nice easy way is a filling cabinet. 4 draw. cut out bottom draw for fire box and drill holes in the other draw bases. i lay a small oven grill in the to top draws to keep food up a little. buy a all steal handel one is best. burn  out the box 2-3 times before  placing food in. the base box is great for controling the fire i smoke mussels fish meat etc.look on trade me buy for $20-40.

Friend has a 4 draw filing cabinet....racks and a ply door... lifted up with a small lpg burner underneath, cake tin for the wood chips, and a water tray (old oven tray) above that.
The burner is small enough to also cold smoke.. he does hams , bacon alsorts of stuff.
For vent, the door leaks just enough, works so left it like that.
Yrs ago my old man had similar stand up drying cabinet converted into a smoker
I was going to build the same as the filing cabinet.. but a special came up on a 4 rack cabinet gas smoker... added up the costs and worked out by the time I had set everything up.. burners trays, the retail special was only going to be a few bucks more.
Found several things a problem.
The door seals sucked, the exit vent too small to allow cold smoking, the burner was larger than should have been, and the lpg regulator was higher rated than needed.. way higher
How I moded including extra shelves in older threads.

Only suggestion I do make... set it up so can cold smoke also... later when get into it, espec on larger cuts and quantities, the end results of a cold smoke and a little tweaking of marinates , over hot smoking are dramatic
Check out some of the older posts that some of the other guys are doing with stuff...amazing is an understatement... some of their home made smokers.

Using the smoker for a food warmer.. eg roast veggies at a large family or club function imparts a very nice , very subtle clean background flavour

Hi Mate,

I made one out of a Supercheap metal toolbox stood on end years ago and its still going fine

It doesn't devalue the house either.

Trays are cheap cake cooling racks from the warehouse and supported by a row of self tappers

Does the meat /fish taste metallic though? (My pet hate with the warehouse stainless ones....)

it pays to burn out all metal cabinets about three times . i donot use gas i like the old burn wood way. i use titree etc, sorry i have no idear how to put a photo on the site,will need to get one of the kids to show me next time they come over the filing cabinet is so easy and i get to send time drinking while smoking what ever. time out

This is what I made from 304 s/s and have since added a Smokai. It work dam fine as either a hot or cold smoker. It also collapses down to briefcase size for storage if its ever put away!...NOT

just put it all together yesterday. all up cost about $130

Joker wrote: And a DIY smoke generator made out of an upmarket Vodka tin, A piece of copper pipe with a T-piece inside the lid, a hollow metal tube running through the cork and an aquarium air pump.

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We have them already built. Check out www.bradleysmoker.co.nz