Making 3D printed developing tank resistant to chemicals

Hello everyone,

I am about to try to 3D print a developing tank for 8mm film. I found a model online that might work (maybe adjustments have to be made to fit the 8mm format but I will look into that). Here is the link: https://www.thingiverse.com/thing:4920658

I was wondering if the b/w developing chemicals would damage the plastic material from the 3D print. Does anyone have experience with this? I was thinking of maybe spraying the components with some sort of isolation spray but then again there might be problems with the chemicals...

Thanks in advance,
Timo

Timo Schön said:

Hello everyone,

I am about to try to 3D print a developing tank for 8mm film. I found a model online that might work (maybe adjustments have to be made to fit the 8mm format but I will look into that). Here is the link: https://www.thingiverse.com/thing:4920658

I was wondering if the b/w developing chemicals would damage the plastic material from the 3D print. Does anyone have experience with this? I was thinking of maybe spraying the components with some sort of isolation spray but then again there might be problems with the chemicals...

Thanks in advance,
Timo

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Why not take some filament and let it soak in your chosen chemistry for a day or two? That would probably indicate any likelihood of damage.

Also, look at what materials are used to make the various storage containers and dev tanks for B&W chemicals today and see if you can use a similar material in your print (Nylon, ABS, etc).

Chris

You could coat the interior of the tank, reel, etc. with a wash of two-part epoxy or polyester resin; then it wouldn't matter much what material it is.

FWIW, I've used homemade developing tubes made of ABS and PVC (plumbing pipe), most commercial plastic tanks are ABS or polypropylene and a few are high impact polystyrene. HIPS is 3D printable, as is ABS (though ABS isn't recommended by experts these days, since it's difficult to print well and other things that are easier to print can replicate its important properties). If you do print in ABS, however, you also gain the ability to smooth/seal your print with acetone vapor.

PETG or PLA+ should be fine. Even regular PLA is probably OK. The models look fairly well designed, and shouldn't require supports (a frequent issue with PETG, at least for me).

Make sure it's an opaque filament.

The main thing with FDM printing for liquids is to make sure that the layers bond completely. Otherwise the surface is porous if not actually permeable. ABS can be smoothed/sealed using acetone vapour, but PETG will need a coating if you want a smooth surface. On the up-side, PETG is pretty resistant to many chemicals.

A smooth surface is an aid to drying and reduces the chance of chemical residue being retained.

Even with black filament you will probably need 3-4 wall thicknesses for opacity - test before committing important materials.

I've made film reels with ABS, no problem. I made a tank spacer with PETG no problem.

grahamp said:

The main thing with FDM printing for liquids is to make sure that the layers bond completely.

Click to expand...

Baking PLA (or any FDM material) prints will help this -- the same procedure that strengthens a print does so by increasing interlayer adhesion, which occurs via a process much like sintering.

Concerning the design as such: there is no spiral, just a plain reel. The film is thus just loosely wound?

I see a single-sided spiral, 4th image on the Thing page. There's a wheel-like over plate; this single sided design is similar to some stainless 16 mm reels I've seen. Looks like this is intended to do 50 feet or so of 16 mm film.