So it looks like this might be a case of "it's probably safe, but...". There seems to be some ambiguity about whether 1) The chance of having a bottle burst is acceptable small 2) OR the consequences of such a burst are acceptably mild 3) AND the chance of dangerous impurities in the drink is accept...

So as a sort of fringe benefit of having spudding stuff laying around, I realized I can carbonate my own beverages with my CO2 bottle. My family goes through about 20L of seltzer a week so it might actually have practical value (!). Anyway, here is my setup: CO2 bottle to QC to modified bottle cap w...

Right, I would imagine there's a large difference between a slowly applied load (filling with compressed air) and a shock load (combustion), you can't just read off the pressure rating. Also, in case anyone is curious I redesigned my apparatus to be a shorter section of 1.5" pvc with a 1" x 3/4" "ba...

Funny, I built a homemade lathe a while ago, and I used old skateboard bearings too. 5/16 as I recall. Here's a link if you're interested, it turned out well enough for turning o-ring grooves in PVC but I ended up buying the 8x14 MicroMark lathe anyway. http://www.spudfiles.com/forums/completed-home...

Just to clarify, I am not trying to burst the pipe, and am just trying to get a feel for how combustion stuff works. Just out of curiosity, how high a mix is it safe to use sch40 PVC with? I assume its easily safe for 1X.

Ok thanks for the advice everyone I guess I just need to redesign my setup.

And while I guess "explode" is a bit imprecise, I think everyone here knows what I'm talking about in the context of an atmospheric pressure mixture of propane and air being exposed to a spark.

Hi, I am thinking of doing some work with combustions, which I haven't done before, and am sort of screwing around with stuff to figure it out. To that effect I am trying to get a chamber of metered fuel/air mixture to explode (no barrel). My setup is a length of pipe which attaches to a small meter...

Part 1: McMaster 4753K52 Spring-loaded Piston Check Valve with stainless steel seat, spring, nickel-plated brass body Part 2: McMaster 48435K72 Pop-off valve Would these parts be okay if subjected to hybrid combustions of say, 30 psi pre-ignition pressure? I would imagine so but thought I'd get othe...

Looks like a good idea. My only concern would be that the interface between the threads would not give enough grip to keep the pieces from coming apart under the high forces of a launch. Certainly if your epoxy casting didn't fit the barrel tightly and the sabot had room to expand outward it would f...

Have you considered modding the valve? For example if you prioritize seal quality over valve performance, you could swap in a stronger spring to hold down the diaphragm. Don't know if it would work but it's a thought.

Is 4 degrees just pulled out of a hat or is it special? I suspect that there's a trick involved specific to that angle, and that you're not looking for a brute force solution using a Taylor series or anything like that.

2.5" SDR 26 PVC (2.635" id) is what you need. It can be a bit tricky to get though. You can buy it online at
http://launchpotatoes.com/index.php?act ... oductId=43

I plan on using a spark plug with a spark gap of maybe 1/8 inch so won't be an issue. Just to double-check, does this setup look okay? (sorry for the crudeness of the diagram) http://img84.imageshack.us/img84/8508/circuit.png And on a safety note, when I'm taking the circuit apart (with the switch o...

As far as the circuit setup and conceptual stuff goes I don't have a problem, my question is regarding the physical attachment points of the ignition coil. The primary (low-voltage) coil attachments are easy, they're the screw terminals on the sides. But there seems to be just a single central termi...

So I recently obtained a cheap ignition coil with an eye towards using it to generate high-voltage sparks. Having read up on how they work, I understand that the low-voltage primary coil connects to the two screw terminals on the "shoulders". The central port is clearly one connection of the high-vo...