Metered Mapp gas Potato gun

[fom]

Well, this is my 3rd potato gun, im only 13 by the way
Spudblaster blaster gave me the C:B ratio and a few types but I did like 90% of it by myself, it has a 6 foot barrel and 16" chamber with over/under config. 80mm CPU fan on 18 volts, double spark gaps with metered mapp gas.

[beebs111]

what do you use for an ignition source? im not familiar with abs, but maybe thats just painted........many of those parts are not pressure rated

[PVC Arsenal 17]

^ ^ It's a combustion, no big deal.

You did a good job by the way. Not bad at all.

Is that ABS, because I've never seen yellow primer for PVC before...

[SpudBlaster15]

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Cras nec placerat erat. Vivamus dapibus egestas nunc, at eleifend neque. Suspendisse potenti. Sed dictum lacus eu nisl pretium vehicula. Ut faucibus hendrerit nisi. Integer ultricies orci eu ultrices malesuada. Fusce id mauris risus. Suspendisse finibus ligula et nisl rutrum efficitur. Vestibulum posuere erat pellentesque ornare venenatis. Integer commodo fermentum tortor in pharetra. Proin scelerisque consectetur posuere. Vestibulum molestie augue ac nibh feugiat scelerisque. Sed aliquet a nunc in mattis.

[fom]

^ ^ It's a combustion, no big deal.

You did a good job by the way. Not bad at all.

Is that ABS, because I've never seen yellow primer for PVC before...

Thanks, and yes its ABS/

and beebs i use a eletric grill ignitor, switching to the red button piezo elecrtic device soon though.

Thanks for the comments.

[beebs111]

i know that it is a combustion, thats why asked what he used for ignition duh! and i like to only use pressure rated pvc parts with my guns, just for safteys sake, even when it is only a combustion, very nice job

[fom]

i know that it is a combustion, thats why asked what he used for ignition duh! and i like to only use pressure rated pvc parts with my guns, just for safteys sake, even when it is only a combustion, very nice job

The ABS im using is sch 40, but thanks for the comment

[PVC Arsenal 17]

Yes, but your parts are DWV (drain waste vent) and are unrated. Sch 40 is only a measure of wall thickness I believe. You can tell if a pipe or fitting is pressure rated if it is marked with NSF-pw.

[SpudBlaster15]

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Cras nec placerat erat. Vivamus dapibus egestas nunc, at eleifend neque. Suspendisse potenti. Sed dictum lacus eu nisl pretium vehicula. Ut faucibus hendrerit nisi. Integer ultricies orci eu ultrices malesuada. Fusce id mauris risus. Suspendisse finibus ligula et nisl rutrum efficitur. Vestibulum posuere erat pellentesque ornare venenatis. Integer commodo fermentum tortor in pharetra. Proin scelerisque consectetur posuere. Vestibulum molestie augue ac nibh feugiat scelerisque. Sed aliquet a nunc in mattis.

[fom]

Yes, but your parts are DWV (drain waste vent) and are unrated. Sch 40 is only a measure of wall thickness I believe. You can tell if a pipe or fitting is pressure rated if it is marked with NSF-pw.

I can name many advantages with ABS over PVC, and I think that the SCH means the psi, 40 SCH is 200 psi and 80 SCH is 400 psi

[mark.f]

Nice gun! Good to see another fan of MAPP gas as well.

BTW, do you have the same problem I got with MAPP gas? After firing, the cleanout cap locks up so tight you gotta get a jar opener to get it off? This happens to me every time I fire.

[Scope]

SCH means the thickness... but a bigger SCH will have a higher psi rating... but it depends on the pipe...

Nice gun!!... i like mapp

Guys can we leave the abs vs pvc thing alone... he didnt post his gun here to listen 2 evreyone fight over it agian

[CS]

To clear things up the 'sch' [schedule] only indicates the wall thickness, it in no regards defines the strength of such. More likely then not you have sch 40 cellular core ABS, which does not carry a pressure rating, and more so it is not intended for pressure. Although it is commonly accepted for use in launchers. Many people, including myself can safely say that they've put 1G rounds threw such guns without failure.

One first has to determine with whatever material it may [PVC, ABS] be if it in fact solid core, cellular core, or some other variant.

"I can name many advantages with ABS over PVC, and I think that the SCH means the psi, 40 SCH is 200 psi and 80 SCH is 400 psi" ~fom

It should be understood by other users that those numbers are 100% wacked. First the first stipulation of this all is you must first determine which material such is, and its cross section [cell core, solid]. Even from there the diameter of the pipe effects the pressure rating. So you cant emit pressure ratings without first regarding changes in diameter of it differences in cross section terms.

"Guys can we leave the abs vs pvc thing alone... he didnt post his gun here to listen 2 evreyone fight over it agian" ~Scope

First I wouldn't consider any such discussions 'fights', rather a convincing of the bull headed. Such discussions take place so that users involved in the conversation, and other forum drifters don't pick up false info because someone is spewing incorrect facts out of there ass. The discussions are simply not at yours, or the posters will to avoid as it is done for safety of forum members. Remember this forum doesn't revolve around you

Anyway to the gun itself, nothing overly complicated, while nice. Possibly could have been a bit more careful what appears to be yellow ABS glue? You also may have wanted to mount the batteries and such inside enclosure of some sort, as well decided on one type of metal for the metering system. You used all 3 hardware available metals brass, black, and galvanized. Also to turn the gauge in ~1/2 turn as currently the pressure gauge is pointing in the opposite direction of the user. Understand I'm being overly critical for your sake, as this launcher appears to be very fun. Simplest tend to be the 'funnest'.

[Scope]

I hear ya Pimp... I just feel bad for people who post cannons only to have a the thread get pulled away from there cannons...

[fom]

Thanks for the comments, and @ pimp my hardware store isnt that big so I had to use what they had, and the pressure guage is like that because my dad won't let me hold it so I place it on a angle.