Testing results and question:

[PyroWalker]

Last night I did some testing to get lift time on some shells, and since I had everything set up, I shot some things that didn't fire in my shows last year. I needed to clear out the space.
Both cakes, Willow Forest by SkyBacon fired. However, the timings were incredibly different! Last year, I had them timed at 34 seconds based on some averages of videos posted online. In my show, they fired about 29 seconds. Last night, one fired at 14 seconds and one fired at 18 seconds.

For you more experienced pyros.... Any scientific reason they may have had such a dramatic difference? They were all from the same case. Does storage in a dry but not humidity controlled environment make a difference over time?

I am hoping I don't need to re-time all my stored product.

(And yes, I realize that consumer cakes will have differences and it is all imprecise guess work for timing. I was just curious as to why such a big difference!)

[PyroJoeNEPA]

If anything, long term storage will slow a cake down due to "wicking" of moisture in the fuses & lift powder---but will not increase the firing time.
I suspect the cause for the faster burn time falls with the actual assembly of the cake in the factory--they are notorious for sticking any extra interconnect fuse they have between tubes in a cake if they run out of the proper burn time fuse. I've seen it many times over the years. It is all about getting the number of cakes required for the daily production run turned out by the end of the shift.
Even with the 1.3g cakes we use for shows the timing varies. So, the moral of the story is not to expect consistency or accuracy in cakes.

[displayfireworks1]

Consumer fireworks just are not build to those exacting specifications. Most the time we hope they perform the same one year to the next let alone fire at the exact same time. LOL. It my understanding this is where Articles of Pyrotechnic products may give you more accuracy.

[hatsgoods]

it might be due to fuse mostly never has a study burn time like others said. my only thought to that is its hard to get the powder to stay the same. as they make so much powder its hard to get the verry same mixture by the grain.

[Birdman]

I have to agree with the others. Although, I find it unusual that there would be such a big difference with cakes coming out of the same case. Even more odd is that these were 200g cakes. I find smaller cakes to be more consistent then larger cakes with more shots. I have to assume it was inconsistency in the manufacturing process.

[mguerra]

Doesn’t matter why, you just cannot rely on consumer cake timing, period. This is why I step script all my shows. Put four identical cakes on 4 stations and fire them on one cue. They won’t sync at all after the first shot. This is why big cake finales always have raggedy straggler endings. If you step script the show, you just hit the step button as each cake(s) ends, no dark sky. For a hard sharp ending to a cake finale, you have to shoot a bunch of 5 second cakes. Which you can buy, or make… Here’s how one guy makes cakes. If you use super fast fuse you can make 5 second or less cakes.
https://youtu.be/Du7gy_Rd_k8

[PyroWalker]

Doesn’t matter why, you just cannot rely on consumer cake timing, period. This is why I step script all my shows. Put four identical cakes on 4 stations and fire them on one cue. They won’t sync at all after the first shot. This is why big cake finales always have raggedy straggler endings. If you step script the show, you just hit the step button as each cake(s) ends, no dark sky. For a hard sharp ending to a cake finale, you have to shoot a bunch of 5 second cakes. Which you can buy, or make… Here’s how one guy makes cakes. If you use super fast fuse you can make 5 second or less cakes.
https://youtu.be/Du7gy_Rd_k8

I have shot several pyromusicals and have had some minor timing issues with consumer cakes, but nothing this significant. My finale endings also have always been on point. I used Cobra and script with Finale 3D. I use a lot of 1.4Pro, but the cakes are almost 75% consumer. These timed great in last year's shows, but I am guessing the storage and possible damage done to them during shooting may have played a role.

[Scotty Rockets]

Regular fuse versus true time fuse. Most C uses regular visco for the time fuse. However there are some 9 shots and most NOABS use true time fuse. True time fuse gives a near perfect break after lift. I’ve built my own shells with time fuse, specifically lampares and I get near perfect timing every time.