prairie. Not an extreme environment but -10f to -20f in the winter and 90f to 100f in the summer. The magazines were stifling in the summer: easily 20 degrees hotter inside than ambient. The propellants cycled through these extremes for 10-20 years with no measured ill effect.

Doug: Your tests were conducted within the 20 year period that the Army uses to scrap ammo.

Your tests were "performance tests".

Did your tests also include the chemical measurement and quantification of the stabilizers in the powder? (My notes indicate stabilizers are either MNA or 2-NDPA . I don't know the names of the chemical compounds that the abbreviations represent. )

The expert I talked to said the Navy scraps stuff when the percentage of stabilizers are less than 20% of original content.

 

[JohnMcD348]

In Central Florida, where I live (Between Tampa and Orlando) It's already gotten to the point the heat and Humidity are stifling. In my garage last Saturday it was 130*. At 5am that morning, the humidity was so bad you couldn't see outside due to the moisture on all the windows in the house. I plan on placing my reloading bench in the garage instead of in my office but I will keep the powder I have in my closet in my bedroom. I purposefully installed a lockable handle on my closet door for the very purpose of being able to hold items in there like my locker and reloading supplies and to be able to keep them out of the ways and out of sight securely. I have wire rack shelving like you can buy at any of the BigBox hardware stores in so that I have plenty of storage space in them even with clothes hanging. And, if done properly, you can use your clothes to cover the items so they are not so easily seen when coming and going into your closet.

 

[MutinousDoug]

SlamFire1,
You are correct that the tests were strictly performance. I gave a 20 year life to the propellants I worked with because I only worked there that long. The company (B F Goodrich) that bought out the one I worked for may still be using the original powders but I would have no knowledge of that.
In any case, we did no chemical analysis of the powders. If they produced the expected amount of gas in the expected pressure/time profile, they were cleared for use. Then, acceptance testing included an average of 10% of the devices being exposed to environmental testing before being fired prior to release of the lot. Use of a new lot of propellant required additional qualification testing as well as acceptance testing.
Incidentally, those of you who are storing propellant in your house might benefit from a reading of your local fire codes. Mine stipulate that powder storage in excess of 5 lbs be in approved, insulated magazines. In the event of a fire, inappropriate storage could compromise your insurance claim. Same with gasoline or solvent storage.

 

[ranger335v]

Contrary to some ideas, cold retards chemical decomposition and helps them last longer, heat accerates deterioation; powder and primers are chemicals. How quickly any of our components will decompose at a given heat isn't something published, as far as I know.

Atmospheric humidity/moisture isn't a problem unless water actually condenses in or on the powder and primers. It probably won't hurt primers even then, if they get wet just let them dry and all should be well. Plastic primer compounds are normally handled wet, like clay, in the factories. They just let the water dry out before shipping them for use.

 

[oneounceload]

I also live in humid FL - while I reload in the garage, I keep powder and primers in the house under heat and air to keep temp swings to a minimum

 

[rskent]

So are we saying, One year, two years, twenty years, what?


rc Thanks for the input, and after living without for about ten
years, I finally broke down and got a couple of wall bangers.