How prime cylindrical stars ?

[ronmoper76]

Simple question (ha!). Has anyone tried prepping a tool full of powder, lightly pressing it, then adding a layer of a prime comp and pressing it all? Maybe it's a way to add a precise bit of prime to one end of a cylinder star.

I have contemplated it often but never tried because i assumed only lighting a star by its ends would seriously impact burn times. I made my first comets last night and i thought about trying it with them. I might just make a couple today and find out for myself

Edited April 30, 2021 by ronmoper76

[Mumbles]

It can and has been done. Generally it's not all that time effective, so it's not very widely practiced. This is in effect a sort of married comet. The same factors apply to this as they do to them. Generally speaking, different compositions tend to have different drying and shrinkage rates. This leads to the separation of the two layers or wafers often. It'd probably work better with charcoal or glitter comets with a BP layer on top than it would for say a perchlorate color composition and BP. As Ronmoper kind of got to, this may also require pasting the sides to ensure everything has even ignition. If you're already going to do that, dipping the surface into BP slurry and BP grains is probably faster and easier. I see it most often used with single fire comets. Still, this is fairly rare to see. I've seen it experimented with in a commercial plant, but I don't know if it ever really went into practice or if it was still too impractical.

 

This has also been used to protect star plates from abrasive metals. The presence of titanium can severely gall star plates. The biggest issue is when it gets between the plunger and the plate and is forced down. This often causes deep scratches or seizing of the plate. One of the multiple tricks to get around this is to do about what you described. Load the titanium composition and lightly tamp it down. Then load a small amount of the same comp without titanium on top. Pressing this generally prevents titanium from migrating up where it can cause problems. In essence it acts as a kind of buffer comp. Being the same composition, more or less, there are minimal issues with cracking or separation during drying.