Wood stove spark risk abatement solution

Do a video of the stove on fire, half the fuel consumed and then have a fan simulate a 10-15 mile an hour breeze onto it and see if it arrests the sparks. Videos are good.

Your 1/4" hardware screen may be too large for good spark control. I'd suggest one size down (1/8") at least

Wow, looking at the news footage from the West Coast, I wouldn't trust anything short of an industrial smokestack scrubber.

"Whether this mod would serve to meet requirements for a particular level of fire ban obviously depends on the requirements of the ban."

What does the federal regulation say about wood fires in a level one fire ban area?

Those holes would much too large to pass as a spark arrestor for the Forest Service on a muffler so I would guess too large on an open flame as well.

Ryan

Four Dog stoves makes these USFS Approved spark arrestors. Appears to be 1/4 mesh.
Obviously a different scenario given the length of pipe the sparks must navigate, but still an interesting solution.

http://fourdog.com/galvanized-spark-arrestor-for-4-inch-stovepipe/

I don't have much more than practical observations of spark arrestors to go on, while I do have practical plus theoretical knowledge of flame arrestors. Flame arrestors can be designed to completely stop a flame front if you know all of your conditions (temperature, pressure, chemicals involved). For instance, a hydrogen-in-air flame front is harder to stop than a gasoline-in-air one. My sense is that there isn't a hard and fast minimum size that provides 100% protection unless it is quite small. A tiny, high-velocity bit of magnesium would require a much tighter screen than a balsa-wood cinder. Still, anything helps. And tighter spacing is better.

Not a UL idea, but I've noticed that the longer a chimney is, the more complete combustion is at the top of the stack – the volatile gases are more consumed in the flame and the cinders are more completely burned out. That means you are getting more complete combustion (a few more BTUs and MUCH less CO), fewer cinders, and less creosote on the bottom of your pot. Starting with a thin-gauge length of SS stove pipe would be a good starting point for a BPing stove, both for the more complete combustion, but also because it would take longer sticks (less cutting!). I've had good luck with a charcoal-starting chimney ($12 in the BBQ section of Home Depot) for camping and boating trips and find it makes for a cleaner-burning fire, is far less smokey, uses less wood and is easier to cook on than an open fire. Super easy with 3-4 self-lighting briquettes and then start tossing in the pine cones and sticks.

Robert, what have you found out about Stage 1 Fire Restrictions and the 1/4" mesh you've come up with around your stove. Is it sufficient?

From montana's fish and wildlife site:

Stage 1 = No Fires – unless site is posted with specific exemptions

Exemption 2: Persons using a device solely fueled by liquid petroleum or LPG fuels that can be turned on and off. Such devices can only be used in an area that is barren or cleared of all overhead and surrounding flammable materials within 3 feet of the device.

In other words, gas stoves with a valve (not alcohol) or you're having cold ramen at night.

Fire restrictions are serious, they are not arbitrary government infringements on your personal liberties. Don't screw around and just get a gas stove, or go no cook.

Too many people think they're "safe" and yet routinely too many forest fires are created by people rather than lightning. Living in a state where a number of hotshots were killed and some of the lushest forests were burned…don't contribute to the risk please. Just follow the restrictions and be a responsible LNT hiker.

"I was asked by someone heading to the Bob Marshall Wilderness under "Stage 1 Fire Restrictions" to come up with a "top screen mesh" that (in combination with a bottom screen) would completely enclose a fire in one of my wood burning backpack stoves. The stainless mesh I used has 1/4" openings." Robert, do you think 1/4" openings is sufficient to abate sparks to a point of allowing this stove to be used in a stage one fire ban?

A washing up liquid bottle top screwed on a platypus makes an efficient spark extinguisher for the escapees.

The top mesh screen I made was at the request of someone who felt it would meet the Stage 1 fire restrictions he anticipated for a particular trip. In looking "Stage 1" up online, it does not seem as though what I built would be allowed unless the area he was headed to had an exemption of some kind in place. I can't comment further on whether or not their was such an exemption. I'm sure that the screen that I built him will not reduce potential sparks to zero, but will reduce/abate them. Just how much abatement is somewhat unknown and certainly weather-dependent. A screen with smaller openings could be used with further spark reduction and also less efficient stove air entry and exit. In the end, we all want to (I hope) do our cooking in a safe manner in the back country. Fires have been started from all kinds of stoves, even those with on/off controls. I do not advocate bending agency rules and regs when it comes to fire bans. I also recommend that you never walk away from any kind of burning stove, especially when there are dry fire-prone conditions. My own preference: In the west when I hike in vulnerable super dry areas, I generally use an Esbit burner (if allowed by the regulatory agency) that is fully enclosed in a Caldera Cone and placed on a non-flammable base surface (like aluminum foil).

I would have a big liability policy a flock of good lawyers and a good excuse in mind for St. Peter. Anyone dreaming of using any kind of wood fire in the west this year is stark raving mad. The smoke from the fires in the North Cascades National Park was so thick that it was causing the high voltage transmission lines from the Skagit River dams to arc to ground, creating yet more fire hazards and they shut down the power generation at three dams to the tune of $100,000 a day in lost revenue. It turns out there are six damaged towers as well. The President declared Washington a disaster area a few days ago. We lost three fire fighters too. The point being is that it just isn't work it to fiddle with such stuff.