Whats The Difference Precision Palsonite Cylinder Set / Vacuum or Hard

[Exibit]

Hi guys

Precision Palsonite Cylinder Set / Vacuum or Hard

Whats the difference between these two Cylinder Sets

Is it better to have a Vaccum Piston, Vaccum Spring Guide

or

Hard Piston, Hard Spring Guide

Many thanks

[Exibit]

Re: Whats The Difference Precision Palsonite Cylinder Set / Vacuum or Hard

Well no wonder I could not find the answer to my question it took loads of searching though I have found the answer


PISTONS

When it comes to pistons, PDI have quite a lot of different designs for different purposes. As explained under CYLINDERS, you need to choose between normal size and B-UP first. Also some pistons have a small diameter for 11mm/8mm springs, so do mind that as well. Most pistons are for 13mm/11mm springs. After choosing the right size, it's a matter of structural strength according to the power level: Barikaru are the lightest pistons, and should not be used with ultra-strong springs. These pistons are the ultimate lightweight option when you need the best precision, as they eliminate a lot of vibrations from the piston acceleration and slap. Then come the aluminum pistons with slits cut into them, and finally the enclosed Hard pistons.

There are two main types of piston heads: Vacuum (VC) and Hard (HD). The Hard piston provides a seal all the time, so it doesn't need to be explained. Both piston heads are ported to provide a tight seal on the way forward without unnecessary friction.

The Vacuum piston has a hole in the middle of the piston head, with a small rubber ball inside. The need for this arises if you're using a long inner barrel: When the piston has pushed all the air out of the cylinder but the BB is still in the barrel, the dropping pressure could reduce velocity. The PDI vent design allows air to get into the barrel to eliminate negative pressure. Please see the diagram on the left for a cut-away view of the design.





SPRING GUIDES

You would think that there's not much to a spring guide, and just one or two types would be enough, right? Well, the spring guide itself is a simple part, but it has to fit the rest of the parts so choose it carefully! Here are the variables that affect the choice:
# 7mm or 9mm spring guide for 11/8mm or 13/11 springs respectively
# Normal or B-UP spring guide to match the cylinder size
# VC or HD type. (VC is shorter to make room for the vent of the piston head; Will also work with other pistons.)

PALSONITE?

Yep, that's what we said when we first heard about this as well. It's a special surface treatment for stainless steel, done in an incredibly low temperature nitride salt bath. Due to material properties, it can not be applied to regular carbon steel. It leaves a nice dull black color to the part, and provides a high surface hardness for reduced friction. It is much more scratch-resistant compared to teflon surfaces, so we finally get to keep and eat the cake!

So I have now made up my mind and will be looking at a hard piston

[TbirdX]

Re: Whats The Difference Precision Palsonite Cylinder Set / Vacuum or Hard

Basically, the VC piston is for barrel lengths over 500mm or so. I run a 430mm barrel with the hard/palsonite combo.

[Exibit]

Re: Whats The Difference Precision Palsonite Cylinder Set / Vacuum or Hard

Tbird thanks for that, I kind of understand now, gone for the Palsonite Cylinder set Hard as I have the G-Spec 303mm barrel

[TbirdX]

Re: Whats The Difference Precision Palsonite Cylinder Set / Vacuum or Hard

TBH, I doubt you'd really see much difference in them at any barrel length. I run a full auto SL9 with a 590mm barrel and that certainly doesn't have a vacuum piston