Wanting to go all grain

I am making a mash tun from 830 quart cooler I have my new drain valve and I want to tie the inside in with CPVC not stainless steel braided, what size holes should I drill through the CPBC to get proper flow without draining too fast or too slow should I do a lot of little holes or less holes bigger drillbit

 

If the holes are too big the grain will simply flow into the PVC so lots of little holes.............

 

This is what I have, does it look okay

 

I would put the holes face down, but other than that it looks good

 

Lots of small holes are best. And it is your valve that should be controlling the flow, not the holes themselves. The gain bed will compact and stop flowing if you just let it run wide open.

 

Looks good! Holes down though

 

Thanks guys, I did not glue The pipe obviously I will turn the holes facedown, wish me luck my first all grain attempt tomorrow!