SpudFiles

I haven't made any spud guns yet, but I definitely plan on making some soon once the weather warms up. Of course, I have a few questions.

First of all, I know that DWV PVC can be used for combustions. I will be using SCH 40 chamber and barrel, but the reducer and end cap I can't find in SCH 40 and don't feel like ordering online. But would propane be safe to use in it since it makes like 60 PSI? If so I guess it's safe to take my water balloon launcher to like 200 PSI then since it's all SCH 40 haha (Not really).

Second, is there ANY website that has just basic ideas for making a hybrid gun? I don't even know where to start on how to make one so just like some basic idea... and yes I will build a combustion and pneumatic gun first.

Third, where do you find ABS pipe!!! I hear it being used in all sorts of sizes and the ONLY ABS I can find is 1-1/2" cellular core ABS which is at a local hardware store. I live in the midwestern U.S. so ABS might be sold like in Europe maybe?

All right thanks if you can help me.

for a basic combustion, dwv fittings are fine. for the hybrid thing, check out the wiki at the top right corner of the page.

So propane will work with DWV?

Well, you are right where you can use DWV parts on combustions. Just about all the parts you get a the hardware store (Home Depot, Lowes, Ace, etc..) are SCH 40. But remember the SCH 40 means wall thickness, not pressure rating. Pressure rated parts say NSF-PW, meaning potable water.

There are many topics on this website that talk about hybrid designs that will easily teach you what you are looking for.

ABS pipe can also be found at a local hardware store. Id you want to make a pneumatic, you need to use pvc pipe and pressure rated parts. You can use ABS as a barrel. There is pressure rated ABS but that is harder to find and would cost alot more.

ABS is sold in the U.S. too.

tyrant_bb wrote:So propane will work with DWV?

I would say no for propane. MY definition of a "basic combustion" uses arosol
as prolellent.

I would say no for PVC DWV, but yes for ABS DWV.

Also I hope your not planning a hybrid for awhile, learning how one works is one thing, but building it safely is another. You can't learn everything from this website, some stuff you have to teach yourself through experience.

You might want to read <A HREF="http://www.spudfiles.com/spud_wiki/inde ... ">this.</a> Should help you to identify pressure rated PVC.

ABS is pipe is ubiquitous to every hardware store in Canada but seems absent in other places.

It's odd, really.

Um another question, about C:B ratios. I heard 1.5:1 is best, but then i heard .8:1 is best? That would mean... the chamber is smaller than the barrel? I don't know how that makes sense but OK. Still confused...

tyrant_bb wrote:Um another question, about C:B ratios. I heard 1.5:1 is best, but then i heard .8:1 is best? That would mean... the chamber is smaller than the barrel? I don't know how that makes sense but OK. Still confused...

1.5:1 is for a basic "spray'n'pray" combustion. .8:1 is for propane at atmospheric pressure.

that is a common misconception that for a spray and pray the ratio is 1.5:1 it is 0.8:1 the same as propane.
so no matter what, for a combustion the best C:B is 0.8:1

I don't think there is anything better about ABS than PVC. Also I would get your parts from Mcmaster.com If you order enough the 5 bucks of shipping will be balanced out by the cheepnes and availability of parts. Also you'll find more direct reducers.

Just keep reading and learning..... that is the best advice I can give you.

You should start simple and work tords advanced or you may end up hurting yourself or others these are not little toys.....they can cause major damage

I don't think there is anything better about ABS than PVC

Apart from the fact that ABS has a greater temperature range, more favourable failure characteristics, higher chemical resistance, higher UV light resistance and higher impact resistance. PVC is one of the worst piping materials, if not the worst, that you could make a spudgun out of. ABS is better, but metals are generally preferable to plastics for these apps.

I believe that since spray'n'prays generate less pressure on average, it could be helpful to use a larger chamber than you would on a metered propane launcher.

The defacto standard "how-to" site for Advanced Combustions is: http://www.burntlatke.com

They are discussed very thoroughly from start to finish with data proving the .8:1 chamber to barrel thing. Good information and fairly easy read....lots o pictures.

Don't fool with a hybrid yet. You'll be amazed the challenges you will run into just getting a standard advanced combustion and pneumatic model operating properly. However, for some interesting hybrid reading...check here... http://www.advancedspuds.com/hybrid.htm

LikimysCrotchus5 wrote: Just about all the parts you get a the hardware store (Home Depot, Lowes, Ace, etc..) are SCH 40.

I wish, all of it is DWV crap..