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-   -   Home made PVC pneumatic cylinders? anyone with experience in this? (http://www.hauntforum.com/showthread.php?t=29657)

gooffy87 11-20-2011 01:19 AM

Home made PVC pneumatic cylinders? anyone with experience in this?
 
This year was my first real haunt year and messed around with the standard wiper motor projects. 2012 I am eager to get into the pneumatic scene but of course, it is a little pricier. Been looking at youtube and other forums and have stumbled upon how to make pvc pneumatic cylinders. Has anyone made these and used them in there haunts?

*I have seen people in other forums talk about the dangers of using these, expanding pvc....so on and so forth. I am only looking for positive experiences and not someone saying how rediculously crazy it is. After all, we haunted have all had to mess around with electricity at some point, pretty dang dangerous......lol(not to make fun but just putting it in context). thanks! PICTURES ALWAYS A PLUS!

BioHazardCustoms 11-20-2011 04:24 AM

If I walked into a haunt that wanted work done, and saw pvc cylinders, I would tell my guys to pack their tools and we would leave. PVC cylinders are extremely dangerous. There is a difference in putting yourself at risk working with electricity and putting unsuspecting haunt patrons at risk with plastic grenades just to save a buck. You can cut the power to a room while you work with electricity.

funhousewizard 11-20-2011 11:45 AM

not to be a smart @$$, but have heard and read plenty of threads on this, i beleive asking for support on this is like making a thread to support the holocaust, i have heard nothing but harsh negative feedback on this.

halstaff 11-20-2011 12:26 PM

This is probably the most volatile subject when it comes to selecting pneumatic components and is a common question especially with those interested in getting started. Granted, as haunters, we're always trying to save some money and build things ourselves but the general consensus seems to be, in this instance, it's worth the extra money to buy the commercially made cylinders.
Check out Automation Direct - http://www.automationdirect.com/adc/...-repairable%29 I've ordered from them several times and have been very pleased with their prices and service.

mroct31 11-20-2011 12:48 PM

Yep, no way I'd use PVC! Getting "cheaper" air cylinders isn't easy you just have to be diligent. I just scored an SMC model that I'm going to use on a coffin sit up for $6.99 on ebay. It took a few days of watching but the deals are still there from time to time. You'll be much better off for so many reasons using real pneumatic parts made for the job they're supposed to do. Air regulators from Harbor Freight $4.99, push in connectors from Poweraire $5, air cylinders from ebay $10+, safety of props...priceless!

corey872 11-20-2011 01:16 PM

I have not personally used one, but the idea sounds interesting. I'm not sure where the 'grenade' thought comes from. Maybe someone got a bad piece of pipe and had one fail at one point and now it is urban legend?

If you look at the specs for schedule 40 PVC, even 3" dia. has a working pressure of 260psi - and it goes up from there as you go into smaller diameters. Most home compressors max out around 120-130psi, so the pipe already has a working pressure double the max you could ever throw at it. If you use a regulator and have a 'sane' pressure in the line - say 50-60 psi, now you have a 4x cushion between the line pressure and working pressure.

[I won't even mention the number of shots I've made on a PVC potato gun, who knows what type of pressure that thing generates!]

Additionally, it's not like the thing is powering a heart/lung machine. If the coffin fails to pop for a kid, it's bad but not the end of the world.

gooffy87 11-20-2011 03:43 PM

Thank u for everyones responses, his year safety seemed kind of like a no brainer pertaining to its importance (this was my firat haunt year). I really want to make what i an n spend on what i cant but seems i will prolly just order some cylinders, suppose they will last longer neway. To clear it up, i wud not be looking to put more than 40 psi at most thru some 2" pvc but i guess im scraping that idea. Thanks for the thoughts

gooffy87 11-20-2011 03:46 PM

Btw mroct, awesome profile icon. Thinking of making a full size dummy this year of that character from trick r treat for my haunt next year, really enjoyed his creepiness!

HalloweenZombie 11-20-2011 07:29 PM

I made a PVC cylinder years ago. I used a washing machine solenoid with it. I got the instructions from a Terror Syndicate book. It worked fine for about half the night, but it was a cold Halloween and the rubber stopper expanded and stuck, so the pop-up stopped working. Truth be told, you really don't save all that much money and it's a lot of extra work for nothing. As far as safety, not one person has ever heard of an actual problem with a PVC cylinder. It's an urban legend.

hauntedyards 11-20-2011 08:38 PM

Tis the season... This is a great time to start hitting Ebay for cylinders and cruise it all year. Even if you dont have a prop in mind you might find a steal on cylinders of various lengths and think... 30"... hey I could make a drop panel or a pop-up. 10" why not a skelerector or scissor. Heck with a "1 why not make something talk!

I'm a halloween hoarder... I bet I have 50+ different cylninders downstairs straight and rotary from 1" to "36 in bores from "3 to 1/2". I have no idea what I will do with them... lol

While you are at it stock up on solenoids... there are some good deals to be had there as well...

Best of luck and welcome to the airhead club!

Brad Green 11-20-2011 08:50 PM

Waaaay back 'in the day' I used home-made pvc cylinders, and while I never had one rupture, let alone go boom, they were an absolute pain in the ass to use and would fail on a regular basis. You are basically working with 'seals' (rubber washers) that never seal properly, tubing i.d.'s that are no where near uniform, and a whole host of jack-legged parts that really don't fit. Even if you completely discount any possible safety issues, these things just aren't worth all the inherit problems that come with them. Just watch Ebay closely and you'll find plenty of genuine cylinders at a great price.

mroct31 11-20-2011 09:31 PM

Quote:

Originally Posted by corey872 (Post 594678)
If you look at the specs for schedule 40 PVC, even 3" dia. has a working pressure of 260psi - and it goes up from there as you go into smaller diameters. .

Not sure about the effects but PVC is rated for liquid pressure not air pressure.
There are plenty of stories online about PVC failing when used with air, maybe not the grenade problem but problems none the less. Why even chance it, hurt yourself that's one thing, hurting a guest...well no more happy Halloweens for you!:jol:

gadget-evilusions 11-21-2011 12:09 PM

http://www.osha.gov/dts/hib/hib_data/hib19880520.html

The reason you should not use PVC pipe either in distribution or cylinders and spud guns is that it will eventually explode, and when it does, people can die. This is documented in the link to an article on the OSHA (Occupational Safety and Health Administration) website.

At my job someone decided it was a good idea to do air distribution thru PVC pipe that was rated at over 300 psi. After only about 1 year the 125 psi air in the system continuously pressurizing and depressurizing fatigued a piece of the system into exploding and hitting ME in the head with shrapnel. These are the same conditions that a cylinder or spud gun will see.

I know everyone wants cheap, but safety should never be sacrificed. Sorry to be negative, but since it's actually happened to be, I believe the urban legends.

ouizul1 11-21-2011 05:18 PM

Quote:

Originally Posted by madmax (Post 594907)
I started to leave this alone because....

Glad you didn't. That's one of the best unbiased responses I've seen on the subject.

I did some searching on the subject and also found that the documented catastrophic failures were in shop supply lines...most of those occurring when someone or something struck the pipe, causing it to rupture and sending shards of sharpness flying about. Searching through a bunch of OSHA and manufacturer's stuff...yes, use of PVC pipe for compressed air without some type of adequate containment layer around the piping is definitely a no-no.

So, when it comes to compressed air and PVC, it seems that the danger lays not in that something WILL go wrong...but rather what happens WHEN something does go wrong.

But hey...it's a free country, and the casinos are always open. :cheeseton:

bert1913 11-23-2011 12:15 AM

i did a internet search for pvc cylinders blowing up and found nothing. if you keep the pressure at or below 30 psi i see no problems with using them.

hauntedyards 11-23-2011 08:11 AM

All PVC pipes using compressed air are by default PVC cylinders.

http://torque1st.clubfte.com/OSHA_PVC_Pipe.htm

"The main problem with using PVC pipe and fittings for compressed gas is not that it
spontaneously explodes but that PVC is a brittle material that can be broken or
shattered with external force unless properly protected. Compressed gasses can be
best described as being analogous to a coiled spring. When a PVC pipe or fitting
fails when under stress from compressed gas it literally explodes like a bomb,
sending shards of plastic flying several feet in all directions. Liquids, on the
other hand, being compressed by only 1/10th of 1% contain very little stored energy.
When pressurized systems with liquids fail, the energy is dissipated very quickly,
thereby creating a much lower potential for hazard.

Colonial Engineering does not recommend the use of PVC plastic pipe fittings in
compressed gas service."

mroct31 11-23-2011 12:19 PM

Quote:

Originally Posted by bert1913 (Post 595212)
i did a internet search for pvc cylinders blowing up and found nothing. if you keep the pressure at or below 30 psi i see no problems with using them.

No problem using PVC for air? Really?

Here was a great explanation I found:

"Think of it this way. Take a scuba tank, fill it with water and apply pressure to the tank by hooking a pipe to a water tower next door. It the tank springs a leak, water will come out but note that water cannot be compressed so you only have the volume of water coming out that the pipe will flow.

Take that same tank, fill it with 80 cubic feet of air compressed to fit the tank (air is compressible) and hook it to a nice compressed air supply. If the tank ruptures now, the air will expand to its normal volume as it escapes. This allows the air to expand in volume from whatever pressure you have (example: 150 psi) to normal air pressure (14.7 psi). In this example, the air would expand to over 10 times its compressed volume state.

That is the difference in water and air. One will create a leak that will spray a lot of water and the other can explode rather spectacularly at times...."

Also here is a picture since you didn't find it:
http://www.monroefiredept.com/Incide...?IncidentID=56

There are some good stories here as well: http://www.garagejournal.com/forum/s...ad.php?t=60109

I like this post as well:

http://www.osha.gov/dts/hib/hib_data/hib19880520.html

Methinks that any corporation, school or individual that has a failure is reluctant to photograph the evidence of going against OSHA recommendations! A quick browse of the internet does turn up dozens of failures. Some nuts still defend PVC, saying things like, "it's only broken twice in 10 years"

Hey, PVC might work great but it will fail at some point and why work with material that is known to have problems when you can work with materials that are well tested and safe? Seems like a no-brainer but we all know someone with no brains! As a matter of fact I'm putting him out next year in my haunt!

yyzmec 11-29-2011 05:08 PM

just wondering what everyones opinion is on modified screen door closers is?

halstaff 11-29-2011 05:26 PM

Quote:

Originally Posted by yyzmec (Post 596448)
just wondering what everyones opinion is on modified screen door closers is?

I feel the small increase in price of using a proper cylinder that's already built is worth it. I don't have time when Halloween comes to worry about a possible failure in a hacked cylinder. I'll save my hack time for something else.

BioHazardCustoms 11-29-2011 05:58 PM

+1 to halstaff. The cost of actual cylinders is not that much different than a hack job. I'd much prefer to use my hack time somewhere that isn't a potential safety hazard.

kprimm 11-29-2011 11:31 PM

Personally, I would Never, Ever use PVC for a pneumatic cylinder. Pvc is way too brittle and becomes even more so over time. I built a simple Pvc cemetery fence a few years ago, and it is already cracking apart and has become very brittle. I feel it would be way too dangerous to myself and anyone else who would come to see my haunt. Way better off to just buy a real cylinder.

scubaspook 02-15-2012 11:24 PM

I know this link is old but it has been a while since I have logged in. Although I agree with real pneumatic cylinders I have made my own out of pvc with no fail and my largest pvc cylinder is a 6 foot piece inside another 6 foot piece and in another so in all this prop rises to a length of 18 feet tall two telescopyng cylinders in one. If you go to the following video and fast forward to 8:06 you will see my rising clown. I have used this for about 4 years now with no problem. I may be lucky but there is not much pressure being used.

walterb 02-16-2012 07:47 AM

Save the time and buy used on eBay, cylinder really are not that expensive

Cole&Jacksdad 02-16-2012 11:27 AM

It cost me through trial and error about $100 to build a PVC cylinder that worked for my first pneumatic. I could have bought a real cylinder for $10-$30. So now I get new and used cylinders on ebay and I don't have to worry if something happens or if the seals fail.

Crazy2ScareU 07-12-2012 02:25 PM

we had one that we used for our first 2 years and it push up a top of a bed where chuck was hiding, worked excellent never broke or cracked, but this year we are adding regular cylinders.

Screaming Demons 07-30-2012 10:42 PM

You can't piece something together for this price: http://www.mpja.com/email/07-24-12.asp?r=336845&s=1

And it's double acting.

BioHazardCustoms 07-31-2012 01:36 AM

Quote:

Originally Posted by Screaming Demons (Post 655788)
You can't piece something together for this price: http://www.mpja.com/email/07-24-12.asp?r=336845&s=1

And it's double acting.

That's a terrific price. I may have to bookmark that page...

Cole&Jacksdad 07-31-2012 03:28 AM

I bookmarked it.


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