This is my "second generation" silencer, and works much better than
the original "Mountain Dew" supressor.  It is also much more involved
to build.  You will need several pieces of specific diameters of
PVC pipe, a roll or two of electrical tape, and a Dremel tool with a
small cutting wheel.  You'll also need some sheet foam, such as
carpet padding.

The big thing here is finding the correct PVC pipe.  You need to find
a 2' length of pipe that fits EXACTLY (or very, very close) around
your barrel.  If your barrel is 1" OD, you're in luck, that's common
PVC.  Otherwise, you may have trouble.

This inner pipe will have to have many slats cut out of it, and this
is where the dremel comes in - I found no other good way to cut
rectangular holes in a pipe.

The crude picture below is sort of a "roll out" of what the
inner pipe needs to look like, if you could see all the way around
it:         (## are the holes cut)



___########__########__########__########__########__########_________
___########____________########____________########___________________
___########__########__########__########__########__########_________
_____________########____________########____________########_________
___########__########__########__########__########__########_________
___########____________########____________########___________________
___########__########__########__########__########__########_________
_____________########____________########____________########_________
___########__########__########__########__########__########_________
___########____________########____________########___________________> 1/4"
___########__########__########__########__########__########_________
_____________########____________########____________########_________
___########__########__########__########__########__########_________
___########____________########____________########___________________
___########__########__########__########__########__########_________
_____________########____________########____________########_________
           \/
            ' 1/4"

I was not able to illustrate the space between the holes
very easily, but they should be about 1/4".  The holes should only
run for about 1'.  With 2" at the end, and the other 10" at the back
to support the silencer on the barrel.  It's important that the silencer
not be able to "wiggle" while on the barrel, because the balls cannot
be allowed to touch the inside of the silencer.

The above pattern is not required, but you need to take out as much
of the inner pipe as you can while keeping it reasonably strong
and rigid, so it cannot easily be bent.  The above pattern works
well though.  It is highly resistant to bending, although it is
easily twisted.  Since twisting it will not cause the ball it hit
it, this isn't a problem.

As viewed from the side, this will produce a barrel that looks like:

*************        ************        ************        ****************
***********************        ************        ************        ******
*************        **        **        **        **        **        ******
*************        ************        ************        ****************
*************        **        **        **        **        **        ******
***********************        ************        ************        ******
*************        ************        ************        ****************

This is probably a bit distorted, but you get the idea.  The holes should
be about 3/4" high and 2-3" wide.  Good luck cutting the holes, it's
not terribly easy.  Draw in permonent marker on the PVC where you
intend to cut before you start.  If you cut through something you weren't
supposed to, you could ruin it.

If you can't manage the above pattern or anything that complicated,
(don't feel bad, it IS a pain to cut) you could try just drilling
LARGE holes in the tube, using a wood cutting bit.  3/4" to 1" holes
should do it, but I don't think it will work as well. (haven't tried
it)

Once that's finished, you need to get another 15" length of PVC that has
an ID about 1" bigger than your inner tube's OD.  The idea here is to
make a 1/2" gap all the way around between the two tubes, for the padding
to fit in.  Once you've got that, wind and wind and wind the electrical
tape around the inner pipe, right after the holes end, on both ends.  You
want to wind enough so that the OD of the tape exactly matches the ID of
the outer pipe.  Don't skimp here: I found that even with this tape,
the majority of what little noise escapes goes THROUGH the tape!  If
you find a better way to seal the ends, TELL ME!  I'm going to be
experamenting with various epoxies and resins when I get the time, but I
like being able to take it apart for cleaning.  I have a commercially
made (and since banned) silencer for PB, and it is much shorter, but
uses LARGE rubber o-rings as the shims.  If you can find some, you
might want to give 'em a try.

Once you finish winding the tape, cut the foam sheet to size and wrap
it around the inner tube, and then slide on the outer tube.  You may
have problems with the pad dragging on the outer pipe and getting jammed
up, try spraying some Pam, or otherwise lubing the outer pipe.

Once it's on, you might want to use some duct tape or other tape to
more thoroughly secure the tubes together.  It should work well
now.  Just slide it onto your barrel and give it a try.  Expect
it to work better on pumps than semis though - a lot of a semi's
noise comes from the blowback air escaping out the side by the
pin, and that's a hard one to shut up.  Using rubber cement to
glue a hand-crafted, VERY thin rubber gasket on the hammer where
it hits the valve can make a quiet pump that much harder to hear.
My Trracer gets quiet enough right now that I can hear the balls
whistle through the air as they travel away from me.  All I get
is a "P-TING" as the 7oz tank rings from the shake of the gun, and
FWWWWWwwwwwwww.....   as the ball leaves!

I made the mistake of loaning this out one day, and got quite
bothered by the newbie with the "cloak"...  I kept getting
shot at and not having a CLUE where it was comming from.  The sound
of the balls hitting the brush around me was louder than the gun
that fired them....


About the padding - I've tried several different kinds of padding, and
gotten all kinds of mixed results.  The padding is there to "absorb" the
sound, and is placed in a position around the sound source and within
a hard wall, so that the sound "bounces" around inside the silencer,
and on each bounce has to go through the padding.  The idea is to quiet
the sound as fast as possible. (the least number of bounces)  I tried
soft foam, and if your containment is not very sound-reflecting, (like
the earlier "mountain dew silencer I described) then a large layer of
soft foam works best.  Here, however, you need something with a bit
more ooomph.  Carpet padding works good.  Another idea I got from an
actual silencer...  scrub pads!  Go to your local department store
and see if you can find those synthetic scrubber pads; they come in
many bright colors, and are usually larger sheets that you cut to
size with scissors.  They have a texture similar to real steel wool,
but less fine.  These sheets are just the right thickness, and seem
to work well.  They also hold up better than carpet padding.


If your barrel is an odd size, (anything besides 1" OD) you may have
trouble locating the proper pipe sizes.  If it's less than 1", (I can't
picture it being BIGGER...) you can "shim" your barrel just the same
way you shim out the inner pipe, using electrical tape.  Just wrap
it around the end of the barrel, and also around the barrel back where
the rear of the silencer gets to.  The idea is to support it from two
points, as far apart as possible.  Be peticular about how many turns
of tape you use - ONE turn can make the difference between a wobble, a
perfect fit, and a stubborn fit.  HINT: wind both shims the same
direction around the barrel, then TWIST the silencer on/off in the same
direction.  This avoids the problem of the tape getting peeled off.

This silencer will probably work best if your inner pipe is at least
1" ID, because this gives the paintball a tad bit of room inside the
silencer.  Any less room and your chances of hitting the inner tube
would really go up. (.68 cal in a 1.00 tube = .16" (1/8") play on each
side)

The biggest factor in how quiet the silencer is would be how hard the
plastic is on the outside.  It seems that the harder the outer shell,
the quieter the silencer.  Get a harder plastic than PVC if possible.


FINAL NOTE
  Legality of silencers is a big issue, and some believe it is quite a
serious one.  The BATF has a very wishy-washy definition of silencers,
but still takes them fairly seriously.  I have not yet heard of a
paintball player being 'gone after' for having a silencer on their
airgun, but there's always a first time.  BATF's definition is as
follows: (this is NOT a quote)   Silencers are defined as devices that,
when placed on a .22 rifle and fired through, will quiet the sound
emitted by a factor of 1 db.  OK, now this means that your silencer
does not have to be DESIGNED for the .22, it just has to WORK on one
to be classified a silencer.  1 db is a measure of magnitude of sound,
and is considered to be the smallest change in volume commonly
detectable by the human ear.  i.e. if you think it got any quieter, it's
a silencer.  Please note this makes all litre bottles illegal.  They
have quite commonly been used by people to play games with their
neighbors. (I've seen this before, they work VERY well, ONCE only though)
This is basically the main reason I don't pay much attention to the
BATF on this issue; their definition is not specific enough to hold up
to legal scrutiny in most cases.  Others have suggested that the rule
may be tightened up by simply adding that silencers must be reusable,
which would significantly tighten the definition.  I personally expect
the BATF to keep it the way it is - law enforcement agencies LIKE
nice broad, general laws like this because they don't invite loopholes.
My honest opinion: don't worry about it.