Kitty Litter as nozzle mix?

[Swede]

So curves in the exit nozzle do nothing? Darn... I always thought they looked good. It makes sense... I think photonics is getting way beyond what we are trying to do!

[dagabu]

So curves in the exit nozzle do nothing? Darn... I always thought they looked good. It makes sense... I think photonics is getting way beyond what we are trying to do!

 

Yes, a bell will make for better transition so the pressure within the motor can be relieved and thus a thinner wall tube can be used. I'm sure you know what a venturi is right? If the convergence and divergence are steep angles to the nozzle, pressure builds on the convergence side and the divergence side doesn't create the vacuum it should further causing a pressure back up.

 

If the convergence is at a steep angle to the tube wall, the convergence is smoother and the divergence being steep also causes more vacuum and thus less back pressure.

 

The real test comes in pounding a blunt nozzle in a tube and drilling the orifice and core after your done. Take both motors and fire them. If you powder is any good, the blunt nozzle should cato. Make one with a convergence but no divergence and you should still see a cato.

 

Now, this is good for BP, I have no idea about anything else but sugar rockets and they all have graphite nozzles with predetermined convergence and divergence angles.

[Ventsi]

I got some bentonite clay from UG, and I must say its terrible. It does not compact at all, nada. I have a bit of food grade bentonite that I picked up a while ago left, but its not going to be enough.

 

Is there anything I can do to make the crappy clay work?

[firetech]

I believe you that it does not work, but thats very odd for bentonite...It should compact very easily, even when pinched between your fingers. If it doesn't pack on its own its probably useless (sorry) however you might want to try adding a 3-4% paraffin wax to it. Just melt down the wax and stir in the clay. Skylighter sells a bunch of chems for nozzle mix which are very common in pottery. I believe a few of them are grog and kyanite. Neither of them are really necessary, but they certainly won't hurt and if anything they will improve your nozzles. I believe it's kyanite that is essentially smashed up pottery which you could really make yourself-you won't need much. Grog you'd have to buy I think, but they are both readily available from pottery stores. Seattle Pottery Supply sells them both in bulk at very cheap prices.

http://www.seattlepotterysupply.com/Mercha...tegory_Code=RMP

The prices for the individual chems are listed alphabetically in the left hand margin. If you look

through they have some pyro chems too but I'm not sure of the purity.

 

Ventsi I've used bentonite and kitty litter before and I have really seen no difference. I haven't done any high pressure testing, but I've never gotten so far as to say that one nozzle mixture would work and one wouldn't.

[Ventsi]

It compacts, but even after I ram the clay into a tube i can push it out as if I had just rammed a bunch of flour in there. I'll try a proven nozzle mix formula and report back. If nothing works I'll go grab some fresh step.

[Eric70]

That's weird about the clay not working out well.

 

It has been stated one way or another in this thread but here is another angle:

 

Here's a link to a tutorial on nozzle clay mix. My mix has been based on it, at least proportionally, and works well:

 

http://www.skylighter.com/fireworks/how-to...-nozzle-mix.asp

 

The only difference is that I obtain my bentonite from the red bag of Special Kitty and grind it up to a fine powder in a coffee grinder. The grog is from smashed flower pots (red clay for me), I smash the pieces down to cat litter size bits and also grind that up in the coffee grinder.

 

Bentonite has kind of sticky quality to it. I can take a pinch of it between my fingers, squeeze it and it starts clumping. That is what we are after and why bentonite clay works well. The grog enhances the mix because it helps the nozzle "bite" or grip into the tube walls and hold better.

 

David Sleeter's book has a similar nozzle mix formula and he stresses that it is important to use the listed amount of paraffin wax in the formula, too little defeats the purpose, too much wax will cause the nozzle to melt and erode - make sure the correct amount is used.

Edited December 19, 2009 by Eric70

[dagabu]

It compacts, but even after I ram the clay into a tube i can push it out as if I had just rammed a bunch of flour in there. I'll try a proven nozzle mix formula and report back. If nothing works I'll go grab some fresh step.

 

It looks like there are a few misconceptions and some problems as well.

 

Grog is smashed up fired pottery, it is very hard, do not drill it. It is used to resist heat and abrasion from the rocket gasses and fill the space.

 

Kyanite is a refractory, it is used in ceramic nozzles and the such. It resists heat as does grog.

 

Bentonite is used due to its ability to expand when wet (hint, hint) and its free flowing ability. It is not a refractory.

 

Hawthorn is a fire clay, it is also used to bolster grog and kyanite.

 

Wax is used to bind the clay when pressed. It allows the particles to slip and slide over each other to lock into place making a tight bind. Hold a blow torch to a finished nozzle, burn the wax out, the nozzle will still be strong and stable.

 

1-3% of wax dissolved in Naphtha until a liquid, intimately mixed with the clay, heated, screened, heated screened and left to cool, screened again and stored.

 

Long story short, use what you like, use what works, change when it doesn't work, be able to change your mind about any process if you need to.

 

D

 

Clay information provided by Continental Clay, Minnesota Clay and Superior Clay of Minnesota. Wax mix provided by Steve Laduke, Steve Kasinski and Danny Creagan

Edited December 19, 2009 by dagabu

[Ventsi]

I must say, I'm thrilled. The mix from Skylighter's website works incredibly well. When I tried the clay by itself I could tap it out with my finger. When I added the screened and crushed red flower pots and wax, it worked incredibly well. I can't even scratch this stuff.

 

Again, thanks guys.

[dagabu]

I must say, I'm thrilled. The mix from Skylighter's website works incredibly well. When I tried the clay by itself I could tap it out with my finger. When I added the screened and crushed red flower pots and wax, it worked incredibly well. I can't even scratch this stuff.

 

Again, thanks guys.

 

Congratulations! That red clay is grog, don't drill that stuff unless you really don't like your drill bit!

 

D

[derekroolz]

Congratulations! That red clay is grog, don't drill that stuff unless you really don't like your drill bit!

 

D

 

 

Sorry noob question, what would I use to make the nozzle, would I use a press to ram the nozzle

[firetech]

Use a mallet.

[dagabu]

Use a mallet.

 

True, you can hammer it but to get consistency, use a press and use the same pressure and dwell time on each rocket. Mallets are a bunch cheaper though.

 

D

[Eric70]

Use a mallet.

 

Yes a press is the optimum way to go and mandatory for whistle rockets and desired for end-burners. However, if you are making Black Powder coreburning rockets and are starting out or on a budget, ramming is the age-old method.

 

Do not use a metal mallet because it is a spark risk and if anything it will damage your rammers, cause the tops to become mushroomed. For my 1 lb cored BP rockets (3/4") I use this hammer, it is a 12 oz Vaughn SF12. Google it. I bought mine at Home Depot. I use the plastic yellow side for ramming. The red side is rubber and will not get the job done, too much bounce. Pour in your nozzle mix and give it 20-25 good whacks, you don't need to "whale" on it but make sure each hit (whack) has some strength behind it - like pounding a nail into wood.

 

 

 

Some will tell you hand ramming BP coreburners is dangerous and you are going to die doing it, which is possible, but if you make safety #1 you will be fine. Safety precautions include using non-sparking material for tooling such as aluminum, a clean workplace free of flammable materials such as chemicals and gasoline, do not mix metals in your fuel and ram it because it could spark.

 

Again, my advice applies to the hand ramming of BP (Black Powder) core-burning rockets. If you are making whistle rockets, a press is mandatory because of the friction sensitivity of the whistle mix.

Edited December 24, 2009 by Eric70

[dagabu]

One better (sorry I dont mean too) is a rawhide mallet.

 

D

[Eric70]

One better (sorry I dont mean too) is a rawhide mallet.

 

D

 

I forgot about that - rawhide would be even better.

 

For my 3 lb coreburner BP rockets I hand ram them with this one, it's a Garland 11009:

 

 

Garland Mfg 11009 Size 9 Loaded Rawhide Mallet 1-3/4" Face

Costs around $20. I figured this one would be *just* big enough for ramming 3 lb BP coreburners and so far it has worked well. Like I said, hand-ramming is good for starting out. I think one of my goals this year will be to build a press. Hand-ramming is noisy and can get tedious after a while. I recommend protecting your hearing. Throw in some earplugs or balled-up kleenex (in your ears).

[Mumbles]

There are some hammers with replaceable faces that people have been fond of recently. I will see if I can find model numbers and sources if people are interested. You can just replace the face when it gets worn from ramming. Really neat idea.

[Eric70]

There are some hammers with replaceable faces that people have been fond of recently. I will see if I can find model numbers and sources if people are interested. You can just replace the face when it gets worn from ramming. Really neat idea.

 

That would be interesting, please let us know what you find!

[WonderBoy]

I use a dead blow hammer. To keep the face of it from getting too beat up, I taped on a square of rubber cut from a bicycle inner tube.

[EEguy]

I used to use a regular hammer on a wooden dowel to pack my nozzles out of fine (-325 mesh) Wyoming bentonite clay. I now use quick cement (anchoring cement) from the hardware store. I use the Ace Hardware store brand, but another brand is Quickrete. The cement powder is mixed up with a bit of water and tapped into my nozzle mold. It cures enough to use within 30 minutes, but I like to make a dozen at a time and let them dry overnight. They are very hard, and there is almost no throat erosion, which was a problem for me when I used bentonite. Plaster of Paris works similarly and yields very smooth white nozzles due to its very small particle size, but it takes longer to dry and is not as hard and strong as the cement.

http://www.nichropulse.com/images/stories/075_nozzle_tilt_small.jpg

I have lots of nozzle test videos you can watch on my YouTube channel: www.youtube.com/user/NichroPulse

These videos are better organized on my website: nichroulse.com (go under the resources menu and select the video library)

 

I like the quick cement so much better that I am willing to part with the -325 mesh bentonite if anyone is interested. I have 13 lbs left. Make me an offer if you want it. www.nichropulse.com/images/stories/Bentonite.jpg

[dagabu]

I used to use a regular hammer on a wooden dowel to pack my nozzles out of fine (-325 mesh) Wyoming bentonite clay. I now use quick cement (anchoring cement) from the hardware store. I use the Ace Hardware store brand, but another brand is Quickrete.

 

Yes, you can cast nozzles with concrete but in the case of a CATO, you will have a rock expelled from the business end. The reasons we use clay are to ensure that the rocket upon CATO will at least break and cause a much lesser dangerous missile and that all materials can return to the earth with nothing left in the grass that can be picked up by a mower and expelled.

 

I have gallons of discarded epoxy that I would love to mix with sand for the perfect nozzle but the missile hazard is just not worth it.

 

What goes up WILL come down.

 

D

[EEguy]

Yes, you can cast nozzles with concrete but in the case of a CATO, you will have a rock expelled from the business end. The reasons we use clay are to ensure that the rocket upon CATO will at least break and cause a much lesser dangerous missile and that all materials can return to the earth with nothing left in the grass that can be picked up by a mower and expelled.

 

I have gallons of discarded epoxy that I would love to mix with sand for the perfect nozzle but the missile hazard is just not worth it.

 

What goes up WILL come down.

 

D

 

 

 

I suppose that is true. I do not launch in the front yard though. I go out to a field that has lots of rocks already.

[Swede]

For the serious mallet types, there are hammers that use cast lead as the face, and when too beaten up to be usable, it is recast, right onto the hammer. Lead will give you a nice inertia, and will not spark. But for the cost of a setup like this, you may as well buy a press.

[Mumbles]

I found the hammers. They are called "Split head hammers". Rawhide would be the material of choice to avoid marring up your tooling. I didn't do too much searching, but you can use that term to shop around for the best deal.

 

http://www.hammersource.com/Split_Head_Hammers.html

http://www.garlandmfg.com/mallets/split.html - a bit pricier, but gives you a good idea how they work.

 

Dan Thames said that the #3 model (1.75" face, 2.75lb) was good up to 3lb rockets.

[dagabu]

For the serious mallet types, there are hammers that use cast lead as the face, and when too beaten up to be usable, it is recast, right onto the hammer. Lead will give you a nice inertia, and will not spark. But for the cost of a setup like this, you may as well buy a press.

 

This one?

 

http://www.grahamtool.com/leadhammermoldsetsmall.aspx

 

http://www.mcmaster.com/#hammer-molds/=569zpg

 

I had completely forgotten about those. My buddy has a car shop and has a set of lead hammers for mag wheels. When they wear out he throws them into the lead bucket. I got three hammers (about ten years ago, they were really beat up) in one bucket and asked him about them. He told me that they are what they use on all of the cast and mag parts on the cars since they don't peen the surface. I melted the lead off of the hammer handle, drilled a hole in a 4x4 the size of the hammer handle, another 3" hole intersecting the first at 90°, wrapped some chip board around the shaft to keep the lead from migrating, filled the big hole with wheel weight lead 9also from him) and gave it back to him for his Birthday.

 

I have rebuilt that one for him twice, I will ask him about it again today when he and his wife come over for NYE. I don't have the 4x4 any more, it got consumed when pouring the second head, 10# of lead was just too much for it!

 

Another idea for making your own...

 

http://www.pyrobin.com/files/mould.jpg

 

Swede, thanks for the reminder!

 

D

Edited December 31, 2009 by dagabu

[Ventsi]

Congratulations! That red clay is grog, don't drill that stuff unless you really don't like your drill bit!

 

D

 

 

My goodness this nozzle mix is tough, I made a 1" Fe fountain and had to drill the nozzle out, woof! Thats was a PITA!

The fountain received a 2g BP bounce to finish it off. When that happened the nozzle shout out about 100ft and fell, still intact, I should have saved it.

 

Here's a video, it was about 10-12ft flame.