SpudFiles

i think you just have to take the plunge and do it.. The power you're getting really deserves a nice pistol. When I get back home I'm going to make a compact hybrid pistol and use shapelock for the grip.. www.shapelock.com .

simple and ergonomic. I really think you should do it.

Is that the US equivalent of polymorph?

I would prefer lopping bits off water pistols etc. and epoxying away, a bit like I had done with this.

yea its the US equivalent. not a terrible price either, $24.95 for 1.1 pounds. Doubt I'd actually need that much, luckily they sell smaller packs.

You could do that, but why not maybe do that, but then skinny down the grip and create an ergonomic grip for your hand? It wouldn't be hard to mount this to some sort of pistol grip. Use some wood or aluminum for the gun to rest in, glue it to that, then attach a pistol grip to that wood or aluminum frame. Maybe even mount the chamber in a square tube if its small enough.. (dunno how much accessibility you have to say aluminum square tubing though).

A gun doesn't have to have a complex shape.. look at the welrod.. a barrel with a grip stuck on it. Honestly, I think that's the best type of look for a gun like this.

What mixture could you ignite with a lighter piezo and a 1 mm spark gap?

as far as I know, JSR has gone all the way to 26x I believe? He was using a piezo ignitor.. but I believe his spark gap may have been smaller.

JDP12 wrote:A gun doesn't have to have a complex shape.. look at the welrod.. a barrel with a grip stuck on it. Honestly, I think that's the best type of look for a gun like this.

A Welrod would be perfect, but still using cartridges. I have a bit more work to do

as far as I know, JSR has gone all the way to 26x I believe? He was using a piezo ignitor.. but I believe his spark gap may have been smaller.

28x actually which is the maximum mix you can get with unpressurised propane - but that was using the flyback ignition.

Using a tiny (literally the width of a paper) spark gap, the highest mix I managed to ignite using only a cigarette lighter piezo was 17x. This was touch and go, but 16x used to ignite "first click".

If you're making a bigger bore launcher (³/₄" or bigger) you don't really need to go beyond 12-15x for more power than is feasible.

dangit.. soo close.

you could do cartridges, but I feel like to have reasonable, appreciable power the hybrid has to be the size of what you've been testing in the past couple pages. For now.. i think a single shot, BD hybrid is in order. Time to go to the store and pick me up some steel tubing and whatnot..

what are the dimensions on this large hybrid? you may have mentioned it, but if you did, I forget.

I want my ignition to be portable, so no flyback for me

What spark gap width would be needed with 11 x mix and BBQ sparker (piezo)?

Has there ever been investigation into using a transformer to step up the voltage from a piezo?

Labtecpower wrote:I want my ignition to be portable, so no flyback for me

What spark gap width would be needed with 11 x mix and BBQ sparker (piezo)?

If it is a BBQ piezo ( the big ones) , you're go up to 1 mm max.
If it is a lighter piezo (the small ones) i'd say don't push it past 0.4 mm

But, you're better off using smaller gaps.
I personnaly use 0.7 mm with a BBQ piezo

.what are the dimensions on this large hybrid? you may have mentioned it, but if you did, I forget.

It's this one, 3/4" bore, 19.25mL chamber volume and 16.5 inches from muzzle to schrader.

What spark gap width would be needed with 11 x mix and BBQ sparker (piezo)?

As small as you can manage, aim for 0.5mm and you should be fine.

Has there ever been investigation into using a transformer to step up the voltage from a piezo?

Not to my knowledge, but skimming through this thread leads me to think it might not work.

No, a piezo has so little energy, it wouldn't pump any practical transformer.

Well now all I need is a syringe, everything else is sorted for up to 10X, spark gap might need a little work, but a 3mm gap should still work at 20X. (I do rather like 50kV)

I've got a few ideas for a stock, I'll need it considering the size of the ignition system. A ~7.5mm barrel should be an option soon, just need to visit a hardware store.

I might need a 1/4 union to get over 10X, it gets difficult trying to fit all the foil in the 1/2 union.

jsr, You should really get some polymorph, you'll love the stuff. It can quickly be cast into pistons, ammo, grips, etc...

Zeus wrote: 3mm gap should still work at 20X. (I do rather like 50kV)

in my experience i dont believe it will be, i will still try aim for a .5mm gap

Well 50kV gets ~50mm in air, maybe 2.5mm would be correct. I'll start off small, then see how far up I can get. I could always go up to 100kV if need be.

1/2 SCH 40 fittings should be ok for handheld up to 15X right? I know it'll go further, but I do enough to try and remove digits or limbs, I don't need another way to do it.