Foam for CNC cutting

[Toby Catlin]

Hi gang,

I have been using some sheets of insulating foam (the foil backed kind for buildings) which cuts very nicely and gives some great crisp edges. However as it is building grade the interior is full of little voids. There aren't many but enough to cause an issue, so I am looking for higher quality alternatives.

Some stuff like this looks ideal but is expensive at £163 for 2x 50mm sheets

http://www.theplasticshop.co.uk/LD33-33kg-foam-sheet.html

Any ideas for cheaper but similar material?

Thanks

Toby

[Henry Sands]

The blue/pink insulation foam used to be the stuff, but it's been replaced by the crappy foil backed kingston stuff and is not produced any more except as a "modellers" foam for 10x the price

[Penguin]

Buliding supplies sells Extruded Polystyrene 600x 2500 x 75 for £40/ sheet

http://www.building-supplies-online.co.uk/cellecta-yelofoam-x2i-extruded-polystyrene-thermal-insulation-boards-50963-p.asp

4d model shop on Leman street near aldgate has half that size for £34 but you could go in and pick it up.
http://modelshop.co.uk/Shop/Item/Styrofoam-LB-X/ITM4933

Cheers

Matt

[Simon Howes]

I've used the blue high density foam from 4D model shop before when doing jobs on my cnc mill.

Its pretty cool stuff with a fine structure so it picks up cuts and contours really well and you can run the toolpath at the highest rate. It makes a lot of dust though.

A cool thing I found with it is you can polish the surface up with vaseline after its been cut and it will smooth it up consideraly as well as sealing the pores. This I found a really useful way of making a plaster model/master from a digital shape in the shortest amount of time.*

*Well, as long as you dont have overhangs...

--
You received this message because you are subscribed to the Google Groups "London Hackspace" group.
To unsubscribe from this group and stop receiving emails from it, send an email to london-hack-sp...@googlegroups.com.
For more options, visit https://groups.google.com/groups/opt_out.

[Toby Catlin]

That looks much cheaper i'll give it a shot and keep an eye out for the pink/blue stuff. 

You say you use the foam to make moulds, I was thinking about using it as a master for fibreglass. My plan was to put down several coats of polyurethane varnish, to smooth out the finish and seal and then PVA glue on top of that as a release agent. Hence my requirement for a clean finish. The other idea I had was to skim a coat of car body filler over the foam surface and then run that last cutting path again which should take it back to a clean finish, PITA tho.

thanks for the advice

toby

[Penguin]

I'm making a mould for fibreglass with it. Plan to paint it with latex housepaint to get a smooth finish. The mould release wax. The internets tell me it works fine.