Press safety ?

[50AE]

I have a 3 ton hydraulic cric lingering around and I was thinking if it would be practical to make a press with it. But I live in a residential area, so I can't afford to have an explosion and it seems one can be quite powerful when people are putting blast shields on their presses.

My main purpose it's to press BP, fountains and BP fueled rockets and small devices. My question is it is risky to get an accident from pressing these devices ? Should I even build a press ?

Edited August 1, 2009 by 50AE

[Aneantis]

You should! A press is very handy in rocketry! Pressing Bp rockets and foutains without metals is very safe. Even pressing Kclo4-whistle is quite safe. Things change when your using metals in bp or whistle!

[50AE]

What if I'm pressing fountains with metallic microstars or some large mesh metal powders like Al and Mg ? Edited August 2, 2009 by 50AE

[Aneantis]

Be sure that you have some protection, if anything would go wrong that you're safe. I my self have a blast screen when I press whistle with Ti.

 

I don't know if there have been any accidents with pressing powders with metals.

[Mumbles]

The only two accidents I know of happened without metals oddly enough. One with straight whistle, one with straight BP. Nothing is completely safe, but a press with a blast shield is about as safe as it gets. If you're planning to be making those devices anyway, a press wont make them any less safe.

[Seymour]

Well, ramming a black powder rocket/gerb is likely to only cause burns as the rammer is shot out.

 

With a press it is not going to be able to eject the rammer, and you have an explosion guaranteed.

 

 

Mumbles, what was the tooling made of with the BP accident?

[Mumbles]

Wooden tooling. It was being rammed too by the way, not pressed. The individual lost at least half of three of the fingers on his left hand. I've heard of someone else (Dan Creagan I think), having the rammer shot out of the rocket and it turned into a gerb in his shop. I guess my friend wasn't so lucky.

 

It was winter, so we think that the very dry atmosphere might have caused a static spark.

[TheEskimo]

Hmmm...I ram all my BP rockets with a nice rubber mallet. I do be sure to wear a good facemask, earplugs, and gloves. I even add in some nice -145 spherical Ti from Skylighter(from the half-off sale; it gives a nice crackle, too). Anyways, I have heard that wearing nice, tough leather or composite workmans gloves can save your dirty little hands from an accidental explosion. It keeps your hands from getting burned, and leather or composite gloves are very resistant to tearing. Anybody hear of this, or have any experience that corroborates or negates my comment here?

[tentacles]

I would suggest NEVER ramming any comp with Ti in it - even spherical. I have a buddy who had a rocket blow up on his press - he was maknig the classic mistake of pressing metal containing comp around a spindle.. Took him a week to find the rammer, and it destroyed his Wolter tube support instantly. Even if you're not putting it around the spindle, if you had a CATO while holding the tube, I doubt there's a glove that could save your digits.

 

He also thought strobe mix was fairly insensitive - said he couldn't get it to go up hitting it with a hammer, or with a drag test on concrete.. I'd warned him a couple times to treat it like flash (much more so than whistle) and now he's got nasty burns on his hand... from grinding riced strobe mix in a mortar and pestle.

[50AE]

So I really can't afford an explosion. So I have to move to a house in the province to be able to use a press. But if I ram and there's a small gap between the rammer and the tube, an ignition will make it shoot out. A press won't and my neighbors won't be happy.

But I won't be able to make corned BP and I'd really like to.

[Ventsi]

I corn my BP by just making it <damp and ramming it in my 1.5" pump into 1/4" pucks, when they are dry they tinkle like ceramic! Makes some damn fast BP.

[Swede]

I have and use a press, but I limit it to straight BP. I think it makes a superior rocket. You can't get 10% of the compaction with a mallet than you can with a press. You can overpress and split the tube, or even bulge the tube support, there's so much power. Nozzles become almost ceramic.

 

A piece of acrylic should keep you safe. Honestly, if you limit yourself to BP or whistle, it should be fine. I think there's more hazard in ball milling BP than hydraulically ramming it.

 

Let's clarify nomenclature: I've been busted here before on pressing vs. ramming. I understand most people think ramming is a hydraulic operation, and pressing is a hand/mallet operation, but in the machine tool biz they are always called "Hydraulic Presses" not "Hydraulic rammers" and this is confusing to me. What's the answer? This is like talking about polverone, riced or corned BP, mill dust, etc, everyone has a different definition.

[Aneantis]

Hi today I did a little test on this subject.

 

I wanted to know if my blast screen on my press would save me when I have an accident while pressing a 1Lb motor. My blast screen is made of two 4mm plexi plates embedded in a wooden frame.

 

So I used a 20 and a 30+gram whistle-device placed 20cm behind the blast screen. The whistle used was high-quality oxy-whistle.

 

http://www.youtube.com/watch?v=EwZnUogRjlM

 

 

I'd like some feedback on this one, and does anyone know the probability of a mishap?

[scarbelly]

@Swede: I always thought it was the other way around. I thought ramming was with a mallet and pressing was with a hydraulic press?

[Bonny]

As far as I know, ramming is witha mallet etc... and pressing is with a press, be it hydraulic/pneumatic or a screw type. Where the risks increase in ramming must be (at least partly) attributed the rapid shock from the mallet. In the case of a press, the force is applied in a slow even fashion.

[Ventsi]

Swede, I agree with Bonny and scrabelly, pressing is with a press and ramming is with a ram{hammer/mallet etc,.}.

 

 

Aneantis:

Great test! Its awlays good to know what could happen. That shield will surely save your ass. Its awlays nice to see other folks concerned with safety.

[Aneantis]

Tnx, you can't be careful enough . I had no idea that whistle can created such a blast I hope the guys that make 2 & 3Lb all have some very good protection.

 

Maybe it saves me but I think my ass would be burnt .

[Mumbles]

If you can find any, I'd suggest trying to find Lexan(polycarbonate). I just have a aversion to plexiglass (acrylic), due to it's shattering.

[Eric70]

It is good to see people are concerned about safety.

 

I am fairly new to all this but have been making BP rockets for over 3 years now. From reading various publications and zeroing in on information posted by seasoned veterans I have come to some conclusions:

 

Any mixtures such as whistle mix containing chlorates are sensitive to shock and friction and should be treated with care. Chlorates have a tendency to be reactive with acids and metals.

 

Nitrates are far safer, black powder is a low-risk endeavor but you still must be mindful of safety measures that include using non-sparking materials, consideration of static electricity and fire hazards that include cigarettes or someone using an open fire pit or grill next door. Wear clothes made of cotton when working with pyrotechnics, don't wear a wool sweater or polyester shirt and slacks because such materials conduct static electricity.

 

Work outside or in a shop that does not have any cans of petroleum or other materials that could catch on fire if something went wrong.

 

Ti (Titanium) should be added only to the delay section above the spindle on cored BP rockets. This spares your spindle of premature wear and the concern of accidental sparking is eliminated.

 

I add a small amount of spherical Ti to the delay section on my 1 lb BP rockets and it sure adds a beautiful effect towards the latter half of the flight!

 

Yes, ramming is done by hand with a mallet. Pressing is done by mechanical means, e.g. a hydraulic press. For ramming use a rawhide mallet or dead-blow mallet that has a plastic composite. A regular old metal carpenter's hammer should not be an option because it will destroy the ends of your rammers and the risk of sparking may or may not be there.

Edited August 11, 2009 by Eric70

[Swede]

On the press vs ram issue, thank you for those who chimed in. I was chastised earlier for using the words incorrectly, but I agree with all your definitions, and this is what I thought all along were correct:

 

PRESSING = smooth, steady hydraulic action

 

RAMMING = pulsed, somewhat violent malleting or similar. I think Hammered would be a better term.

[drtoivowillmann]

Some security tips from a professional:

 

* Never press whistles, they may undergo detonation and tear off and throw around metal parts of you press or pressing-mold.

* If you use pressing molds which cover your paper tubes, the prts that cover never must be made of metal but of industrial

BAKELITE, like Celeron or Pertinax (two famous brands of it).

* Put your body close to the comand of the press and install firmly a steel-shield of about 5/8" thickness between your body

and the pressed good.

 

That's all ! Good luck and enjoy your work !

 

Greetings from Brasil:

 

Toivo

[Bonny]

Some security tips from a professional:

 

* Never press whistles, they may undergo detonation and tear off and throw around metal parts of you press or pressing-mold.

 

 

Toivo

Whistles have to be pressed (NOT RAMMED) to consolidate...how else are they supposed to be made?

[dagabu]

Some security tips from a professional:

 

* Never press whistles, they may undergo detonation and tear off and throw around metal parts of you press or pressing-mold.

* If you use pressing molds which cover your paper tubes, the prts that cover never must be made of metal but of industrial

BAKELITE, like Celeron or Pertinax (two famous brands of it).

* Put your body close to the comand of the press and install firmly a steel-shield of about 5/8" thickness between your body

and the pressed good.

 

That's all ! Good luck and enjoy your work !

 

Greetings from Brasil:

 

Toivo

 

In a way, I agree with Toivo. Whistle mix has a lot of stored power in it. Pressing has been somewhat problematic and there have been accidents making whistle rockets.

 

He is correct that the brisiance of the whistle mix will part the clamps, shatter the casing support and send it all out radially in a spray. The problem with phenolic (BAKELITE, like Celeron or Pertinax) materials is that they too will become shrapnel and will cause injury just like PVC.

 

Where I disagree is the idea that a clam-shell (if that is what he meant by metal) is more dangerous because of the material used. This is simply not true. Clam-shells will survive the detonation intact (two halves separate from each other) where hose clamps will not.

 

The other place that I disagree with Tovio is the idea of 5/8 plate steel for protection. If I were concerned with being shot, I would agree but but the idea behind a safety shield is not to withstand the blast intact but to absorb the impact.

 

"What the hell?!"

 

Please let me explain: The shield is attached to the press and if it is like my press, it weighs a little more then 100#. I place a 5/8" sheet of steel on the pump side and now I have 200# of steel that when a motor detonates will end on top of me mitigating any benefit of the shields protection. OK, lets bolt it down, now I have a press that will not only land on me but will not move when I push on it because whatever metal is still attached to the floor is going to hold it down on me.

 

Has anyone seen Danny Creagans video with a blast shield and 500grams of whistle? It is a single sheet of (1/2"?) poly carbonate and it is shattered by the blast, no bolt holes, no mounting just sitting there in a field. The function of the shield is to absorb, deflect and protect the person in front of it, NOT cobtainment. a 5/8" plate will become a missile and because of the mass, the inertia will compound the soft tissue damage.

 

A shield should be mounted to separate from the press (press stays there and the shield is blown off) , absorb as much energy as it can and stay intact so that shrapnel cannot penetrate flesh. Only multilayer plywood or multilayer polycarbonate will do this effectively.

 

These are not my ideas, these ideas are taken directly from the EOD FM 9-15 manual.

 

Ideas?

 

(Please make your disparaging comments to the US military, they wrote it.)

Edited January 25, 2010 by dagabu

[KruseMissile]

^ was the EOD doing it with HEs(like they usually do) or whistle type? Also how does a bolted down press land on top of you after an engine explosion? Is this information good for small rockets at 1lb size? Thanks

Brian

[dagabu]

^ was the EOD doing it with HEs(like they usually do) or whistle type? Also how does a bolted down press land on top of you after an engine explosion? Is this information good for small rockets at 1lb size? Thanks

Brian

 

Forgive me for my blunt reply:

 

The book I am referencing speaks to force, brisiance, absorption, its not a HE or LE book.

Picture the press against a wall where most of us put them, the wall acts as a mirror reflecting the blast back at the press. The shield if mounted too rigidly acts like a parachute capturing the force of the blast. The force has only the sides to escape since the top and bottom are used to press the rocket.

 

Now for the math: If a 3/8" anchor bolt has shear force of 1000# and four are used to bolt it down, one in each corner, the back two will be subjected to the shear force, not the front two. The front two bolts become the fulcrum and the blast shield becomes the application point which on my press is four feet from the ground. The distance from the front to the back bolts is 12" giving the lever a 4:1 ratio thus the blast of the rocket motor only needs to provide 500# of dynamic energy to shear the back two bolts and send the entire press into your lap.

 

"The force applied (at end points of the lever) is proportional to the ratio of the length of the lever arm measured between the fulcrum and application point of the force applied at each end of the lever. Mathematically, this is expressed by M = Fd."

 

I do not know what the actual force of a 1# whistle or black powder rocket would be, perhaps someone here would have that information.

 

I hope this helps some.