Nozzle Failure

[skid68]

Check out my gold glitter wheel I set off tonight. It is the Gold Glitter comp from Skylighter. 10 parts airfloat to slow it down. The nozzle is tapered on the inside, and had a 1/4" hole. The other driver that didn't blow out the nozzle looked like it has slag build up. Do you think that is what caused the other nozzle to blow out? I think so because the drivers kept getting faster like the nozzles were getting smaller. Do you think a 3/8" hole would work better, or would that be too big? Also, is it normal for this comp to slag up?

 

[media]http://www.youtube.com/watch?v=y3mYeehuFFY&feature=youtu.be[/url[/media]

Edited July 2, 2013 by skid68

[dynomike1]

That was cool!!!!

[FlaMtnBkr]

What was the ID of the tube? What is the complete formula? Was it ball milled at all? If not were you using fine chemicals or was your KNO3 granular like sugar? What was the nozzle made of? Rammed or pressed? We really need a lot more info, otherwise we would just be guessing like you.

[skid68]

1# 3/4" ID

 

Gold Glitter

Meal D

65

Sodium Oxalate

8

Antimony Sulfide

15

Magnalium, -200 mesh

10

Charcoal, Airfloat

2

 

Screened not ball milled.

Nozzle was kitty litter, rammed.

Thanks.

[Jappel]

Really nice!

[Seymour]

It was lovely! The spritsels were bursting so big and distinct, and you had pretty good power there too!

 

I'm definitely going with that being slag build up causing the blowout, and along with centrifugal force as the reason that glittering was weaker at the end. Other than simply blocking the way and creating a porous cinder that may allow gasses out but catch the sparks, the spinning collects the heavier sparky bits on the wall of the rube as it's thrown outwards and often the sparks never make it to the nossle. You can cut open a fast spinning wheel driver afterwards and find a considerable volume of spark to be gathered in the corner where it collects.

 

Your wheel was going at a decent enough rate that this could occur. It can be avoided by angling the driver more outwards, so energy is going in to throwing sparks out as well as at at 90 degrees.

 

As for the slag buildup that contributed to the nossle failure, this is indeed quite normal for glitter compositions. This cannot be cured as such, but you can treat the symptoms.

 

A layer of a much cleaner mix, such as BP + Charcoal can be added once or a few times to "cough up the slag".

 

Using corning dust or fine grain as part of the meal component makes it somewhat cleaner.

 

As you yourself suggested, make the hole bigger. Personally I have used either 3/8th or no choke at all with similar compositions (though power is greatly lost if you want to use it as a driver).

 

Lastly, there is probably a limit with most glitter fountains in terms of how long you can stretch it out for until the slag builds up that you cannot get past. By keeping the burn time under this limit and by lighting one after the other if a longer lasting effect is desired, one can easily and effectively achieve close to ideal effects for as long as you want.

[fredhappy]

Lovely wheel,I love the glitter.

 

I ve had the same issue with too much thrust..You could either enlarge your nozzle a bit (I use a hand drill), or swap the meal D for screened meal made with pine charcoal.

 

Keep it up,wheels are awesome.

 

Beste

 

fred