Author Topic: Presses  (Read 1166 times)

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Offline Bismuth

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Presses
« on: October 13, 2013, 09:57:01 PM »
What presses are you guys running?

I've got an arbor for simple stuff, but I'm looking into getting a more serious one going capable of bigger devices. The whole topic has my head spinning for what is going to be the best pick. Right now I'm just looking at making one like Ned or what really was first put out as Dan William's press, see: http://www.skylighter.com/fireworks/how-to-make/hydraulic-rocket-press.asp#news
                                                    http://www.brianredmond.net/dwilliams/press/press.html

But then I've got the issue of my hand falling off from all the manual jacking. Then there's compressed air driven hydraulics and all that. That's when I do a lot of reading and you get so many mixed opinions some saying compressed air is not the way to go, and opinion after opinion. So what is the best way to go?

Offline leedrill

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Re: Presses
« Reply #1 on: October 14, 2013, 12:48:58 AM »
hey bismuth ill say i dont know much about the pneumatic rams but they have their limits depending on size just like gears they get pretty big to do larger jobs. ill say this, i want my next press to be able to press 8" comets to shoot straight from the gun. now to me id want to press the comet to that of a bp motor or whistle but seeing that i just re did the calculations like 100 times questioning my mathematic skills can some one check over this for me if they feel im wrong because i feel its not right { area of 8" circle = 3.14xr2 ,   3.14x{4x4}=50.24"squared  . 


http://www.translatorscafe.com/cafe/EN/units-converter/pressure/38-31/psi-ton-force_(short)%2Finch/


as per that site it does not do metric but in long tons , 6500 psi to long ton of force per inch squared = 2.90 long ton and where as the long ton is      2240 lb the metric tonne is 2204 so to say youd want a bit more than is needed keep it at the long ton so 2.90ton per square inch x 50.24 square inches = 149.696 ton jack required for an 8 inch with 6500psi on the comp im sure you could get away with less but ill say after working around anchors and drtlling i have a pretty good knowledge of hydraulics and after doing 32 strand anchors with a 750 tonne jack i really cant imagine any pneumatic or hand operated jack really working when you say you want to get something bigger what do you have in mind

Offline Bismuth

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Re: Presses
« Reply #2 on: October 14, 2013, 10:56:02 PM »
I only want to do rockets up to 3lb, and use the press for comets and starplates.

I looked over your calculations and the answer you've obtained seems illogical considering there's barely 60t presses for sale to the public. The mathematics seems fine, but I think there's a problem with reasoning and something has been left out. Such as where is the tool-end in the calculations? As an engineering student, I probably should understand this all better than I should, but I just never bothered with this stuff (till now).

http://www.wichitabuggywhip.com/fireworks/rockets/presses.html#pressure

Is a great website to check out for calculations.

Offline leedrill

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Re: Presses
« Reply #3 on: October 15, 2013, 12:29:45 AM »
http://www.amateurpyro.com/forums/gallery/image/2320-press/    you have to add me as a friend on apc to view but that is my press i had to weld on the square tube on the bottom to have enough room for my 3lb core burners  and even with a 2" high P2F gauge i have room to spare it cost me $80 in total and came with a 6ton jack but i have a 12 ton that fits it but would want to reinforce the welds before making it out with a larger jack not my welds but the factory weld on the frame . i have 2 sheets of 5mm hardened steel on the bottom for the working area and the threaded rod and poly carb for the blast screen i want to triple up on the screen though all 1cm apart from each other i will feel much safer when i do that


as for your statement about my calculations the tool end is not included because i would plan on having an external p2f gauge so you will always know your tooling calculations by knowing the surface area of the inside of your tube or comet pump ect ect.   so if you know the size of the piston in the p2f gauge then you go off that in relation to the tooling/id area i.e. if i where to  press a tube with 1"squared surface area to 6500psi on the comp and the P2F guage had a 1" squared area piston then i would have 6500psi on the comp and the jack piston area and so on is irrelevant and i can do the maths on how much force the jack is applying by knowing how much pressure is on the comp {6500psi= 2.9long tons for 1" squared area }    i.e.   6500psi on an 8" id =   {area of 8" circle = 3.14xr2 ,   3.14x{4x4}=50.24"squared }    so if there was a P2F guage that went that high it would be {6500x 50.24} 326560psi


 as i said i have worked a lot with very large jacks and on the large anchors when underground in tunnels ect ect  in the wall we have drill in install a extensometer and put load cells on 10% of the anchors the extensometer measures vibration while rock breakers and blasting takes place the measure the vibrations and the load on the anchors with a computer  { you are right none of us have easy access to these things  }

but say i had a P2f guage with a piston the same size as the as the area of the id {50.24" squared then the gauge would read 6500psi instead of the very dangerous 326560psi which you wouldn't achieve even at the deepest point in the ocean but the jacks i use at work have their own detachable calibrated gauge that runs off the internal ram of the jack

this is what i use at work

http://www.precisionpt.com/pdfs/multi-strand-stressing-jacks-609-cs.pdf

and this is what i want in my shed the 200ton version of course
as im sure anyone would
http://www.enerpac.com/en/industrial-tools/hydraulic-presses/bpr-series-roll-frame-presses

now i will say even after all that 150 ton for a 8" rammer not only seems illogical but more than is needed would probably not even need to bind them if pressed like that or 1% moisture would probably never find its way out this is why ive asked someone to check over my first response because 150ton seems crazy but id like to think i kinda know what im talking about with pressure and force but i really dont know that much only what ive done but is good to talk about it

my jack is from supercheap 6ton and is a great buy at about $80 if you want to go that option very easy to modify and sturdy little setup  dont know wether id manage the 4lb core burners though with the extra couple of inches maybe if i had 7 rammers that i could change after every 3 increments

sorry for the lengthy response and lack of punctuation 

Offline leedrill

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Re: Presses
« Reply #4 on: October 15, 2013, 12:52:16 AM »
sorry i forgot to add as im sure you would know but thought id add it for any whom read this in your link   

http://www.wichitabuggywhip.com/fireworks/rockets/presses.html#pressure

the only real relevant part as the way i see it is this sentence



To be very accurate, you could use one of the PtoF gauges sold by Wolter (see picture above) and know exactly what was applied to the top of the ram. Use that number, divide by .3068 for a 5/8" tool and you are done. However, it is more important to be consistent that extremely accurate.

 because in the chart on the bottom  it is not stated which id assume it is supposed to be all the first no.s are in psi and the next no.s are in pounds per internal surface area  which is why i keep questioning my calculations because say my 50.54" squared is rounded off to 50 to make it simple then i have 6500lb of pressure on each square inch so 325000= 147metric tons it seems so logical but yet such a large no.

Offline Falcon

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Re: Presses
« Reply #5 on: October 15, 2013, 08:54:12 PM »
Wow leedrill, talk about going all out, that's some head spinning stuff!

Here's what I use for pressing my 4lb BP core burners and making black powder (12t hydraulic bottle jack)


This is not actually my press, but its very similar (same construction) just used the image for showing you.

12t is plenty of force - I worked it out that I use roughly 6t for pressing the 4lb motors to 6500 pound force

As for the manual aspect you mentioned; I find manual pumping is easy, and it also makes it very easy to control the force on the tooling. If you over do it you can bend and damage the spindle, or jam the piston on. I find the manual control very good here.

Another benefit is that these presses are comparatively cheap, ~$130-$150, with everything included.

I broke my last press which used a wood frame (pretty thick though) and 6t bottle jack. I was in the middle of pressing BP when this happened so I needed a press, quick, to finish. That's why I went and got one of these (on the same day too!) from a somewhat local store (Paramount Browns) So far its done everything I have needed it to.

When I'm pressing 3/4" or less devices (fountains, rockets etc) I just use my 2t arbor press, its so easy but the stroke isn't that large

Offline Bismuth

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Re: Presses
« Reply #6 on: October 20, 2013, 08:51:00 PM »
What arbor press do you have Falcon? And what sort of PSI can you get out of it?

Offline Falcon

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Re: Presses
« Reply #7 on: October 20, 2013, 11:05:06 PM »
2 ton arbor press - measured at 400 psi with a wolter pressure gauge:
http://machinerydisposals.com/page9.php?view=productPage&product=133&category=19

Could probably get a lot more pressure out of it if I bolted it down and used a longer arm, but that's just with only moderate effort at 400 psi.

Offline Bismuth

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Re: Presses
« Reply #8 on: October 30, 2013, 08:52:07 PM »
Catched up with a civil engineering subject that I have an exam for, and in the stages of planning for my power-pack hydraulic press -- my mathematics is now up to scratch again..

Your calculations are correct Leedrill, but there are some issues with the whole idea in itself. Aside from the obvious fact that a 8" comet is a ridiculous size (which is why they hardly exist -- you need a HUGE press), you could probably get away with much less PSI on the comp than 6500 psi. Ned Gorski presses his 4' comets at 2000 max PSI for example. There's no harm with pressing higher psi, apart from maybe charcoal base compositions, which apparently lose their integrity with higher PSI -- but other people have pressed glitter comets at 4000 PSI. You'd also probably put a large cavity into a 8" comet if you were to do it, and that would decrease the surface area on the comet itself too.

I'd make a meteorite shell before I made a comet that big. This is all based off reading and just what I think,  I don't have PRACTICAL experience with making large comets.
« Last Edit: October 30, 2013, 09:27:00 PM by Bismuth »

Offline leedrill

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Re: Presses
« Reply #9 on: October 30, 2013, 11:58:10 PM »
cheers for checking on the maths bismuth as im sure a couple of people thought in my first post 150ton is crazy. Even for that size i mean to be honest i did not think pressure would jump that quick with larger id sizes and yeah that sounds about right i mean most of the comets and stuff are hard because of a binder. To take a famous phrase { no point in re inventing the wheel } i mean i have not seen anyone pumping stars or comets to that high of a pressure with these things the binder is heavily relied on and the pumping is just to hold shape while curing and get a good density.
 
Makes sense with the charcoal based ones unless everything is milled quite fine you would get a sponge effect of it wanting to retain shape

{obviously this would lessen with softer char but the hot charcoals arnt as desired in streamers and the likes of other effects }

yes the meteorite shell would be cool but incase you have not seen an 8" comet here is some footage from this years pgi
im pretty sure they are made by bill bahr and is the  phenolic bound comp off fire working


here is one getting blown to pieces out of the tube

★ FIREWORKS ★ GIANT VOLCANO MINE ★ 8" COMET ★ PGI 2013 ★


and 2 performing

8 inch Ti comets


now you cant deny how cool that would be up close id almost rather see that than a meteor shell