As i was encountering some issues while printing I came to the conclusion that my PLA filament must have gotten wet(bubbeling noises while printing, bad printing quality etc.)

The normal approach to get PLA and other filaments dry is to expose it to temperatures that would slowly evaporate the water and also lower than the glass transitioning temeperatur of the material. So to dry PLA we would need at least 40°C and at maximum 60°C.

The established way to do this is to buy a Food Dehydrator and put it in there for a couple of hours at 50 or 55 °C.

But to be honest these things are just a chamber, a heating element, a fan and some basic electrical components to control the temperature. So nothing that can't be done by yourself.

The chamber can be improvised with some cardboard and as a heating element we will take an old PC.

Normally these come with fans so this is also covered and the temperature control can be done manually with the help of a simple temperature probe.

DISCLAIMER:

This can potenially damage your PC and is not recommended on your daily driver. Even if everything is reversable, the heat will have an additional toll on your components. So please use an old PC that you dont need anymore. ;)

Supplies

Old PC
Cardboard box fitting a spool of filament and at best covering your outlets of your pc
Temperature probe
(Masking) tape

Step 1: Prepair Your PC

So to get enough temperatur in our chamber we need a lot of heat from our pc.

This means we need to create a lot of load on the CPU and if present also on the GPU.

Since modern CPU's and graphic card produce a lot of heat when you create a artifical load on them, for instance prime95 or furmark and so on, this shouldnt be a problem. Also gaming, mining or folding@home are options to create enough load.

If you have a watt meter you can check how much power your PC consumes.

Normally 99% of the consumed energy of your PC is converted into thermical energy which we need to dry our filament.

For instance the PC I used for this consumes about 270W at load which is pretty ok for this application.

If you want more heat you can always overclock your CPU, put some more voltage on it and deactivate energy saving features. But be warned this is on your own risk.

Also make sure that normally passively cooled components have enauogh airflow. This means espacially the northbridge and the mosfets.

In short:

Create a massive computing load on your CPU and GPU
Overclock your components if needed
Make sure nothing gets to hot

Step 2: Control Your Airflow

To get the heat of your PC where we want it we have to direct it to the prefered exhaust.

It's recommended that you direct it to the top to use natural thermal convection effects. ( in short heat naturally raises upwards). You could also use the rear exhaust if you dont have a top exhaust but this will be harder.

The best way to direct the Airfolw is to cover all exhausts (except the top one) and also limit the amount of air the intake can suck in. This can easily be done with some masking tape.

Also dont forget to cover little slot and cutouts in your case.

In short:

cover all not needed air exhausts
limit air intake

Step 3: Make Your Heat Chamber

Take your carboard box and make a cutout for your exhaust.

In my case I have made a cutout of 140 by 285mm for my two fans and fixed it with some masking tape to the case.

I'm aware that every case is different and I cant give you proper instructions in this step but i may suggest that you try to mount your fans on the other side of the case as I have. this helps a lot.

Also now you can place a temperature probe in the chamber preferably at the top. In my case I used an arduino nano with a 100k temperature sensor and a tiny Oled dsiplay. This is normally sufficantly accurate but actually you can take here also an oven thermometer.

Step 4: Place Your Filament and Heat Up

So now we just have to place our filament inside the chamber and do some heating with the PC as discribed in step 1.

The temperature should be climbing slowly. After 10 minutes or so the max temperature should be reached.

If it's to low you have four options to go here:

reduce the speed of your exhaust fans
reduce the speed of your intake fans
Cover more of the intakes
Seal of your chamber with masking tape so the hot air cant escape so easily

Also you should make sure that you didn't forget any exhausts.

To fine tune the temperature you can use a fan controller but make sure not to overheat any components of your PC.

So now if the temperature is right where you want it you'll have to wait about 4 to 10h until your filament is dry. This actually varies a lot by the level of contamination of your material and the temperature of your chamber. As long as you dont reach more than 55°C you cant damage your filament so the longer the better.

With my seutp i reached about 45°C for 10h and after that my filmanet was as good as new.

Also makle sure to store your filament in a zipper bag with some moisture absorber after it cooled of. Otherwise you will have to do this all the time x-D

I wish you some happy drying and also happy printing :)