Reloadable Cakes

[Falcon2]

I have an idea lately for relaodable fireworks cakes;

 

Some of use haven't got access to thousands of cheap cardboard tubes of every size we can just through away after 1 use. So what I'm wondering is can:

1) Cardboard tubes be used multiple times, maybe after coating in epoxy or polyurythane/varnish

2) Is it possible to use other materials such as polyethylene to construct cakes of small diameter tubes say 7/8" tubes which can be used indefinitely

 

Do you through away cake tubes after 1 or 2 shots or are they resilient enough to withstand multiple shots?

[dagabu]

I have an idea lately for relaodable fireworks cakes;

 

Some of use haven't got access to thousands of cheap cardboard tubes of every size we can just through away after 1 use. So what I'm wondering is can:

1) Cardboard tubes be used multiple times, maybe after coating in epoxy or polyurythane/varnish

2) Is it possible to use other materials such as polyethylene to construct cakes of small diameter tubes say 7/8" tubes which can be used indefinitely

 

Do you through away cake tubes after 1 or 2 shots or are they resilient enough to withstand multiple shots?

 

Yes, cardboard tubes need to be treated if you use then multiple times. I have been told that Minwax Wood Hardener is the best and I have heard the same about waterglass. I use fiberglass and HDPE all the time and I am confident that the fiberglass can be reloaded as much as I like but the HDPE starts to melt and go egg shaped with multiple firings.

 

-dag

[nater]

I have noticed HDPE will get soft if you reload and fire from it without the mortar cooling down first. If you only use it for one shot a show, it will last for quite a long time.

 

Fiberglass seems to hold up to reloading and firing in the same show a little better, but has other drawbacks. The lip on the open end of the mortars tend to break off ofer time. I have also seen fiberglass mortars shatter from a malfunctioned shell and throw out sharp pieces. For this reason alone, I do not use fiberglass mortars.

 

Carboard starts to unravel over time, but it can been treated in various ways to prevent this. Several people in our club reuse spent cake tubes in their projects.

[pyrojig]

Yes, cardboard tubes need to be treated if you use then multiple times. I have been told that Minwax Wood Hardener is the best and I have heard the same about waterglass. I use fiberglass and HDPE all the time and I am confident that the fiberglass can be reloaded as much as I like but the HDPE starts to melt and go egg shaped with multiple firings.

 

-dag

 

 

 

 

This is great idea. I too use spent tubes from the cakes and reload them. Most of the time they are in pretty good shape depending on what burst they use. I Love the idea of minwax to harden the tubes. I have had great luck with it in building bullet proof rocket tubes. Great stuff!!!

I imagine that the tubes if using a bp burst could be used several times. I like a hotter break, and therefore end up destroying my tubes every time. I have a great source to free tubes after firing professional shows, I take the fallout tubes and store them for future use.

[dagabu]

Fiberglass seems to hold up to reloading and firing in the same show a little better, but has other drawbacks. The lip on the open end of the mortars tend to break off ofer time. I have also seen fiberglass mortars shatter from a malfunctioned shell and throw out sharp pieces. For this reason alone, I do not use fiberglass mortars.

 

They turn to powder mostly and then you get "glass-spiders" if you are too close but for re-loadable mortars, they are the best choice.

 

-dag

[Mumbles]

Pyrojig, I think they were talking about mortar tubes here, not actual insert casings. In my opinion if you can reuse insert casings you're not doing it right

 

One trick I've heard with plastic tubes, and maybe fiberglass too, is to put a short piece of metal tubing or a rivet in the fuse holes in the bottom. It helps to prevent the fuse and lift from enlarging the holes over time. As long as you're only firing once per night plastic should last quite a while with very little maintenance. The tubes will need to be occasionally cleaned out.

 

With the paper tubes I was told to soak them with calcium chloride, dry, and then fill with sodium silicate. This produces the insoluble and refractory calcium silicate on the interior. They wont last forever, but probably close to it. I really don't see any reason you couldn't do the same treatment on the outside instead of coating with linseed oil or some other waterproofing coating.

 

http://www.pyropage.com/Misc/cardboard.html

[AdmiralDonSnider]

I too use found cakes to test my comets and stuff. They last a while depending on the quality, but the first thing that desintegrates is the clay plug in my experience. The fuse hole is also enlarged (see Mumbles post).

 

The gold standard are reusable aluminum racks. See my older thread:

http://www.amateurpyro.com/forums/topic/3923-reloadable-bombette-batteries/page__p__54377__hl__%2Breloadable+%2Bbombette__fromsearch__1#entry54377

[nater]

They turn to powder mostly and then you get "glass-spiders" if you are too close but for re-loadable mortars, they are the best choice.

 

-dag

 

I thought the same thing until I saw a premium consumer canister shell shatter a fiberglass mortar, sending sharp pieces of shrapnel flying. It wasn't thrown as far as PVC, but it was still sharp jagged pieces of fiberglass. However, if you are reloading and firing during a show, I don't think any other type of material would be better. HDPE gets too warm and deforms and cardboard will catch on fire with too many reloads. Personally, I do not reload in a show. I will during club shoots where shells are launched one at a time, but we try to bury enough mortars so they can cool down in between shots.

 

I'm getting a little off topic though, for a "reloadable cake" I'm assuming the OP means something he can load up, fire one day, then make more inserts and fuse it up again for another day. I don't see this being much different than any other type of rack, so cardboard, fiberglass, and HDPE would be appropriate.

 

 

 

[pyrojig]

That is a nice rack. LOL no pun intended.

I saw a great tutorial on Dans site I believe... They used hdpe tubes ( may have been pvc) and a passfire brass tube through the base of the fanned tubes. Im sure they where only safe for the use of light bombettes or comets.

You are correct about the clay plugs. One way to seal it is to use hot glue when re-fusing.

I really never have cases survive the burst.

 

 

@ Mumbles

 

I believe that the the minwax could be used for both firing tube and shell as well. It would keep the tubes reusable for quite some time. For the shells the added strength should improve burst and star spread for the small shells.

 

I too use found cakes to test my comets and stuff. They last a while depending on the quality, but the first thing that desintegrates is the clay plug in my experience. The fuse hole is also enlarged (see Mumbles post).

 

The gold standard are reusable aluminum racks. See my older thread:

http://www.amateurpy...h__1#entry54377

[Falcon2]

Ok thanks everyone,

What I have been using so far, is tubes coated with west systems epoxy. Creating a sort of cardboard polymer. I seal all of the inside of the tube and the muzzle. This soaks in to the cardboard but probably not as much as wood hardner, creating an inflammable really hard surface, nice and smooth too!

I was trying to see if theres a better option but it looks like cardboard is the way to go.

 

I was looking at these tubes for a reloadable 7/8" cake so that is pretty much cardboard or HDPE.

 

 

I believe that the the minwax could be used for both firing tube and shell as well. It would keep the tubes reusable for quite some time. For the shells the added strength should improve burst and star spread for the small shells.

 

 

One way I have always though to improve shell bursts was to make it so the casing fails at around the same point as the plugs whether they are clay in the case of bombettes or something different in the case of canisters. This has worked for me pretty well so far - I don't even glue my bombette tubes - a piece of masking tabe on the outside is it! I get pretty nice bursts, but I haven't got any photos yet. If you strengthen the casing too much your only going to get end plugs blown off and a dodgy burst.