Tube support

[Davidg1]

Can anyone in the UK supply one of these to fit 1lb tubes?

 

http://www.skylighte...ell-Support.jpg

[mikeee]

Some pyro's use pvc pipe and stainless steel hose clamps.

Some pyro's are also using rolls of light gauge brass wrapped around the tube with hose clamps.

[Davidg1]

Yes.done both but the hose clamps and tubing are not efficient when making several motors.

[Col]

I use an electric screwdriver fitted with a socket for the hose clamps, it only takes a few seconds to reach the torque setting. A clamshell is nice but they`re a lot more expensive than a basic tubular support. I press 10 motors in a session, tightening and loosening the hose clamps is the quickest part of the job

 

[mikeee]

Davidg1,

 

I agree the pvc pipe and hose clamps really slow down the process when making a number of motors.

I have also messed up a spindle trying to use a pvc tube support.

The metal machined clamshells are nice and quick to use.

I have a couple of supports manufactured by Ben Smith that are quick to put on and take off. (Collet Sleeve)

You might check and see if Ben Smith will ship to your location.

http://www.firesmithtools.com/#/tube_supports/

[mikeee]

I read an article about some of the builders that make large motors over in Asia that use sand packed around

the tube to support the motor pressing process. An oversize pipe with sand poured between the outer wall of the

motor tube and the inner wall of the pipe. You would need a screw in collar on top to contain the sand under pressure.

When the motor is pressed remove the screw in collar and pour out the sand, the motor should come right out.

[leedrill]

the clam shell and collet sleeves would be so nice to have but the problem to me is the price i only make 3lb motors but in order to to make my bp core burners /whistle / endburners /and stingers id need 3 different length supports i could get away with using a 7" support from ben for the 4" stingers but would need longer custom rammers and same for the 10" coreburners. the endburners would need longer rammers so in turn to make the array of motors i make now id need both of the 3lb supports being $630 for both and would still need custom rammers for my stinger tooling total cost of some where around $700 i really cant justify that

 

and when going from worm drive hose clamps to t bolt hose clamps the cheaper option is quite good and quite quick with some practice and i can get up to 10 000 psi with the t bolt hose clamps with the worm drives the start to snap by the 5th or 6th increment because they just stretch under that pressure and go flying accross the room and when pressing whistle its rather nerve racking

[mikeee]

I was reading an article on pressing motors written in the late 90's and they covered different styles of tube supports.

One of the types was a clam shell made of hard wood with bolts going thru both halves just like the metal ones.

If you could get some good hard wood and use a steel or aluminum plate on the outer side of each half you could increase the strength.

It would be pretty easy to drill or router a hole the correct size to match the OD of the rocket tube in the wood.

You could also use the same concept using a hard plastic material instead of the wood with metal to back it up.

[Col]

leedrill,

maybe you could drill and tap the top of the rammers to add an extension like a pool cue? The extensions would only need to be basic round stock, drilled and tapped, You might get away with off the shelf hexagonal bar (internally threaded) as long as it fits inside the tube, the business end of the rammer will keep it straight.

[leedrill]

i have thought of this before and also just thought of just doubling up the rammers with only the bottom one tapped with a t-bar with thread on the bottom to use as the bottom rammer extractor but still means almost $700 in extras as opposed to my home made supports

[hindsight]

Since Mikeee mentioned Ben Smith's tube support, thought I'd mention Rich Wolter's http://www.wolterpyrotools.com/image/pyrotool_194.jpg. Rich does beautiful work, has customized tube supports for me and others, and his off-the-shelf "special tube support" works like a charm.

[mikeee]

Wolter Company also makes top quality tooling for the pyro industry.

They also provide other pyro products, equipment and custom services.

Both Ben & Rich will make custom products for anyone that asks for it.

[Gunzway]

My problem with tube supports is that voice at the back of my head asking 'What happens if the rocket I'm pressing goes off with the support on the tube?' Especially for larger whistle rockets, I can't even imagine what a PVC support would do. Yes, any sane man would use a blast shield, but that's not to say it's safe. It only takes one person to walk in to check up on you and a freak accident to happen.That's why I also prefer Wolter's design over Ben's. Wolter's SHOULD snap into two and if orientated, will go left and right of the operator. Ben's? I can't say for sure what happens if a 6lb whistle rocket goes off.

Edited October 22, 2013 by Gunzway

[leedrill]

i have to say that is the most valid point in safety of the two designs i have heard {am surprised i haven't had it come up in conversations about them before } let alone i have not really thought about them in that way as ive said to a few people i want my blast screen to be layered i really dont feel safe behind one sheet of poly carbonate even a 1" thick piece would not prevent as much as 2 x 1/2" pieces with a 1cm gap in between them but to say that one of bens supports ruptured pressing a larger motor id have to say 10 x 12" pieces might not leave you injury free and there would be no way to be sure which way the support rings would fly let alone how it would let go but with rated bolts in the clam shell design you would definitely be safer in my book if being conscious of orientation

 

once again great point i have finally gotten my act together to start making some clamshell style supports will be sure to post some pics when done

[Col]

For 6lb whistles its probably best to use a remotely operated press with a nice thick steel blast shield. Here`s an article on shield material performance.

http://www.thecalderwoods.org/tom/blastShield1.htm

I think the method used to attach the shield to the press is at least as important as the shield material, the strongest material wont help if it doesnt stay put The location of the press is a consideration, most seem to be located against a wall which will tend to reflect the rearward wave back at the shield,

Apart from shrapnel, you may have a fireball to deal with, If the fireball tracks up the wall behind the press, it could use the ceiling to get above or behind you, especially in a small confined workshop. Some jack based press designs dont provide much protection to the hand that operates the lever.

Edited October 22, 2013 by Col

[Gunzway]

@Leedrill: Cheers. Two sheets with a gap definitely improves the overall integrity of the shield. You press pretty large motors quite regularly, so it's definitely a consideration that should be made when using tube supports. But that goes for even the person who presses only the one in their life-time too

 

Look forward to seeing the finished product!

 

@Col: Nice link there --- bookmarked. Fair point on what I would think is a neglected consideration when affixing the shield material to the press - that it needs to be attached firmly. You nailed my other thought on the head too. I was thinking about the idea of reducing the shrapnel throw-out (especially when using a PVC support) by placing it against a wall, so it didn't fly in all directions (360 degrees subtracting blast shield) . But then I began to wonder at the consequence of the force of the explosion being reflected and confined to one direction. I wonder what sort of damage it could cause. I've got no real solutions right now, and it's something I'd like to work out.

 

I don't know anyone personally who has had a press accident with a large whistle rocket. There is a talented whistle maker here who doesn't post much anymore who I re-call having an accident pressing one. Nothing serious apart from a fright and singed leg hairs. All dependent on how much fuel is pressed into the tube as well. I wouldn't think many accidents happened past the spindle region when pressing?

[Bensmith]

In all reality, it isn't absolutely necessary to have tube supports sized for each standard length of motor. It's certainly convenient to have supports sized for core burn and end burn motors, but as other have mentioned, one support is all you need. Longer rammers marked appropriately will allow one to use these longer supports with shorter motors (and these longer rammers aren't that expensive at all). Stingers actually work quite well without a support. A simple 1 ton arbor press is all you need. They are quite forgiving...

 

In reference to accidents. I've been around two accidents that occurred while building rocket motors. One happened right next to me and the other just a minute or two before I got there. In both situations the rocket ignited while a rammer was being removed. Bits and pieces of flaming fuel went everywhere. The PVC tube supports shattered and peppered the area with shards and hose clamp bits. The damage was minimal but could have been much worse had a bunch of loose comp been lying in the area. The injuries were primarily scratches and lacerations from the PVC and clamps. A few burns where rocket fuel landed on clothing and skin but that's really all. The likelihood of an accident happening while building a motor is not during pressing.... it is while the rammer is being twisted and removed after pressing an increment. This is the point at which friction is introduced to the building process. This is why it is absolutely essential to clean your rammers after each and every increment of fuel. Failing to do so causes fuel to get caught between the bore of the rammer and the spindle. Friction introduced when removing a rammer can (and does) ignite the fuel.

 

In the above situations, plastic supports shattered and sent debris everywhere. A metal support would hold up just fine. The rammer and spindle would be sent flying, but the support will still be sound. If an accident were to occur while pressing, the support (either a two piece design or my collet design) would bend and "burp" at the joints. The support would be rendered unusable, but certainly wouldn't shatter. This was tested a while back by ematching a whistle motor inside a support and press. The results weren't really as sensational as one might imagine. However, with this being said, accidents are far more likely to happen if your work area is a mess, you have comp lying everywhere and you fail to clean your rammers after every increment. An accident while pressing a motor is significantly less likely to occur.

[leedrill]

thanks for your input ben great to hear your feed back

 

ill definitely say id love to see a vid or pics of the e-match to motor in a press testing mainly just the aftermath

 

ill agree with you that one support can be used and would be cheaper to buy rammers for the 3 main motors in one size but i have taken to wanting to press everything not ram and i know have a support for hummers, stingers, endburners, gerbs , coreburners , and buzzbombs all with kind of different rammers and my spindles have been aquired over time not with the quality supports you and others offer in mind i wish i had of invested in a support first and had everything else in mind while buying tooling i.e. rammers to suit . but will not see it being worth it cost wise unless i make all the rammers my self witch to be honest will never be of the quality of yours