In an effect using cigar boxes, I want to reveal a prediction using fire. So, I thought about writing the prediction in a paper with some (almost invisible) substance that, when ignited, would burn slowly to reveal the prediction.

The problem is that, the method I've seen uses potassium nitrate (?) (aka salpetre).
and this product isn't avalaible anywhere I looked...

Can someone help with a different product to do the same thing?
Thank you

I don't know of any other common chemical that will do what you want. However, I have never had any trouble finding saltpetre (also spelled, at least in English, saltpeter). Perhaps you are not looking in the right places. Have you tried an internet search? Saltpetre has a number of industrial uses such as in preserving certain foods by pickling.

Alternatively, you might try writing the message on a piece of cardboard and covering it with flashpaper. This isn't what you asked for but it is a revelation by fire.

Sid

SOMETIME'S A DIABOLICAL MIND COMES IN HANDY, ESPECIALLY WHEN YOU'RE A MAGICIAN.

I did an experiment.

I just took a piece of FP and wrote a message on it (al la "fingerpaint" with white glue (Elmer's Glue-All).

I dried it in the microwave (NO, this WILL NOT IGNITE THE PAPER), touched a cigarette to the paper, ... and ........ VOILA!!.

My message was left in an easily-read ash on the plate.

I'm claiming invention of this effect, but I'd be pretty amazed if no one's come up with this before.

It's a pretty spectacular way to reveal a force, or whatever.

If you are a news group user, go to alt.pryotechnic, There are endless ways to get pot. nitrate there. You can also search the other pryo groups. Further, you can request ideas. Most of the posters there are helpful... Did you know that if you cover a coin with FP and light it, the area under the coin will not burn? Write your prediction where the coin will cover it. Nice effect. Slim Price
:sun:

You can get Potassium Nitrate (KNO3) From http://www.Skylighter.com They also sell other pyrotechnic-related chemicals

I'm trying to solve the problem in alt.pyrotechnics as sanscan told me.
Unfotunately, Skylighter does not sell this product outside the USA.

Thank you anyway, Photovoric
Thank you all for your help and for your ideas.

One way I have used is to glue flash string to the rear of the paper spelling out the word you wish. As long as you use a thick enough paper, and keep it from being back lit you can achieve the effect I believe you are looking for.

Cheaptrick, I don't recall where I read or saw it, but it seems it was in an old 1950's magic book that had that same idea. And while I don't think it was Elmers glue, it was some type of liquid glue.

If I can find the reference (I would just have to come across it again, because, I don't have time to look through all of my books) but I do believe it probably predates you, and your "invention".

Good thinking, and since you "discovered it" without the reference, that is commendable, but just not new.

BroDavid

Thank you all.
I've already found saltpeter (in a store that sells chemical products to schools).
Anyway, I found that, for my purposes, it burns too slowly.
I think the ideas here are stronger.
If I don't find a way to "use" the time it takes to burn the image in the paper, I might use one of these ideas.

cheaptrick, you have an interesting idea. I will go home tonight and see for myself. thanks.

Sorry Cheaptrick,
While you came up with this on your own, it is not a new idea and has been used before. In fact I used the concept several years ago.