Silicone layer detaches with third-party supplier's resin


I’m searching for a rubber-like material for a while and tested the Formlabs flexible resin and others. Unfortunately nothing matched my requirements so far.
Now I did a try on Photocentric’s Flexible UV.
The result is looking promising at a first glance.

But see what happend after a few hours:

As you can see, the silicone layer has detached off the tray.
Has anyone seen a problem like this before?
I’m not sure, is it the resin liable to this issue or did i get a deficient (new) tray?

Best regards

Hi Juergen,

Photocentric’s flexible resin contains a component that swells PDMS and will therefore ruin every tank you put it in. Like you, I learned this the hard way. I was surprised because their store page says, “Resin successfully tested with SLA 3D printers CTC, Formlabs 1 and 2 using their standard resin settings.” Perhaps you can contact them to see what they suggest.



Please excuse the overly-technical jargon, but… GAAAH!

(runs to check tray full of FunToDo) …whew. But talk about “caveat emptor”!

Hi Robert,

thanks for the affirmation.
And yes, this comment beneath the product made me full of hope, the resin should work with our printer.
In the meantime I received a note from your colleagues at support too. They confirmed this matter.
And it’s Isobornyl acrylate that makes the PDMS swell.

So, if you had the same issue, did you contact the makers of the resin?
What was their statement about?

Is it just the flexible resin from Photocentric that causes this this issue?

I rather comprehend your, respectively Formlabs reticence to criticize a third-party product in public, but I really wish I had seen this info before.

@Volguus: I will see, what i’ll be able to obtain…

No, I didn’t try contacting Photocentric about the issue. I know some on this forum have discussed using their firm resin. I haven’t tried it myself, so I can’t speak to its compatibility.

I agree it’s unfortunate that this happened to you. Here’s hoping you’re able to get it sorted out.

I’m a “fix it yourself” kind of guy, and coming from the viewpoint of you having nothing to lose at this point, your photo seems to show that the peeling didn’t actually extend to the clear optical window, in which case there’s a chance it might be salvaged. Maybe you could try to rinse out the tray of as much resin as you can, even with IPA. There’s a possibility that once the contaminant is removed, the PDMS may shrink back to its original shape. If the shape does recover and it’s still adhered to the clear acrylic, you might be able to re-glue the edges of the silicone down to the orange plastic with superglue, one of the few things that does stick to silicone. A nice size bead of gel-type superglue might form a sufficient seal around the edge of the PDMS to keep new resin from getting underneath.

This is all theoretical based on what I know of silicone and acrylic from my propmaking days, but if you were just going to throw out the tray anyway (I doubt Formlabs would consider replacing it!), what’s the harm in trying it? Naturally a better alternative would be to recoat the tray with new silicone, but that’s probably not for everyone’s skill/budget level.

Instead of messing up tanks and wasting material and money have you tried printing a part out, make a mold and using one of the urethanes from Smooth-On?
Typically printing many parts on any resin based printer gets costly and can be expensive. In most cases the parts are not that hard to make a mold and cast. Urethanes will run between $80 - $170 a gallon vrs $150 a liter for printer resin. Sample kits are usually under $30.

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Thanks, but in the meantime the silicone has released nearly completely.
My dealer made a identical test by himself, with - no surpise - the same result.
He gave us a credit note and is willing to replace the tray.
No complaints on this side. :slight_smile:


That’s good news they at least replaced the tank.

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