WOOD combustion v.2 yeah, you heard me...again

[Eddbot]

ok, a while ago i made a wood combustion that, well...didn't work, it's here

anyway, on to the working one!
everything (almost) is made out of wood

the barrel is a 10" long 3/4" dowel with a 1/4" hole drilled through it

chamber is 4 slabs of 3/4" pine glued together then drilled out with a 1 3/4" forstner bit

the "clean-out adapter" is a wood circle with a weird shaped washer bolted to one side and a length of metal (found at ace near the L-brackets) on the other, when pushed in, the washer compresses and seals against the lip, then twist to lock underneath the screw brackets

ignition is a stick lighter peizo

oh, and it shoots airsoft bbs

pics:


whole gun


barrel


seal locked


seal unlocked


sealing face


handle/twist/door/thing (i have yet to come up with a proper name for this)


chamber


size comparison


damage comparison

anyway, that's about it

[Killjoy]

Well it looks good thats for sure haha. But the powers just a little lacking, still, looks good, nice work there.

[starman]

I remember your other one... This one looks a little more substantial, although the power doesn't seem to be that high. Is it too late to drop a longer barrel in there?

Still, I'm partial to working with wood...this has a sense of cool to it. I'll bet after a few shots you'll get a nice aromatic burning wood "air" about the thing.

[biggsauce]

Now that really is something. A little stain or some laquer, this thing could look good on a mantle... 8)

How did you drill out your bore?

[MrCrowley]

Cool stuff, too bad about the power though.

[starman]

Now that really is something. A little stain or some laquer, this thing could look good on a mantle... 8)

How did you drill out your bore?

Forstner bit...mentioned in his original post...

[biggsauce]

Ah, but with a hand drill? Thats a pretty steady hand to drill that good of a hole through that dowel

[Eddbot]

the chamber was drilled out with the forstner, the barrel was started on a drill press then finished with a hand drill, i had to go buy a 12" long 1/4" bit, but it was worth it

edit: i think i'm gonna try a heavier projectile tomorrow, it seems to me that the bb is just too light to expect alot of damage

[psycix]

Hahah I remember the old one you made.
You surely fixed up the door on this one (no square burning mark xD)
How airtight is it?

[JDP12]

hmm thats really cool nice job

[bigbob12345]

Nice job
I think I might make a wood pneumatic, maybey even a piston valve out of wood
It would probably blow up but....

Never know when this or the other one will blow up, but that just adds to the fun

[bluerussetboy]

Nice and clean this time around. The wood is probably absorbing some of the combustion heat leading to your lack of power. If you had an old Model T coil bolted on there instead of the BBQ sparker it would look pretty cool.

[Ragnarok]

The wood is probably absorbing some of the combustion heat leading to your lack of power.

I think the more likely reason is the incredibly short barrel, relatively low pressures, inefficient C:B ratio, and to some extent probably fuelling issues as the chamber is small. That pellet will be way out of dodge before the pressure is up.
Over the very low time frames involved, the difference between the amount of heat PVC would absorb and the amount wood would absorb is inconsequential.

Nice work Eddbot - that's got to be one of the world's most unique spudguns. With a little cleaning up on the tape, and a bit of varnish, it could also be one of the best looking too.

[psycix]

Nice and clean this time around. The wood is probably absorbing some of the combustion heat leading to your lack of power. If you had an old Model T coil bolted on there instead of the BBQ sparker it would look pretty cool.

Why should wood absorb more heat then PVC or even metal??
As ragnarok said:
Its the short barrel ( and thus the C:B ratio)

[bluerussetboy]

It's called R-value. A material’s R-value is the measure of its resistance to heat flow. Go back to school