fred815 Posted October 30, 2012 Posted October 30, 2012 I happened to notice this firesmith tool. What's the advantage?? Does this elimanate some of the math??
Col Posted October 30, 2012 Posted October 30, 2012 It tells you how much force is on the rammer, the commercial versions are calibrated to 1 sq. inch area to make the math a little easier. You can make one fairly easily with a 10T short bodied ram and a pressure gauge.
Mumbles Posted October 30, 2012 Posted October 30, 2012 There are two big advantages to me. #1 You don't need to modify your press to accept a gauge if it didn't already come with one. Not everyone has the skill set or ability to do this. #2 It takes some of the calculations out of it. If it's like the Wolter gauge, it has a piston that is exactly 1 square inch in area. Thus if you want to deliver 8000psi to 3/4 tooling, it's just a quick calculation. 8000psi * .441 sqin = 3528 reading on the p2f gauge.
Bensmith Posted November 20, 2012 Posted November 20, 2012 The P2F tool is designed to standardize pressing forces ("fuel density") independent of any gauges (or lack thereof) on a press. It's really just a closed-loop hydraulic system that has a piston with a known surface area. If you are working with an arbor press or any other press that might not have a system for gauging the amount of pressure being applied to the comp, the P2F tool eliminates any guesswork. You simply read the gauge on the P2F tool and stop applying force to your comp when the needle reads your desired pressure. Since making reliable pyro is a matter of consistency, the P2F tool ensures that all of your comp is "smooshed" to the same density. It's one of those tools that's actually easier to use than describe. Do send me an email if you have any questions ben@firesmithtools.com -Ben
Ubehage Posted August 23, 2015 Posted August 23, 2015 I have been searching for one of these gauges for the past 4 months Whatever I try searching for, all I can find is nozzled gauges intended for measuring air-pressure. Can anyone help me, what is the correct name for such a tool? And does anyone of you know where to buy a good one in the EU?
calebkessinger Posted August 23, 2015 Posted August 23, 2015 Build one. Mini ram disassemble and put a guage on it.
dagabu Posted August 24, 2015 Posted August 24, 2015 http://www.wichitabuggywhip.com/fireworks/ptof/ptof.html 1
calebkessinger Posted August 24, 2015 Posted August 24, 2015 Thanks Dave. I'm not very good at searching stuff out like that. Especially since a lot of the time i'm posting from my phone.
rogeryermaw Posted September 3, 2015 Posted September 3, 2015 Is there a quick reference table that gives the multipliers for various tool sizes given a 1 square inch piston gauge?
Mumbles Posted September 3, 2015 Posted September 3, 2015 This might be what you're looking for. http://www.wolterpyrotools.com/pcg.pdf The only multiplier you need with a tool having a 1 sq in piston is the area of the tooling. I do have a question about this too actually. I've heard this mentioned, but do most people use the area of the whole tooling, or on account for the face cross sectional area? IE, would you say the first rammer on a 1lb rocket tooling has an area of .441 sq in, or take into account the 1/3" hole to accommodate the spindle reducing the effective area to .354 sq in?
ddewees Posted September 3, 2015 Posted September 3, 2015 either/or Mumbles.. Many do account for the actual area of the tooling, but most don't actually adjust the pressure relief valve for it. I usually just eyeball the number I'm going for on the gauge based on each rammer being used. I typically set the relief valve for the solid ram, since it requires the greatest force. And there are others that just set it to a solid ram, and apply full pressure regardless of the actual surface area of the hollow rammers. I have rarely seen problems with "too much" pressure, other than some shorter tubes, or wrinkles on the exterior (assuming a quality tube support is being used). This spreadsheet has an area where you can account for the hollow diameter, and get the numbers you need. http://i1149.photobucket.com/albums/o588/SaltLakeAreaPyros/pressing_zpshkr2jjqx.png https://www.dropbox.com/s/sw4tiytiq2yzj5n/Pressing_Comps_V2.xls?dl=0
rogeryermaw Posted September 3, 2015 Posted September 3, 2015 something i wonder is how having that rammer hole full of spindle and what powder squeezes by may cause frictional losses and affect readings...however i doubt it would change anything...as has been stated before, precision is less important than consistency.
ddewees Posted September 3, 2015 Posted September 3, 2015 In most cases, if you're doing it right, there is no contact with either the spindle or comp inside the drift. Granulating/Ricing your propellant greatly helps in this area, but even dry powdery comps aren't much of an issue. Drifts should be cleaned out after each increment...
schroedinger Posted September 3, 2015 Posted September 3, 2015 Press the nozzle clay to full force, after that just start with about 2/3, then 3/4 of force and rais it by gut feeling works good. On the last rammer around the spindle use full force. If you go full force the whole time it also works good, but the tube will be 5 mm shorter then with reduced force.
rogeryermaw Posted September 3, 2015 Posted September 3, 2015 Mumbles, thank you for the link but it may be broken. I am on a phone so I'll try the computer later but the page opens and says only "not found"
ddewees Posted September 3, 2015 Posted September 3, 2015 I can't press nozzles to full force... I'd never get the drift back out. I typically press nozzles to half force, then hope the next increment of propellant finishes the job. I've fought with too many stuck rams in clay to ever do that again. 1
Mumbles Posted September 4, 2015 Posted September 4, 2015 Fixed the link. As per usual, it added a space into the hyperlink for no reason.
Col Posted September 4, 2015 Posted September 4, 2015 (edited) I can't press nozzles to full force... I'd never get the drift back out. I typically press nozzles to half force, then hope the next increment of propellant finishes the job. I've fought with too many stuck rams in clay to ever do that again.I press to half the force and then tip out any excess clay before pressing to full force accounting for the area. The drift gets stuck because the loose clay automatically gets between the spindle and the drift when you insert it Once its semi compacted, clean out the drift and remove the loose stuff from the tube, you can then press it to full force and the drift will come out without too much effort. Edited September 4, 2015 by Col 1
ddewees Posted September 4, 2015 Posted September 4, 2015 I'll give that a try Col, thank you. I have noticed there is always something loose in there after pressing a nozzle if I tip the motor over.
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