cpvc pipe for reloadable cake

[Bonny]

I would like to build the 25 shot reloadable fan cake on passfire. The build instructions call for 1" O.D. thin wall 100 PSI PVC. I have only seen CPVC pipe in my local hardware store (but I haven't looked that hard). According to wikipedia article CPVC is more ductile see here:

 

http://en.wikipedia.org/wiki/Chlorinated_polyvinyl_chloride

 

Will the CPVC be strong enough? I'm only looking at firing 7/8" or 1" comets.

[TheSidewinder]

A side question...

 

Isn't Parlon (Chlororub?) simply raw CPVC powder?

[GalFisk]

No, parlon is chlorinated isoprene.

[Mumbles]

Sidewinder, you're thinking of Saran. CPVC, PVC, and Saran are similar molecularly. You can think of CPVC as a middle ground between saran and PVC.

 

They are produced by different methods however. PVC and saran are made in the same way. Saran has twice as many chlorine molecules as PVC does. This is essentially saran. I couldn't find a good picture with chlorine, so just imagine chlorine in place of fluorine.

 

http://www.coleparmer.com/techinfo/images/...tance_img_7.jpg

 

This is PVC

http://media.allrefer.com/s4/chars/ref95.gif

 

Notice the similarity. Saran has a second chlorine directly opposing the first on PVC.

 

CPVC is chlorinated PVC. While this sounds the same as saran it's not quite. CPVC is produced from already polymerized PVC. It's likely that the chlorination is not as perfect as Saran, as it is not present at the time of polymerization. Wikipedia gives values of something like 1.5 chlorines per polymeric unit. It is also unlikely that the chlorine is added directly across from the first chlorine in all cases. CPVC is kind of a disordered half-ass Saran.

[Bonny]

So...chemistry aside, will the CPVC be OK for my cake?

[jacob]

Yes if you're only shooting small comets CPVC should be fine, apparently it has a higher temperature rateing then PVC as well so it may work better.

[Mumbles]

I never like recommending PVC or CPVC. However small diameter(1" and under), is quite resilient, especially with the lower pressure lift we place in them. There is still a very real chance of them exploding, but as long as it's barracaded, it should be alright. I'd give at least 1/16" of clearance between comet/insert and pipe wall, and clean the tubes out between reloads to prevent buildup.

 

However, for the newbs. PVC or CPVC is not an acceptable mortar. Above 1" the PVC/CPVC gets weaker, while the lift and break charges gets ever stronger.

[Bonny]

I was just by home depot and they have 1" ID PVC pipe there...and the wall looked about 1/8". Now it's just a matter of where I buy to determine if I use CPVC or PVC. The comets I make for these are 7/8" so clearance should be fine too.

[TheSidewinder]

Sidewinder, you're thinking of Saran. CPVC, PVC, and Saran are similar molecularly. You can think of CPVC as a middle ground between saran and PVC.

*****SNIP****

About halfway through that my eyes glazed and my teeth started to itch, but I do see what you mean about the similarities in the processes and resulting products.

 

I knew ONE of those branded Chlorine donors (Saran, Cholororub, Parlon, etc) was simply CPVC.

 

I always read the comp recipe and cross-check any substitutes for suitability anyway, just to be safe, but I've noticed you can make QUITE a few substitutions within the pyro world and this category seems to be one of the most flexible.

 

M

[ST1DinOH]

not to sound like a saftey natzi here...

 

but for the love of god, don't use PVC for anything containing a comp.

 

if it can explode or even defligrate it should never go inside something that can become razor sharp projectiles.

 

there's so many other options available...personaly i'd use paper tubes that have been waterglassed.

 

repeated use of PVC causes all sorts of little fractures in it. it's a brittle material. eventually the lift in one of thoes tubes will be enough to break the PVC.

 

so durrability isn't going to be all that great with PVC...and it's dangerous as hell, so why not use parellel wound paper tubes that have been waterglassed. thoes things would last you forever and be safe as can be.

[Mumbles]

The 1" pipe has something more on the order of 3/16th walls, not to be picky or anything. They are 1.375" OD, and what I use as the canule former on my 4" can shells.

 

I do agree with ST1DinOH, if paper is available, that would be best. If you do go with one of the plastics, I really plead that you place it behind a barricade at all times.

[Bonny]

Although I personally don't like the idea of PVC pipe, it is a quick easy option. Normally I would have made them from steel, (I know, I know...) I fire all my 1" shells from steel mortars...nothing bigger, but it would be much too heavy to lug around.

 

Maybe I'll put this project on hold for now, and have a look around for some paper tubes or even luck out and find some HDPE. My family's business is packaging and plastics, so I have a lot of great (pyro) resources I should really start to exploit. As the purchaser maybe I should try an order some "sample" 1" ID heavy wall tubes

[ST1DinOH]

Although I personally don't like the idea of PVC pipe, it is a quick easy option. Normally I would have made them from steel, (I know, I know...) I fire all my 1" shells from steel mortars...nothing bigger, but it would be much too heavy to lug around.

 

Maybe I'll put this project on hold for now, and have a look around for some paper tubes or even luck out and find some HDPE. My family's business is packaging and plastics, so I have a lot of great (pyro) resources I should really start to exploit. As the purchaser maybe I should try an order some "sample" 1" ID heavy wall tubes

here's some other options for ya bro...

 

didn't mean to come off like a saftey freak or anything but PVC/CPVC/SCHED 40, ect...it's all bad juju when you are putting comp in it.

 

here's some good 1 inch tube options

 

http://www.cannonfuse.com/store/pc/viewPrd...11&idproduct=80

^nice little RW+B design on them

 

or

 

http://www.pyrocreations.com/inc/sdetail/522

^cut them to any length you want

 

there's lots of other online stores that sell this stuff...might check around for better prices or sizes and most of all...shipping costs.

[Bonny]

didn't mean to come off like a saftey freak or anything but PVC/CPVC/SCHED 40, ect...it's all bad juju when you are putting comp in it.

 

here's some good 1 inch tube options

 

http://www.cannonfuse.com/store/pc/viewPrd...11&idproduct=80

^nice little RW+B design on them

 

or

 

http://www.pyrocreations.com/inc/sdetail/522

^cut them to any length you want

 

there's lots of other online stores that sell this stuff...might check around for better prices or sizes and most of all...shipping costs.

No worries, there's no room for scimping on the safety part. The PVC pipe I was looking for was schedule 80 though, heavier wall. Anyway, Cannonfuse doesn't ship up here (Canada), but I did just remember that a division of my company uses 1" ID tubes that I think are already 6" long and have a 1/8" or 3/16" wall, which will be fine as I have used 1/8 wall tubes on comets this size before.

Anyway, I'll find what I need somehow and be sure to post a video when I use the cake...probably May

[ST1DinOH]

 

didn't mean to come off like a saftey freak or anything but PVC/CPVC/SCHED 40, ect...it's all bad juju when you are putting comp in it.

 

here's some good 1 inch tube options

 

http://www.cannonfuse.com/store/pc/viewPrd...11&idproduct=80

^nice little RW+B design on them

 

or

 

http://www.pyrocreations.com/inc/sdetail/522

^cut them to any length you want

 

there's lots of other online stores that sell this stuff...might check around for better prices or sizes and most of all...shipping costs. 

No worries, there's no room for scimping on the safety part. The PVC pipe I was looking for was schedule 80 though, heavier wall. Anyway, Cannonfuse doesn't ship up here (Canada), but I did just remember that a division of my company uses 1" ID tubes that I think are already 6" long and have a 1/8" or 3/16" wall, which will be fine as I have used 1/8 wall tubes on comets this size before.

Anyway, I'll find what I need somehow and be sure to post a video when I use the cake...probably May

well hell man anything you can get for free is great!

 

take full advantage of that

 

hell you could even sell them on e-bay for some extra chem money

 

in fact...if you can get tons of thoes tubes i'd be interested in buying some. i was just thinking of ordering some 1 inch tubes to build a big ass reloadable zipper carcass...so if you can come up with a solution and a price send me a PM we might be able to work out a deal.

 

i'd love to get started on this project soon before it gets pushed aside and i run out of time.

[Bonny]

well hell man anything you can get for free is great!

 

take full advantage of that

 

hell you could even sell them on e-bay for some extra chem money

 

in fact...if you can get tons of thoes tubes i'd be interested in buying some. i was just thinking of ordering some 1 inch tubes to build a big ass reloadable zipper carcass...so if you can come up with a solution and a price send me a PM we might be able to work out a deal.

 

i'd love to get started on this project soon before it gets pushed aside and i run out of time.

I don't think I can get enough for free to re-sell... I have a mountain of 3" ID tubes here at work, a quick look estimate of at least 1000 pcs 40-48" long, with a mix 1/4",3/8",1/2" wall. I could sell some of those but Canada post is a huge rip off.

[ST1DinOH]

well hell man anything you can get for free is great!

 

take full advantage of that

 

hell you could even sell them on e-bay for some extra chem money 

 

in fact...if you can get tons of thoes tubes i'd be interested in buying some. i was just thinking of ordering some 1 inch tubes to build a big ass reloadable zipper carcass...so if you can come up with a solution and a price send me a PM we might be able to work out a deal.

 

i'd love to get started on this project soon before it gets pushed aside and i run out of time.

I don't think I can get enough for free to re-sell... I have a mountain of 3" ID tubes here at work, a quick look estimate of at least 1000 pcs 40-48" long, with a mix 1/4",3/8",1/2" wall. I could sell some of those but Canada post is a huge rip off.

thats the beauty of e-bay...they pay the shipping

 

if you happen across a surpluss of thoes 1 inch tubes and want to part with them i'll gladly pay you a fair price for them...but if you aren't swimming in them then i'd horde them all for myself if i were you.

 

[jacob]

Hey I just remembered, if you're looking to build a small diameter reusable cake, Lowes hardwere stores sell straight sticks of 1'' LDPE water line for cheap, I think I paid about $3 for a 5' piece last time I got some, I may be a bit off on the details but it's worth a look.

[Bonny]

Hey I just remembered, if you're looking to build a small diameter reusable cake, Lowes hardwere stores sell straight sticks of 1'' LDPE water line for cheap, I think I paid about $3 for a 5' piece last time I got some, I may be a bit off on the details but it's worth a look.

I'll have to check my other local hardware stores...no Lowes here in Manitoba (yet). I think they have just opened somewhere in Canada. I may just go with the paper tubes for now.

[Bonny]

Finally found some HDPE pipe for this project!

I am getting a friend to p/u as it is a little far to go to get it. The pipe has 1.315" OD and about 1/8" wall. Only cost about $13 for 25'.

My next question is what sort of glue is good for HDPE?

[jacob]

As far as I know there is no glue that works for HDPE, about the only way I know of to bond two pieces is by heat welding, what do you want to do with it?

[Bonny]

As far as I know there is no glue that works for HDPE, about the only way I know of to bond two pieces is by heat welding, what do you want to do with it?

Heat welding in not really an option as it will likely deform/warp the tubes. If you read the topic you'll see what my plan is...

[pudidotdk]

There's really no glue for HDPE.

Screws are probably the only option here, that why I have to install my lift bars in the end caps instead of gluing it on.

[Bonny]

There's really no glue for HDPE.

Screws are probably the only option here, that why I have to install my lift bars in the end caps instead of gluing it on.

I'll be using screws/nails to fasten the end plugs. I should be able to secure the tubes with tape and maybe some contact cement or something to help once they are set in place with a jig to hold them.