dagabu Posted January 2, 2010 Posted January 2, 2010 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. Sweet video, loved the bounce! What the heck did that poor bit do to you! Meany! (told you so) D
Ventsi Posted January 2, 2010 Posted January 2, 2010 Sweet video, loved the bounce! What the heck did that poor bit do to you! Meany! (told you so) D Thanks! That bit came as the arbor I had to use in a hole saw to drill 20+ end plugs with it jumping all over the place. Crap China manufacturing is all I can say.
EEguy Posted January 12, 2010 Posted January 12, 2010 (edited) I have made three videos specifically for this thread. They demonstrate the different nozzles discussed here. (325mesh NOT kitty litter) I have found that the pure bentonite clay nozzle suffered the worst throat erosion. Adding the ceramic grog significantly decreases this erosion. I used the clay/grog/wax ratio suggested by Skylighter. I will be adding one for kitty litter bentonite on my channel soon. Edited January 12, 2010 by EEguy
dagabu Posted January 12, 2010 Posted January 12, 2010 Thanks you for posting that, It is nice to see the results of careful testing.
Swede Posted January 13, 2010 Posted January 13, 2010 I have made three videos specifically for this thread. They demonstrate the different nozzles discussed here. (325mesh NOT kitty litter) THANK YOU. Those are some excellent and well-made tests. Nicely done!
FrankRizzo Posted January 22, 2010 Posted January 22, 2010 Using a hammer to create a nozzle is called "ramming". Please press your nozzles for accurate testing.
dagabu Posted March 5, 2010 Posted March 5, 2010 I have had a lot of poured nozzles blow out and prefer to press them now. D
EEguy Posted April 6, 2010 Posted April 6, 2010 So far, I have had pretty good luck with the putty and the cement "cast" type nozzles with respect to blow-out. I recommend internal horizontal grooving of the tube where the nozzle contacts the tube. It's not always necessary in my experience with lower power sugar propellant, but with BP, APCP and ANCP it becomes much more of an issue. With pressed or rammed bentonite clay/grog, I still recommend the grooving. I've even seen thru-holes and screws used to eliminate plug and nozzle blow-out.
Ventsi Posted April 6, 2010 Posted April 6, 2010 Can coarse[80+mesh] blasting grit be used instead of grog/kyanite in nozzle mix? I'm sick of busting flower pots, even with a good dust mask I can feel it gritting between my teeth.
dagabu Posted April 6, 2010 Posted April 6, 2010 Can coarse[80+mesh] blasting grit be used instead of grog/kyanite in nozzle mix? I'm sick of busting flower pots, even with a good dust mask I can feel it gritting between my teeth. Why are you busting up flower pots? And what the heck is blasting grit? You meat sand blasting grit? Google ceramics, go get a bag of kyanite and hawthorne and a bag of grog from a clay supplier.
Ralph Posted April 7, 2010 Posted April 7, 2010 Why are you busting up flower pots? And what the heck is blasting grit? You meat sand blasting grit? Google ceramics, go get a bag of kyanite and hawthorne and a bag of grog from a clay supplier. grog is smashed pottery
Mumbles Posted April 7, 2010 Posted April 7, 2010 Grog specifically is crushed ceramic, not just any pottery.
dagabu Posted April 7, 2010 Posted April 7, 2010 Not only is it crushed ceramic but it is also tumbled to reduce the sharpness of the edges and it is graded according to mesh size. There is almost no similarities when you hold both pottery and grog in your hands. D
Ventsi Posted April 7, 2010 Posted April 7, 2010 So would aluminum oxide[ceramic] blasting media work in place of grog? Not the pure white stuff but the brownish media. Its small shards resembling sand. I'm asking because I have a bag of it in my schools shop that nobody wants so if it is I might use that.
dagabu Posted April 8, 2010 Posted April 8, 2010 So would aluminum oxide[ceramic] blasting media work in place of grog? Not the pure white stuff but the brownish media. Its small shards resembling sand. I'm asking because I have a bag of it in my schools shop that nobody wants so if it is I might use that. That stuff is going to be extremely abrasive and will scratch spindles. I would stay with the stainless spindle to start and see how much kaolin or Bentinite you need to soften the mix. D
FrankRizzo Posted April 8, 2010 Posted April 8, 2010 (edited) Grog is completely unnecessary unless you ram your nozzles with a hammer. If you use a press, you can just use lightly milled kitty litter (with a bit of mineral oil if you live in a humid climate). Edited April 8, 2010 by FrankRizzo
dagabu Posted April 8, 2010 Posted April 8, 2010 (edited) Grog is completely unnecessary unless you ram your nozzles with a hammer. If you use a press, you can just use lightly milled kitty litter (with a bit of mineral oil if you live in a humid climate). I think the point is that you CAN use just lightly milled kitty litter. The grog is an important ingredient if you are in need of a refractory ingredient, kitty litter is not refractory and you will see erosion in bentonite. Bentonite is also much more fluid then grog, it will press out more then will grog and can lead to undue stress on the tube and takes longer to compact. Steve Laduke has 48 years of experience and is widely considered the expert in pyrotechnical rocket. Straight kitty litter is only marginal in performance. D Edited April 8, 2010 by dagabu
FrankRizzo Posted April 8, 2010 Posted April 8, 2010 I disagree. Grog is only necessary when when the compaction pressure is not high enough to produce a dense nozzle. It damages tooling, and will produce sparks if you attempt to drill through a bulkhead containing it. I use lightly processed kitty litter (so that some of it remains as +20mesh) with a few percent graphite, and have never had problems with erosion of my nozzles. Steve is a great guy and a great rocket builder, however, he's also stuck in his ways on some things. You should have seen the look on his face when Dan Thames demoed his benzoate rockets at the Fargo, ND PGI convention. Up until that point, Steve claimed that only salicylate could make a good whistle rocket. Many of us knew better. Anyway, we'll have to get together in Appleton this year and talk shop. I can show you the way I make my nozzle mix.
dagabu Posted April 8, 2010 Posted April 8, 2010 I disagree. Grog is only necessary when when the compaction pressure is not high enough to produce a dense nozzle. It damages tooling, and will produce sparks if you attempt to drill through a bulkhead containing it. I use lightly processed kitty litter (so that some of it remains as +20mesh) with a few percent graphite, and have never had problems with erosion of my nozzles. Steve is a great guy and a great rocket builder, however, he's also stuck in his ways on some things. You should have seen the look on his face when Dan Thames demoed his benzoate rockets at the Fargo, ND PGI convention. Up until that point, Steve claimed that only salicylate could make a good whistle rocket. Many of us knew better. Anyway, we'll have to get together in Appleton this year and talk shop. I can show you the way I make my nozzle mix. I really like the way benzo sounds I started out using bentonite and then adding kaolin but ended up with hawthorn and grog. Its like making BP, I like one way, you like another. "and will produce sparks if you attempt to drill through a bulkhead containing it" I have never been able to hand twist a bit that fast D
FrankRizzo Posted April 8, 2010 Posted April 8, 2010 Oh, you sure can produce sparks when hand-drilling through grog-containing bulkheads.
FrankRizzo Posted April 9, 2010 Posted April 9, 2010 It's simply a hardness issue. The porcelain grog is significantly harder than the tool steel which drills are made from. The forces present on the edge of a twisted drill are *very* high.
dagabu Posted April 9, 2010 Posted April 9, 2010 I am just not having that problem at all. I have been using the same bit for the past several months (it has red tape around it for a stop since I press a 1/2" plug) and I have not had the issues you are speaking to. I am using 80 mesh grog, that may be one of the reasons as the size in inconsequential, it is all about the refractory nature and ability to bite the wall. D
Swede Posted April 9, 2010 Posted April 9, 2010 I thought that the idea behind grog/kyanite is two-fold - one, it reduces erosion at the nozzle from the hot gases, and two, it "bites" the tube wall more effectively, preventing nozzle blow-out. I have zero doubt that with a good press, a bentonite clay-only nozzle will perform, but I personally am a fan of kyanite. It's cheap and importantly consistent. I'm thinking that the Alox media will do the same as a fine grog or kyanite, but the effect on the tooling is harsh. One problem is that blasting media tends to be pretty fine, and if too fine, it will negate the tube wall biting benefit. Consider too that any form of ceramic or mineral will abuse tooling to some degree. Alox is hard and sharp, but so is grog, even if tumbled. Maybe it's the cost of doing business if you want to use a ceramic additive to your nozzle mix.
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