Re-using Desiccant Sachets

[Aramcheck]

I've been using the FLO Dual-Fit Desiccant Cap on our 2x Newtonian scopes, but once the sachets have gone green I'm having trouble getting them to return to their 'orange' dry state.

Simply placing them on a radiator doesn't seem to be working.

Any suggestions much appreciated...

Ivor

[Tomatobro]

the nearest I have got to returning them to the brown colour is to put them on a plate, stick them in the microwave on defrost for a while. keep checking on progress to see how they are getting on. I store them is a jam jar with a tight fitting lid.

I tried some at full power but the plastic melted.

Edited October 12, 2019 by Tomatobro
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[symmetal]

It will work putting them on a radiator but it can take up to a week for them to turn yellow brown. As this doesn't work in the summer, I thought of utilising the 60W tube heater on the floor of the airing cupboard. The hot water tank had been removed and the heater does a good replacement job. I just placed a perforated aluminium place above the heater and keep the sachets and tablets on the plate. Again it takes a week to dry them and just leave them there until needed. I happened to change two sachets yesterday from my FLO eyepiece caps which are the green ones. The Zwo tablet bag is actually open in the picture. 

Alan

[WanderingEye]

2 hours ago, Aramcheck said:

I've been using the FLO Dual-Fit Desiccant Cap on our 2x Newtonian scopes, but once the sachets have gone green I'm having trouble getting them to return to their 'orange' dry state.

Simply placing them on a radiator doesn't seem to be working.

Any suggestions much appreciated...

Ivor

They should return to there origonal colour, a good few time’s, when put in microwave on low power for a minute or two, if not then they are probably no good, but if you bought new from FLO then they should be good....

[PeterW]

Dry heat is best to get the moisture out. I used to recondition desiccant in an oven at 120C.

PEter 

[Tomatobro]

This post reminded me that I had not changed mine for a few weeks, and i am down to my last two dry ones.

There are now thirty in a fan oven at 120c, been in 25 mins so far will report on results

[Tomatobro]

2 hours @ 120c. Green as Holly when they went in

[tomato]

I have found that they require several sessions in the microwave at partial power to return them to their anhydrous state. I have two large perforated containers which I can open and spread the beads onto a saucer, this speeds up the process significantly. It is a fun game though, getting them back into the containers afterwards, those beads can bounce!

[Geoff Lister]

I stick them in the oven after the Sunday roast/Apple crumble has been removed. I read somewhere that if you use a microwave, when most of the water has been driven off, there is no "load" for the microwave energy and it puts more strain on the magnetron.

Geoff

[RT65CB-SWL]

14 hours ago, Tomatobro said:

...

I tried some at full power but the plastic melted.

Same thing happened to mine! 

[Aramcheck]

Thanks folks! I tried the microwave on defrost & results were mixed... Although the crystals came out the right colour, the plastic outer bags got a bit shriveled in the process.

Next time I'll try the oven!

Cheers
Ivor

[Carbon Brush]

The general rule for reusing silica gel (with or without indicator colouring) is a couple of hours, or more, at a little over 100C.

The only restriction is whether the glue or bag may be damaged by the heating.
If so, never mind, you have tried.

Having an allergy to opening my wallet, I tend to hang on to any suitable size silica gel bags that come my way. Noting the 'do not eat' labelling.

At this temperature the oven won't use a lot of electricity and you can of course puts lots and lots of bags in there. Just allow air to circulate around them.
Think cooking sausage rolls rather than stacking sandbags!

HTH David.