Sources for various sized tubing?

[AzoMittle]

I want to try making my own cake, and not a 500g cake but more than a tad bit larger. I plan to make it reusable by following Dimock's instructions. http://www.pyropage.com/Misc/cardboard.html

 

Who is a good (read: cheap) source for tubing? Roughly, how thick should the walls be? Parallel vs spiral matter at all?

[pyrokid]

500g cakes top out at 2.25" shells, so I would imagine you are looking for tubes in the 3" range. I suggest looking for discarded plastic [vinyl iirc] wrap tubes. A business in my area gives them away for free. They are heavy gauge, parallel wound tubes with internal diameter ~3.05" and outer diameter ~4.05" [and length ~15'].

 

The Chinese frequently use spiral wound tubes in their cakes but I think parallel is the way to go for durability and maximum strength.

Edited March 15, 2016 by pyrokid

[AzoMittle]

I was able to get some 4" and 5" spiral in 6'+ lengths from a carpet supply, it was mixed quality but beggars can't be choosers. I'm looking for tubing specifically for stars (< 1") and comets (2.5"). I don't mind paying for it as long as price isn't exorbitant.

[Mumbles]

You may want to look into Phil's website for small(ish) sized tubes. http://www.ihaveadotcom.com/cart/index.php?main_page=index&cPath=72_118&zenid=vpsva7f3q6j8n45v0g1p7kblv1 They're fairly inexpensive, and fairly strong. The treatment outlined by Myke Stanbridge will certainly help too. You may want to consider using fiberglass or HDPE for the larger sizes too. I think it'd cut out a lot of headaches, and add an extra degree of insurance that everything will work, since these will likely be unsupported from the sound of it.

 

How were you planning to fuse these? If you were considering chainfusing like normal cakes, I'd suggest an extra treatment with waterglass around the fuse hole to give extra protection. I've read of people using metal ferrules.

[AzoMittle]

Chain fused with visco/QM, I already have a bunch of brass grommets so I was going to use those.

 

I still need to figure out how I'm going to support it, but I do plan to; preferably such that I can easily refuse it, so probably in a way I can just pull out entire rows/rings of tubes at once all together and then just slide them back into place. Maybe like a mini mortar rack.

 

Hoping to make a Devil in the Tailors at some point, but baby steps first. At Western Winter Blast there was an interesting little C-class cake from Brother's called Minigun Ammo, I'd like to make something like that too but using 2.5" comets and 4" shells instead; we've all heard of 500g cakes, I think it's time for a 500kg cake.

 

 

edit: Also trying to work out plugs, I'm thinking wooden, or epoxy mixed with sand.

Edited March 16, 2016 by AzoMittle

[lloyd]

Azo,

For years, I had a contract to refurbish reusable cakes for a major theme park. Even HDPE tubing suffered pretty significant wear and tear over many firings. (good for about ten or twelve firings before needing some serious rebuilding work).

 

I'd say paper - period - is NOT a good candidate for reusable cakes, no matter how you treat it or grommet it. Ours were plugged with a hot-melt adhesive, captured by wire threaded through the tube bottom before plugging, but I don't think that was the best solution... just expedient at the time.

 

I'd go with HDPE, plugged with wood (bolted), and with replaceable grommets for fusing. You can get by with pretty thin-walled HDPE "coil tubing", if you're willing to spend the time to straighten it. If not, the same tubing is available in 'sticks' from some dealers. We went with coil pipe, because we used so much of it (hundreds of cakes in the cycle at any one time), but sticks are easier to deal with in terms of being straight, and amounts you have to buy at one time.

 

Lloyd

[AzoMittle]

Lloyd if you don't mind my asking what about the HDPE needed rebuilding? Did it crack or just get caked up with dirt from firing or warp or what? I thought HDPE would last for years because at the club shoots we're dropping shells constantly for hours each night, there are a lot of them that get rotated through though so maybe I just don't notice it.

 

Good to know though, HDPE it is.

 

10-12 is actually a decent amount for my purposes; I figure I won't be shooting from it more than a handful of times a year, and with 2 or 3 cakes that would probably last me a few years, by which point I'll probably want to build something different anyways.

[lloyd]

Azo, they had to be cleaned after every firing. In fact, part of the choice to use hot melt for plugging was because they could then be immersed for washing.

 

Even though we scuffed up the inner bore in the plug area, some plugs would let go. We generally would replace the whole tube if that happened.

 

The mouths would slowly distort, usually curling inward, which reduced the mouth diameter. That required reaming at least once over a cake's life..

 

Some tubes would survive four to six firings, then develop splits (don't know if it was a defect or just material fatique).

 

Fuse holes would enlarge, and in HDPE, that's more-or-less unrepairable, so we very soon started grommetting the holes.

 

LLoyd

[schroedinger]

Azo for easy fusing you can use small diameter metall tubing that goes through a whole row. Cut a hole into the tube so that the hole is inside the tube. This way when fusing the cake you only need to insert a piece of match, visco for slow firing and black match for instant fusing.

[Arthur]

Rumour and youtube has indications that the Chinese are already making monobloc cake cases out of papiermache. these should have openable fuse holes on the bottom so the inner tubes are easily re-fused. All depends whether they are coming into your country and in sizes that you want to use.

 

Plugs are price sensitive! wood plugs cost and have to be glued in place in paper or nailed into plastic tubes. I've used polyester resin filled with hot dry sand easily. -Mix the resin cold for long pot life, add hot sand so speed the cure.

[schroedinger]

Arthur do you mean the pyromould system? Yes they are bottom fused, and can easly be refused after you burn one. Much faster then building a cake the traditional way and very reliabel.