# DIY - Ground Glass: Butter Churn Method Member P I posted the following in a Dec 31, 2021 Primer Reloading chat: Member P Clean & Easy glass processing: The downside of my wife's gift of a broken pyrex measuring cup was that the chunks were mostly quite thick and very very mortar / pestle unfriendly. I pondered it for a while and then decided to try pulverizing as a first step. I used a brass 3/4” NPT pipe cap, a 6” nipple and a 2' long 5/8” metal rod to pulverize chunks. A few small chunks are tossed into the capped nipple, it is placed on the floor and the metal rod is used to lightly hammer the glass. The pulverized mix is dumped, run through the sifting screen set and the bigger stuff goes back in the “to be pulverized” pile. The finer stuff that is one or two screens bigger than desired gets final processing in a mortar and pestle. The process is much easier and cleaner than my initial attempt using mortar and pestle only to process glass. Member A: Get a section of steel pipe(at least 18-24 inches long), a screw cap and a steel rod a little longer than the pipe. Drop chunks of glass to the bottom and pound it up with the steel rod. After doing this for a couple minutes, pour out and sift (with proper respiratory protection of course). You can quickly make enough 100 mesh glass to last for many thousands of primers. We can call this the “butter churn” method. Member B: Not my idea, but works great. A steel or iron water pipe several feet long with threaded cap, and a metal rod that is a close-ish fit inside and at least a hand hold longer than the pipe. Glasses and a mask, damp rag held around the bar at the top. Pound the crap out of it then remove the cap and sieve the contents, big pieces go back in. This goes really fast! Credit to the member who came up with this, I can't remember who. Sacrificial coffee bean grinder Those electric coffee grinders you can pick up at thrift stores cheep, I use them to make black powder. Not really the finished product, just to pulverize the ingredients before adding to ball mill Member e I had a decorative glass business and I used a kitchen sink grinder to grind glass cutoffs into various size grit for fusing. The grinder was ran dry and not positioned in the sink drain. Periodically, I would have to let the grinder rest due to over heating issues. I have also heard of people using wood chippers for volume glass grinding.