trag Posted September 21, 2009 Posted September 21, 2009 Yes, the Special Kitty brand in the red bag is all Bentonite. The yellow bag has some additive for odor control, but the amount is negligible and you don't need to adjust for it in any way. Thank you for clearing that up for me. I appreciate it. For adhesion, use fractured Grog. It's available at pottery supply stores, and that's where I got mine. It's roughly 40 mesh. (I think Graphite would *decrease* wall adhesion?) Graphite mostly reduces nozzle erosion. I wasn't complete in explaining my thinking. My thought was that the graphite would help with nozzle erosion, but the "expanding graphite" would increase its volume as it is heated during the rocket firing. If well mixed, this would cause the overall volume of the nozzle material to expand, and it should press more tightly into the tube wall because of the expansion. Of course, it might not be enough of an effect to be helpful. It might also simply cause the nozzle material to crumble as the expansion might force the compressed particles apart. Or it might cause the nozzle to close up. So plenty of ways it could go wrong, but it might go right too.
dagabu Posted September 21, 2009 Posted September 21, 2009 Thank you for clearing that up for me. I appreciate it. I wasn't complete in explaining my thinking. My thought was that the graphite would help with nozzle erosion, but the "expanding graphite" would increase its volume as it is heated during the rocket firing. If well mixed, this would cause the overall volume of the nozzle material to expand, and it should press more tightly into the tube wall because of the expansion. Of course, it might not be enough of an effect to be helpful. It might also simply cause the nozzle material to crumble as the expansion might force the compressed particles apart. Or it might cause the nozzle to close up. So plenty of ways it could go wrong, but it might go right too. It looks very interesting but I am afraid that it will do to the nozzle what humidity does to Bentonite, it swells the clay and the nozzle chokes causing CATOs. This is the reason for the wax in the clay to effectively seal out all of the water. I have headings blow and tubes blow but have never had a nozzle blow out... never. Take a look at my Avatar, its 1.5 times diameter in length and all of that clay is pressed to 5000 lbs per inch causing the casing to bulge .001 or more. When I mix a new batch, I take a ram 1/2 the diameter of the clay and press out the nozzle on the press. If it doesn't withstand a minimum of 500 lbs I don't use it. the only time this has happened was when using kitty litter right out of the box with flavor crystals. For what ever reason, the colored crystals would not compress well and separated when the pressure was released. My favorite mix is 50/50 mix of Bentonite Kaolin. 10 lbs of each in a bucket and add one wax toilet ring dissolved in camping gas (patience, it takes a while) and passed through a screen several times to distribute the was. Let dry until you cannot smell any gas. It takes at least a week. Dave
Ericz Posted September 21, 2009 Posted September 21, 2009 Just buy fine bentonite powder ? It makes much stronger enplugs or how u call it , and i never had a cato with it , with that kitty stuff its anoying because u cant ram it , at least i dont got the power to ram it so good it stays in. www.silex.nl its maybe far for u all buy a kg bentonite is only 1,50 so the costs for shipping and the normal price in total is nice. Or where the f u wanna buy bentonite grtz.
trag Posted September 21, 2009 Posted September 21, 2009 I was just speculating, thought experimenting. Bentonite and grog are quite affordable from Seattle Pottery Supply. The bigger issue, if I order from them, will be shipping. They have good prices on a couple hundred pounds worth of stuff I'd like, but the shipping by USPS, e.g., is about $1 per pound, which more than double the actual cost. Driving up from Texas would not be economical. I've been hunting for a local (Austin, TX) place with similar stock, but have had no luck so far. What does delivery of a small pallet by a trucking company typically cost?
Ericz Posted September 21, 2009 Posted September 21, 2009 Hmm i can give u a site that was silex but i cant do more i do not know anything about shipping costs with a truck But u can order much then and make a nice price i would ask for lots of free like 5 % off the price or something Ciao
dagabu Posted September 21, 2009 Posted September 21, 2009 (edited) I was just speculating, thought experimenting. Bentonite and grog are quite affordable from Seattle Pottery Supply. The bigger issue, if I order from them, will be shipping. They have good prices on a couple hundred pounds worth of stuff I'd like, but the shipping by USPS, e.g., is about $1 per pound, which more than double the actual cost. Driving up from Texas would not be economical. I've been hunting for a local (Austin, TX) place with similar stock, but have had no luck so far. What does delivery of a small pallet by a trucking company typically cost? Check this out! http://www.texaspottery.com/acatalog/raw-materials.html I get a 100# bag of it for $26.00. Edited September 21, 2009 by dagabu
Mumbles Posted September 21, 2009 Posted September 21, 2009 The guy on ebay selling ceramic media is also from Texas. IMO, his prices on chemicals are rather high, but clay is dirt cheap. (Pardon the pun being a form of dirt and all). If you're going to pick something up, get all the stuff you can. Calcium Carbonate and sulfate come to mind. Extremely cheap, useful in some situations, but the box or bag they get packed in is worth more than the cargo inside. Some other items more useful and more expensive should be available too.
Swede Posted September 23, 2009 Posted September 23, 2009 One last pitch for being done with it and buying bentonite. I just got to try out some *real* super fine bentonite clay. My mom bought a 1lb tub , for god knows what but I swooped a little and tried it as a nozzle by ramming it. I must say it worked absolutely great, nice smooth, easy to drill in to , no flaking, super hard etc.. So I've given my cat litter away and placed an order for 1lb of clay from Cracker. I'll make some legitimate nozzle mix once I get it. PS: This was pure % Bentonite, or at least so the box states. It costs $7 and I was making fun of my mom the whole way home for buying it. From a pottery shop rather than a specialty store, it's not expensive. Add grog or kyanite, wax, and mix per Sleeter, and it makes ceramic-like nozzles that grip and will not fail. Why flog yourself trying to powder cat litter when bentonite is 100 pounds for $16 from a place like Seattle Pottery? There are almost always local stores that will carry it at a similar price. It works. When you think about the time and expense that goes into a good rocket + header, it is false economy to scrimp on the nozzle IMO.
Ventsi Posted September 23, 2009 Posted September 23, 2009 Swede, I'm with you on this one. IMO cat litter is a pain to powder and is the same price if not more than bentonite. I decided to buy just one pound and ad it to my order from underground [$2], but I might go with Seattle instead and get some CuO too. I don't do rockets but I am planning a few beefy fountains as part of new years {1" or 1.25"} and those nozzles go through a hell of a beating so I want some good nozzle mix. Anyway for what its worth , I have tried Fresh Step before and It was pretty good, but not as good as the pure milled clay I tried recently. And it doesn't annoyingly smell like *ocean fresh* every time you press something.
dagabu Posted September 23, 2009 Posted September 23, 2009 (edited) One last pitch for being done with it and buying bentonite. From a pottery shop rather than a specialty store, it's not expensive. Add grog or kyanite, wax, and mix per Sleeter, and it makes ceramic-like nozzles that grip and will not fail. Why flog yourself trying to powder cat litter when bentonite is 100 pounds for $16 from a place like Seattle Pottery? There are almost always local stores that will carry it at a similar price. It works. When you think about the time and expense that goes into a good rocket + header, it is false economy to scrimp on the nozzle IMO. Boric Acid 1 lb. $2.46 Kyanite - 100 mesh 25 lbs$13.50Iron Oxide - Red 5 lbs $2.90Hawthorn - 50 mesh -50 lbs$15.00Brick Grog Super Fine - 48 mesh 25 lbs $14.25 Pretty sure I found my clay source, and a couple others as well. It's 20 miles from my house! I am going to use a mix I got from a Passfire friend,61% Hawthorne clay 16% fine grog 15% Kyanite8% candle wax Dave Edited September 23, 2009 by dagabu
trag Posted September 23, 2009 Posted September 23, 2009 Boric Acid 1 lb. $2.46 Kyanite - 100 mesh 25 lbs$13.50Iron Oxide - Red 5 lbs $2.90Hawthorn - 50 mesh -50 lbs$15.00Brick Grog Super Fine - 48 mesh 25 lbs $14.25 Pretty sure I found my clay source, and a couple others as well. It's 20 miles from my house! Dave, what source are you looking at for that? It does not match either Seattle Pottery's on line prices, nor the link you provided earlier for Texas Pottery. I found this place Armadilloclay in Austin, Tx but their price scheme is weird. Still, I think it's better than Seattle Pottery would be after paying for shipping but I'd like to find something closer to as nice as Seattle is. For example, Armadillo charges:Bentonite-2 lbs $6.64Bentonite-5lbs $13.28Bentonite-50lbs $26.56 They go from almost $3/lb to about $.50/lb with no quantities between 5 and 50 lbs. It would take me a long time to use up 50lbs of clay I think. Their Grog:Grog-2# $4.77Grog-5# $9.54Grog-50# $19.09 Still, one of the attractive parts of possibly ordering from Seattle Pottery is their pricing on KNO3--assuming they actually have and ship the stuff on their price list.
Mumbles Posted September 23, 2009 Posted September 23, 2009 Thats a pretty normal price list to me. The stuff is so cheap, it's not worth their time to break it down from bags.
dagabu Posted September 23, 2009 Posted September 23, 2009 (edited) Dave, what source are you looking at for that? It does not match either Seattle Pottery's on line prices, nor the link you provided earlier for Texas Pottery. I found this place Armadilloclay in Austin, Tx but their price scheme is weird. Still, I think it's better than Seattle Pottery would be after paying for shipping but I'd like to find something closer to as nice as Seattle is. For example, Armadillo charges:Bentonite-2 lbs $6.64Bentonite-5lbs $13.28Bentonite-50lbs $26.56 They go from almost $3/lb to about $.50/lb with no quantities between 5 and 50 lbs. It would take me a long time to use up 50lbs of clay I think. Their Grog:Grog-2# $4.77Grog-5# $9.54Grog-50# $19.09 Still, one of the attractive parts of possibly ordering from Seattle Pottery is their pricing on KNO3--assuming they actually have and ship the stuff on their price list. I'm sorry, its Continental Clay in Minneapolis. I now have 100# of nozzle mix of the new clay and would be open to selling some if anyone is interested. I'm not into charity work so lets call it $2.00 a pound plus shipping. Remember, if it fits, it ships. USPS is our friend. Dave Edited September 23, 2009 by dagabu
trag Posted September 23, 2009 Posted September 23, 2009 Thats a pretty normal price list to me. The stuff is so cheap, it's not worth their time to break it down from bags. I suspected that was the underlying cause. It is much easier to sell a whole 50lb bag than to dish it out 5lbs at a time. Plus, they either must break down an entire 50 lb bag and store all the smaller bags, or maintain an open, partially used bag of every item which they sell in smaller quantities. That can turn into a lot of floor/counter/shelf space. But, as it says in one Dilbert cartoon, what I want is better products for free. :-) What I'd really like is to live near Seattle Pottery or a business just like it and be able to drive over and partake of their selection at their prices.
dagabu Posted September 23, 2009 Posted September 23, 2009 I suspected that was the underlying cause. It is much easier to sell a whole 50lb bag than to dish it out 5lbs at a time. Plus, they either must break down an entire 50 lb bag and store all the smaller bags, or maintain an open, partially used bag of every item which they sell in smaller quantities. That can turn into a lot of floor/counter/shelf space. But, as it says in one Dilbert cartoon, what I want is better products for free. :-) What I'd really like is to live near Seattle Pottery or a business just like it and be able to drive over and partake of their selection at their prices. Yup, that's what I did today. I got to walk back to the warehouse and see what they had. They thought that I wanted a 100# bag of Hawthorne and just re-bagged 50# when I corrected them. BTW- very artsy people and attractive women helping. Very plesent experience all in all. Dave
TheSidewinder Posted September 24, 2009 Posted September 24, 2009 Continental Clay? Hmmm... That sounds familiar. I think I bought my fractured Grog there, 3 years ago.
dagabu Posted September 24, 2009 Posted September 24, 2009 Continental Clay? Hmmm... That sounds familiar. I think I bought my fractured Grog there, 3 years ago. Prices were pretty good, girls were pretty, Red Iron Oxide was less per pound then dirt! Cool! Dave
dagabu Posted September 25, 2009 Posted September 25, 2009 &*^$#@@^)(*^$&$# spindle!! I tried the new mix on my 3# spindle and didn't like the feel of the walls pressed to 5000# so I upped to 10000# and I bent my spindle. Yes... I went past the "do no pass" line on the rammer, I know, I know. Gonna add some Bentonite to the mix for that glassy feel. Dave
TheSidewinder Posted September 26, 2009 Posted September 26, 2009 Torqued your spindle, eh? Ouch. Hope you got it back into spec. And I'll bet you won't do that again.
dagabu Posted September 26, 2009 Posted September 26, 2009 Torqued your spindle, eh? Ouch. Hope you got it back into spec. And I'll bet you won't do that again. Nope, it's gone... Its gonna take a few days to get to making a new one (or three) so no rockets for the next week.
TheSidewinder Posted September 26, 2009 Posted September 26, 2009 Yow! That isn't "bent", that's... "toast"! Good idea, making a spare (or two) for the future. And are you sure you didn't damage the interior of the Rammer?
dagabu Posted September 27, 2009 Posted September 27, 2009 Wow. That is well and truly tweaked. Bummer! It looks like the spindle might be a two-piece affair, w/the spindle end welded on? I don't have a lathe, and had considered fashoning a spindle like that, but hadn't gotten to it yet. I have been using a metal filled epoxy for the nozzle piece since it is easy to form with hand tools. I have a lathe on the way and I will be making them all out of Al now. Yes, It ruined my rammer too
dagabu Posted September 27, 2009 Posted September 27, 2009 (edited) I have been using a metal filled epoxy for the nozzle piece since it is easy to form with hand tools. I have a lathe on the way and I will be making them all out of Al now. Yes, It ruined my rammer too Here is the new nozzle mix that was recommended. The compaction was by far greater then straight Bentonite and my band-saw threw sparks where you see the black line right at the end of the convergence. I have great hopes for this mix and will send some rockets up as soon as I can get my tooling done. BTW- this tooling is around 25 years old and the nozzle was based on a rocket bell used in the 1960s. I use the straight wall divergence nozzle that the sidewinder uses of 79° rake. The reason is that the propelent gasses push against the walls of the nozzle as well as pushing against the air. This makes better thrust and straighter flight since ash and slag can block part or all of the nozzle diameter. Edited September 27, 2009 by dagabu
Swede Posted September 28, 2009 Posted September 28, 2009 I've always liked the look of the classic divergent nozzles created and used by NASA over the decades. They LOOK cool, and when you are creating a male nozzle form from aluminum or some other material to create clay nozzles, it isn't particularly hard to make a good one with a bit of hand work, files, silicon-carbide paper, and such. If you make your own tooling, taking the time to create a high-quality form like this will pay big dividends, as the nozzles you make will really help the rocket perform well.
dagabu Posted September 28, 2009 Posted September 28, 2009 (edited) I've always liked the look of the classic divergent nozzles created and used by NASA over the decades. They LOOK cool, and when you are creating a male nozzle form from aluminum or some other material to create clay nozzles, it isn't particularly hard to make a good one with a bit of hand work, files, silicon-carbide paper, and such. If you make your own tooling, taking the time to create a high-quality form like this will pay big dividends, as the nozzles you make will really help the rocket perform well. You mean the bell shape? I like the look to but after a lot of conversations with a now deceased Rocket Scientist friend of mine about five years ago, I decided to follow his advice and go with the straight wall tapered solid fuel nozzle for small rockets. Bells work very well with the frequency of liquid fuel burns but the solid fuels like the constant direct refraction. If you look at a Hi Bay light, you will see that a bell is used to reflect the light out and down around the light bulb which is actually just getting in the way of all the light it is making. Liquid fuel has a lot of photonic energy, much more then solid fuel and that photonic energy can be harnessed in the form of thrust by refocusing on the burn tail and increasing the burn temperature all at no additional cost. Dave Edited September 28, 2009 by dagabu
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