Wetsuit construction methods
Myron
My wife and I started scuba lessons last night, and when equipment
descriptions were being given, the instructors noted that surfing
wetsuits are different than diving suits. They stated that use of a
surfing suit after a few dives (that's made for regular air pressure)
will cause the bubbles in the neoprene to compress and stay that way,
thus reducing the effectiveness of the suit. I can't remember what
terminology they used, but I seem to think that surfing wetsuit bubbles
are made chemically, and dive suit neoprene bubbles are made another
way. I don't plan on many dives requiring my winter rubber, but I
don't want my 4/3 to become a 2/1, either. Is there any basis to their
claim, or is it an attempt to snag yet a few more dollars from a
consumer? Please cc: any replies to sun...@beer.com
Thanks,
Myron
Sent via Deja.com http://www.deja.com/
Before you buy.
Timothy B. Maddux
>... will cause the bubbles in the neoprene to compress and
No way. Neoprene is neoprene, and there's no reason
why it would deform plastically under pressure. I've
crushed all kinds of different neoprene when using it
as vibration-dampeners for computer equipment, to what
looks like as little as 1/100th original thickness,
and it's always come back.
Your suit will compress under the pressure while you're
down there, the water is colder, and there's no sunlight
to warm you, so you might still find that 4/3 insufficient.
I've always been glad to have an insanely thick dive suit
when diving off Cali, even though it means sweating buckets
until I get in the water.
>Please cc: any replies to sun...@beer.com
--
.-``'. Tim Maddux, Ocean Engineering Lab, UCSB
.` .`~ http://www.me.ucsb.edu/~tbmaddux/
_.-' '._ "From the essence of pure stoke springs all creation."
norm bosse
won't compress as much a depth therefore keeping you warmer. The surfing
suit will compress too much and will not be as warn.
Norm
Doc
"norm bosse" <bossd...@mediaone.net> wrote in message
news:aVGG4.38207$YU2.6...@typhoon.ne.mediaone.net...
Typically, surf suits are half the thickness of dive suits, so I can
understand where that misconception comes from. But as Neal ( I think )
said, foam neoprene is foam neoprene.
Doc
>
>
sdbchguy
> The only thing I've been told is that diver suit neoprene is
> denser so it won't compress as much a depth therefore keeping
> you warmer. The surfing suit will compress too much and will
> not be as warn.
I was always under the impression that the cells in neoprene foam
were essentially open (vs closed) voids that could (eventually)
fill with water. In that case, compression effects should be a
short-term phenomena until the water gets a chance to work it's
way into the cells.
In order to test this impression, I carried out an experiment
this morning. First I weighed my dry 6mm/3mm full-wetsuit. It
weighed 4lb 2oz (4.38lb). Then I measured the area of the rubber
sheet in it (14.3 sq-ft), and computed the volume of the foam
(0.234 cu-ft) from that area and various thickness (after
measuring the latter with a pair of verniers).
The Handbook of Chemistry and Physics says that the specific
gravity of neoprene is 1.25, hence that rubber weighs 78
lb/cu-ft. Since the suit weighed 4.38 lb, that means that there
is 0.056 cu-ft (4.38/78) of actual neoprene in the foam, with the
remaining 0.178 cu-ft (0.234-0.056) of volume occupied by
gas-filled cells. In short, by volume, the foam sheet is about 25
percent rubber and 75 percent voids. The question then becomes:
"What fraction of this void area is closed, and what fraction is
open to the water?"
To examine that, I put the suit in a bucket of water (wetsuit
depth: 3" to 16") and let it sit for 80 minutes. That's not much
pressure to force water into any open cells, but it was
submerged for a pretty long time. Anyhow, at the end of that
period, I took the suit out of the water, let it drain for 15 sec
to let the superficial water run off, and then weighed it. It
turned out that it had gained 2.06 lb. At 62.4 lb/cu-ft for
water, that corresponds to a water volume of 0.033 cu-ft. That's
slightly less than 20-percent of the volume of the voids in the
rubber (and equal to a little over half the volume--60
percent--of the actual rubber in the suit). So it would seem that
I was wrong, and most of the cell volume is actually closed (or
that it requires a greater water pressure than I could generate
in order to fill the remainder of the voids).
As long as the wetsuit was wet, I got a little curious as to how
long it might take to dry out. One might expect that there would
be a decreasing rate of water loss with time as the remaining
water would be 'deeper' into the foam.
So after weighing the wetsuit, I hung it over a railing, then
weighed it at a number of other intervals (2 min, 30 min, 80 min,
125 min, 195 min, 390 min). The weight of water retained in the
wetsuit decreased approximately exponentially during the first
two hours or so (that would be consistent with water retained
only in the relatively surficial cells). But there was with a
slight slowing in that rate, indicating some water was retained
in deeper cells. Basically, about one-half of the water retained
in the wetsuit was lost every 30 minutes (environmental
conditions: out of the sun, in 75% relative humidity, and an air
temperature of 64-degrees).
Unfortunately, I didn't pay close enough attention, and after two
hours, the wetsuit was exposed to increasing amounts of direct
sunlight--and the rate of loss of water substantially increased.
By 390 minutes, the remaining water weight was less than 1 oz
(0.063 lb).
Anyhow, this crude experiment would suggest that most of the
voids in the rubber are closed cells. Therefore--as you
indicated--the compression of those voids at depth could
substantially increase the rate of loss of heat. It also suggests
that "wetsuits" are really not all that "wet"...except perhaps in
comparison with "dry suits".
SDbchguy
* Sent from RemarQ http://www.remarq.com The Internet's Discussion Network *
The fastest and easiest way to search and participate in Usenet - Free!
Beable van Polasm
"Doc" <jfm...@capenocodspam.net> wrote:
>
> "norm bosse" <bossd...@mediaone.net> wrote in message
> news:aVGG4.38207$YU2.6...@typhoon.ne.mediaone.net...
> > so it
> > won't compress as much a depth therefore keeping you warmer. The
> > surfing
> > suit will compress too much and will not be as warn.
>
> understand where that misconception comes from. But as Neal (I think)
> said, foam neoprene is foam neoprene.
Well I don't know anything about rubber, but don't surfing
wetsuits have the zip on the back, because you don't want
to gouge the zip into your surfboard, and diving wetsuits
have the zip on the front because you don't want your
oxygen bottles (tee hee) gouging the zip into your back?
That's the main difference as I understood it.
cheers
Beable van Polasm
--
My latex suit is working beaut
'Cause I'm not cold at all!
http://members.xoom.com/_______/index.html
Ape Man
compression and destruction of the gas filled bubbles of which the neoprene
is made. Thus, a brand new suit will be warmer than an older (used) suit of
the same make and model. This is due to pressure exerted by increasing
depth-I don't know whether the difference would be noticeable while using
the suit for surfing after having used it for diving.
Doc
"Ape Man" <uwa...@rcn.com> wrote in message
news:8cj63o$nr6$1...@bob.news.rcn.net...
Interesting....I wonder if the stretching and such that a suit used only for
surfing would get would have the same effect. I have noticed on older dive
suits and surf suits that the rubber seems to get a little leathery and more
prone to cracking and such. Could that be an indication or something
else....