Powder Storage

[Bucksnort1]

About 4.5 years ago, I moved to the Valley of the Sun (Phoenix area) from Colorado. Before moving, I posted a question about storing powder in 100 degree plus temperatures. I cannot find my post to read replies.

What I didn't know before moving is that not only are the summer temperatures brutal, at times, (last summer, we had 145 non-consecutive days of 100 degree plus temps) but there is a monsoon season where the humidity is higher than one would expect for the Sonoran desert.

A friend has suggested a test I do to see if humidity affects powder starting now and running through the end of the monsoon season, September 30-ish. I have been storing my powder, but not primers, inside my house.

But back to my original question. Does anyone store powder in high temperatures? Powder manufacturers recommend storing in a cool dry place but they don't specify what cool is.

[NoSecondBest]

I’ve kept powder in my house for years here in the North East where the temp stayed between 65-80 degrees and the humidity was 30-70% and none of it ever went bad. I think that anything over those temp’s can degrade powder based on all I’ve read over the years. You’re definitely in an area where the temp is too high to store anywhere but inside. You’re idea of “high humidity” by NY standards is bone dry. I remember being in AZ and they were complaining about excessive humidity at 22%. It was bone dry to me on that day.

[hounddawg]

page 5 - underlining by me

https://hodgdon.com/wp-content/uploa...s_02-11-14.pdf

Conditions for safe storage

Store at 21°C (70°F), 50% relative humidity (decomposition becomes measurable above 50°C (122°F).
Store in original container. Keep container tightly closed. Store in a cool, dry, well-ventilated place away
from all sources of ignition.

[T. O'Heir]

"...Store at 21°C (70°F)..." That being 'room temperature'. If it's too hot for you, nothing else will like it either.
"...see if humidity affects powder..." High humidity absolutely can and will affect powders mostly if the can is the old cardboard type. Probably won't with a plastic can. Low will not. My apartment is 80 F and drier than Death Valley(yes I do have too much time on my hands). Nothing is bothered by that.
There's no reason not to store your primers in your house. There's no reason not to store 'em on the same shelf as your powders either.

[jpx2rk]

I've stored powder inside the house with the normal heat/cooling to suit me and the family. NO issues or problems with any powder, even some powders from the mid 80's that I used up last year.

[RC20]

You don't say what temp the powder is seeing? If its in a non cooled shop then it will break down sooner than 70 deg temps inside a cooled house.

Mostly you do the best you can.

Keep out of direct sunlight.

I assume you have AC? If so I would store it in the house where its the coolest.

A stretch thought is a refrigerator to store it in. The door would cover the venting requirements.

Humidity is a non issue (no you don't want dripping water in the powder of course). The variance of Humidity that Unclencik had a while ago was minuscule. Just keep the lid on as we alwyas do, you can let stabilize for a bit when re-loading but you don't need to desiccant it.

I have been doing some very close tracking of loads with Lab Radar, amazing that you need 3 grains to see 100 fps difference. Other factors are much much higher impact.

[Bucksnort1]

NoSecondBest, Today's humidity was 8 percent. I do not do humidity well. I complain when the monsoon season (June to September) humidity is around 40 percent or more and my evaporative cooler in the garage isn't as efficient as with lower percentages.

My house is air conditioned so temps are 70 to 75 degrees and that is what the powder is seeing.

I've not had problems with primers being stored in the garage but I will take the advice and store them inside with the powder.

[reddog81]

40% humidity is on the low side of normal. There are times in July and August where I run a dehumidifier in my reloading room to keep it under 70%.

[RC20]

My house is air conditioned so temps are 70 to 75 degrees and that is what the powder is seeing.

Powder will be fine. Mine probably averages a bit cooler but by 5-8 degrees at most. Of course we have to HEAT our houses.

40% Humidity is damned low overall, good thing you did not come to the Philippines with me that one time! Its higher that up in the cold North even.

Forget what the lowest I saw on a trip to Idaho, 10% or something, I was good to about 85 deg in that, still ok to 105 with a fan.

[Shadow9mm]

I worry about temp more than humidity. I have some of the large MTM ammo crates. I keep my powder in those. the Hodgdon bottles will stand up in the larger ones. helps keep the humidity balanced, but no where near thick enough to hold any pressure.

[armoredman]

I'm just south of you in the CG area and I've been reloading down here for 15 years or so...I store my powder indoors in a wooden magazine, (filing cabinet), with no issues. I also keep the primers inside as well, but on the OTHER side of the room.
We haven't really had a monsoon season for the last two years, which means this years might be a real lulu. The most moisture in your air would be your swamp cooler, not the local rains. If you have A/C you are golden. With swamps, as long as everything is sealed, no worries.

[Shadow9mm]

one day, when I get my own reloading room, I'm building a wooden cabinet....

[RC20]

I go full bore (pun intended) with armoredman on the Primers. Mine are not across the room but they are separate compartments.

Never thought about heat and primers, always been stored in the general area as the powder.

I didn't think Swamp coolers were allowed anymore. Saw em when I was down in that area back in the early 70s.

[RC20]

According to this, 150 deg is the max for primers and storage.

https://saami.org/wp-content/uploads...oc-Primers.pdf

[Heavy Metal 1]

I keep my primers and powder on the concrete floor of my non-climate controlled garage and have not had any problems. Even on hot days it remains cool near the floor.

[RC20]

Thermal mass can work nicely. Not good for batteries though, on a piece of wood.

[Unclenick]

Bucksnort1,

The 2013 Norma print manual shows that taking powder from 80% RH to 0% RH raises the burn rate by about 12%. So if you develop your load in damp conditions, you may need to knock your powder charge down to compensate, and vice versa.

[jetinteriorguy]

Originally Posted by armoredman

I'm just south of you in the CG area and I've been reloading down here for 15 years or so...I store my powder indoors in a wooden magazine, (filing cabinet), with no issues. I also keep the primers inside as well, but on the OTHER side of the room.
We haven't really had a monsoon season for the last two years, which means this years might be a real lulu. The most moisture in your air would be your swamp cooler, not the local rains. If you have A/C you are golden. With swamps, as long as everything is sealed, no worries.

Just curious, why store the primers away from the powder?