Metal stove jack

This slip in metal stove jack protects a tent from a hot stove pipe. It has very high-temperature resistance and can be changed for different pipe sizes.

Introduction to the removable metal stove jack

I like to see the stove pipe temperature maintained at a safe level at about 100 C (212F) where it passes through the tent canopy. This is for stove efficiency and heat protection for the tent. Even so, I still provide the tent canopy with extra protection by the use of a tent a protective stove jack because exceptionally high temperatures can be reached in a stove pipe when burning ‘found bush fuel sticks’.

A brief runaway burn in a tiny tent stove pipe. It was unnoticed at the time but was caught by time-lapse photography. A good reason to have a stove jack, even when most of the time it is not needed.

So what stove jack to use?

Conventional fibreglass reinforced silicone rubber sewn in ‘stove jacks or boots’ are used in North America (example of conventional stove jack or boot).

I resisted permanently sewing the above heavy clunky piece of hardware into my ‘beautiful, slick, soft, light (800 g) and stuffable silnylon tent canopy. This would have added significant bulk and weight to be backpacked around on every trip regardless of whether or not I was going to use the stove or not. I also required my stove jack to have the versatility to work effectively with a variety of stove pipe diameters.

An ultralight metal stove jacks- removable alternatives

Tubular stove jack

I tried insulated tubular stove jacks that fitted with a concentric air gap around the stove pipe (see photo below). I designed these to protect both the sloping internal tent surface before the stove pipe passes through the roof and on the other side as the pipe exited from the roof.

These were made of 0.1 mm stainless steel or titanium foil with a thin zirconia ceramic insulation layer that was covered by either silnylon fabric or a layer of 0.025 mm stainless steel foil with a silnylon rain flashing fixed to it. These jacks were very effective and they could be put unobtrusively through my tent surface by opening up a small length of the French seams and back stitching the two end of the new opening. The stretch of the nylon fabric allowed the tent gland to be inserted and when it was removed the opening would naturally heal and not be a source of rainwater leakage. This arrangement also made it possible to have multiple experimental stove pipe locations in one tent.

These removable tubular stove jacks worked well enough, but they were quite difficult to install quickly while setting up a tent with a stove in bad weather, when a stove is most needed.

They also were too fragile to be carried directly in a backpack and they took up too much of the crowded space within the protection of my best, tiny, and strong tent stoves that can neatly contain there rolled up stove pipes.

The tubular stove jack was also complex to make and fiddly to adjust to the slope of the tent. Lastly, it was not easy to pass the assemble rollup flue pipe up through the gland without catching on the keen edges of the many flue pipe retaining bands, even in good weather.

A removable aluminium stove jack a water-shedding pocket on a tent. The yellow cord and cord lock hold the keeper flap in place. The sheet can be substituted with a plastic window when the stove is not deployed. The flue gland design is flexible and adds minimal weight and stiffness to the soft ultralight tent canopy. — A variety of protective metal stove jacks. A loadbearing stove jack for a tent that used the stove pipe as the tent pole (left and shown below). Cylindrical stove jacks (centre). Sheet stove jacks that slip into pockets or clip into ‘seam opening'(right).

A pyramid tent pitched with a tent stove in the middle. The prototype design used the stove and stove pipe as a substitute for the tent pole and used the load-bearing stove jack shown, on the left, in the above photo. The tent apex attaches to the cone of the stove jack by a very simple but innovative load-bearing hem with a drawstring that is sewn to the apex of the tent.

End to the stove pipe tent pole

Melting of the aluminium stove pipe and discovery of rollup stove pipes put an end to the double use of a stove pipe. However, the load-bearing hem has remained a feature of my tents as it is so simple strong and versatile.

Enter the removable flat metal stove jack

My next removable and flat stove jack design is much simpler and still does not add significant weight or bulk to the tent canopy. This design uses a removable rectangular aluminium sheet stove jack with an elliptical hole in it and it is inserted up into a waterproof pocket that is permanently glued and or sewn to the outside of the tent.

A micro cord-lock & cord is used to lock the gland in place. When no stove pipe is required I substitute the aluminium sheet with a rectangle of clear plastic sheet that is cut from a ‘shirt box plastic’ and it becomes an oval window.

This simple aluminium stove jack worked well as it has minimal contact with the flue pipe to transfer heat from the stove pipe and it also has a large surface area to act as a heat sink.

In strong winds, the oval hole in the gland can interact with the cylindrical pipe and act as a ratchet to lift the stove pipe off the flue connector on the stove. This problem was solved by using a metal ribbon and nylon cord to tie-down the pipe to a stove leg.

The empty tent stove jack pocket that is ready to fit either the stove jack (or another one) or the substitute plastic window.

Tim

Addendum

This post dates back some time now and could be considered redundant. However, it contains some fresh ideas and lessons that may be helpful to others. In my opinion, it has been largely supplanted by my very light, compact, soft, simple, ‘unlosable’ and fixed silicon/cotton glue/sew stove jack.