# Adding dye or a "light blocker" to elastic resin

**URL:** <https://forum.formlabs.com/t/adding-dye-or-a-light-blocker-to-elastic-resin/22363>\
**Category:** Experimental\
**Created:** [February 19, 2019, 11:57am UTC](https://forum.formlabs.com/t/adding-dye-or-a-light-blocker-to-elastic-resin/22363 "2019-02-19T11:57:00Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![FrankHaring](https://avatars.discourse-cdn.com/v4/letter/f/a88e4f/32.png) [@FrankHaring](https://forum.formlabs.com/u/FrankHaring)\
**Post date:** [February 19, 2019, 11:57am UTC](https://forum.formlabs.com/t/adding-dye-or-a-light-blocker-to-elastic-resin/22363/1 "2019-02-19T11:57:00Z")

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So i am working on a project for which i print several tubed structures in order to get a very low effective stiffness. I have successfully created these structures with the flexible resin (see picture). Since the elastic resin became available i am trying to print these with this resin as well. But i notice that the light bleeds trough and the resin over-cures, clogging the tubes, and imprinting a negative surface structure on the insides of the tubes.

To see if i can ‘fine tune’ the light penetration i want to mix a light blocker or a dye through the flexible resin.

I am thinking of using the [Fine Tuner LB1 “Light Blocker”](https://www.3dresyns.com/products/print-quality-fine-tuner-lb1-light-blocker) from 3Dresyns, but i am wondering if this additive is mixable with the elastic resin from formlabs, or if it is better to use a dye instead of a light blocker ?

 ![test%20samples](https://us1.discourse-cdn.com/flex025/uploads/formlabs/original/2X/3/38e86e2ba1a0f74df467965f4bdab079f8f38cda.jpg)

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**Author:** ![PrintmasterFlex](https://avatars.discourse-cdn.com/v4/letter/p/7bcc69/32.png) [@PrintmasterFlex](https://forum.formlabs.com/u/PrintmasterFlex)\
**Post date:** [February 25, 2019, 11:25pm UTC](https://forum.formlabs.com/t/adding-dye-or-a-light-blocker-to-elastic-resin/22363/2 "2019-02-25T23:25:42Z")

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We use epoxy dye and it came out nearly opaque. Depends on your goals.

I was shooting for a soft pink, and what we are doing now is just using the left over IPA from our Castable Wax formwash and putting the elastic in there.

But yeah, the elastic resin soaks up a TON

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**Author:** ![groveland](https://avatars.discourse-cdn.com/v4/letter/g/f17d59/32.png) [@groveland](https://forum.formlabs.com/u/groveland)\
**Post date:** [June 11, 2019, 5:43pm UTC](https://forum.formlabs.com/t/adding-dye-or-a-light-blocker-to-elastic-resin/22363/3 "2019-06-11T17:43:28Z")

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Great to know. How much dye did you mix into the cartridge?