# Suggestions for making the High Temp resin less brittle?

**URL:** <https://forum.formlabs.com/t/suggestions-for-making-the-high-temp-resin-less-brittle/14320>\
**Category:** Experimental\
**Created:** [July 31, 2017, 8:16pm UTC](https://forum.formlabs.com/t/suggestions-for-making-the-high-temp-resin-less-brittle/14320 "2017-07-31T20:16:11Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![jbroderick](https://avatars.discourse-cdn.com/v4/letter/j/e56c9b/32.png) [@jbroderick](https://forum.formlabs.com/u/jbroderick)\
**Post date:** [July 31, 2017, 8:16pm UTC](https://forum.formlabs.com/t/suggestions-for-making-the-high-temp-resin-less-brittle/14320/1 "2017-07-31T20:16:11Z")

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Hey guys/gals, I’ve been using the High Temp resin for molding prepreg carbon fiber, and each time I’ve used it I manage to crack the mold at some point in the process. My cure temp is 250 deg F. Anyone have any suggestions for a resin mix that might make for more forgiving mold properties? As I understand it my cure temp is not high enough to require the full HDT of the High temp resin, so I thought I may have some leeway. Right now I have clear, tough, high temp and grey (all formlabs) resins to play with. …

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**Author:** ![Frew](https://avatars.discourse-cdn.com/v4/letter/f/c0e974/32.png) [@Frew](https://forum.formlabs.com/u/Frew)\
**Post date:** [August 1, 2017, 3:39pm UTC](https://forum.formlabs.com/t/suggestions-for-making-the-high-temp-resin-less-brittle/14320/2 "2017-08-01T15:39:38Z")

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High Temp is one of the more brittle materials to work with and fully curing the part won’t help to make it less brittle but will improve the tensile strength so that it’s less prone to cracking. For Injection Molding, we had success fitting the printed parts in an aluminum cavity to cut down on cracking and improve the lifetime of the printed molds.