SpudFiles

See below pics for Gun on PROTO stand (not final) and HGDT results with 500psi burst disc

I guess the photo's speak for themselves.

Have all the stainless, will be welding it up when i get some extra time, the stand is mainly all 2 x 1 box tubing (plain carbon steel)

Burst pressure of the weakest part is the 3" sch10s 316 piping, which is 4200PSI.

Now i'm definatly not an expert in the hybrid realm, are these results im getting from HGDT even close to what i might actually get in real life with a 10X mix?

Also having the burst disc pressure at 500PSI? Not to sure about burst disc's and how they effect the safety of a gun so if that seem's arai just let me know.

Thanks and comment if you feel like it!

I cant wait till you build it (well i can...... but i dont want to )

500PSI isn't enough, the disks are bursting before the combustion is complete. I use 750PSI for a 10x mix in my hybrid, generates about 1000PSI if I recall correctly. Just keep fiddling with the burst disk pressure until you reach a pressure you're comfortable with. At 1000PSI, you have a 4 to 1 safety factor. Try putting 1000PSI as the disk burst pressure or something like that.

Looking good though, should be a mean cannon

looks very nice, cant tell if its in the drawing but you should put a recoal absorption system

Chinnerz - me neither... lol. This thing will take about a month to complete with my schedule.

Thanks MrC - exactly what I was looking for. I'll look around to see what people have done to find a 1000psi semi-calibrated burst disc.

Recoil absorption will be a must - the stand will be re-thought out to think of a more appropriate way to hold this thing lol - it's way more powerful than I initially imagined with a 200psi burst disc lol.

Here's a sad sight.... 10X hybrid vs 10 Gallon.

Also updated views of the design. I'm liking where it's heading

Revisions:

No more swiveling action on the stand

legs are not equilateral - the rear legs are now only 60* apart for better stability - also shovels have been added on the rear legs to help transfer force into the ground and not the shooter as much.

Spread of support legs greatly increased for a lower profile so it doesnt topple over on each shot.

New handles

Mapp gas tank and meter chamber added.







..... my gosh.... where do we stop calling these things "spud guns"? lol it looks kinda scary.

At my local supermarket I can get a huge foil tray like this for a few dollars and with a 3/4" union it gives me 80 burst disks. The disks are very reliable and bursting pressure is somewhere around 300PSI for a 3/4" union. Annoying thing is cutting them out.

Find a roofer and pick up a roll of flashing.

If you have an old washing machine you can make high pressure ones the easy way. Use a piece of conduit and a launcher.

Technician1002 wrote: If you have an old washing machine you can make high pressure ones the easy way. Use a piece of conduit and a launcher.

And what pressure do you think that will burst at?

Gun portion is now welded up!

Stand will be done probably in the next month lol.

All pneumatics are ordered - Everything's going to be electronically operated (except the burst disc and loading lol).

Here's some pictures of the gun sofar - I'll probably be doing some pneumatic and low mix tests in the month until the actual stand is completed.

I've also got a neat spark strip design in the works...

Awesome Cant wait to see it finished.

Looks great! That was a good idea to put handles on the union...

Yeah I was looking at those handles too, great idea!
Will you be going over 10x mix at all?
Looks really awsome, a little like Larda's but not 200x

not planning on going over 10X. Even 75% of what HGDT says the power at 10X will be is more than enough for my satisfaction lol.

The handles on the union are nice, but the heat from welding them on missahped the threaded colar about .01" or so out of round... I managed to get rid of 90% of the binding with a simple air grinder, but now I think ill just put some lapping compound on it and practice my driving lol.

Larda's Hygac is certainly a nice piece of fabrication this gun will aspire to!

Here's another photo of inside the chamber... and the all important weld penetration lol. The butt weld cap on the rear of the chamber had a bit thicker wall than the chamber so getting proper penetration was a bit tricky since both parts where not perfectly concentric.

A butt weld is easer to do if the edge of the metal was beveled before welding so the groove is filled when welding. Were the edges beveled before welding?

Yep - standard 60* bevel leaving about 1/3 face flat. The eccentric nature makes it hard to get 100% penetration, that's why it's nice to have pipe clamps for tacking it up lol.