I've had very good luck with a spark plug on my 2" chamber on my hybrid. I use an NGK CR6E plug, which is an extended plug with 10mm x 1.0mm pitch threads. I drilled a hole through the side of a 2 inch coupler and simply threaded it with a standard M10x1.0 tap. I also wrapped a little bit of yellow ...

No, unfortunately I do not have any chrono readings on this gun. The EMT seems to work fine, and it is a great deal lighter than a similar length of Schedule 40 iron pipe. Since my last posts, I've leaned out my 7X mixture a little bit and am actually having a bit of trouble finding potatoes that st...

You'd be surprised how well the recoil absorbs into the shoulder with no pad. Even with just a T-shirt, it's entirely manageable (at 7X with a small potato I suppose). The machine shop is in the next town over, and to be honest I've spent all I want to spend on machining. After I got it, I realized ...

Obviously, my next step in design would be weight reduction. However, I'll just leave this here...
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(It works pretty good)

Nope, just the standard GoPro housing. Tougher than nails that thing is. Anyways, haven't posted for a while because I've been having some trouble with my piston. This is mainly due to the fact that I have very little patience to wait for epoxy or JB Weld to dry, and I couldn't get my large diameter...

I have now switched to manometric metering, for two reasons: A) I really had no idea where I was at with fueling before. I thought I was around 5X, but not really sure since I couldn't get any other mix numbers to work. I can't be bothered to measure the precise volume of the meter nor chamber, so m...

It's a bit goofy looking, but with the 90 street elbow against my shoulder, the piston housing goes over top of the shoulder, and you hold it like a rifle. It actually feels pretty good, and it is comfortable to shoot. Well, I got the video up! These are the two shots from the pics in my previous po...

So far I have had around 25 successful shots with this thing. I've zeroed in on a good mixture at 5X. Only had one piston failure, I managed to melt the sealing face. I replaced it, and now it works good as new. My bumper design appears to be working. The washers that support the rubber disk have be...

Lots of progress today and yesterday. I assembled the piston housing, chamber, meter, and trigger circuit and have it all attached! In my excitement, I didn't take very many pictures, but can explain a few things. I fine tuned the spacing on my piston and used JB weld to seal around the nuts and was...

Duly noted. All my pics should be resized 50% smaller now. A little more progress. Since the washers I am using to create the gaps for the o-rings on the piston are a way smaller diameter than the o-rings, they fit really loose in the gap ie. they are all over the place. You can see this in my previ...

You know, after the winter we had up here, I am definitely considering buying a set of those. No kidding even.

It is indeed! I modelled it in Solidworks and printed on my RepRap. It came out quite nice I think, and it's really comfortable.

I have read about manometric. My problem is that I don't have access to a small PSI gauge that I could use to do it accurately, and McMaster-carr will not ship to Canada. I found this out trying to get a reducing rod coupler. Plus, I like the idea of the "air through meter" design of SB15's if it he...

I've considered your advice, and have come up with something for now. I have removed the nipple from the reducer at the back of the pilot housing. Instead, I have another of the large rubber "furniture feet" that I used on the sealing face, and I have put this on the back of the piston. It is placed...

If you liked Quebec, you ought to come out to Saskatchewan. Nothing but open fields for hundreds of miles. A good spud range is never more than 5 minutes away, even if you live in the center of the biggest city!