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Rain cap for stove-pipe

PostPosted: Mon Jul 14, 2014 6:29 pm
by Andy BB
Not sure if this has come up as a topic before, but a thought on the rain-cap. I currently own a SO 8-man tipi with large Ti stove, and have previously owned a Kifaru 4-man and SO 6-man tipi, all with stoves. (Still to try out my new LBO base/tarp/base with stove jack in the tarp and one LBO, but thats a story for a different time...) I've never used a rain-cap, and have not yet - touch wood - had any problem with spark-holes in my tents. ON rare occasions I have had the odd bit of rain falling into the stove when cold (when its going that's not a problem!), but that has never been a big deal.

I can see a "theoretical" problem with the rain-cap. That is, any sparks that make it past the spark guard in the stove - and there will always be some - tend to rise rapidly on the column of hot air above the stove pipe, where it cools and dissipates beyond the tipi when they return to earth. However, stick a rain-cap on the top of the pipe and there seems to be a much greater chance of the still-hot spark bouncing back off the rain-cap, straight back onto the tent. It's basic science :)

Any thoughts?

Re: Rain cap for stove-pipe

PostPosted: Tue Jul 15, 2014 7:14 am
by kevin_t
Hi Andy

You are somewhat correct, some of it depends on type of wood etc. We advise people to get a longer pipe when they use a rain cap.

Re: Rain cap for stove-pipe

PostPosted: Tue Jul 15, 2014 10:38 am
by Andy BB
True, different types of wood generate more or less sparks. But all generate some! (and how often is it we find a nice seasoned bits of bone-dry oak just lying around in the woods - you use what you find) I've noticed colleagues who have Nordic style tipis - very popular in Europe - all seem to have problems with spark holes despite the tipi materials being significantly thicker than SO, and they virtually all have rain caps. The other issue is that - without a rain-cap - the escaping air from a stovepipe travels dozens of feet into the air. In any breeze, any residual sparks just drift off downwind as they cool. Even with no wind at all, the rapidly rising air from the pipe creates strong vortices as it comes into contact with the colder air, moving the sparks away from the tent.

The one advantage of rain caps that I can see is if you load up your stove with wood before you go to sleep with the intention of lighting it first thing in the morning. A heavy rain overnight could create some damp tinder. Solution of course is not to put your wood in overnight:)

Re: Rain cap for stove-pipe

PostPosted: Tue Jul 15, 2014 11:13 am
by kevin_t
Or 12 inches if snow stuck down your pipe :)

Actually are the Nordic ones forced down all around or open on ends ?

We try to keep spark holes at a minimum thus add a bit of pipe if you plan on using it

Re: Rain cap for stove-pipe

PostPosted: Tue Jul 15, 2014 11:49 am
by Andy BB
Dig out the snow to make your brew with:)

From memory, they have the top section closed at the top, but with hole/vents below it to act as spark arrestors, which seems highly illogical, particularly as the spark arrestor holes are enormous!!