8 replies to this topic

[cooperman435]

Hi

Im making e matches and as most of you have discovered soldering nichrome wire is impossibe without special flux so Ive decided to go down the route of resistors namely surface mount types.

Sorry to ask an already partly answered question again but you guys have more experience than me under your collective belts and in this line of hobby its best to avoid too much experimenting so..............


Is anyone using resistors to make e matches already? If yes then.........


what are the ratings you have found best to use?

where do you get them?

How much? (I have found series 805 surface mount resistors on the rs site but was suprised to see them at 40p each? I was lead to believe they were more like 4p each?)

any info or leads will be gratefully apreciated..
Phill

Edited by cooperman435, 29 November 2006 - 01:03 AM.

[leosedf]

You can try normal (Dual Inline Package) resistors of 4,7 Ohms and 8,2 Ohms, try to find carbon resistors to test them out and then try to use metal film resistors to find what's best for you.
SMD's are not that good because you have to solder (solder melts if it get's heated too much) and they are constructed by a different method, i don't think they will work correctly.
I think there's allready a topic about electrical firing system.

[scoobie]

Hi

Im making e matches and as most of you have discovered soldering nichrome wire is impossibe without special flux so Ive decided to go down the route of resistors namely surface mount types.

Sorry to ask an already partly answered question again but you guys have more experience than me under your collective belts and in this line of hobby its best to avoid too much experimenting so..............
Is anyone using resistors to make e matches already? If yes then.........
what are the ratings you have found best to use?

where do you get them?

How much? (I have found series 805 surface mount resistors on the rs site but was suprised to see them at 40p each? I was lead to believe they were more like 4p each?)

any info or leads will be gratefully apreciated..
Phill

Howdie, I recently purchased a load of 10R 0.125w resistors which came to about £2 from RS for a couple of hundred.... they 'can' ignite green visco on their own when connected to a car battery, but would recommend dipping them in a BP slurry then dipped in a NC mix...

Good luck

Edited by scoobie, 29 November 2006 - 12:27 PM.

[leosedf]

Yes, but you need a car battery.
How fast they ignite? i use BP slurry too.

[scoobie]

Yes, but you need a car battery.
How fast they ignite? i use BP slurry too.

They ignite in about a second-ish.... I guess it could vary depending on the added resistance of the wire to the resistor....

If you want a low current alternative (but more expensive) just use the estes model rocket igniters.... They work off a couple of a couple of AA batteries

[leosedf]

yeah but they are not that cheap like resistors.
I am trying to figure a way to do them fast burning, metal film resistors seem to be better.

Edited by leosedf, 29 November 2006 - 12:45 PM.

[BigBang]

Using resistors is not a reliable way to make e-matches. Resistors are actually desiged not to catch fire, altho they quite often do!

If price is more of an issue than reliability, then you can go down this road, but you will need a power supply which can supply a heavy(ish) current.

RS is quite expensive - you can try CPC, they have quite a large range of resistors, and are cheaper than RS.

Any value between 1-30ohm will work, depending on the voltage/current rating of your power supply.

[BrightStar]

When I last tried it, I found that very small zenner diodes work better than resistors, as the heat is concentraated in a smaller area around the junction. Choose a voltage rating smaller than your firing voltage, eg for 12v try a 6v zenner, and it will glow yellow hot as it melts. On some, you can remove the plastic casing with appropriate solvents for a quicker effect. The polarity when connecting is important.

[BigBang]

Again, as with resistors, using zener diodes requires a high current power supply because when you reach the zener's strike voltage it becomes a virtual short circuit. This will work, but again will not be reliable.