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Prometheus Hard Pistons

Sonic01

By Sonic01,
in Technical Discussion

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greg

greg

Posted
Posted
The only difference between the max and the regular is that you get a half tooth piston. This is necessary if you're running helical gearsets. I've used the regular piston in 500fps applications with no problems. They are made of the same materials. In fact, the regular piston has more material.

 

Helical gearsets are a joke. They actually CAN'T handle as much force, they just mesh cleaner. Also, any error in engagement will destroy them.

 

Again, thanks for clearing that up. ;)

 

I will be giving these a go. I'll let you know the results after I've stuck one in my hi-speed, piston chewing cqb test bed. (P90 :rolleyes: )

 

 

Greg.

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greg

greg

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For things just like a piston its sometimes worth just buying the sucker in the UK rather than importing considering the higher shipping charge and potential for being stung by customs which is whatever that may be plus 13.50 if you do get picked up.

 

http://www.airsoftqms.com/index.php?cPath=28_39

 

Prommy Pistons in the UK for those looking

 

 

Oh, my.

 

I love you. Placing an order as we speak. (Oh, it's only 8:15, they ain't open yet :rolleyes: )

 

I am the unluckiest importer in the UK. Without exception, I always get held up (the record was 6 weeks on a prommissed 3day delivery, that arrived in the UK 2 days after placing the order!), taxed & faulty products, that aren't worth returning.

 

This is truly good news.

 

Blimy, I've just had a propper look at the site. They've got the lot! Even promy barrels.

 

I bet they ain't in stock :rolleyes: .

 

 

Greg.

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Vercingetorix

Vercingetorix

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I am a bit novice when it comes to dremel bit names... which ne exactly is the milling bit? I used a blueish-greed conical shapped bit that came with my kit.... Also, anyone got a link, or can explain how exactly to do this angle of engagement correcting? I am gonna probably go with a lipo soon, putting me in the 30rps range with 400 w/ .25s, so I'd like to correct that and have my setup last longer... I was thinking of getting some sorbthane and cutting em into pisto shims, would this work? Sorry to derail, but I've always been curious....

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greg

greg

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Oh, my.

 

I love you. Placing an order as we speak. (Oh, it's only 8:15, they ain't open yet :rolleyes: )

 

I am the unluckiest importer in the UK. Without exception, I always get held up (the record was 6 weeks on a promised 3day delivery, that arrived in the UK 2 days after placing the order!), taxed & faulty products, that aren't worth returning.

 

This is truly good news.

 

Blimy, I've just had a proper look at the site. They've got the lot! Even promy barrels.

 

I bet they ain't in stock :rolleyes: .

 

 

Greg.

 

 

Can you believe this:

 

I finally find a UK promy supplier, &,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

 

They can't supply any thing 'till next week due to a dispute with their carrier!!!! :mellow:

 

Never mind, at least they have them in stock, & after 3 years (that is when AD shut down?) another week wont hurt. :rolleyes:

 

Fingers crossed I'll bust a piston at GZ this weekend, so I'll have something to shove a new one in. :D

 

 

Greg.

 

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greg

greg

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Also, anyone got a link, or can explain how exactly to do this angle of engagement correcting? I am gonna probably go with a lipo soon, putting me in the 30rps range with 400 w/ .25s, so I'd like to correct that and have my setup last longer... I was thinking of getting some sorbthane and cutting em into pisto shims, would this work? Sorry to derail, but I've always been curious....

 

No link. Do a search for more precise details, but basically it usually involves backing th piston away from the cylinder head with spacers, in order to align the pick up tooth (on the back of the piston) correctly with the gear.

 

It is rarely correct with out of the box set ups, unless the manufacturers know something we don't. Typically CA pistons are about 3mm too far forward & others can be up to 5mm out!

 

The correct thickness Sorbthane stuck securely to the cylinder head would seam like a great idea. I have not heard of anyone successfully doing this. I think it would help noise reduction & reduce stress & vibration too. Laylax sell sticky back washers made of it it for VSR's to reduce noise & I use it in both of mine. It comes with a tougher dubber stuff that sticks on top & faces the piston head. Th e diameter is about 5 mm smaller than an aeg cylinder, but they might do.

 

I think it should be fine in semi's but it may not hold up under full auto. & like on the vsr, it will be a real pain if they break free! Unlike the vsr, this wont take a few minutes to fix. :huh:

 

 

Greg.

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infected

infected

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The correct thickness Sorbthane stuck securely to the cylinder head would seam like a great idea. I have not heard of anyone successfully doing this. I think it would help noise reduction & reduce stress & vibration too. Laylax sell sticky back washers made of it it for VSR's to reduce noise & I use it in both of mine. It comes with a tougher dubber stuff that sticks on top & faces the piston head. Th e diameter is about 5 mm smaller than an aeg cylinder, but they might do.

 

Um, Greg... I'VE DONE THAT. :)

 

My M249 and Spoonman's Mp5 and M14 all have sorbothane on the cylinder heads. It makes the gun quieter and absorbs the impact better. It also corrects that angle of engagement. I'm currently experimenting with putting sorbothane betwen the piston head and piston body. This allows you to adjust the AOE, without losing volume in the cylinder. The possible downside is the weaking of the piston head due to the ability to slightly piviot since it is mounted to the spongy sorbothane. We'll see how it holds up this weekend.

 

More info on sorbothane can be found here:

http://forums.airsoftmechanics.com/index.php?topic=1109.0

 

As for AOE here are two pictures (one with Good AOE and one with Bad AOE second)

right32dd6626tv2.jpg

wrong32dd3c47as7.jpg

 

I believe it was Corvid who supplied these pics.

 

There will be more on AOE when I do my 100% gun write up.

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infected

infected

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`yeah, I was thinking of using it(the sorbothane) to shim the the piston/piston head, and if you were to just tighten up the piston head and apply loctite, I doubt it'd get to loose, especially if your the type that does an internal checkup every 1-3 months or so.... Thanks guys!

 

Careful with that loctite. I've found that most brands will soften plastics (just ask my poor m249). I've had that piston head sling off there 3 times! I stopped using it because of that. I actually ended up putting tiny tiny tiny dabs (about 3) on the piston before affixing the piston head. If I needed to change a part, just take the screw out and snap the glue easily. It just keeps the piston head from being able to turn.

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greg

greg

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1, Um, Greg... I'VE DONE THAT. :)

 

2, I'm currently experimenting with putting sorbothane betwen the piston head and piston body.

 

1, Excellent. Great minds think alike. Did you use the Lalax ones? If not, what? How did you bond it? & has it broke free at all?

 

2, Um, 'FEC'...I'VE DONE THAT!!!!!!!!!!!!!!!!! ^_^ Spooky! Not quite, I used a rubber tap washer. So far (onlt about 3000 rnds) so good.

 

 

Greg.

 

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infected

infected

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1, Excellent. Great minds think alike. Did you use the Lalax ones? If not, what? How did you bond it? & has it broke free at all?

 

Nope. I bought my sorbothane in a sheet from McMasters. The only thing is, it's a booger to cut. Don't expect clean cuts unless you have access to a water jet cutting machine. I just used a pair of scissors and trimmed away till it was about the right size. Here's the thing. This stuff turns to goo when you put super glue on it. So, using that to apply it, this stuff slightly "melts" and then sticks to anything. So I just depending on the application I either glued it to the cylinder head pad, or took off the stock cylinder head pad and put it in it's place. The super glue holds it really tightly. Thousands of rounds on my m249, and it's still on tight. The mp5 is still testing (this weekend will be the first real test), and the M14 will truly be tested this weekend too.

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infected

infected

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why is it again that you just can't cut it into disks and shim the piston/piston head? Applyin this same superglue technique you could do the same thing without velocity loss, correct?

 

Actually you can. See the sorbothane comes in sheets (if you order from where I did). Then you can cut it into a disk, and use a paper hole punch to pop a hole in it. Shim out the piston head using that. The catch is this. When the piston slams forward the sorbothane is going to compress, which means for a moment in time, the piston (which is smaller than the cylinder), could slightly shift off center. Upon the next cycling, with the piston off center you could damage the gearbox and such. I noticed this problem when I recently tried this. After applying the sorbothane, I realized that the piston was slightly off center in relation to the piston head, and as such, it wouldn't cycle all the way into the cylinder. Now, using the super glue method, you could glue it all together and make sure it wouldn't shift while being fired, but then if you needed to change the piston or piston head, you'd have to spend about near eternity to rip it off, or replace the whole assembly.

 

I'm testing the setup with an MP5 with sorbothane in between the piston and piston head with no glue. The setup right now shoots 29 rps, at 245 fps. It will be upgraded with an m100 in the future to conclude the testing to see if there are any problems.

 

By shiming the piston head instead of the cylinder head, you don't lose volume in the cylinder, and still have energy absorption.

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Vercingetorix

Vercingetorix

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what about getting some sort f stick on backing? kinda like the way a label has the sticky backing? I know they must sell heavy grade sheets of a two sided yp thing, kinda like double sided tape, but stronger.... There's a guy on the airsoft canada forums who made a sorbothane kit to replace the cylinder head dampers and add a piston head damper to guns, and he must have used such a thing on his kit, otherwise, how would he get it to stick? Telling customers they need to find their own adhesive wouldn't exactly make a product sell the best :P so I'll dig up the link and edit it in.... The way I see it, it'd be more or less the perfect solution.....

 

edit, found multiple: http://www.airsoftparts.ca/store2/index.ph...526103437bccdee

 

http://www.airsoftcanada.com/showthread.ph...7005&page=8

 

as you can see they say self adhesive backing, which is exactly what I am talking about.... now where the hell can I find it <_<

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