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Unread postPosted: Wed Feb 16, 2011 12:49 pm
Author: chenslee
Nope. No metering. Just a pressure regulator, an orifice, and a hole. The breech is open when feeding so spent fumes make their way out.

Using combustion pressure to shut the air/fuel hole has crossed my mind.

I work under a heavy load of self-imposed constraints. Cost, manufacture-ability and assembly, usability, cost of operation, repair-ability. If I can buy something off the shelf that keeps me from having to drill a hole or cut something, I'll design my butt off to integrate it. Everything in that picture is either water jet cut, McMaster Carr or 8020 extrusion.

It's one thing to lovingly hand craft a toy, it's another when you are being "threatened" with the possibility of having to build 25 of them, in a week. You start thinking about ways not just to bolt on off the shelf components, but on how to eliminate the bolts altogether.

For example, the new ball pusher has 11 parts, no bolts and can be assembled in about 60 seconds. The old ball pusher required 3x cut to lengths, hole transfer, pilot drill drill to 1/8, drill to 3/16, counter bore, finish drill to .2, then a #10 tap in the mating part, 2x 1/4-20 tap, 2x sanding and 2x 9/32 drill throughs. I replaced ALL that garbage with an extra water jet cut and two McMaster Carr parts. Cost went up about a $1, but it saved me an hour of headache.

Unread postPosted: Wed Feb 16, 2011 9:07 pm
Author: Technician1002
I wonder why you haven't referred to my comments regarding the definitions you provided

Never argue with a fool, you can't win. It is why I don't argue with perpetual motion magnet motor builders. If only they can get a few more percent efficiency they CAN get over unity.

(and you can't have an air piloted valve which isn't air actuated)

Very true, however you can have a pilot valve that is actuated by something else, such as a sprinkler valve (when used as intended) is actuated by water, but the pilot is actuated by electric current. The point that a sprinkler valve is air operated is just semantics. It is sold as a water valve. It could be oil, air, water, gasoline, etc.. Big deal.

Unread postPosted: Mon Mar 14, 2011 1:49 am
Author: Cain
I have spent the last several days reading your entire blog, beginning to end, and I have a few questions before attempting to build my own.

In the contest thread, there is a download link to some "Very detailed schematics". This is just a .pdf file with some closeup views and cutaways, no lengths or values are included. Would you be willing to upload any of your inventor files?

How about the barrel/combustion chamber/bolt length? I used the tennis balls to attempt to recover the lengths, and so far the closest I can guess is the barrel is 17 inches, the combustion chamber is 8, and the bolt is between 6 and 7 inches. How about the space between the barrel and combustion chamber?

Also, have you tried using any other torch heads? I have one that broke a while ago (Produces large candle-like flame or weak blowtorch flame) and was thinking of trying to use this for the fueling. What do you think?

So far, I have the entire fuel system completed (Last part is that blow torch), I've started an attempt to re-draw this in inventor (Doesn't help that I can barely use inventor), and I've started looking for 2.5" ID aluminum tube.

All the flat plates I can have CNC plasma cut for free (I'm the only person that knows how to run the CNC plasmacutter at our school), so none of that is an issue.


Unread postPosted: Mon Mar 14, 2011 2:09 am
Author: jackssmirkingrevenge
Cain wrote:In the contest thread, there is a download link to some "Very detailed schematics". This is just a .pdf file with some closeup views and cutaways, no lengths or values are included. Would you be willing to upload any of your inventor files?

Note that this now a commercial venture so exact plans might not be readily available.

Unread postPosted: Mon Mar 14, 2011 9:18 am
Author: chenslee
Hey Cain,

JSR is right, it would be a disservice to my partners to divulge design particulars. HOWEVER, I have a cadre of useful .ipt assets that would be useful, like the USG ignitor and regulator.

I have never tried a different propane torch.

Contact USG, they have a 10' length of hard to find 2.5 ID tube. They can cut it to length and square the ends.

As for inventor, I started this project as a design exercise for inventor. Now look at it.

Unread postPosted: Mon Mar 14, 2011 10:04 am
reverse engineering shouldn't be a problem... you know the general working principle so you might as well build one yourself...

IMO designing stuff is the best thing in spudgunning... if you're not interested in it then you might as well buy a ready made product - that would be definitely cheaper than building one yourself

Unread postPosted: Mon Mar 14, 2011 10:20 am
Author: chenslee
You should DEFINITELY buy ready made product. :wink:

Unread postPosted: Mon Mar 14, 2011 5:26 pm
Author: Cain
Guess I'm paranoid that if I don't build it exactly like yours, it won't work. Illogical, I know.

I'd buy one, except I'd much rather build something like this myself. I love building things. Also, I'm a jobless (Hopefully not for long) highschool senior :P

I'd nearly forgotten you'd started selling these, so that's completely understandable.

Thanks for the tip about USG, I had a look around our school metals shop and I couldn't find any, started to wonder if it was an uncommon size. I never realized they had such a large amount of products. I don't see any 2.5" ID or OD aluminum tube though...or did you mean I need to email them to inquire about it?

If anything, this project has inspired me to learn how to use inventor...been reading tutorials all day, amazing what it can do.

Thanks for such a quick reply. I'll be sure to start a thread when I can actually begin construction, probably going to draw and make a template for the trigger/grip today and start milling it tomorrow.

Unread postPosted: Tue Mar 15, 2011 8:12 am
Author: chenslee
I have a saying, Inventor fixes 100 problems and makes 99 more. I spend about 20 minutes a day cussing because that infernal program is such a clunkgasm of un-streamlined garbage. It's great at first, but then you realized that the people who made it never bothered to go back and actually USE it.

Ultimate Spudgun is a company inside of a R&D company, inside of a Machine Shop. Want custom camber adjustment plates for your Scion xB? Car mounted T-shirt launchers? Adjustable Honda Ruckus suspension? Nuclear submarine drive shafts? Same company. So yeah, shoot them an email. 2.75 OD, 1/8 wall is an uncommon size. I had to order a 20ft stick of it myself. Which reminds me, I still have some of it left, so if USG doesn't have it, I do.

PM me your email and I'll send you those ipt files.