kpknd Posted August 31, 2014 Posted August 31, 2014 (edited) I got tired of the clay nozzels eroding too much so I experimented with Durhams water putty. I made up a number of 8oz. and 1lb motors. some with just a solid plug pressed in one end and drilled to the right diamater, and some using the tooling to form the nozzel. I let the putty dry for a day or two before drilling out the solid plugs. I also nozzeled some tubes with roughened surfaces inside where the nozzel is located and some smooth. The drilled nozzeles where loaded with a solid culmn of fuel then the core was drilled out by hand with a drill bit a little smaller than the nozzel. The tooling formed nozzels and tubes where placed back on the tooling spindle (after letting the putty dry a few days) and loaded with BP fuel. One thing of note is that the putty swells a little when it dries, so it is nessecary to drill out the nozzel with the same diamater bit as the throat . I tested 6 variations and each one worked well. The higher thrust was evident by the sound. Now I need to mill another pound of fuel and start flying models. Oh, I also ran out of fire clay, that is another reason I used water putty. Edited August 31, 2014 by kpknd
Bobosan Posted August 31, 2014 Posted August 31, 2014 Did you use the convergent tooling rammer to form the water putty nozzle while the tube was on the spindle? How workable is the water putty using this method?
pyrokid Posted September 1, 2014 Posted September 1, 2014 I wonder if anyone has ever worked with a mix of bentonite clay and Durham's water putty. Perhaps a plug could be rammed, then sprayed with water to make it stronger or somewhat resistant to erosion.
dagabu Posted September 1, 2014 Posted September 1, 2014 I got tired of the clay nozzels eroding too much so I experimented with Durhams water putty. I made up a number of 8oz. and 1lb motors. some with just a solid plug pressed in one end and drilled to the right diamater, and some using the tooling to form the nozzel. I let the putty dry for a day or two before drilling out the solid plugs. I also nozzeled some tubes with roughened surfaces inside where the nozzel is located and some smooth. The drilled nozzeles where loaded with a solid culmn of fuel then the core was drilled out by hand with a drill bit a little smaller than the nozzel. The tooling formed nozzels and tubes where placed back on the tooling spindle (after letting the putty dry a few days) and loaded with BP fuel. One thing of note is that the putty swells a little when it dries, so it is nessecary to drill out the nozzel with the same diamater bit as the throat . I tested 6 variations and each one worked well. The higher thrust was evident by the sound. Now I need to mill another pound of fuel and start flying models. Oh, I also ran out of fire clay, that is another reason I used water putty. Have you tried Precious kitty, kitty litter? I launched a couple dozen rockets this past weekend with pounded kitty litter nozzles and all of them flew fine. Durhams works great but pound for pound, is expensive.
nater Posted September 1, 2014 Posted September 1, 2014 You can dampen durhams ever so slightly and press a nozzle and motor like normal. It still needs time to cure, but does leave a strong nozzle. I had no signs of erosion with a hybrid #2 motor. (50/50 BP and sali whistle) A problem with the durhams is that it is fine enough, it still tends to flow under pressure and get stuck between the rammer and inside of the tube. I second the kitty litter Dag mentioned above. I was hesitant to try it after my first experiences with bentonite kitty litter had unacceptable results. Something about that brand works better for me. These nozzles press nice and hard with no performance altering erosion.
dagabu Posted September 1, 2014 Posted September 1, 2014 ...I second the kitty litter Dag mentioned above. I was hesitant to try it after my first experiences with bentonite kitty litter had unacceptable results. Something about that brand works better for me. These nozzles press nice and hard with no performance altering erosion. Strange? Huh?
nater Posted September 1, 2014 Posted September 1, 2014 Strange? Huh? Very strange. One would think that ~ 8-20 mesh chunks of bentonite would be the same, no matter what the brand. I first tried the cheapest kitty litter from WalMart as was often recommended, which no luck. It worked fine for nozzled smokes and now pressure devices, but I ended up dumping it in the litter box for the cat instead. From there, I moved to Hawthorn bond fire clay with a little wax and a little graphite. This works quite well, but as I have posted many times, tends to flow under pressure and cause the rammers to get stuck. Waxing the tubes solved this problem. The Precious Kitty litter is my go to now. It's on the shelf at Pet Smart and does the job well.
dagabu Posted September 1, 2014 Posted September 1, 2014 $17.00 for #40 delivered via Amazon.com, I am very happy.
ddewees Posted September 1, 2014 Posted September 1, 2014 I'll have to try the precious kitty stuff... the bulk petco stuff you scoop yourself works fine for me.
Blackthumb Posted September 1, 2014 Posted September 1, 2014 Kitty liter...cheap red bag from WalMart....used oil.....or oil dry from NAPA.....works great for me all these years....
kpknd Posted September 2, 2014 Author Posted September 2, 2014 Did you use the convergent tooling rammer to form the water putty nozzle while the tube was on the spindle? How workable is the water putty using this method? My rammer is flat. The putty is verry workable, It seems to work best if it is just dampened enugh to clump together otherwise it will gum up the rammer and squeze betweenthe rammer and spindle and stick to the spindle a little, I also give the spindle a coat of silicone spray.
kpknd Posted September 2, 2014 Author Posted September 2, 2014 Have you tried Precious kitty, kitty litter? I launched a couple dozen rockets this past weekend with pounded kitty litter nozzles and all of them flew fine. Durhams works great but pound for pound, is expensive. Do you ram the litter as granules or mill it first? I tried floor dry and it didnt work.
kpknd Posted September 2, 2014 Author Posted September 2, 2014 I wonder if anyone has ever worked with a mix of bentonite clay and Durham's water putty. Perhaps a plug could be rammed, then sprayed with water to make it stronger or somewhat resistant to erosion.That sound interesting. The water putty sets up very fast, I wonder if the clay might help to slow it down some in a damp state. Maybe 50/50?
Blackthumb Posted September 2, 2014 Posted September 2, 2014 I add used or clean oil to dampen...then hit some of it in a coffee grinder and mix in with rest....never had a problem....
kpknd Posted September 3, 2014 Author Posted September 3, 2014 I tried bentonite powder with a little oil and still didn't like it. I rammed up a nozzle with water dampened bentonite , wait for it to dry and see. When ramming with damp clay or water putty, it looks to be more damp after ramming, probably because the water is forced out. The damp bentonite feels waxy after ramming.
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