Honestly, I'd just buy a gas mask from a surplus shop.
This one looks pretty similar to what you want, and is only 15 bucks, about the price of the resin and glass you'd use for the pep. In addition, a store bought one will be rubber, and more comfortable to wear.
The S10 is only 35 bucks on some sites, and theres a couple on eBay for only $8.11. Even if you can't order off the internet, search military surplus stores around your area. They'll most likely have them.
Unless you're not in the position to purchase one at all, I definitely suggest doing that. Another bonus is that you can get filters, and use it as a respirator. Lung and eye protection, all in one!
