PU Resin for Layer Damping?

[Kchink]

Not trying to put you off, I'm intrigued to see the final test results.

Just warning you, that standard polyester resin may attack the butyl. I may be wrong about that but the styrene (solvent) in polyester can be pretty aggressive. Epoxy or polyester infusion resin (less styrene content) I know are safe. I use butyl rubber to seal a vacuum bag prior to infusion, to make composite part's.

In fact I could test friendliness of butyl - polyester next time I'm in the workshop if your interested?

[pippin88]

For a 3D printer gantry I would think about carbon fibre instead. Stiff and damp.

[Voicecoil]

Ons of the originators of damped PU compound of course is Sorbothane - though whether they sell the resins to cast your own I don't know.

For a 3D printer gantry I would think about carbon fibre instead. Stiff and damp.

Stiff yes, damped not always in my experience, I guess it all depends on the type of resin used to bind the fibres. A pal of mine who works in F1 gave me a sheet of thin (~0.5mm) woven carbon fibre sheet - if you hold it up and tap it with a hard object it sounds like tapping a sheet of metal - and the edges are bloody sharp!

[Kchink]

I would tend to agree with Voicecoil, I think there are better materials for a gantry than carbon. Then again for a 3D printer or plasma/laser it may be fine??? But I will say this...

String instruments like pianos and violin's are made from carbon fiber for it's resonance characteristics, I know the fabric laminates are engineered to enhance this - But still, they wouldn't use that material if it wasn't suitable.

If we're going down the composite route, Flax or Jute fiber's on the other hand would be better in my mind. These are used to make door cards in vehicles, for example. Forming the structural component and sound dampening in one piece, instead of multiple layers of different materials for a similar effect, thus reducing weight.
And as you say, different resin matrix's could enhance dampening Futher.

[pippin88]

Damping in composites depends on the fibre material, length, orientation, the resin, number and orientation of layers etc.

As a general rule though, carbon fibre will be more damp than aluminium.

I wonder if the push for super light moving parts in 3D printing is not the optimal strategy. I think vibration damping and stiffer structures are overlooked. Not hard to use bigger motors to move a bit more weight.