alpini, do a search, lots of good info on building them...just use a little fiberglass insulation in the construction...i use a pair of dividers from a drawing set to punch the holes, i havent found the hole size to be critical, tho some will tell you it is.16 evenly spaced holes do as well as 32, in my limited tests...and some tell you to use j-b weld to seal the joints, which i also found unnecessary.even the flue tape is not needed, if care is used to fit the cans together tightly...believe me, the more you make, the easier it gets...i usually make one, from start to boiling water, in about 25 minutes, that includes watching t.v. and drinking coffee too! try one, and let me know how you like it...