SpudFiles

So Im looking at making a micro hybrid. Since I have no experience at all with hybrids Im gonna be asking around a bit . It will probably run off of butane, have a gauge built into it and be made out of sch80 or most likely steel pipe.

My problems are a small enough measuring system for both compressed air and butane, where to find or how to make a small enough burst disk coupling and how to make it a safe handheld.

Measurements will be as such:
Chamber: 3/4" x 2" long
Barrel: 15mm x 8" long

Other specs will come as I make or find them.
So any help or ideas guys?

Well you can get pretty small unions, I have a ~1/2" one on my last cannon. Otherwise flare fittings are an option.

Haven't myself, but people have used syringes for metering small chambers. You could look at a different fuel with a wider flammability range to allow for greater error, such as ether (starter fluid). I've had pretty good luck with that, when not wanting to fiddle with a perfect mix.

Might as well make it steel, since the cost for that size will be minimal, and then you know you're safe. I believe it was 1/2" steel fittings have been tested to failure here, so unless you get real crazy with the mix, you're good. On that note, how high a mix are you thinking of running?

I also have no experience with hybrids, but I do know that it would be safer to go with the steel pipe over the PVC.
The only other thing I can say is, that research is you friend. Check out other hybrids for ideas, and even look at inonickname's Micro Advanced Spudgun for help with metering...
Would you get the parts locally or are you planning on getting them off the internet, like McMaster?

Edit: Daccel beat me, I'm a slow typer...

Well, if you're going with low mixes then a syringe (get the highest quality one you can) with a small tubing setup is ideal. For much higher mixes then a scaled down 2 valve (or 3 way) metering system with a regulator would work fine. For air pressure either use a pump with gauge to pump to ideal pressure (I'll be using a shock pump) or a regulated air source.

Unions are available down to 1/2", and if you had machining facilities or some creativity you could possibly build smaller.

As it will cost bugger-all, I'm going to have to say steel at this size.

And woot, mention!

Good luck

Haha yeah Ive been running over this idea since Chaos posted his failed version Tacticool. Ive got enough steel around the place anyway. I was also looking at Daccels Spray n Pray method (thanks Daccel ) for fueling but theres the obvious limitations there.

unions are avalible down to 1/4 maybe even 1/8 on mcmaster but if you are not ordering parts then 1/2 would be your smallest. if you plan on using mixes above 10x then you could use the method where you fill the chamber to a sertion psi of fuel then add the compressed air

Place called Couplers over ere has unions down to 1/8" in store (aswell as anything you can ever want for spudding, it = heaven).

I bought a 1/4" SS one for making a small hybrid, gonna start it soon.

An option for fueling micro's is to make a larger pre-mix chamber where a conventional hybrid meter is used and then the mixed is used to purge/flush/fill the micro. Just a thought.

I'd go with small aluminum tubing and plates and fasten with screws.