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A better way to wash prints

It’s really only the boundary layer of resin and IPA that counts when cleaning a print. The bath itself doesn’t do anything.

I thought of a more efficient and economical solution.

I’m now using a peristalic pump to hose down the prints. The force of the fluid stream strips off the resin quickly; a couple of minutes seems to do the trick. It’s like the difference between a tub washing machine and a front loader.

The prints are clean in a fraction of the time of manual dunking or wash station times, and I use a very small amount of fluid; just an inch on the bottom of the tank, which gets sucked up and forced onto the print. It then flows down into the reservoir of fluid on the bottom to be cycled again.

It’s not only faster, it’s way more economical and less wasteful. Dirt cheap compared to what Form is suggesting for the 3L.

I’m using this: (Stepper peristaltic Pump 24V Small Intelligent Variable Speed high Flow lab Liquid dosing Pump Kamoer DIP 3 Rollers 5-670 ml/min BPT Tube 4.8 mm ID x 8 mm OD), $150 on Amazon. You have to buy the hose separately.

This model delivers about 700 ml per minute, which is fine for Form3 size prints. I might go for a larger flow for 3L prints. I’ll report back after my 3L is delivered and in use.


Yes, I’ve had similarly good results when using a pump. I’ve even designed and printed a nozzle so I get a nice jet of IPA. I use a small cheap chinese 6v immersible pump that I bought a few of for another project. I had thought of using a peristaltic type but I’ve never got around to sourcing one. I’ve been meaning to design a ‘shower head’ type of arrangement but I’ve not got around to that either yet. I’d also need to get a pump with a higher capacity than the one I have been using.

Interesting. Are you manually hosing off each part or is there a way to configure this for a production batch? I currently clean many parts in multiple form wash units to support a production environment.

I went with a peristalic pump for safety and economy. I felt better about minimal fluid to pump contact, and this solution permitted use of a trivial amount of IPA.

I don’t know if a shower head would be efficient unless you had high flow in order to get into all the crevices.

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It takes so little time for each part I think it’ll serve for a production environment. i might go with a higher volume pump if the pieces are large and you really have a lot of them; I’ve found units that deliver up to 1.5 lpm (adjustable).

By hand washing you can spray into all the hard to reach places; a couple of minutes per part would probably suffice. In addition, you can feel when the part is clean, meaning an absolutely minimal exposure to IPA, which is a good thing.

As for a production batch, it depends on the part; without a high volume, high pressure solution, you’re at risk of missing hard to reach areas. Plus, you’d get a lot of IPA vaporization, which I’d rather avoid.

We recently switched back from pumping IPA over the parts to dunking for 3L parts. We use 99% IPA and given the size of the parts you get more vaporization. As such the natural recourse is to get a fan to provide fresh air. The fan so greatly accelerates vaporization that you quickly have a hazardous volume of vapor. This is a scaling issue with cleaning 3L parts.

Pumping is without a doubt better, it is already used pretty standard with other SLA printers, effectively dish washers designed to handle IPA. My fingers are crossed the the 3L wash station due the end of the year uses this pumping technique.

Important point. Thanks for sharing!

Have you tried a less aggressive concentration of IPA? 99% might not be necessary, and that would reduce the vaporization, while still taking advantage of the pump.

My 3L is coming today, and I’ll try diluting the 99% that I have, starting with 70%.

I’ll report back after I get some prints done.

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Rob, I just bought a 3L and was wondering if you’d still recommend the pump option?

Yup. I recently switched to a less expensive submersible pump, with greater flow. I had been afraid of IPA and submerged electric components, but it’s working fine.

The bin is large; 24" by 18" by 12",tilted so the lower left corner is deep enough to submerge the pump, while keep the IPA volume small. A few hundred ml.

Since the volume is so small, I don’t use it for very many prints.

I also have started to cover the bin, leaving a smaller opening, just big enough to fit my arms. The clear plastic lets me see what I’m doing, while keeping the fumes to a minimum.

I also stop after a couple of minutes, and rub the surface with a cloth where I can get access; it makes for a shorter cleaning cycle.

So, the workflow is now hose the part for two minutes, rub the surface with a cloth, hose for a few minutes, drain the IPA for reuse a time or two, then a short cycle with fresh IPA.

I hope this helps.