14 replies to this topic

[www.oliverbrown.co.uk]

I got my new toy this morning, a brass 3/4" crossette tool, had a play this evening and the first one popped out fine but from there onwards every one has stuck to the rammer where the cross is formed, thus the plugs don't form properly.
I was using Veline red capped with tigertail.

Any ideas what I have done wrong?

In this clip the guy dips the cross forming end in something
The more I think about this I think it may be down to the liquid content of the star mix....

Edited by Cherry Bomb, 12 November 2011 - 12:43 AM.

[Mortartube]

I can't be sure what he is dipping the pump into, but it may be something like mineral oil or even graphite just to add a bit of lubrication to the pump.

[Arthur Brown]

Well with all compounds there is skill in the actual instructions, more than just the recipe! The dampness of compounds determines whether or not the compound will function (esp glitters) and cohere, and remain solid in use. Impact consolidated compounds will cohere with MUCH less fluid that cut or pumped items.

In the video the operator has a cone shaped pile of powder which suggests to me that it is a powder too dry to clump together, maybe not totally dry but certainly not a soggy patty like mass. I have previously seen video of a star maker using a ganged pump tool that used almost dry compound so please don't pass by the concept of near dry pressing.

Yes, it's possible that there is a lubricant for the tool, it's a guess that this would be either veg oil, mineral oil, or even water, having heard of Chinese manufacture, possibly it's either a waste product from elsewhere or the cheapest suitable product - likely water.

Anyone with real knowledge may actually NOT say, but I suspect that there are processes in real Chinese manufacture that do not reflect the "hand cottage industry" that sometimes they may wish to portray.

Tubes rolled by machine, stars made by automatic machine etc are part of my musings.

Edited by Arthur Brown, 12 November 2011 - 12:34 PM.

[helix]

It seems to depend on the comp but you don't need much water at all; the dryer the comp the easier they seem to come off the tooling. I know its not how its shown on the video but I have had more luck removing the internal section of the crossette pump whilst leaving the actual crossette in the tubular part of the pump and pushing it out with a flat ended round bar the same ID as the crossette. This takes longer but the ends of them tend to be better formed. I've tried graphite, parlon and magnesium stearate powder on the crossette tip to try and make them come off easier but didn't have much luck. A mix with 5-7% water content and dipping the end of the tool into a little WD40 worked best for me. Good luck, these are a real PITA to make.

[Pyro.1]

Over wetting will create the sticking issue, also the same problems can come from scored and pitted tooling. try with minimal water and dip the tip in graphite first.

Paul.

[Peret]

I have a tool like that and the first time I used it I had the same problems. Worse, in fact, because I used a titanium composition and it jammed my tool so badly I had to separate it with a hammer. You need a very dry composition - it's best to use a press rather than hammer, as then you can use even less water. I use cooking spray as a release agent, inside the tube as well as on the ram, and I wash and dry the tool after every comet. Yeah, I know how long that takes, but otherwise your productivity suffers more by most of the comets falling apart as you try and extract them. I got over the titanium jamming problem with a hard rubber tap washer under the crossette tip. It's a tight fit inside the tube and wipes it thoroughly clean.

[dan100]

how are you binding the veline red?

[www.oliverbrown.co.uk]

Well you hit the nail on the head! I left the mix out on some paper for about 12 hours and tried again, much better results, still not forming correctly but better, then I left it out for another 16 hours and almost there now, nearly perfect so much so I think by breakfast tomorrow it will work fine!
Arthur, I would totaly agree there may be a few of the Chinese using cottage industry techniques but 99% would be cheap machinery running flat out, caring far more about quantity that quality.
Dan, 75/25

[Arthur Brown]

I suspect that the thermosetting resins used in star compounds as fuel and binder may be rolled but may also be pressed on a tablet press from the pharmaceutical industry.

Now when buyers visit factories in China they are shown the factories that they expect, but I ASK not state are these the real factories?

[Pyro Harold]

This seems to be a good guide: http://www.amateurpy...rossette-stars/

[Atom Fireworks]

I suspect that the thermosetting resins used in star compounds as fuel and binder may be rolled but may also be pressed on a tablet press from the pharmaceutical industry.

Now when buyers visit factories in China they are shown the factories that they expect, but I ASK not state are these the real factories?

Thats a good point that Arthur, from their point of view they COULD show the potential customer the old school traditional techniques to fit with the whole chinese firework manufacture theme, however as soon as the customer puts their order in a factory owned by the same company using higher tech means to mass produce stars ect actually makes the order. Ive disected a couple of preffesional shells and all the stars seem to have been rolled however in cakes ect ?????

[RegimentalPyro]

I think I can answer this seeing as I was the one holding the camera! I have also been plagued by crossettes sticking but found that wiping the tooling beforehand with an oily rag, and also dipping the pin in water helped considerably.

I hope this helps.

[dan100]

Dan, 75/25

at first i thought you gunked the pump up with rg and acetone ive always granulated/screened charcoal comps if i over wet them [this should be suitable for veline waterbound stars [correct me if im wrong]] and let it dry a bit re weigh it etc, for pumping anyway, now im a bit stricter on myself.
ive made some good 1" comets that only need 5% water if you consolidate them hard enough the trouble is it does not look like enough, again screening the comp helps distribute the moisture and squeezing the comp between you fingers or fist it should only just bind , then fall, the presure you apply when forming the finished stars will/should hold until dry, just the nack
i cant wait to get my hands on some crossette tools, i can make some very shiny stars with just copper pipe and a wooden dowell.

dan.

[www.oliverbrown.co.uk]

I may be able to help you out there Dan, I'm in the middle of upgrading my workshop with a bigger lathe and a mill, should be in production by the middle of next week!

Here's the dried blanks, worked pretty OK in the end, just need to test some burst now, was going to try .5g of flash or some FFF B/P

[dan100]

nice stars they look a bit meaty where they break, should be good, on the tools... christmas list .

dan