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Desiccant Recommendation

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#1 Toxo144

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Posted 21 July 2019 - 07:10 AM

Questar gang,

 

These last 2 years have been awful in terms of rain and humidity in my locale.  I am looking at SorbentSystems Dribox rechargable desiccant for use in both my Q50 and Q7 cases.  It says they can be reused, redried in an oven, and have a nice color change to indicate when the desiccant needs drying again.  The price isn't too bad either, 4 boxes for less than $20.  The health hazard warning did make me raise an eyebrow, but it still should be relatively safe. The 2" x 2" x 1" dimensions of the box might make it a tight squeeze for the Q50 case, but for the Q7 there is plenty of room.  Does anybody here have experience with this product, or recommend any other manufacturer or suppliers desiccant product?

 

Thanks in advance,

 

Toxo

 

 



#2 agmoonsolns

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Posted 21 July 2019 - 07:15 AM

If you store everything in the same room, then you could use a small dehumidifier. 



#3 Optics Patent

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Posted 21 July 2019 - 12:12 PM

A dehumidifier might reduce the desiccant recharge demands but it’s rare to have a room that is sealed off from the building ventilation system. You’d also need a way to monitor and a color change desiccant pack is ideal for that.

I do this for my shop room but everything has desiccant any in the case. And they do regularly need recharging. The ones in hard Pelican type cases need it rarely.

#4 theApex

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Posted 21 July 2019 - 12:14 PM

I'd been using these for several years:
https://www.ebay.com...g-/371771231900

Until I found out it was simply calcium chloride in a neat, rather expensive package.

I bought it in bulk (it's already cheaper per pound than the product above, for starters) a few moths back and it has been putting up nicely with many (too many) wet days since, for both my scope, binoculars and camera gear - all stored in three separate plastic storage boxes with calcium chloride inside the absorber's discarded packages.

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Edited by theApex, 21 July 2019 - 12:23 PM.


#5 spereira

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Posted 21 July 2019 - 12:30 PM

I just purchased these:

 

https://www.ebay.com...353.m2749.l2649

 

smp



#6 theApex

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Posted 21 July 2019 - 12:30 PM

Oh yes, on a per-pound basis, both items mentioned above still came up cheaper than the comparatively small dessicant packs of yore.

Not to mention more hassle-free, as there's no reheating or anything similar involved, but the simple top-up of said packages whenever they fill up with moisture or its contents become a gooey white paste, every 5-to-6 months.

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Edited by theApex, 21 July 2019 - 12:33 PM.


#7 agmoonsolns

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Posted 21 July 2019 - 02:53 PM

The room doesn't need to be completely sealed off, just close the door.

 

You monitor the humidity reading by looking at it, there's a built in hygrometer which tells you the humidity level. It can also be set to turn off or on when the humidity of the air reaches a certain level. Very efficient, quiet, and rooms with a dehumidifier in them feel wonderfully dry too. Having an actual numerical reading for a room is just a bit better than opening a case to dig out the desiccant and look for a color change (when you remember to do it).

 

The desiccant only takes care of localized moisture. That's great if you only want to dry out one small area. The nice thing about using an air filter/dehumidifier in a room is it keeps the whole room dry and clean so you don't need to worry about mold spores or anything growing anywhere near your scopes. This keeps everything dry - your scope, cases, eyepieces, and all of your equipment.

 

So many people forget to recharge their desiccant regularly. With this, not only does it keep the small area around the desiccant dry (very small when locked inside a case where air doesn't circulate), it keeps everything dry. Pretty nice having a dry, dust-free room to put a dew-covered scope in to dry it out before storing it. If you put even a slightly moist telescope inside an air tight case, you will end up with the problems. You really need to make sure it's totally dry first.

 

 

A dehumidifier might reduce the desiccant recharge demands but it’s rare to have a room that is sealed off from the building ventilation system. You’d also need a way to monitor and a color change desiccant pack is ideal for that.

I do this for my shop room but everything has desiccant any in the case. And they do regularly need recharging. The ones in hard Pelican type cases need it rarely.


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#8 Optics Patent

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Posted 21 July 2019 - 05:19 PM

That might well work in a home without forced air ventilation and a door that reliably remains closed.

#9 RobertPettengill

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Posted 22 July 2019 - 07:03 AM

I have three reusable desiccant solutions that I use.  I avoid plastic packaging because it tends to melt easily in a microwave or oven.

 

* These 40g metal canisters are what Pelican sells for their cases. The metal case makes them very tough.  The little clear window makes it easy to asses their condition. They usually recharge in about an hour and a half in a toaster oven at 350. The downside is that you can't dry them fast in a microwave oven.  The 40g size fits nicely in a Questar case.  Amazon sells them from multiple sources and sizes.  https://www.amazon.com/Hydrosorbent®-Dehumidifiers-Canisters-Desiccant-Dehumidifying/dp/B005V2B29A/  

 

* An old 35 mm film canister will fit snugly in a 1.25" eyepiece focuser.  Drill some small holes in the bottom of an old 35mm camera film canister and fill the canister with the little desiccant packets.  If you have had the Q interior exposed switching eyepieces or cameras in very damp conditions.  Put it away with one of these in place instead of the eyepiece and you can be sure to have nice dry air inside the Q.  Look for packets in paper packaging (I've found them in bulk on Amazon).  Most are plastic that will melt in the microwave.  The paper ones can be dried in a microwave within a few minutes.  If you go longer than 30 to 60" at a time they may scorch.  The packets puff up with the hot humid air.  Although you can't see the desiccant, if you push them down and they don't inflate then most of the moisture is out. Make sure your canister holes are smaller than the desiccant particles in case a bag tears.

 

* An inexpensive solution is to get desiccant in bulk unpackaged.  I also bought an inexpensive set of small, about 3x5" drawstring canvas bags.  I label the bags with a Sharpie - "Desiccant/Poison".  Half fill the bags with bulk desiccant and then securely double tie the bags closed.  These can be quickly dried in a microwave as well.  The burlap has less resistance to steam so they don't inflate the way paper bags do.  When  you check them while drying them out they feel noticeably moist until they are dry.  A few minutes in the microwave will do it in bursts of no longer than 60".  The desiccant can get quite hot and a fire isn't out of the realm of possibility.  Letting them rest a minute or two with the microwave door open while moisture continues to escape and the desiccant cools down a bit between short heating sessions works reliably for me.

 

It looks like the plastic boxes you mentioned above are somewhat heat resistant, but the recommended oven temps are lower than those for the metal boxes and the drying times are longer.

 

An orange colored silica gel which is less toxic than the blue gel is available and might be a good choice.  I think it is your only choice in the EU.

 

;rob


Edited by RobertPettengill, 22 July 2019 - 07:24 AM.


#10 Optics Patent

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Posted 22 July 2019 - 04:35 PM

I use the bulk pack approach and use what are sold as tea bags for herbal infusions. Semi transparent but the trick is to use a bright flashlight as backlighting to see the condition. I put a small clear packet alongside as “canary in the coal mine” to give a fast visual alert.

#11 BillHarris

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Posted 21 August 2019 - 03:15 PM

I just stumbled across this excellent thread. Thanks!


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