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helix

Member Since 02 Apr 2009
Offline Last Active Mar 16 2019 09:47 PM
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#82479 Comets

Posted by helix on 21 July 2014 - 11:12 PM

Yes married comets are normally a colour and a streamer type composition both the streamer and colour sections are pumped and then they are pasted together using a couple of turns of lightweight pasted kraft paper.  Both ends of the comet are bare and are lit from the burst, the coloured wafer would normally be primed.  You need to make sure the kraft paper wrap is tight to the sides of the comets otherwise fire can pass inside the paper.  The colour wafer and the tail comps should burn for about the same time so you get a streamer effect with a coloured head, very similar to a cavity comet but you dont have so many issue with the compatibility of compositions as you can isolate the colour comp from the streamer comp.

 

They take longer to make than cavity stars/ comets but should stay together better.   They can be quite messy to make, especially if your star comps use a water soluble binder as the paste in the kraft wrap starts to dissolve the sides of the comet.  You can paint the sides of the comets with some NC solution to stop this. 


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#81976 Looking for Paper

Posted by helix on 15 April 2014 - 11:22 AM

Something along the lines of acid free tissue paper perhaps would work - 

 

http://www.globepack...143&network=pla




#81905 Small star rolling machine

Posted by helix on 09 April 2014 - 09:04 PM

I think it would be quite challenging to roll stars with a tyre that would fit in a rock tumbler.  Making sure you didn't over wet the cores etc would be difficult also if you start with very few cores then its hard to get them rolling.  You might be able to use parlon screen pressed stars as cores and roll over the top of these.  You can also roll the stars in a mixing bowl by hand if you have plenty of time.

 

I have a small roller that I made out of an old expansion vessel from a hot water cylinder that I cut an opening in the end of it and filled/ adapted the other end to mount it to a variable speed motor - it works quite well, the vessel is about 350mm diameter.


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#80809 1lb Rocket with Header

Posted by helix on 19 November 2013 - 09:22 PM

That was some break! - what did you use for burst out of interest?

 

Really good to see some videos on here again.




#80804 CATO's

Posted by helix on 19 November 2013 - 04:35 PM

I would agree that although NEPT are expensive, they are hard to beat - especially when you take into consideration the time and effort involved in making the motor and heading.

 

I don't know if any one else here has been experimenting with waxing the inside of the tubes as per Dave F's method.  Ive been trying this out and have had pretty impressive results.  Using straight 75/15/10 BP on a longer than standard 1lb BP spindle without a CATO.  The motor was pressed to 9000psi on the comp using a hydraulic press.

 

I have one of Peret's test stands and recorded the thrust:

 

http://www.pyrobin.c...1lb rocket .jpg

 

I doubt it would be possible press straight BP on a 1lb motor like this without the wax.

 

If you are having CATO problems its worth a try.

 

Projected height lifting a 4" cannister shell if anyone is interested:

 

http://www.pyrobin.c...b rocket ht.jpg


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#73485 blackpowder wont ignite in confined space

Posted by helix on 13 June 2011 - 10:16 PM

Proceed with caution if you are blending the whole lot in a coffee grinder - you may find that some of your bp makes its way to the innards of the grinder, ignites and ruins your day.


#72959 New pyrotechnics book!

Posted by helix on 17 April 2011 - 07:28 PM

Exciting news? - I don't think so, bad news more like.

So I can learn how to jump into a hedge, make fake ID, syphon petrol and conceal alcohol as well as make fireworks - doesn't exactly portray fireworks in a good light.

Books like this can only cause trouble - what's the target audience - yobs/ halfwits?