What resin and additives exactly do people normally use for moulding the stator?

[Wind Empowerment Technology WG]

Reposted from an email by Jon Persson:

What resin and additives exactly do people normally use for moulding the stator?

Looking at www.polyfibre.co.uk, there are quite a few to chose from, and the recipe book gives only general advice.

Cheers,

Jon

[Kostas Latoufis]

We use vinyl ester, talcum powder and the appropriate catalyst.

We used to use polyester resin in the beginning, but it cracks easily
and allows water to enter the magnet rotor disks.

Cheers,
Kostas

On Mon, 13 Apr 2015 01:26:19 -0700 (PDT), Wind Empowerment Technology
WG wrote:
> Reposted from an email by Jon Persson:
>
>> What resin and additives exactly do people normally use for moulding
>> the stator?
>>

>> Looking at www.polyfibre.co.uk [1], there are quite a few to chose

>> from, and the recipe book gives only general advice.
>>
>> Cheers,
>> Jon
>

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[esteban.vandam]

We use epoxy just like Jonathan, it's easier to work with, it has better results and it's less toxic to breathe (compared to polyester). We use mostly an accelerator (called "endurecedor" in spanish) that gives us 20 min aprox, which is good enough. And also, instead of talcuum we use quartz powder. The main disadvantage is the cost, but it's not a lot more on the overall cost of materials, and it has a lot of advantages. We never used vinyl ester because we haven't found it here in small quantities (they sell a minimum of 20 kg)..

Cheers

Esteban

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[gael]

We use vinyl ester, talcum powder and the appropriate catalyst.

It's cheap, around 9€/kg, give a nice result as long as you do it properly :

- i use between 1 and 3 % of catalyst depending on the temperature.
- I always add a little bit of talcum specially for the rotor mould. It's an advice from the resin manufacturer. It's avoid the overheating of the reaction wich lead to crack between the resin and the metal rotor.
- if it's hot do it in a cool area
-if it's cold, put the resin and the catalyst in a warm place.
- to avoid holl in the final resin, take care when you put the top of the mould. For example with the rotor mould put the metal piece in the same time and not to big one...

Gaël.

[Jay Hudnall]

I'm a big fan of Vinylester as well.  Just make sure to always add the catalyst and mix well before adding the talc. 

We always respect the 1,5% dose for the catalyst.  Several times when we have varied this percentage, the resin heated too quickly, or in the other scenario, never hardened.

For the Talc, we use around 50% of the resin weight.

Resin is better fresh! The official shelf life of vinylester is 6 months. Keep out of direct sunlight!

Always paint or galvanize the disks before placing the magnets. Vinylester alone will not protect against corrosion.

A+
Jay