Can't dry my dessicant in a gas oven

I've been trying to improve print quality for ages and recently bought some orange/green indicating desiccant and left it with the filament a vacuum storage bag over the weekend. The prints on the following Monday were all I could wish for but on the following days the print quality has been going down hill.

While the filament is on the printer I've been heating the desiccant in the oven at between 75 and 120 Deg C but its colour doesn't change and has not returned to the colour it had when it arrived and its weight is increasing.

I've been keeping the filament and the desiccant to the vacuum storage bag overnight and when not in use.

The gas oven is probably the problem because moisture is produced when gas burns.

I can't think of a relatively cheap off the shelf item that I can buy in the UK that has a heated enclosure with slow ventilation to get rid of the moisture.

Online there are references to solving this problem by, for example, building a DIY system with a controlled Peltier device to provide heat and also with a cold surface to condense the moisture but that's beyond my skill set.

An electric oven could be bought but I don't think the head cook would approve the expenditure.

Suggestions would be welcome.

Incandescent light bulb in an enclosure.

Put the stuff in an open pot and set it on your printer's heated bed. Set the temperature to 100C or so and leave it sit for a while. Stir it once in a while. It will take a couple hours but it will dry out.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Toaster oven from a thrift store.

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Newbie with Folgertech 2020 i3.

Assuming it is a silica gel type dessicant, use a microwave oven. It is very simple to do.

Spread it out on a shallow tray and put it on the high setting. Open the door and check at say 1 minute intervals and you can see the water coming off as steam. Once no more steam comes off, give it one final minute.

I have used this method many times. Not for 3d printing but for another project.

I have 500gram bags of silica gel type desiccant that are placed inside my filament box.
Dried them by using the microwave method.
I weighed them first, they weighed 580grams, set the timer for about 5 mins, keeping an eye on them, beware they get very hot.
Repeated the above and once the weight had drop just below 500 grams, they were dry.
Took about 20mins to dry them out

Edited 1 time(s). Last edit at 01/25/2016 06:09PM by orictosh.

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Supporting 3D Printers with Parts and Build services.
Printer: Ormerod 2 (528.4) Duel extruder set-up with Aluminium X-Rib, RRPro Firmware v1.11-ch (2016-04-08)

Throw it in the freezer. Along with your filament. That's where I keep my polycarbonate when I'm not printing - no hissing or popping when I run it, and parts are turning out great.

Trying to eradicate dew by baking in a gas oven...pretty sure it's been tried before without success.

Edited 1 time(s). Last edit at 01/26/2016 01:27AM by MechaBits.

I have been using a dry box with silica gel desiccant to store PLA filament for a year or so at the makerspace. Someone suggested that I look into other desiccants and I found this:
[www.absortech.jp]

CaCl, available cheaply in large quantities (50 lb bags) this time of year in the northern hemisphere (for melting ice on sidewalks and roads) will provide a drier environment than silica gel. Put it in a plastic container with holes in the top and set it in your dry box and it will keep things super dry. You'll know when it's time to replace the desiccant when the plastic container contains mud.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Silica Gel is however re-useable and the colour change indicates when it needs to be re-generated. When dry the crystals are blue, turning to pink when spent. It is water of crystalisation which is bound to the molecule. It is not present as "free" water.

Industrial air dryers for instrument air use Silica Gel as the desiccant.

A humidity meter inside the storage container would be a more scientific method of seeing what is going on. They are cheap enough to buy now. Silica Gel should be able to pull the dew point down to -40 deg C, which is absolutely bone dry for all practical purposes.

Edited 1 time(s). Last edit at 01/26/2016 08:23AM by dave3d.

Instructions for color changing dessicant I have bought recommends baking in an oven, but adds that the door should be propped open so the moisture can escape. Sticking something like a wine cork between the door and the frame is sufficient. If it is a convection oven, the door can be left closed.

Not answering the OP's question, but crystal cat litter is silica gel. That's a pretty cheap and easy (local) way to buy silica gel.

I'm trying to remember, but not sure, isn't water one of the by products of burning natural gas? If it is, that could be why it won't dry in a gas oven. Relative humidity is too high.

Of course, I might be completely wrong here. Chemistry class was way to long ago.

A gas flame produces water and carbon dioxide as the products of combustion, so forget that method.
A microwave is so easy it has got to be the preferred way.
Not sure about cat litter, but silica gel can be bought very cheap on fleabay. It is used for flower drying among other uses.
A quick check and it is less than 10 GBP per kg.
Also I see the colour change says orange to green! Mine was blue to pink. Some also seems to be just white, so not sure now about the colour change!

Hi All

Thank you for your replies. I'm now using the microwave on medium for 5 minutes.

Having carried out lots more tests I'm now thinking that the good results achieved when I first tried the desiccant weren't due to drier filament. Embarrassingly, the good results were more likely to be due to a failure of my Z (height - I'm British) homing procedure because I can only reproduce those results when the height calibration is set 0.2mm low.