SpudFiles

What is the best way to meter propane for a 30ml chamber? I am thinking a syringe but other than a syringe.

1 mL syringe, the type used for insulin injections

If you don't have ready access to the real medical stuff, you can get veterinarian type syringes at Tractor Supply Co. Not sure if they have those in Nova Scotia or not....possibly the local farm supply as exists there.

I have a epoxy syringe tube you know the double one. I split it in half to have one tube and cleaned it out. I poured in 2.5ml of water into the tube from a medicine cup and made a mark poured in another 2.5ml and made another mark and whatever. I found out that I think about 4% of the chamber is 1.2ml so 2.5ml should be good for 2X correct? I know it isn't optimum but it would be repeatable.

Sticky_Tape wrote:I have a epoxy syringe tube you know the double one. I split it in half to have one tube and cleaned it out. I poured in 2.5ml of water into the tube from a medicine cup and made a mark poured in another 2.5ml and made another mark and whatever. I found out that I think about 4% of the chamber is 1.2ml so 2.5ml should be good for 2X correct? I know it isn't optimum but it would be repeatable.

Shoot for a 4.3% (yes a tad over theoretical optimum) propane load per X. You could use MAPP gas and get a 10% (or so) more energetic shot. If you use MAPP, meter out about 4.8%.

If you have a way of sealing it after you fill, it should work fine. I would suggest also getting an accurate volume measurement of your chamber (with everything in place, fans, spark strips, etc) via the water measure method as well...maybe you have already done that.

I have and surprisingly it came out at 30ml. I tried to use the steel wool ignition method but it didn't work for some reason well back to piezo.

jackssmirkingrevenge wrote:1 mL syringe, the type used for insulin injections

I have a 1/2ml syringe

we use it to give my cats medicine. I can fuel a pen tube accurately....

well I got my hybrid working at 4x mix pretty cool I never thought I would get one working so easily. I was happy when I got the satisfying BANG well more like pop but anyways it's cool.

EDIT: I made a video got a little recoil there.[youtube][/youtube]

That. Is. SICK

I want one now.... In faaaccctttt...........

Shweet!

Well done Sticky.

Got a bit of snap to it don't it.

Mini piston hybrid?

That's cool . Micro hybrid plinker!

It does have a bit of snap. Actually I made a 1/2'' barrel for it after coming home from spending my christmas money. I fired a marble out of it outside it made my neighbour jump from about 100' away You two should try to make one it's easy as hell I surprised myself how easy it is I should have made one long ago. The burst disk holder idea goes to daccel it's a flare fitting they make great mini burst disk holders.

I'm just wondering how to get the ignition in... I have lots of various copper and brass and was thinking of making one of these.

How to you wire in your ignition without it shorting on the walls?

Excellent! Great work running your requirements down and getting the job done. You made it seem easy by doing your prep work...not something many will take the time to do.