What do people use for testing and prototyping ?

Its just a quick question to see what people use for testing and prototyping, I've been looking at expanded PVC foam, anyone use it ? Is there a good ebay supplier and anything other than foam , up sides down sides etc ?

I don't tend to test/prototype stuff using a different material, but I gather you can use 2-part expanding polyurethane foam which enables you to make up whatever shape is required. You can also get special types of foam made specifically for prototyping.
Wax is another option since you can in theory melt down the swarf and use it again and again.

Found insulation foam, Celotex, Kingspan PUR type from Wickes, B&Q builders merchants , skips on new builds...... OK to use.

Cheap , comes in 50 and 100mm thickness natively, usually foil faces, that just peels off.

Its not enirely dimensionally stable, tends to cup like wood a bit when foil is peeled.

It does wear tools, at least wears hand saws used for cutting it in bulk, so will take the edge if new milling bits.

Still kinder than z being lower than expected ;-)

Dont think this is a general Poly URethane foam property, just insulation board may have glass strands or someat mixed in.

Can get PUR foams in all sorts of densities, its used as a core for surf boards and as model board made for pattern making and priced accordingly.

PVC foams are used in sign making but tend to be more like 5mm thick.

I've read about people using building insulation for a number of things other than insulating buildings lol, think it depends a lot on what you are prototyping & testing but I would be inclined to go along with Jonathan & use the same material as you intend to use for production, especially when it comes to testing.

I'm loving the idear of re using the wax like Jonathan has suggested, dont think that will do much harm tot he cutter, this is all because I have never used a CNC or software for one before and I jsut want to be sure I have some experience before I start on expensive materials.

Being new to it myself I don't know if this would help with your learning process but what about a cnc simulator?? Have seen a couple on the net & they were free, from what I could work out they were being used as a training aid so might be ideal & no material cost involved at all, plus no chance of damaging your machine.
Sure someone with more experience will be able to comment. Wouldn't mind finding out if this would be helpful myself.

Machinable wax, generally blue , holds very fine detail well, and can be used in lost wax casting

Trycut - the easy cutting machinable wax for CNC milling machines, lathes etc

Foam comes in many grades, Cellotex and 1/4" cutters from Toolstation, thanks Jonathan, are a cheap and available way of prototyping,

Meshcam test on logo into cellotex with 1/4" 5mm cutter, can`t be any harder on cutter than wood or MDF.
Attachment 6993

Celotex Cavity Wall Board 50mmx1200x450 - Polystyrene Insulation - Insulation -Building Materials - Wickes

at the other end of PUR foams, modelling and tooling board

Modelling | Resins Online

Then move into epoxy boards used by F1 teams and aerospace, priced for the target market....