DIY crash pad

am sure this has been asked before... I am interested in making crash pads for an indoor bouldering wall.

I found some information about foams used for bouldering:
https://www.foambymail.com/blog/have-the-confidence-to-climb-higher-with-bouldering-crash-pads/

sounds like a 1 to 2in thick closed-cell foam layer goes over 2 to 3in open-cell foam layer?

Seem to be that foam in raw form is expensive stuff!  Anybody already figured out the best way to do this? I am thinking Alibaba might have raw ingredients?

It needs a cover as well, just to keep it clean, something really simple... dunno if this project is worth pursuing...

cheers

Probably not worth doing, and unless you know exactly what you're looking for, its going to be really expensive getting samples sent to you.

Used mattresses. Cheap or free. Covers with carpeting so no gaps

Since it doesn't have to be portable, if you go with foam, you should use a much thicker layer of open cell.  maybe 12 inches.  you could also look for used foam.

When my local gym replaced their pads they offered the old foam for personal use, cheap or free.

Joshua has the best bet for cheap foam.  Call around to any gym you're willing to drive to and ask if they have recently replaced their flooring or are planning to within your time frame.  By far the cheapest way to do it.