# Machined buoyancy

**URL:** <https://discuss.bluerobotics.com/t/machined-buoyancy/15804>\
**Category:** General Discussion\
**Created:** [January 11, 2024, 3:17pm UTC](https://discuss.bluerobotics.com/t/machined-buoyancy/15804 "2024-01-11T15:17:52Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Jhans](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.bluerobotics.com/jhans/32/18197_2.png) [@Jhans](https://discuss.bluerobotics.com/u/Jhans)\
**Post date:** [January 11, 2024, 3:17pm UTC](https://discuss.bluerobotics.com/t/machined-buoyancy/15804/1 "2024-01-11T15:17:52Z")

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Can anyone recommend someone that who machined buoyancy for a Bluerov2 that can be rated to 1000m depth?

Cheers

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**Author:** ![SDI](https://avatars.discourse-cdn.com/v4/letter/s/ac8455/32.png) [@SDI](https://discuss.bluerobotics.com/u/SDI)\
**Post date:** [January 12, 2024, 1:58pm UTC](https://discuss.bluerobotics.com/t/machined-buoyancy/15804/2 "2024-01-12T13:58:25Z")

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There are several suppliers out there that offer this. However, it comes with a cost for the machining. My question is: Do you really need machining at all? Is it because you want a fancy geometric shape?

I don’t know how familiar you are with _ **Divinycell,** _ _but a 1000m rated unit has significant less buoyancy than a 200m (BR) unit, so you will have to apply more **Divinycell** and thus it will not fit inside the blue plastic boxes anymore._

_I have purchased sheets from DIAB and done the cutting and shaping myself, but I only have 300m rated foam._

> **[Divinycell - PVC foam core materials from Diab](https://www.diabgroup.com/products-services/divinycell-pvc/)**
>
> Diab's high-performance PVC foam core materials with excellent strength-to-weight properties. Read more about Diab's all-purpose series here.

For some of my other projects I have used [http://www.airboat.co.in/index.html](http://www.airboat.co.in/index.html) to perform machining. I believe they also do Divinycell.

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**Author:** ![wholm](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.bluerobotics.com/wholm/32/4469_2.png) [@wholm](https://discuss.bluerobotics.com/u/wholm)\
**Post date:** [January 12, 2024, 9:47pm UTC](https://discuss.bluerobotics.com/t/machined-buoyancy/15804/3 "2024-01-12T21:47:58Z")

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Here at Mission Robotics we’ve used Engineered Syntactic Systems MZ-22 syntactic foam on a number of vehicles. It’s rated to 1000m and is fairly light, 22 lbs/ft3 as opposed to 18 lbs/ft3 for the Last-a-Foam R-3318 that Blue Robotics sells, and 25 lbs/ft3 for Divinycell HCP100.

[https://esyntactic.com/products-solutions/syntactic-buoyancy-materials/microsphere-syntactic-foam/mz-grade-microsphere-syntactic-foam/](https://esyntactic.com/products-solutions/syntactic-buoyancy-materials/microsphere-syntactic-foam/mz-grade-microsphere-syntactic-foam/)

We previously used to epoxy coat the R-3318 foam for operations down to 500m. This works, but is very time consuming. The syntactic foam is expensive, but is easy to cut and shape, and doesn’t need any surface coating if you don’t want to bother. Though it looks nicer when painted.

-W

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**Author:** ![wholm](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.bluerobotics.com/wholm/32/4469_2.png) [@wholm](https://discuss.bluerobotics.com/u/wholm)\
**Post date:** [January 13, 2024, 12:55am UTC](https://discuss.bluerobotics.com/t/machined-buoyancy/15804/4 "2024-01-13T00:55:34Z")

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For folks wondering about epoxy coating Last-a-Foam 3318, see this thread (and perhaps others too):

[https://discuss.bluerobotics.com/t/epoxy-with-fiberglass-cloth-for-reinforcement-for-foam-flotation/10144](https://discuss.bluerobotics.com/t/epoxy-with-fiberglass-cloth-for-reinforcement-for-foam-flotation/10144)