Smoker bar­beque build

Mor­ph­ing two drums into a cold smoker

The Shed - - Front Page - By Jude Wood­side and Evan Wade Pho­to­graphs: Jude Wood­side

W hen my friend Evan Wade said that he was go­ing to build a smoker from two 200-litre drums, I leapt at the chance to cover it as I had been want­ing to cover a Tex­as­style smoker build for some time. This isn’t quite a tra­di­tional off­set smoker like a Texas smoker — it can be used in the same way, but this is pri­mar­ily a cold smoker. Evan is very par­tial to meat, fish, and es­pe­cially smoked sausages. He had found the design on the in­ter­net and fol­lowed more or less the same process as the de­signer: jmil­lerid.com/word­press/cat­e­gory/55gal­lon-drum-smoker/.

The drums that he sourced had pre­vi­ously contained cook­ing oil, so they would be safe to use for food. Be aware of what your drums have pre­vi­ously contained, as it could in­flu­ence the taste or even the safety of what you eat. Be­ware of drums that have held volatile liq­uids like pe­tro­leum prod­ucts. Apart from the dan­ger of poi­son­ing they can also ex­plode, es­pe­cially when empty.

Cut­ting the drum

This design calls for two drums welded to­gether in a T-shape. That re­quires cut­ting the bot­tom bar­rel so that it ac­cepts the hor­i­zon­tal one. It’s pos­si­ble to lay out the shape in­volved by work­ing the design out in CAD or by de­vel­op­ing the shape via tra­di­tional sheet-metal de­vel­op­ment draugh­t­ing.

To do this (see panel on page 46) you will need to be able to print the re­sult­ing design in ac­tual size, so you will need sev­eral sheets. You can then wrap the print­out around the drum and cut to the line. Or you could just wing it as we did, us­ing a flex­i­ble rod and know­ing the four points where the curves would meet to draw a fair curve be­tween them that ap­prox­i­mated the shape of the de­vel­oped curve.

The drum was care­fully cut with a thin-blade abra­sive disc but it could be cut with a jig­saw.

It is im­por­tant to keep the cut as close as pos­si­ble to the line or you could find large gaps that would be dif­fi­cult to fill later when you weld the two to­gether. It took some trim­ming and some ad­di­tional work to ac­com­mo­date the rolling ribs on the hor­i­zon­tal bar­rel but even­tu­ally Evan got a good fit be­tween the two drums. The wing-it sys­tem proved quite good in the end and re­sulted in a good fit for the bar­rels with only a mi­nor bit of fill­ing at the end.

Door

The next task was to cut a door into the main drum. To do this Evan marked out the door pa­ram­e­ters with mask­ing tape. This will also al­low you to get a good vis­ual on door size and make cor­rec­tions eas­ily. With the shape set, he cut along the back edge of the door with an abra­sive disc. It’s wise to at­tach the hinges prior to cut­ting the rest of the door. You can at­tach them with screws but it’s a good idea to weld plates in place to hold the screws prop­erly, or sim­ply weld the hinge with plug welds through the screw holes.

First, clean off any paint around the area that the hinges will be welded to. These drums are usu­ally of very thin gauge (20 gauge), or barely 1mm thick, so it’s im­por­tant not to crank up the MIG volt­age or wire speed too high.

With syn­er­gic ma­chines like the BOC Smootharc Elite, set the thick­ness to some­thing like 1.6mm or less. The hinges are stainless and 2mm thick. Weld al­ter­nate holes at op­po­site ends of the hinge to spread the heat and pre­vent warp­ing. It is pos­si­ble to run a weld bead along the edge too, but it pays to re­duce the volt­age to pre­vent burn­through. Avoid hinges with ny­lon bushes as they might not re­spond well to the tem­per­a­ture.

Plug welds

Make sure that both the hinges are in line and square to the door, es­pe­cially if you are weld­ing them. With the hinges

The wing-it sys­tem proved quite good in the end

in place you can pro­ceed to cut the rest of the door. Do it care­fully — you want the door to be able to close rea­son­ably tightly.

The next stage is to re­in­force the door and pro­vide a lip for the door to close on. Weld­ing heavy-gauge metal to thin sheet metal is of­ten best achieved with ‘plug welds’ — welds made through spe­cially punched holes in the sheet metal or the heav­ier gauge. Plug weld­ing works in a sim­i­lar way to spot weld­ing, where a se­ries of dis­crete spaced welds hold the piece. The fi­nal re­sult can look very in­dus­trial chic — like riv­ets if you space them reg­u­larly. Punch the holes with a drill or more eas­ily with a jog­gler and punch plier as used for au­to­mo­tive body re­pair.

The se­cret to weld­ing thin met­als with MIG is to keep the metal as cool as pos­si­ble and use short bursts widely spaced to avoid dis­tor­tion or burn-through. It pays to move the weld around to pre­vent over­heat­ing any par­tic­u­lar re­gion. The welds will be small enough that they will be un­likely to cause any dis­tor­tion pro­vided that you do spread the heat.

Roller

Before the 3x40mm strips could be welded in place, the strips for the sides needed to be shaped into a fair curve.

The ideal means of do­ing this is with a roller. The roller con­sists of three rollers set in a tri­an­gle with the mid­dle roller able to be screwed down. The strip of metal is passed be­tween the two bot­tom rollers and the top ad­justable one and after each pass the mid­dle roller is tight­ened down slightly more, caus­ing the strip to bend grad­u­ally on each pass un­til the de­sired curve is ob­tained.

Light-duty rollers are quite cheap al­though they can only roll limited gauges — in this case up to 5mm thick mild steel, which is more than enough for this job. Each strip was bent to fit and then tacked and welded in place. Evan felt that the door it­self was a bit thin and re­quired some re­in­force­ment to pre­vent it ei­ther warp­ing or twist­ing in use. Two more strips were cut and welded to the in­side of the rolling ribs, tacked first, then a small bead was run, tak­ing care not to burn through.

With the door set it only re­mained to add a han­dle, cut from 12mm square tube.

Clean­ing

Now came the messy bit. These drums had been painted on the in­side and that paint had to be ground off to pre­vent it from con­tam­i­nat­ing the food be­ing pre­pared through re­leas­ing fumes or burn­ing dur­ing the cook­ing process.

If you at­tempt this, make sure that you wear ap­pro­pri­ate per­sonal pro­tec­tive equip­ment (PPE), in­clud­ing a dust mask. Cover your hair (if you still have any), oth­er­wise you will be wash­ing it out for days.

Once the two bar­rels are cleaned of paint they can be tacked to­gether. First grind off any paint in the vicin­ity of the join on both bar­rels. Place the drums in po­si­tion and mark the con­tact for the up­per one from the po­si­tion of the lower drum. Keep the weld tacks spaced to pre­vent any dis­tor­tions. Later the weld can be made com­plete, but in the first in­stance it’s enough that the two drums are con­nected.

With both drums joined it was time to fin­ish the lay­out of the top unit. First Evan tacked strips of 25mm an­gle iron to the sides and back to hold a se­ries of rods or mesh from which to hang sausages or meat for smok­ing. The smoke and heat gets gen­er­ated in the lower bar­rel. A se­ries of holes needed to be drilled through the base of the up­per drum

To keep the doors tightly closed on both drums re­quires latches

to al­low the smoke to come through. These are best and most eas­ily cut with a step drill. The holes should be cut in a di­a­mond pat­tern, mak­ing sure they stay within the lower drum.

Join­ing the drums

Weld­ing the two drums to­gether with a solid bead is im­por­tant to avoid air in­take and smoke loss. It is also im­por­tant to avoid burn-through — to en­sure that, it’s a good idea to cut the volt­age, or, in the case of syn­er­gic ma­chines, set the

ma­te­rial thick­ness to around 1.2mm.

You will still not be able to run a long bead. It’s best to work in short bursts that are well spaced and re­turn to fill in the gaps. Where there are gaps that need fill­ing — no mat­ter how good your ini­tial fit­ting you will likely have some — build up the gap in a se­ries of runs, al­low­ing the bead to cool be­tween runs. Take some time — don’t try to rush it.

Burner

The last process is to mark and cut the door on the lower drum for the burner/ smoker.

The process is the same as before. Cut the rear of the door and fit the hinges and then cut the rest of the door. Punch the holes for the plug welds and bend the curves in the steel strip to fit the curve of the drum. Hold­ing the strip in place with

clamps, tack every other hole and then come back and fill the re­main­ing holes.

To keep the doors tightly closed on both drums re­quires latches. The latches are at­tached with pop riv­ets and serve to keep the door tight to the steel strips at the edges re­tain­ing the smoke and the heat. The top drum took two latches and the bot­tom door took one.

Reg­u­la­tor

To reg­u­late the air­flow, the burner holes should be drilled with a small hole saw along the base of the burner and through a strip of metal that acts as a damper. The damper strip was cut from the rem­nant of the up­right drum so it matched the cur­va­ture of the drum. The damper strip is held in place with self-tap­ping screws set to let it slide to con­trol the air­flow.

A han­dle was made from a piece of 25mm dowel. At­tach­ing the strip in place with tape or by tight­en­ing the screws on which it slides al­lows the step drill to cut through the damper strip and the base of the drum, at the same time en­sur­ing the holes line up.

Evan cut a cir­cle of steel from the re­main­der of the up­right drum to act as a con­troller for the smoke re­lease in the top drum. The cir­cle was bolted to the side of the top drum and holes cut with a set drill through both the cir­cle and the drum. A han­dle of 25mm dowel was then at­tached to the con­troller to reg­u­late the smoke re­lease.

The burner for the smoker is set in a bas­ket in the lower drum to al­low it to be re­moved eas­ily for clean­ing. In our case we used an of­fice waste­bas­ket in lieu of a more per­ma­nent so­lu­tion. The fi­nal step is to paint the whole thing in a high- tem­per­a­ture paint. Two stan­dard bar­beque grills fit in the lower part of the top drum to al­low meat or fish to be laid there, and rods or mesh on the up­per shelves can hold sausages for smok­ing.

Evan Wade lay­ing out the shape of the two-bar­rel joint

Cut­ting the lower bar­rel

Trial fit

The cut bar­rel

Cut­ting re­lief for the roller ribs

Nice fit

Cut­ting the back of the door

Clean­ing the in­side

Weld in short runs

Cut­ting the holes in the damper

Weld­ing the hinges on the lower drum

Cut­ting the burner door

Thick­ness set­ting for at­tach­ing the two drums

Clean­ing up the welds

Light­ing the smoker

Smokin’!

Smoke re­lease

Drilling the smoke re­lease

In­ter­nal grills

Newspapers in English

Newspapers from Australia

© PressReader. All rights reserved.