spark strip question....

Boom! The classic potato gun harnesses the combustion of flammable vapor. Show us your combustion spud gun and discuss fuels, ratios, safety, ignition systems, tools, and more.
hoarp001
Private 4
Private 4
Posts: 79
Joined: Tue Jul 17, 2007 4:09 pm

Tue Jul 31, 2007 3:57 pm

Hi,

I have just finished making two spark strips for a combustion gun. each spark strip looks like this:

http://www.peter-hoare.co.uk/sparkstrip.jpg

It has three 1mm gaps, and i am powering both of them from my 100,000v spark generator (stungun basically) and I am worried the sparks wont be big enough to ignite the gas in the chamber. I had a breif go, using the strips to ignite the blowtorch and nothing happend.

They will be about 25cm apart in a 50cm long chamber, firing on either mapp or propane.

Any help would be great.

Thanks.
User avatar
iPaintball
Corporal 2
Corporal 2
Posts: 695
Joined: Sun Mar 04, 2007 8:37 pm

Tue Jul 31, 2007 4:01 pm

With a regular combustion, you could increase the total gap size to an inch. Probabaly more effective...
Summer Projects:
CO2 tank hybrid: Gotta fix the meter :(
Cane gun: Needs a pilot/fill setup
1.5" piston valve gun: Almost done
User avatar
Pete Zaria
Corporal 5
Corporal 5
Posts: 954
Joined: Fri Mar 31, 2006 6:04 pm
Location: Near Seattle, WA

Tue Jul 31, 2007 4:13 pm

My combustion gun has a spark strip with five, 2.5mm gaps, for a total of just under half an inch. Works excellently. If you have the resources to make a longer spark strip (to cover more chamber area) with more, slightly larger gaps, I'd recommend doing so.

However, your strip should work. A hot enough spark, regardless of size, should ignite a near-stoichiometric propane mixture.

Peace,
Pete Zaria.
User avatar
noname
First Sergeant 4
First Sergeant 4
Posts: 2698
Joined: Mon Apr 10, 2006 9:19 pm
Location: Bay Area, CA

Tue Jul 31, 2007 7:33 pm

It'll work just fine, although as Pete stated, larger strips for bigger chambers will be more effective. I have 4 sparks each about a millimeter long because I'm using a BBQ igniter in a huge cannon, and they ignite the fuel just as well as any other spark.
Post Reply