---
title: FPU 50
slug: materials/fpu-50
description: Discover FPU 50, a unique two-part polyurethane resin designed for high impact strength and durability, resembling polypropylene. This comprehensive document provides essential guidelines on proper mixing and curing methods for this Carbon resin.
docTags: 
createdAt: 2024-06-28T18:17:44.228Z
---

# Overview

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**FPU 50 **(Flexible Polyurethane) is a rigid 2 part resin that is unique in the additive industry, with properties similar to polypropylene. Offering high impact strength and cycle life, it is designed to withstand repetitive stresses.
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# Resource Links

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**[About the Material
](https://www.carbon3d.com/materials/fpu-50)**Material overview and uses cases  
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**[Technical Data Sheet
](https://docs.carbon3d.com/files/technical-data-sheets/tds_carbon_fpu-50.pdf)**Mechanical properties and data
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**[Safety Data Sheet](https://www.carbon3d.com/stewardship)**
*Login required*
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# Protocol Sheet

This downloadable handout provides important usage information, including instructions about compatible hardware, storage, resin dispensing, washing and curing. Print it out and bring it into the lab.

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**English**
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**Spanish/Español **
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::File{src="https://api.archbee.com/api/presign/uXbZOKjJTGpPhjapQ8fvM-IPHg7M5yaXvtfGWWc2lcc-20250129-165351.pdf" label="FPU 50 Protocol v04.04 REL_ES.pdf"}
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**German/Deutsch**
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**Japanese/日本語**
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# Resin Dispensing

FPU 50 **must be stirred** after dispensing and between every print. While all resins require stirring to check the window for bits of cured resin between prints, FPU requires more vigorous stirring to ensure proper mixing of the part A & B components comprising the liquid resin. 

FPU 50 parts can sometimes exhibit small, localized regions of reduced toughness due to the part A & B components settling between prints. **Stirring the resin mitigates** negative effects to the material properties.

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# Curing

## No UV Flash before Salt Baking

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Some resins recommend a short UV flash curing prior to salt baking. This process is **not recommended** with FPU 50.

- Additional UV light after printing can cause brittleness in FPU 50.
- To maintain FPU's remarkable ability to withstand repetitive stress with its flexibility, it is important to limit UV exposure to only the printing process.
- The UV light used to shape FPU parts in printing is carefully calibrated to maintain material properties in the final part.
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