Smoke ***BS

[planters]

For the 4th I am assembling some smoke "devices". Great success last year with sugar, KNO3 and paraffin. The mix was loaded into Al foil and the cylinder rolled up until 4-5 layers of foil surrounded the mix. The ends were crimped (one around a wick) and that was it. The result didn't look like much, kinda an over sized "roll your own", but the smoke was good and smelled a little like cotton candy. Just now, tried to "upgrade" by placing a few hundred grams into a PVC pipe with press fit end caps, unglued to avoid dangerous overpressure (one drilled for the wick). BAD IDEA! There is a reason they call it polyvinyl CHLORIDE. I'm sure they used it at Ypres. The plastic burns, the smoke grows darker, more sinister and then the smell...oh boy.

Any alternative suggestions?

[Photonbeam]

In the old days we used what was called "heater coil smoke", ammonium chloride I believe. Put in a salt shaker, sprinkle on pyrex skillet on hot plate. Or in one of those cone shaped ceramic heating elements with a light bulb base, mounted on a board. Nasty acrid smoke but it worked.

[planters]

No...No, I don't want a more effective killing machine!

I was thinking about something more in line with a better way to hold a less toxic smoke mix or the mix I described.

[Photonbeam]

I like the sugar mix smoke candy aroma. Melt and pour into paper tubes.

[planters]

We tried that last year and the problem is the ends. The smoke production improves and less or no flame devlopes as the internal pressure increases. We used hydraulic cement to plug the ends and they popped out. The aluminum worked better, but more than a couple of ounces and the aluminum would burn through. Also, tried wet paper towel layered with the aluminum and this was the best, but a hassle to construct.

[luxilid]

I've been using paper tubes from Hobby Horse and making plugs by tamping bentonite clay powder into the ends with an aluminum rod slightly narrower than the ID of the tube. You can seal both ends and hand drill a hole for the fuse on one end.
The bentonite forms a pretty tight seal and I have made rockets with these tubes and never had an issue with the ends blowing out.
http://www.hobbyhorse.com/pyro_tubes.shtml

[VDX]

... use the aluminium foil and wrap into wire gauze for stability and smoke exit ;-)

Viktor

[planters]

I'm not sure how the wire gauze would work.

luxilid,
Thanks for the link. Where did you get the bentonite? Did you mix the powder with a liquid to form some kind of plastic plug?

[luxilid]

I get the Bentonite clay from pyrochemsource.com along with all other pyro related chemicals.
The clay forms a tight plug by compression alone, nothing else added. There is a model rocketry website that describes the process in a bit more detail:
http://www.jamesyawn.net/modelrocket/nozzle/index.html

[planters]

Thanks so much for the links. Too bad I didn't post this a weak earlier. I will be more than ready for next year, especially after I do some experimenting the rest of this month.