Dye the Flexible 50A

Hi All,

I want my part printed with Flexible 50A to be white, can I use alcohol or any other type of paint to mix it with the resin?

My printer is Formlabs 3+.


I’ve used alcohol ink in the past with varying degrees of success, mostly dependant on what color you’re looking to end up with. and it’s readily available at any craft or hobby store.

I want it to be white, so do I just mix it with the resin before the printing starts and keep adding along the way? And would that damage the resin tank in anyway?

Thanks a lot !

Hi @Abood123,

I would recommend looking over our Guide to Dyeing, Painting, and Coloring SLA Parts. Dyeing the liquid resin is a potential option depending on your use case. Sticking with the proportions of ink and resin outlined in the guide will yield the best results.


I just have one more question which the guide doesn’t include, shall this process shorten the life span of the tank in anyway?

I want it to be white, so do I just mix it with the resin before the printing starts and keep adding along the way?

DO NOT add alcohol ink to the resin.
using alcohol ink to color parts is achieved by applying the ink after the part has been cured.

You can technically add it to the resin and Formlabs even sells a kit to do this https://formlabs.com/store/materials/color-kit/

You can choose to add any alcohol dye at any of the 3 stages: resin, alcohol wash, and after uv cure.

I haven’t tried it yet, but I plan to try an alcohol dye in the wash stage because it won’t effect the resin, it should allow you to use on multiple versions of the resin, and after curing I would think it’s harder to absorb the dye.

Hi all,

Just to briefly follow up on this - based off the article I linked previously, it should be OK to add alcohol ink to the liquid resin itself in adequate proportions (~10 mL alcohol ink per 1 L of resin). The article suggests doing so for Clear Resin and warns that doing the same for Elastic or Flexible may lead to variable results, but in my experience dyeing these resins in the same way can work very well. Alternatively, dyeing the parts after they have already been printed can also be a great option.

I stand corrected.
My only experience adding alcohol ink to the resin tank turned into a huge mess.
Even though the ink appeared well mixed into the resin, I still ended up with a mis-print containing mass amounts of swirl lines, prompting our team of 5 to declare this effort a fail (and a failure we all learned from).
Success was acheived when we dyed the parts after curing.(white resin/yellow ink)

No worries! Dyeing the liquid resin can produce variable results as this does affect the curing process, so dyeing the parts after post-curing is a good option especially if larger batches of similarly dyed parts are not needed.

I am a dental lab, a couple years ago I went down this rabbit hole to print out soft tissue for our model work. I know that formlabs has recommended the 80A in conjunction with the coloring kit but the result was soft tissue that was not soft at all, almost rock hard actually. So the 50A when printed turned out to be far more tissue like, the problem was the coloring kit turned the resin into a semi coagulated mess. I was informed about the alcohol dye but as RD_lab stated at that time formalbs stated to do so after the print and during or after the wash. The results are somewhat disappointing. am very curious about being able to add the alcohol dye to the resin itself. If you know of a lab who has done this successfully could you provide me the brand or source of the dye and the exact measurements they used, this could really speed up the trial and error of figuring it out for myself. The 50A resin isn’t exactly cheap.

Hi @mctech,

Thanks for getting in touch! I can provide some clarification here. The coloring kit pigments contain material which alters the curing properties of the resin. The Color Base Resin is made with this in mind, whereas other resins are not, which may explain the altered material properties you noticed.

In terms of adding dye to the liquid resin, we technically do not recommend it per our Guide to Dyeing, Painting, and Coloring SLA Parts. This is due to the unique challenges that flexible materials pose when printing. With that said, in my anecdotal experience, you can achieve similar results to Clear Resin with Elastic 50A when adding alcohol dye directly to the liquid resin. I would use the same proportions of dye to resin outlined in the guide as with Clear. I don’t have a specific brand to recommend, but I would expect most alcohol inks to perform similarly.

Thanks, I’ll keep this in mind when I get the chance to look into it again. Thanks

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