3D printed Dosing Reservoir

Luckyduck · Nov 17, 2023

Has anyone here 3D printed Dosing tanks? I was planning on using Acrylic to build 2 liter boxes for my dosing chemicals to hook to my doser but was wondering if I could 3D print them instead. I know PETG has pretty good chemical resistance but would I hold up? Anyone done this yet?

Townes_Van_Camp · Nov 17, 2023

Luckyduck said:
Has anyone here 3D printed Dosing tanks? I was planning on using Acrylic to build 2 liter boxes for my dosing chemicals to hook to my doser but was wondering if I could 3D print them instead. I know PETG has pretty good chemical resistance but would I hold up? Anyone done this yet?

I've only printed temperature probe brackets, snail guards, I don't know about how well it holds water long term. However, it's not that durable. Especially after compared to the price of a 1.5-2 L reservoir.

I know my printer is slow. But dang that sounds like a slow print.

GK3 · Nov 17, 2023

Luckyduck said:
Has anyone here 3D printed Dosing tanks? I was planning on using Acrylic to build 2 liter boxes for my dosing chemicals to hook to my doser but was wondering if I could 3D print them instead. I know PETG has pretty good chemical resistance but would I hold up? Anyone done this yet?

PETG would almost certainly leak. You can’t post process PETG unless you cover it with epoxy. Raw PETG may appear to hold liquid but it’s only a matter of time before it moves through one imperfect layer and through the infill.

You’d want to use a material that can be post processed like ABS. You can use acetone to post process and fuse the layers together. ASA is another material this works with.

DaJMasta · Nov 17, 2023

Almost any layer based construction isn't going to be watertight. There can be issues with water absorption, but bubbles from printing (just from humidity in the filament) or other extrusion irregularities would create small leaks in the part - and thanks to capillary action, any tiny hole would wick liquid away continuously.

An alternative is post processing, but you could also just coat it with something - a sealer used for other porous materials would work just fine and there should be plenty of options. Even something as simple as a plastic bag could do the job provided it didn't have a hole, you really just need a barrier.

Luckyduck · Nov 17, 2023

GK3 said:
PETG would almost certainly leak. You can’t post process PETG unless you cover it with epoxy. Raw PETG may appear to hold liquid but it’s only a matter of time before it moves through one imperfect layer and through the infill.

You’d want to use a material that can be post processed like ABS. You can use acetone to post process and fuse the layers together. ASA is another material this works with.

Thank you for that. I had a feeling. I hate ASA lol warps like a ***** and I don't have great ventilation in basement. I'm gonna go back to my original idea of Acrylic or glass bottles and 3D print a holder for them.

Luckyduck · Nov 17, 2023

DaJMasta said:
Almost any layer based construction isn't going to be watertight. There can be issues with water absorption, but bubbles from printing (just from humidity in the filament) or other extrusion irregularities would create small leaks in the part - and thanks to capillary action, any tiny hole would wick liquid away continuously.

An alternative is post processing, but you could also just coat it with something - a sealer used for other porous materials would work just fine and there should be plenty of options. Even something as simple as a plastic bag could do the job provided it didn't have a hole, you really just need a barrier.

Alright. Good food for thought. Thanks!

Kerbash · Nov 17, 2023

Ive printed my overflow using PLA and water proof it with a solvent (dichloromethane), still water tight 2 years in.

GK3 · Nov 18, 2023

Luckyduck said:
Thank you for that. I had a feeling. I hate ASA lol warps like a ***** and I don't have great ventilation in basement. I'm gonna go back to my original idea of Acrylic or glass bottles and 3D print a holder for them.

Have you seen the voss water bottles people sometimes use? Those would be awesome with a 3D printed holder. Actually I may go do that for my new build.

Mschmidt · Nov 18, 2023

I'm using old milk jugs. 2 weeks in though, so no long term review yet though.

If your bed is hot enough you may get a smooth first layer, that would be water tight. But then you would have to print the sides and fix them together some how. At that point acrylic would be easier.

Tavero · Nov 18, 2023

Kerbash said:
Ive printed my overflow using PLA and water proof it with a solvent (dichloromethane), still water tight 2 years in.

PLA will degrade over time. It's not a question of if but when. This happens especially fast in caustic environments (sodium carbonate/ kalkwasser ect) and environments with lots of bacterial activity.
How many wall lines did you use. I printed a UVC casing but used 12 line thick walls. So hopefully the degredation will limit itself to the surface of the wall.

Kerbash · Nov 18, 2023

Tavero said:
PLA will degrade over time. It's not a question of if but when. This happens especially fast in caustic environments (sodium carbonate/ kalkwasser ect) and environments with lots of bacterial activity.
How many wall lines did you use. I printed a UVC casing but used 12 line thick walls. So hopefully the degredation will limit itself to the surface of the wall.

I did make it quite thick 3 mm completely solid infill. I did hear that PLA degrades but I dont know, before I 3d printed a batter box cover out of PLA too exposed to the sun and rain, 4 years in now and its still together. I think post processing with solvent really binds the layers together, cause that was the main issue I had with PLA was the layers came apart.

exnisstech · Nov 18, 2023

GK3 said:
Have you seen the voss water bottles people sometimes use?

I just finished making 4 of these. I used the 375 ml glass bottles. I can get a weeks worth of 2 part in them. This is my first time using a doser so didn't want huge containers in case of a malfunction dumping it all.

Tavero · Nov 19, 2023

Kerbash said:
I did make it quite thick 3 mm completely solid infill. I did hear that PLA degrades but I dont know, before I 3d printed a batter box cover out of PLA too exposed to the sun and rain, 4 years in now and its still together. I think post processing with solvent really binds the layers together, cause that was the main issue I had with PLA was the layers came apart.

Nah. You don't need solvent smoothing to prevent layers of your prints coming apart, but maintenance, calibration and proper slicer settings. I can print a single wall thick print in vase mode and it will be water tight. I only use DCM to weld my prints together, but if I can print it in one piece and the part needs to resist degradation, I'm using petg.
Degradation isn't always obvious and visible. Parts can still look fine until they suddenly snap under tiny load because they became so brittle.

dangros · Dec 1, 2023

Tavero said:
Nah. You don't need solvent smoothing to prevent layers of your prints coming apart, but maintenance, calibration and proper slicer settings. I can print a single wall thick print in vase mode and it will be water tight. I only use DCM to weld my prints together, but if I can print it in one piece and the part needs to resist degradation, I'm using petg.
Degradation isn't always obvious and visible. Parts can still look fine until they suddenly snap under tiny load because they became so brittle.

dangros · Dec 1, 2023

Sorry, I'm new to printing. VERY new. Printer isnt here yet. I want to also print probe holders and sock holders - which I have a great design for copying one that has a tiny reservoir for where the water is piped into the sump and over flows into the socks...
Would this be an unreasonable ask for filaments? I dont know anything about coating or treating them to be water proof either.
My printer will probably be a Qidi 3 plus but havent pulled the trigger yet. It's in my cart

Malcontent · Dec 1, 2023

Even if it leaks a little the water would just drip back into the sump, right? I'm pretty sure you could print this and have it hold water well enough to work.

exnisstech · Dec 1, 2023

Malcontent said:
Even if it leaks a little the water would just drip back into the sump, right? I'm pretty sure you could print this and have it hold water well enough to work.

I don't think having dosing containers leak into the sump would be good thing which is what the OP was asking

Malcontent · Dec 1, 2023

exnisstech said:
I don't think having dosing containers leak into the sump would be good thing which is what the OP was asking

We kind of went off on a tangent about sock and probe holders which I assume were being fed a stream of tank water...

bratfink · Dec 1, 2023

I wouldn’t assume that anything made by an FDM process will be water tight, regardless of material choice.
Post finishing might mitigate but the fundamental build structure doesn’t support a sealed container.
SLA or SLS processes are more reliable for water tight parts. SLA is quite brittle though and easily cracked.

dangros · Dec 1, 2023

Malcontent said:
We kind of went off on a tangent about sock and probe holders which I assume were being fed a stream of tank water...

sorry, didnt mean to hijack if that's what I did. Same premise though. I personally dont care if it leaks as long as it's not a result of chemical breakdown or compromising the structure over time as the OP is concerned with.