SPARK PROOF MATERIAL FOR TOP?

[wsmcycle]

How could you prevent stack-sparks from burning holes in a canvas top? I have purchased a bimini top for my boat "light-er-up", but I don't want to light up the top. Is there a flame retardant or something that can be applied to canvas?

[87gn@tahoe]

You could make it out of Nomex, it would be a bit pricey though...

[barts]

If the top is really canvas, rather than Dacron (synthetic canvas), you can treat it with borax and boric acid, but it will require additional treatment after it gets wet (not very practical for a boat). I have a SunBrella canopy which we made; it has a few holes melted from sparks but Sunbrella is considered fire resistant according to California Fire Retardant Standard (CA-117).

If it is synthetic, it will melt (and self-seal) rather than burn from a spark.

If you want to be spark proof consider fibreglass

- Bart

[Lopez Mike]

O.K., Bart. Now you got me thinking about how to spell glass cloth and all the stuff that goes with it.

A Google search of fibreglass gets 1000 hits and a search of fiberglass gets 41,000 hits. Also, I notice that this window underlines fibreglass as misspelled!

Is fibre a British spelling? I cannot reliably spell much of anything so spell checkers are my life line to credibility!

If your boat is raining fire regularly, I suppose an aluminum cover would work. I'm bald so I guess I would need a tinfoil hat like a few of the U.S. presidential candidates this year (snort).

[gondolier88]

If it's a real problem, perhaps you could fit a spark arrester in your funnel?

Greg

[wsmcycle]

spark arrestor. I guess that is screen wire? What mesh would work good? It would reduce the draft some but I exhaust up the stack most of the time anyway so i have plenty of draft.

I looked more closely at the material and it is not plain ole canvas it has a slick underside for waterproofing. I suppose it might get holey after a while but that might give it an interesting look. I could point out how lucky the passengers were to have the top.

I will put a screen in the top of the stack first.

Thanks

[Lopez Mike]

The railroad people beat this problem to death back in the nineteenth century what with the grass fire problem around the tracks. Some of the solutions were rather fetching. I think you might be the only launch with a Cabbage Stack if you decide to go that way (grin).

[DetroiTug]

A screen spark arrestor is what is used on the canvas wall tents with wood stoves. It's just 1/4" or 3/16" hardware cloth. Works really good, I have a wall tent that is about ten years old, no holes in the canvas roof. If there is really high stack velocity drawing embers out, you may try increasing the stack diameter to lower the velocity.

Make the screen with as much surface area as possible and mount the screen so it can be easily inspected/removed. It needs to be cleaned daily.

-Ron

[87gn@tahoe]

Make sure the screen is secure in your stack. If not and you happen to be burning liquid fuel and have a flame-out and re-light, you may find the spark arrestor on top of your canopy, or elsewhere

[DetroiTug]

Another note on the canvas wall tent/ stove pipe set up that could apply to steamboats. They use some sort of rubber boot around the roof jack that actually touches the pipe. I've seen the stove pipe red hot all the way to it at night and it never melts. Not sure what kind of rubber it is, but it would be suitable to seal up around a stack and canopy. A steamboat stack should never get as hot as a woodstove exhaust. It came from Montana Canvas. They make the tents, so they'd probably sell just a stovejack.

http://montanacanvas.com/additional-tents.php

-Ron