As far as I know "the 18mm ply box"was there to hold sufficient BP for bigger users while still being carryable. The required properties being that one botttle could flare off without detonation without setting off the rest. MY UNDERSTANDING is that you can store BP on any container that doesn't confine and that deters propagation to near by containers, The powder store must be of restricted access but NOT too closed so that a small fire doesn't become contained and go high order.
I don't see a problem with having a scaled smaller version, or a version with fewer holes.
BUT it's all best determined with detailed input from your ELO.
AFAIK the Society Company Limited still exists and has funds but no functional membership to keep the funds in the black and the basic admin chores done.
I have a UK interest but go to the USA to do things that are lawful there but not here.
There is no reason why the Society shouldn't attract members BUT there needs to be a good number of people who want to be in a revival for the long term knowing that the UK system is not friendly and actually doing manufacture is best done in an overseas place where their laws permit.
IF there are at least twenty people interested in running the society, fulfilling the official roles as Chair, Secretary etc, and willing to do live pyro in the USA then the society has a future.
One of the tasks the Society once had was to research the hundreds of historic old fireworks companies that once supplied the UK retail market. There was information posted to the forum once which will vanish if the forum goes. Restarting this project and finding a public library willing to hold the product (book!) would be a very interesting project.
Take a 16" pair of hemis, find which way they fit best (they are never truly spherical!) and cut off the top of one of them.
Drill and tube the fuse holes. and place the 3" shell inserts.
add tissue inside the 3" shell layer. Pour willow stars into the interstitial gaps between the hemi and the inserts. Then add an instant fused 6" shell in the centre and fill the space between tissue and the 6" inner petal with break on rice hulls (available from USA rice growers!). Then attach the upper ring of hemi and build up the tissue, inserts and willow stars to the top, then firmly fit the lid of the hemi.
After an initial pulling together and taping, the ball was passed to someone with a wasp and for the donation of lots of tape, it came back well wrapped and ready to fuse. The magnets were found and removed and the three pieces of time fuse fitted and crossmatched. 3lbs of coarse lift was in a bag and had a long QM leader and fixed to the bottom of the shell. Then I had to plait and affix the handle and the lowering rope so that it could be lowered gently into the tube. When it was all finally dried in the sun it went to the ready box for the dug-in mortar site and was dropped into the mortar in turn.
Additionally the mortar tube was so far in the ground that there were steps down to the muzzle! A muzzle break would probably have been retained!
That formula is close to "tiger tail" which performs like a dud on the ground, but performs well when blown through the air. Try the star as you wish to use it and cut it small til you are confident that it will burn out before reaching the ground.
After several years nurturing a friendship, an invitation was made available to me privately, to go o the USA, to a site licensed by BATFE and the local authorities there, and build a shell!
This was something special of an invitation so it had to be something special of a product. PLUS I had to travel there totally inert, and return by air totally inert too. BUT ingredients could be ordered to be delivered at the site.
Here is the video, This is what a Brit did under a BATFE licence in the USA.
This was my first attempt at a shell! But a lot of design effort went into it. Probably 100 people from the USA were making things under the licence, some were recognised as being good builders and one UK builder made his mark.
I'm in a truckstop on the way to LAX at the moment, so may not reply for some days.
I'll continue writing up the build with a couple of pictures from home, maybe next week.
NO I will NOT share the invitation unless I know you well. No I will not advise you what to do. A 16" shell may be above 100gNEQ -I could barely carry that shell.
To all the ELO's watching, enjoy! It's pretty and it was all lawful in the BATFE licensed place. I have the skill to do it but the wisdom to NOT do it in the UK! I have to get through US and UK border protection yet!
The big issue is that to supply to an EPP certificated individual the vendor has to be and EPP certificated supplier. When you normally send out IBCs of various chems to businesses why would the big companies jump the hoops to become an EPP certificated vendor for the odd 100ml - 1litre. Also the ADR transport of chems is viable in tonne quantities but in 100g bottles expect a £50 surcharge.
Ebay may still be your best bet
For a smaller vendor the test of "business" may be more flexible but will include business paperwork and the ability to receive packages between 0700 and 1630 -typical goods inwards times
One of the "workshop not lab" means of telling the carbon content of steel is to hold a sample to a grinding wheel and watch the sparks, High carbon lots of nice sparks - low carbon nothing interesting.
Small tube salutes or maroons are as safe as you can get in pyro, BUT there is always a tiny risk of incident. Pyro is NOT inert so there is a risk, but it's small. BUT this incident is usually BAD and there is a lot of energy in flash.