3 replies to this topic

[Give_me_APCP]

I was messing around with strontium nitrate, aluminum, and epoxy, and found that the ratio I first used made for a very bright ground flare (it seemed very bright anyways). I didn't weigh this small amount, and wondered if some formula may be around for those 3 chemicals before I try guessing again to make some larger flares.

Can anyone recommend a flare formula using strontium nitrate, Al, and epoxy/binder ratios?

Actually, what I would like to make are some flares which have a very fast burnrate, and a very large light output per size. I do not need extended burntimes.

Thanks.

[BrightStar]

The majority of strontium nitrate flare comps use approx 50/50 strontium nitrate and magnesium, perhaps with +10% PVC. One aluminium based forumla I did find was 'Red Wingtip Flare' in Davis COPAE used for signalling between aircraft in WWI. The formula is:

Strontium nitrate - 24 parts
Flake aluminium - 6 parts
Sulfur - 6 parts

It was bound with shellac and pressed into 4.25" long by 1.625" id cases and would burn for 1 minute at 12,000 to 15,000 candlepower.

I haven't tried this myself - would be interested if you can make it work.

[Give_me_APCP]

The majority of strontium nitrate flare comps use approx 50/50 strontium nitrate and magnesium, perhaps with +10% PVC. One aluminium based forumla I did find was 'Red Wingtip Flare' in Davis COPAE used for signalling between aircraft in WWI. The formula is:

Strontium nitrate - 24 parts
Flake aluminium - 6 parts
Sulfur - 6 parts

It was bound with shellac and pressed into 4.25" long by 1.625" id cases and would burn for 1 minute at 12,000 to 15,000 candlepower.

I haven't tried this myself - would be interested if you can make it work.

Excellent, thanks.

I don't have sulfur here currently, so I may just try SN/Al bound and pressed.

Now these are obviously red flares, is there a flare composition which is much brighter in general, like a white?

[BrightStar]

I don't have sulfur here currently, so I may just try SN/Al bound and pressed.

From my experience, the sulphur is necessary with Al based flares - they generally will not ignite without it. The magnesium used in the modern comps is sufficiently reactive that it's not needed.

The white version of the historical Davis wingtip flare is:

Barium nitrate: 77 parts
Aluminium flake: 13 parts
Sulfur: 5 parts

Again shellac bound, pressed into the same case and will burn with 22,000 candle power for 1 minute.

Do see my scary crackling perc / al flare test in the lances section here:

http://www.pyrosocie...p?showtopic=915

Will be interested to hear how you get on using the epoxy binder with these.

UPDATE: Just tried a small batch of the Davis wingtip red this evening in the garden, dry pressed and using 400-mesh atomised Al. It was no-go, even with a very hot prime. Tried again with fine bright flake Al (horrid, messy stuff) and it took fire with a simple dusting of BP. It burnt a very bright pale red. Here's the vid: Davis wingtip red flare test - 10g comp hand pressed in 1" tube (divx avi, 1.9Mb)

Edited by BrightStar, 27 October 2006 - 09:27 AM.