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improving the BL-520 but need help with mapp gas

Post questions and info about combustion (flammable vapor) powered cannons here. This includes discussion about fuels, ratios, ignition systems, safety, and anything else relevant.
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improving the BL-520 but need help with mapp gas

Unread postAuthor: chrissilvermancs » Mon Mar 30, 2009 10:21 pm

well i saw it on the web sight then on the home page and i cant believe the price tag for something not perfected. (notice i didn't say it wasn't good)
so i decided i could build a better one for a lot less. first i happen to own a big piece of 6" (just need to get the other parts) love his design. so im also going to build my cannon bulpump. but this is one of my design changes i will have. first i do not know how or why they put that barrel on the top but i cant so im going to reduce it to 3" and then but a female adapter on it and use the pass through design to be able to have the same bullpumb look but still have the interchangeable barrels. "pass through-burnt latka (http://www.burntlatke.com/pass.html)

my second change would be two handles i plan take my airsoft awp and cut the wood like the handles/grip like the gun and some how use my tazer and integrate a trigger out of it also fan control on the outside.

then the usual fans and spark strips and such.

have any other ideas please add


BUT I REALLY WANT TO USE MAPP BUT NEED A LITTLE HELP
can u please push me in the right direction i have done a propane meter the old school pen and paper and graphing calculator. but i just need to know the differences in the formula AND MOST IMPORTANTLY WILL IT EXCEED 120 or 220 psi because the two type of pipe i was planning to use are pressure rated to that!!!!!!!
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Unread postAuthor: mark.f » Mon Mar 30, 2009 10:34 pm

well i saw it on the web sight then on the home page and i cant believe the price tag for something not perfected


WAT

Of course, nothing is perfect, but it'd be a damn sight to see somebody build something better for the hundred or so you'd probably wind up laying down on it.
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Unread postAuthor: jook13 » Mon Mar 30, 2009 11:50 pm

Perhaps the overall design could be improved, But I seriously doubt you can match the craftsmanship and overall slickness of his setup. I think people seriously underestimate how much time, effort, and money goes into machining all these parts.

I imagine purple primer stains and lots of pipe clamps or duct tape when I picture your attempt. sorry to be blunt.
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Unread postAuthor: chrissilvermancs » Mon Mar 30, 2009 11:57 pm

can people stop criticizing the post and help. and second r u saying you could not build that thing for under 1k. and what do u mean by

you'd probably wind up laying down on it.


if your going to insult me at least make sence.

i will admit its good i like the design. but theres some simple things you can do to make it better is all im saying.

so if you would like to add anything or help me with my mapp gas problem thank you

edit 1:
this would be my second combustion because all i have done was add on ideas to my first one and i will make this one he right way if you are talking about my posted cannon "the ghetto cannon" but i can and will make this one correctly so if we can get back to topic thank you
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Unread postAuthor: jook13 » Tue Mar 31, 2009 12:05 am

The pressure difference between propane combustion and mapp gass combustion is very small. I honestly dont see it going above 100 psi.

somebody made a program that helped me a while ago, here is the link. Open the program and on the bottom there is a tab to click for mapp gas.

http://www.spudfiles.com/forums/hcmp-t13837.html
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Re: improving the BL-520 but need help with mapp gas

Unread postAuthor: jagerbond » Tue Mar 31, 2009 12:16 am

chrissilvermancs wrote:well i saw it on the web sight then on the home page and i cant believe the price tag for something not perfected. (notice i didn't say it wasn't good)
so i decided i could build a better one for a lot less. first i happen to own a big piece of 6" (just need to get the other parts) love his design. so im also going to build my cannon bulpump. but this is one of my design changes i will have. first i do not know how or why they put that barrel on the top but i cant so im going to reduce it to 3" and then but a female adapter on it and use the pass through design to be able to have the same bullpumb look but still have the interchangeable barrels. "pass through-burnt latka (http://www.burntlatke.com/pass.html)

my second change would be two handles i plan take my airsoft awp and cut the wood like the handles/grip like the gun and some how use my tazer and integrate a trigger out of it also fan control on the outside.

then the usual fans and spark strips and such.

have any other ideas please add


BUT I REALLY WANT TO USE MAPP BUT NEED A LITTLE HELP
can u please push me in the right direction i have done a propane meter the old school pen and paper and graphing calculator. but i just need to know the differences in the formula AND MOST IMPORTANTLY WILL IT EXCEED 120 or 220 psi because the two type of pipe i was planning to use are pressure rated to that!!!!!!!


Look forward to your design, On our BL-520 and 415 the barrel is offset to allow for a full chamber length vent tube. This helps to evacuate exhaust gases from the dead area were the barrel and our machined PVC offset piece. We will soon be offering a 6" offset with 2.875" (2.5" schedule 40 OD) barrel pass through. On yours you can use a T for venting the dead space. Here's the thread on the one I built last year, and similar to what you propose. http://www.spudfiles.com/forums/viewtop ... tml#204141

Your MAPP and Propane can be metered in the same way, the MAPP gas has a faster flame velocity but still within the realm of 6" pressure rated schedule 40. Our tests on our BL-520 showed PSI spikes of around 60PSI on the MAPP gas.
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Unread postAuthor: mark.f » Tue Mar 31, 2009 12:17 am

Let me clarify then.

jagerbond's cannons' quality is untouchable by the average hobbyist.

Also, the layout is pretty damn slick. The "offset coaxial" (I still don't get that term seeing as "coaxial" means "sharing the same axis" :) ) layout allows him to fit a venting/mixing fan and electronics for it into the chamber, and the way he mounts everything to the cannon is very durable. The actual plastic piping itself would probably break before his components and pieces would.

I don't see how anybody without a sizable amount of money, time, beau coup tools, and of course, skill, could one-up the BL-520.

Just a question, but what is your budget for this cannon?

Now, as for performance, you could easily match the BL-520 with common parts and even a tight budget. But if you're going for an overall better cannon, I don't see it happening. I don't even think I know but one other member who probably has a chance of doing it, either.

I was not trying to insult you. Learn to listen to advice and criticism (note: listening to advice and criticism does not mean you have to follow it).

EDIT: because I might be coming across as an asshole, I'm not talking down to you, Chris. I've seen the stuff you've built and it doesn't just build itself. I guess I'm just reacting a little strongly to this thread because I like to see people build cannons to meet personal goals and to learn, rather than to "one-up" somebody else's design.

EDIT II: Also, to answer the main question, MAPP gas simply has a different stoichiometric ratio to air. While propane is 4.2% fuel:air, MAPP gas is more around 5% fuel:air (I use 4.89%, but it really is not that critical). Check the wiki for different fuels.
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Unread postAuthor: jackssmirkingrevenge » Tue Mar 31, 2009 2:00 am

chrissilvermancs wrote:if your going to insult me at least make sense.


It wasn't an insult, it was just rightly pointed out that you'll be very hard pressed to copy the BL-520, let alone improve it. No one's stopping you from trying though ;)
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Unread postAuthor: MrCrowley » Tue Mar 31, 2009 2:53 am

MAPP gas is more around 5% fuel:air (I use 4.89%, but it really is not that critical). Check the wiki for different fuels.

If I recall correctly, Burnt Latke says 4.6%
Just pointing out :)
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Unread postAuthor: inonickname » Tue Mar 31, 2009 3:42 am

I don't see you getting the labor, cnc work and materials done, along with a profit to survive on under 1 grand. But, you're the one who wants to try so I guess we may as well help..

I believe the reason that the barrel is offset is to fit a fan (and the electronics for it within the chamber without using a wye or compromising fan size. (doh, just saw his post..statement still stands)

Propane vs. Mapp velocities

Burnt Latke

Check out his site, it has everything except perhaps the latke vent ( :? ).

You can probably come good in how far and fast you can lob a spud, but aesthetics and the end product will be hard to match.

Mapp gas is close to 5%, it will be fine in a pressure rated chamber, hardly much more go than propane. The ideal mix may change extremely slightly as MAPP is just a cocktail of hydrocarbons, and I'm not sure how tight the regulations are.

Good luck with it, I'm sure Jager would be happy to use some of your ideas if you can show up something impressive. But we'll have to wait and see, won't we?
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Unread postAuthor: starman » Tue Mar 31, 2009 3:47 am

So you've decided you can build a better one for less... :roll:

Do you have any clue about the special parts designed for the BL-520? Any clue what design and CAD time costs? what machining parts cost? especially for relatively low count runs? What about your time or someone elses time to assemble and test the thing? That costs money too. On top of that, there's a marketing budget that is required as well as putting some money in his pocket so he can put food on his table. This is a business for him, not a hobby. I would hope he could sell them for $5000 ea...more power to him.

The cost of something is much more involved than just the value of the raw materials you put into it. It's the perceived value to the customer, the very basis of the free market system.

Also, that you would make such a pronouncement and then turn around and ask the Spudfiles community for fairly basic fueling assistance is the height of absurdity. It's obvious, the BL-520 has much background, thought and design time put in to it....something I'm not sure you fully appreciate. It's easy to now stand on his shoulders and claim you can one-up him.

Sorry Chris, I don't mean to be over slammin' ya...but... Jagerbond is a Spudfiles member and a new sponsor of the site. Considering that, I just found your post and claims to be lacking decorum.
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Unread postAuthor: inonickname » Tue Mar 31, 2009 6:16 am

Starman, I agree. What he's saying is rather rude. Sure, a thousand dollars seems like a lot to pay for a gun..but when you count this isn't mass production..along with all the other factors and the end product is well worth it's money.

Not to offend, I think you can match the power..that isn't hard. About the reliability..appearance...cnc work..all of that.. it wont happen. Cutting up an old airsoft gun may not get you there.

If you perhaps asked jagerbond what things he think could be improved on, then act on that it would surely be beneficial for both..for you as a cannon builder and him as a business holder.
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Unread postAuthor: jagerbond » Tue Mar 31, 2009 2:50 pm

inonickname wrote:If you perhaps asked jagerbond what things he think could be improved on, then act on that it would surely be beneficial for both..for you as a cannon builder and him as a business holder.


cam lock style breach cap for quicker loading
sling mounts

Comes to mind
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Unread postAuthor: CpTn_lAw » Tue Mar 31, 2009 3:42 pm

There are things to improve in the design, that's obvious...but em..well, I see a lot of cannons on spudfiles, over the past 4 years there has been a serious increase in number of members and cannons, but except some phenomenons (BtB, Larda, Clide, sorry for the name ^^) very few have come to make something really out of the ordinary.
Now, i am not saying you are not one of the few people making things "out of the box" but...you have little experience in spudguns and that might not come to your advantage ^^;

Well there's only one thing you have to do now, impress us ;)
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Unread postAuthor: chrissilvermancs » Tue Mar 31, 2009 8:49 pm

its not that i dont have the experience (but thanks for assuming) i just never posted my cannons for over a few years after i build them i have a other account but i do not remember anything of it so i started over.

again i like jagerbonds cannon and i happen to have most of the parts to make a six inch version of it.with some modification

and if you are criticizing me on a few of my cannons it is because the two cannons i have posted were my first cannons that were slightly improved that i made like two years ago. and i know alot more not than when i started.

which is why im asking about the mapp gas because i did the math like a year ago and when i started i did know about map gass and i could not find the post that talked about it

the reason i posted was not to offend jagerbonds but was for any other ideas to improve it and help with the gas equation.

and also lets be realistic with out the custom parts with are nice but not necessary it can be under 200. and i do know why he sells them for 1k and yes the quality and reliability is great. other than the metal parts im hoping to match it and i have all summer to do it if that what it takes

but thanks for the help with the mapp gas but and im open for suggestions to the cannon before i start the build
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