Spolettina Fuse Delays
Spolettina (or Spolett.ina to give its original Italian name) is a time delayed fuse intended to join fireworks such as shells by their quickmatch fuses and provide a reliable and accurate delay between each one. We tested out some samples from Komodo Fireworks, the authorised UK dealer.
Spolettina in detail
Users of Pyroclock will be familiar with the concept of using fuse delays. The Spolettina system at first look is slightly simpler, having just one in and one out connection. The various delay times available range from 1 to 5 seconds and are colour coded for easy recognition.
The principle use of timed delays is to allow one single cue on the firing system (or one external fuse) to fire a whole sequence of timed shells or other fireworks one after the other. Where accuracy or consistency is required this type of delay has many advantages to manually cutting slower fuse such as green visco or PIC for those lucky enough to still be hoarding some.
According to the Spolettina website, the internal delay fuse is the “Portugese” type and it goes on to say that it is “well known and appreciated in the fireworks industry for its accuracy and reliability.”
Pyroclock users will also note the lack of a vent hole. This is intentional, as Rob Sosbe, Director of Komodo Fireworks explains: “These delays do not need a vent hole to work and create sealed joints. Hot gases escape through the sheath during firing and this in turn eliminates the problem of leader whip from the firing shell breaking the chain.”
The sheath itself is waterproof and flexible even down to -55C which will please those of you lucky enough to be displaying over the wonderful British bonfire night season with every sort of bad weather it can throw at you.
The delays vary in price depending on quantity ordered and the time delay, but expect to pay in the region of 30p per delay.
Spolettina in action
Connecting quickmatch to the Spolettina delays is very simple as Rob explains: “As you can imagine we have done a considerable amount of field testing – over 12 months – on this new product to find the best techniques for fusing.
“We have found that the simplest and 100% reliable (so far) way of linking pipematch leaders is to bare approximately 5mm of blackmatch on each leader before inserting into the delay, crimping the pipematch in place with a hog ring tool and aluminium rings.
“Cable ties are equally effective although a little more time consuming and costly. The ring tool however takes literally seconds to secure the fuse into the delay.
“We have successfully managed to link up to four leaders from a single delay and the crimping tool holds everything nicely.
A hog ring tool is commonly used in fencing and is like a staple gun that crimps a metal staple around into a tight ring (these are available from Komodo along with the Spolettina).
“Our initial experiments with the delays demonstrated how simply a chain of shells can be put together and obviously as it creates a flexible chain there are no issues with casing up your finished shell chains for shipping out to site. No more lengthy plastic strings as you get with Pyroclock!” Rob added.
We conducted two tests with some Spolettina delays. It should be pointed out these are not exhaustive tests and in particular are not long term experiences over a number of shows. Our busy Fireworks Forum remains the best place for professional firers to discuss their experiences of this product going forwards.
For the first test a number of delays were given to a professional crew who kindly allowed me access to film them in action. From these set up shots you can see a total of three shells were fired using two delays (between shells 1 and 2, then between 2 and 3).
No particular instruction was given to the crew on how to insert the fuse and as you can see they have all been secured with cable ties.
Both delays performed well as you can see in these photos and video. Note the initial shell was fired at the same time as the delay was instigated to shell 2, which makes assessing the timing difficult, but I have included a slow motion replay so you can study it in more detail.
For the second test I simply attached various lengths of quickmatch in series to simulate a chain of shells. Fusing was intentionally lax in some cases to test whether having a gap between the blackmatch and the internal delay fuse mattered. I also stripped the outer paper off some quickmatch joints where it was doubled over and inserted, but others just had a cut along the bend. All of them worked fine.
Creating a chain is quite simple once you have some practice. You take the shell’s quickmatch leader and bend it over a little way from the end. Making a cut in the bend (or stripping off some outer paper), this bend goes in the “out” end of the previous delay. Then, the free end of quickmatch is inserted in the “in” end of the next delay. No extra lengths of quickmatch are required unless your shell leaders are short! When each delay burns through it ignites both the shell and the next delay at the same time.
As you can see in this video the delays once again worked fine. The last one is edited off this clip however because I had secured the quickmatch ends on the back of the wood – when the second to last one fired it cross-ignited the quickmatch coming out of the final delay. It’s easy to explain this here but once the clip gets posted around this fact would be lost and people would wrongly think the last delay fired right through immediately. I studied the slow motion of this clip in detail and the flash from behind the wood confirms a cross ignition from the exposed ends of the quickmatch which can be followed through to the final end of the last delay. But to avoid confusion, this part is edited out of the clip.
Conclusion and further information
Based on limited testing of samples this product shows huge potential and not surprisingly has been a popular topic of discussion in the Professional section of our Fireworks Forum.
Komodo Fireworks, the authorised UK distributor, is happy to send sample packs out if you have an interest in trying them for yourself. You can view their website here for more information about them and their contact details.
You can view more of our Spolettina photos in our Flickr gallery.
An English translation of the Italian Spolett.ina website can be found here.
With thanks to Rob Sosbe at Komodo for the samples and his time, plus a big thanks to Colin and the Dynamic Fireworks team for allowing me to squeeze a few of these into one of their shows to film for the first video.