I built these tuns for $75 each thus far, that includes the 10 gallon cooler, ball valve and bulkhead, as well as the thru the wall digital therms. I should go into freaking business. No shipping, pickup only!
Great idea and I like your SS false bottom in your mash tun. It looks like the steamer insert you see in the kitchen section of stores. Ingenious solution and I like that it can easily fit different diameter coolers.
You CAN buy stoppers at Lowes, BUT they are a VERY HARD rubber, I was concerned that they may not seal as well. So I purchased the stoppers at a homebrew store, they are more "squishy" and seal perfectly.
I bought true-temp digital therms at Target for $8... the stoppers were like .40 each... I am brewing with that system this weekend, my SS false bottom and SS sparge arm are enroute as I type... looks like a great weekend to brew!