Ramming Clay Nozzles

[GrayKat58]

Looking for a little advice on clay nozzle forming.

I'm basically a beginner/hobbyist, working on a small scale for my own enjoyment. I started out casting nozzles for rockets and gerbs using water putty. It produces a nice result, but takes a lot of time and effort. I got some cheapo Wally World kitty litter and processed it down to the consistency of fine sand. I have used this mix for making solid bulkheads and it's worked perfectly. However, I was never really happy with the way they came out when drilling out the hole when forming a nozzle. I turned some aluminum tooling on my lathe to fit in a 1" ID rocket tube (5/16" aperture). The issue I'm having is that when I remove the tube from the tool, the clay at the very end just drops out, leaving a rough surface that's a bit shorter than the intended length. The remainder of the bore is just fine and hard as a rock. I've tried a couple tool variations, adding the nozzle clay in increments, adding paraffin, always the same result.

Anyone with experience in this area? My thinking now is that I need a different type of clay mixture.

Thanks!

[IndianaPH]

GrayKat58-

Let me start this off by saying that, until recently, I have no experience in making fireworks. But, I recently attended a club event and participated in a seminar that showed us how to make gerbs. It was the first time I had ever built anything. I do remember that there was a specific cat litter that was used in the nozzle material and it had graphite added to it.

If you haven't already, you should look at joining fireworking.com Ned's site has a lot of useful information. If you go to the Fireworking 101 tab, I believe lesson #13 is Making Gerbs.

[PyroJoeNEPA]

Try adding a small amount of mineral oil or Vaseline to it.
Also, I know some people that add a small amount of "grog" to their mix. [grog is finely ground up clay from broken flower pots.

[GrayKat58]

Thanks IndianaPH, I should have noted that I have scoured the internet extensively before posting here. I have watched pretty much all of Ned's Fireworking YouTube videos, some several times :) I can see a nicer result is possible, but I'm just not getting it to happen. Being newly retired and on a more limited budget than I am used to, I have been reluctant to add $40 to my already-extensive list of hobby subscriptions. That may be the way I have to go eventually.

Interesting that graphite would be added. Seems like that would keep the particles from adhering, but maybe it's so it releases from the forming tool more easily. Some claim Fresh Step clumping litter is the way to go. I guess I'll try that next. I'm going to accumulate a lot of litter if it doesn't work...

[GrayKat58]

Thanks PyroJoel. If my clay was crumbly overall, I'd be inclined to try the grog mixture. Might try it anyway if I can't find another solution. The crumbly texture seems to only be an issue right at the opening to the nozzle, it's rock-solid just past the opening.

Another thought is that the tube is not springy enough to expand around the end (I'm using thick walled 1" tube from Phil's General Store). I haven't yet tried it on a different size or style.

[displayfireworks1]

Thanks PyroJoeNEPA for answering some of these making fireworks questions. Particularly questions that are not about how to make the biggest and loudest firecrackers. While there is place for that discussion, it needs balanced with other fireworks products. I personally am fascinated with seeing home made fountains. In particular with large, bright , long duration and most importantly it must be quiet. No crackle etc. Years back some of these large cone fountains made their way into the 1.4 class. The large gray cone I believe we called them. It would be probably be a great starter project.

[belmec3825]

Looking for a little advice on clay nozzle forming.

I'm basically a beginner/hobbyist, working on a small scale for my own enjoyment. I started out casting nozzles for rockets and gerbs using water putty. It produces a nice result, but takes a lot of time and effort. I got some cheapo Wally World kitty litter and processed it down to the consistency of fine sand. I have used this mix for making solid bulkheads and it's worked perfectly. However, I was never really happy with the way they came out when drilling out the hole when forming a nozzle. I turned some aluminum tooling on my lathe to fit in a 1" ID rocket tube (5/16" aperture). The issue I'm having is that when I remove the tube from the tool, the clay at the very end just drops out, leaving a rough surface that's a bit shorter than the intended length. The remainder of the bore is just fine and hard as a rock. I've tried a couple tool variations, adding the nozzle clay in increments, adding paraffin, always the same result.

Anyone with experience in this area? My thinking now is that I need a different type of clay mixture.

Thanks!

I too am a beginner at this hobby and love it!. From what i've learned and tried now with success, is the kitty litter clay. I grind it in a cheap coffee grinder i bought at goodwill for $1.99. I paid $1.00 for the kitty litter at the dollar tree and presto, i have clay powder that works great for compacting. For smaller or weaker tubes that could possibly split under force, i sift the litter to use the finer stuff.

I'm by no means a pro at any of this, but so far this work pretty good.

[displayfireworks1]

From 2013.
I always liked this video of Harry using a coffee grinder and chemicals.
.

https://www.youtube.com/watch?v=Q7pd66KGDjc

[GrayKat58]

Thanks to all who have offered suggestions. I obtained some clumping cat litter from my daughter. It had a finer consistency than my generic litter, so I didn't process it any further on the first try. I still got nearly the same result as before with the material at the very end crumbling off as I removed it. Next try will be processing the clumping litter to a finer powder and possibly making a tool with a radius at the base. Doesn't seem like this should be so hard....

http://www.pyrotalk.com/bulletin/attachment.php?attachmentid=5428&stc=1

[GrayKat58]

OK, I think I have resolved this issue. What was happening was that I put a measured amount of clay in and rammed it with my wood dowel rammer. A small amount of the clay was getting up inside the hole of the rammer and preventing it from fully compressing the particles. If I had just given it an initial compression then dumped out any loose clay, it would have all been well. In the mean time, I made a new die with a radius at the base of the aperture and also a slight taper to allow the nozzle forming portion to exit cleanly. Also deepened the hole in the rammer a bit just to be sure. I'm now getting the results I expected from the beginning.
http://www.pyrotalk.com/bulletin/attachment.php?attachmentid=5435&stc=1

[PyroJoeNEPA]

Great looking nozzle. Glad you got the issue figured out. Also, nice job on the spindle you made.

[GrayKat58]

Great looking nozzle. Glad you got the issue figured out. Also, nice job on the spindle you made.

Thanks. Nice to have a lathe. :D