:: View topic - cheap [?] HDPE for tipspacers

I just found out about your site, and I have to say it's awesome. I passed the link along to the folks at Make and they posted it on their blog of diy coolness.

I was looking at the white plastic cutting board in my kitchen thinking it might be made of noncrappy plastic. By looking around the internets it turns out that cutting boards with the "NSF approved" (not the National Science Foundation nsf.gov, look at nsf.org) are made out of HDPE. Now I think that HDPE isn't as strong as ABS or UHMWPE but it might be a worthwhile option. Since you can get cutting boards almost anywhere.

Edit-

I forgot to mention that you'd probly want to profile the tipspacers with the core since cutting boards are ~1/4" thick.

Thanks! the make site is pretty cool.

I believe HDPE and UHMW is very close and are in the same polyethylene family. I don't see why HDPE wouldn't work.

from what I know, HDPE does not bond with epoxy at all. That may cause some problems.

why not just make a small test piece? you can try flametreating the plastic beforehand.

Has anyone had any experience with polycarb for a topsheet? Or does anyone know if it can be used? I really like the finish and look of it but i'm not sure if it would bond very well. I talked to some plastics guys that said it has its own special glue but would probably bond with epoxy. It just seems like a good option for a topsheet (lots of strength, very durable). Right now I'm deciding between p-tex and polycarb. Also what thickness would I need? and would I have to abrade it?

I'm in your same shoes SLC. Check out page 2 of my journal for this same qustion & the KKK's answers. Judging by thir failure with polycarb & success with P-tex I think I am just going to go with the p-tex. OTOH I brought home some samples of polycarbonate to do some test laminations with. I think it would be great if we knew for sure it would bond adequately. Perhaps the heated press will result in better bonding & allow the durable use of polycarb. I have really been frustrated by the plastics side of the project lately. I had hoped to use local suppliers for the plastic's & wood. Now I've pretty much resigned myself to ordering the sidewall/tipspacer ABS and topsheet materials from Durasurf(crown plastics). Little Kam raised the great point that it's easier to get it all from one place. I hope that shipping doesn't cost to awful much on the longer ABS sidewall pieces.

We tried polycarb and it doesn't bond very well. I did a test piece with our heated press and it still does not bond. If you have access to a sandblaster, I think it would work much better than a random orbit sander.

-kelvin

I'm just about to start on my mould and I'm wondering how much the mdf costs for a mould like the one in the how to section on this site. How thick of mdf should i get? 1 or 2inch thick ?

We use 3/4" mdf and it is around $30 for a 4x8' sheet. You will probably need 1.5 sheets for 1 mold (2 ski mold).

Kelvin