Form 2 excess rashing and debris formation during printing

Hello Everybody,

Back in late February, I made a post on severe rashing I was getting on my parts. Since then, I have implemented suggested changes and the rashing has been heavily reduced but is still present.

The list of fixes and precautions include:
-Cleaning everything (including tools) with 99% Isopropyl Alcohol.
-Always wearing gloves
-Cleaning the Resin Tank (V 2.1) with IPA(to get rid of extra resin) and then a 2nd and 3rd clean with Novus#1 and a few brand-new microfiber cloths(single use).
-Filtering the resin after each print.
-If in the tank, the resin is stored with the lights off and always under the cover of the Form 2.

Despite this, I am getting large amounts of particulate formation during the print. I am not sure if this is being caused by the rashing or if it is a symptom of the problem that is causing the rashing. When checking the tank after a print, there is a layer of sludge a few mm thick. I am attributing this to two things and I’m not sure how much each matters. First, my tank, despite being very well cleaned is clouding after each print.

The clouding is permanent, and no amount of cleaning has been able to remove it. It also, appears to form in two layers; one at the surface of the tank and one between the rubber layer and the hard tank backing. The large smudge in the above images was the result of a single print.

The second cause of particulate formation maybe the leftover particles that made it through the filter. The resin is filtered into a glass beaker and the optical disturbances, in the picture below, are the result of resin bits on the side of the glass that got through the filter. The resin is not forced through the filter but is gently stirred with a thin metal rod to help prevent build up.

Do any of you all know or have an idea on what is causing this? As stated above I am not sure if the particulates are caused by the rashing or if they and the rashing are caused by the same problem.

Here is some images of the rashing. This is the print that caused the large smudge to form in the above tank but other prints in different tanks also cause smudges to form.


Maybe the laser beam diffuses as it passes through those cloudy areas, causing the sludge. Is your tank new? I remember Form2 has a heat map for the tank, maybe those areas are too much used and you need a new tank?

All these steps, missing the one you should have tried long ago… a new tank.

That hazing you see in the film is permanent. It’s not “dirt”, it’s the surface of the film that’s been roughed up by prior prints (the peeling process can cause “wear”). The quality of your prints is lousy because the laser light is being diffused and scattered by the rough surface. The debris is probably from the same cause - stray laser light curing stuff that’s nearby but not actually attached to the model, so it floats free.

Replace the tank and I bet the problem goes away.

As an aside, the Form2 tanks are acrylic. IPA will cause the plastic to crack over time. Avoid getting IPA on the orange plastic.

Perhaps. The tank I used is not new, but, It had no clouding before the print. The clouding is the result of a single print.

The tank I used is not new as I pulled it out of storage but, it had no clouding before the print. The clouding is the result of a single 8 hr print. Using a newer tank still results in rapid clouding; which is why I went through the old ones in the first place.

I don’t know why it is clouding so fast.

Also good to know with the IPA but at this rate I’ll need a new tank regardless.

Well… it had no clouding that you noticed… in the pictures above, which are the ones with resin in the tank vs. clean/dry no-resin? And what resin are you using? Clear?

I have to question the advice of using IPA to clean the tank/film. Especially multiple times. Was that a recommendation from FL?

Honestly, I have never cleaned a tank except for when there’s been a print failure. I let it drain (I have a little fixture so I can leave tilted on-edge overnight), if there was a failure I gently peel any left-overs off the film, and then I just reuse it with a new resin or put it away for future use. Any remnant film of the old resin will have no effect on the tank in storage, or on any new resin used with the tank later. It’s not worth worrying about.

Cleaning the Resin Tank (V 2.1) with IPA(to get rid of extra resin) and then a 2nd and 3rd clean with Novus#1 and a few brand-new microfiber cloths(single use).

The film is kind of delicate, easily abraded. Not something you want to be scrubbing all the time, microfiber or not. You’ve cleaned this one tank more than I have ever cleaned any tank I’ve ever owned, and I’ve been printing with FL printers since I got my Form1+ in 2015.

I have to think this is the source of your problem, cleaning the tank. I used my Form2 for a few years before I updated to a Form3, and I never, ever had this issue. But I never cleaned a resin tank like you have cleaned yours. Used them until they were used up, scraping off any leftovers from failed prints along the way, and then threw them in the trash (after a day outside in the sun) when they were no good anymore.

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Hi all,

Echoing Randy’s post, it’s certainly possible that cleaning the tank in this way could have exacerbated the issue. Our recommendation for Cleaning Form 2 Tanks is to clean the interior of the tank using a metal scraper tool. If similar issues persist, even with brand new tanks, sharing this info with our Support Team would be a good way to get further guidance.

Thank you Jesse and Randy,

I will order a new tank and see how it works out. Hopefully the problem goes away and if it doesn’t then I will contact the support team. Thank you for all your advice!


Whoa, this is your problem right here. NEVER use IPA on acrylic as it ruins it.

Here is one of many links that describes this.,the%20surface%20of%20the%20acrylic.

Is there anything you recommend that dissolves the resin without damaging the acrylic? From my limited experience, Novus #1 is alright but not as good of a solvent as IPA. If not, then Novus it is.

The problems you’re having appear to be due to damage to the tank film. Since you’ve said you’ve “cleaned it”, that’s almost certainly the cause. To prevent the problem, just stop doing that. :slight_smile:

You don’t need to “dissolve the resin”. Just tilt the tank at an angle and let as much resin as your patience permits to drain out. The tank doesn’t need to be dry of old resin to be put away in storage, nor does it need to be dry of old resin if you’re adding a new resin.

The only time I can think of where it might conceivably matter is if you’re adding clear to a tank that had colored resin previously. For that, I’d take the time to let the tank drain overnight. I still wouldn’t wipe it down, though. Otherwise, the 0.0001% of the old resin that remains behind and mixes with the new resin when you reuse the tank won’t “move the needle” on anything. You can ignore this.

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I have this issue and I’ve changed tanks and cleaned windows etc and I still get debris build up in the new tank even after one fairly small print and rashing too. Driving me mad, as have no clue what causes it, as it has only just started happening and seemingly no way forward at present. If you do solve the issue please report back.