Desiccant reactivation

[largom]

I have a large supply of desiccant in approx. 8 oz. packs made of some kind of paper. Printing on the package says it can be reactivated in a temp. of 245-260 Deg. F. for 12 Hr. min.
My question is this: Could this be reactivated in a microwave at considerable less time, or would I be playing with fire?

Larry

[felix]

Try a small bag and see. Leave on a flat saucer and watch for the bag charing condition. If the bag has moisture and salts enough to allow "friction", then you know there is activity. When moisture is finally gone the trouble will show up. Hopefully, the moisture will go through the bag enough to preserve the bag. I think the bag will char before the granules are dry. Then you have to take the granules out of the bag to thoroughly de-humidify them. ... felix

[AZ-Stew]

I don't think the desiccant will react so as to cause a fire, but you may find that the moisture inside the desiccant particles will turn to steam, causing the desiccant to explode like pop corn. If it stays in the bag it may end up being useless. If it breaches the bag you'll make a mess in the microwave. Stick to conventional heating.

Regards,

Stew

[mtnman31]

I reactivated a bunch that comes in the bags (weigh about 1/2 lb each). Bags are similar to Tyvek envelopes that post office has. With the first batch I tried, I melted a few bags and had a HUGE mess in the oven. The lowest temp will remove the moisture, but the problem occurs when the oven cycles on and off to maintain its temp. The oven cycling on would get the rack just hot enough to melt the bags and dump desiccant all over. The simple fix was to just put a layer of aluminum foil on the rack to protect the bags from the higher heat of the element as it cycled. After the foil was in place I only melted a couple bags that were touching the interior walls of the oven. I reactivated probably 40lbs and have had enough to last me going on four years now. My fresh bags are getting low and I will have to do some more here pretty soon.

Remember, once you remove the moisture, you need to keep them sealed up airtight until you use them. They suck the moisture out of the air and in a humid climate can get tapped out rather quickly.

[AkMike]

My question is this: Could this be reactivated in a microwave at considerable less time, or would I be playing with fire?

The question should be "what will my wife do to me if I make a mess in the kitchen?"

Be afraid... Be VERY afraid!

[alamogunr]

I've reactivated desiccant bags several times in the oven. The bag will degrade over several cycles. I just use an old pie pan or cookie sheet. I also have some desiccant that I got from my employer before I retired that was in quart cans. I just poured this into the pie pan and set it in my gun safe. When it turned pink, I put it in the oven(an old toaster oven) and left it overnight.

I don't know if desiccant loses its effectiveness over many cycles to reactivate it or not. I called the supplier to ask and was told they didn't know since most of what they supplied was used to ship with the customer's product. They did say they would be interested if I found out. I haven't kept track of it.

John
W.TN

[largom]

Thanks for the reply's. Think I will start with the regular oven but will try one bag in the microwave "just to see what happens".

Larry

[Orygun]

I've been trying to find more info on desiccants and have ran across some interesting discussions, one of which is listed below.

This came from here: http://www.agoodco.com/Desiccants/Desiccants.html

"A dopant may be included in the desiccant as a humidity indicator to show, by color changes, the level of humidity. This color change will normally occur when the humidity level reaches about 40 - 50% which provides visual notification of when the gel is approaching saturation and should be replaced or regenerated.

In the United States this dopant is usually cobalt (II) chloride (CoCl2) which is pending classification as a ‘category 2’ carcinogen. When cobalt (II) chloride is added as an indicator, the drying agent is blue when still active and pink when exhausted, corresponding to the anhydrous and hydrated forms of CoCl2, respectively".

[anachronism]

I just put the bags in the food dehydrator for about 24 hours. It doesn't hit 245 degrees, but it seems to work perfectly

[jsizemore]

My neighbor has a medium snap cap pill bottle to put her hearing aids in overnight that has a desicant pouch in the bottom. When it changes color, I put it on a plate in her microwave and set it for 30 seconds. I stop it after 20 seconds and look at it to see if it has turned blue through the pouch. If it hasn't started changing color I stick it back in and pull it out after 10 second intervals until it has started to turn blue. It doesn't all need to be blue when you take it out cuz it will continue to activate until it has disipated all it's heat. Again you only need to keep it in the microwave long enough for it to START changing color. Good luck

[montana_charlie]

You could probably lay a small bag (or the package for the hearing aid) on one of those electric coffee cup warmers, and leave it till it starts to turn blue.

They are also great for melting a small can of lube to pour into your Lyman 450...
CM

[MtGun44]

You will get much longer life out of the bags if you don't go so hot. Try about 150F for
overnight. Works good for me. Scorched some bags trying the temp on the label. I think
that is so you need to buy new ones rather than using them for years.

Bill

[jsizemore]

I went with what the instructions told me.

[lwknight]

Those baby diapers are suposed to hold like 20 pounds of water. Can you just throw a diaper in the gunsafe to keep it dry?

[JIMinPHX]

I dry mine out in a regular oven. It usually only takes about 2 hours. Any temperature over 212 F will work, but above 250, things seem to happen faster. I've melted a few of the plastic type bags too. If that happens, then I just dump the desiccant out into a pan & use it loose or dump it into an old pillow case & tie a knot in it. Either way, the desiccant still works fine. I think that 2 hours probably gets the stuff about 90% dry. It's enough to get all blue dots on a moisture test strip. I think that 10 more hours to get the last little bit out of it is probably a waste. All the above info that I gave was based on my experience when I lived back east, where it was humid. Now that I live in the dessert, I don't ever need to cook that stuff anymore.