Surprised how quickly mine arrived, will test it out when I have time.

edit: 3 AA batteries in series gives off a nice spark with a healthy buzzing sound. Only tested it on a spark plug gap since (my interpretation of) the eBay listing says not to vary the spark width while it is powered.

If you're capable of it, go for it. I have one machined from aluminium, so using aluminium itself is not a problem. You'll need to cut some o-ring grooves if you don't include them in the mould for casting.

It can be quite difficult to find a setup that works consistently. You want the flat part of the union (probably the piece you modified, in the middle in the pic below) on the barrel. The reasoning here is that you want the most surface area for the disks to be pushed against. This prevents them sli...

~NooooooB~ wrote:Sorry to bore you all, I just get excited talking about it

I was looking at notes I had taken in uni during my first semester the other day and I saw pages and pages devoted to designing Mjollnir or calculating o-ring tolerances and piston forces

Well you only need the piston to move back about an inch or so but you also need to fit in a bumper. Really, you want to keep the pilot valve as small as possible so you have less air to vent. It may be trial and error. Instead, focus on maximising flow through the pilot valve. A burst disk is an ob...

I assume it wouldn't have enough flow but it could work. Others have used much smaller pop-off valves and just deal with premature piston closure.

Fair enough, though it goes back to what DYI said about trade-offs between performance and ease of use.

You could even skip making the burst disks fail in specific ways and just chuck on a shroud to catch any shrapnel.

It's something I did consider and while DYI is right, I believe there's another reason too. The beauty of the spool valve is that it opens AS SOON AS peak combustion pressure is reached. You can dial it in very nicely so the valve is opening when you want it to. With a burst disk, you'd have to have...

Nice find, I just picked one up myself. I have a 30kV BBQ sparker that has trouble at 9X and 10X mixes so I've been looking at other options. Hopefully this one does the trick, although it seems to be a bit more picky with the input supply. Not sure if lithium batteries are required to get the most ...

Well you've done well for youself, paaiyan
She's a beaut, too*!


*gun/car/wife/house, take your pick

I had wanted to do something similar a couple years ago. I asked a guy down at the local dive shop and he just said to stick it in the middle of a field, crack the valve, and give it a few hours. I was in a rural town so didn't have to worry about people interfering but I never got round to doing it...

I will not put the phone numbers on this website, i think it would be a better idea to keep a small list and PM this list to members joining the group. Well it's only a country code, provider prefix, and one random digit but ok :D I should show up with a name... I set it when I made an account. I s...

Oh really, how do you do that? Everyone came up according to their numbers when I first joined the group.

Labtec, maybe you could update your first post with numbers identifying each member. You'd really only need the country code plus the first three* numbers (e.g. +64 210 for me), unless someone has an objection. *Two members from the same country using the same mobile provider would have identical nu...

I've joined.

I have a WhatsApp group with about 15 friends and it's a pretty good way of staying in touch and sharing whatever is on your mind/going on. See something interesting at the hardware store? Snap a pic and send it to the group.