40 replies to this topic

[cat]

Probably some people know my passion propulsion systems, over the years I?ve probably tested a few hundred e-match formulas. Ok, so this is a stupid question but I can?t come up with a good/fun solution. There are a lot of creative people here, so let?s hear some ideas. I?m looking for a good way to test e-matches for performance. Normally besides the electrical standards tests I..

1) Ignite an APCP grain covered in High temp grease (fake oxidation)
2) Place one centered in a 1inch clear HDPE and note the burn pattern after cleaning residue.

I?d love to hear some good ideas, especially creative ideas, but they have to provide some useful data.

-cat

[Kembang Api]

I had been experimenting with my own e-matches for months now. I never think about testing it. The only test I done was installing it in my shell. It will be an interesting subject to discuss.

Any way what kind of composition that you found best? I had been doing with a BP powder and add up to 5% of dextrin.

[cat]

Any way what kind of composition that you found best? I had been doing with a BP powder and add up to 5% of dextrin.

It really depends on what your using them for.. If you?re looking for a *very simple* general purpose match 3 parts meal powder, 1 part 325mesh Mg/Al with a NC binder is pretty effective. Give me a little more information on what your trying to light and I could probably dig up a formula or two.

[Kembang Api]

Mainly for the used on my shell and some cake or Roman candle.
Your composition mention the used of Mg/Al which is hard to find, could I replace with Al.
Thxs

[alany]

This is my bridgeless e-match composition:

http://www.vk2zay.ne...ition.php?id=34

I know you already have this, and I've posted it before, but I want to add some additiional information:

I've found some issues with it recently. It degrades within a few days unless you seal it off from air very well. It also attacks the copper wire slowly and degrades the Magnesium very rapidly in humid conditions. Dipping it in syrupy NC helps, but it isn't perfect it extends their shelf life to a few weeks - maybe I need to lay it on thicker. I just make them up on demand now, rather than storing them.

The perchlorate version which I use as a hot-prime has a nasty issue too which I discovered the hard way. It is fine bound together well, but some flaked off a comet I primed with it as I put it into the stargun (insufficent binder I guess?), loose it is basically magnesium based flash which produced a very violent lift... I am very glad I use cardboard starguns!

[cat]

Mainly for the used on my shell and some cake or Roman candle.
Your composition mention the used of Mg/Al which is hard to find, could I replace with Al.
Thxs

Using Al, with Fe2O3 (red) with a fast fire of at least 75% BP works well also. Again your not lighting anything difficult I would STRONGLY suggest sticking to BP slurries! They will more then handle anything you?ve mentioned.

A simple booster can be made with 75% AP, 7% Al (2mic), 18% Airfloat charcoal. This mixture should be bound with thinned NC/Acetone. An addition of 1-2% Mn2O3 can be added to sensitize the mixture (this will allow for thinner nichrome). This mixture is MUCH more hazardous then a basic BP/Magnallium mix. So handle with extreme care and don?t store dried pyrogen.

-cat

[cat]

This is my bridgeless e-match composition:

http://www.vk2zay.ne...ition.php?id=34

I know you already have this, and I've posted it before, but I want to add some additiional information:

I've found some issues with it recently.  It degrades within a few days unless you seal it off from air very well. 

Hello alany,

I hadn't seen you site before, but your formula contains Mg, Al & KNO3 without boric acid? Are the metals coated? There are a few reactions going on here, unless your Acetone is distilled it contains more then 5% H2O, This can aide in the reactions that are killing your matches. Be sure to dry your matches (honestly a little sun helps) then seal the matches with Vinyl resin or thick NC (15%). This should really help extend the useful life. Incase it wasn?t inferred, coated metals and 1% boric acid & 1% MgCO3 can also help.

As for your prime, this is the one that uses KP & Al? If it?s flaking off you probably need to bind with more NC, this can slow the burn significantly and adding a fast fire of meal powder can help.

[Kembang Api]

Hi Cat, Thank you for the information.
You mention about BP slurries, Is that just meal powder and 5% dextrin mixing it with water to a slurry form?
What I have done is to mix the BP with a bit of warm water make it into a paste like form and roll into a small star and than press it into the nichrome wire. let it dry and coated with NC (Made from ping-pong ball)
Sometime it still break off easily or connection failure in the between nichrome wire and the copper wire. Soldering is a time consuming job.
Thanks for the AP composition, I will try it out sometime in future.

[cat]

You mention about BP slurries, Is that just meal powder and 5% dextrin mixing it with water to a slurry form?

Sorry sometimes I shorthand things and don?t explain when I should. When I say BP Slurry I mean adding enough 10-15% solution of Nitrocellulose dissolved in acetone to wet the meal powder to a consistency of thick paint. You want it thin though that you can dip your wires into it and not have it all drip back off.

I don?t always solder my wires either (just depends on the comp and its intended use) when I don?t, I sometimes use a wire-wrap tool and bend the finished ends over.

-cat

[Wow had time to read the board twice today, that?s a new record for me]

[Kembang Api]

Thank you so much for the detail. I will try them out using my ping-pong solution. By the way do you know which indusatry that used NC powder that maybe I could get it from. I try the paint company but they don't have it. That is the only industry that I know of.

[cat]

I will try them out using my ping-pong solution. By the way do you know which indusatry that used NC powder that maybe I could get it from.

Ping-Pong balls work well, but they are low-nitration and they contain a lot of fillers including camphor. The only industry I can think of is specialty finishing (things like high end guitars, antique restoration). Again the products you?ll get from these places contain lots of fillers, binders, anti-drip, etc. Some smokeless powders are high-nitration (13%) cellulose (niter of cellulose actually) and are (IMHO) the best material to use. Maybe a new thread should be started. I have in the past seen instructions to remove additives from NC used in some brands of smokeless powder (it was a magic site, try googling).

Edited by cat, 29 December 2004 - 07:18 PM.

[Phoenix]

Look in a model aeroplane shop. There is another topic about NC laquer that goes into more detail.

[Kembang Api]

I had found a company that carry this industrial NC wetted in Alcohol or water. They have 3 grade, low nitrogen grade, medium nitrogen grade and high nitrogen grade and a minimum of 65% - 75% of cellulose nitrate. Is this the right stuff?

[adamw]

Er thats sounds not unlike 'guncotton' to me. If it is not in a solution then it must be a solid in an medium that it is insoluable with, so it cannot be a laquer!

[cat]

Er thats sounds not unlike 'guncotton' to me. If it is not in a solution then it must be a solid in an medium that it is insoluable with, so it cannot be a laquer!

Well it?s packed in water or (some kind of) alcohol, it can be removed dried and dissolved in a solvent. Without knowing what the other ingredients are or its intended use it?s pretty hard to guess if it would be useable.