|
Jay,
Interesting data. I would expect in many
applications, that you would have to cut the patterns out of the cloth for
infusion molding in advance, just like you would for hand lay up. Your
correct that the the infusion molded parts are lighter and stronger, and great
for surface craft. We don't tend to need the weight savings. But strength is
always a plus for us. Of course if we need more strength, we would just lay up
another layer or two. As for me, I don't like to have to fight getting all
the bubbles and voids out during hand lay up. Not to mention the fumes and
making such a big mess.
It may very well not be totally practical to set up
infusion molds to produce just a few MBT's of this configuration. But they say
practice makes perfect, and I need a lot of practice.
Besides we might have a run on K boats in the near
future. ;}
Regards,
Brent
From: Jay K. Jeffries
Sent: Friday, August 28, 2009 9:06 AM
Subject: RE: [PSUBS-MAILIST] Gel Coat Type for
Depth Brent, Here are some figures from the
article in Professional Boatbuilder that I spoke
of:
You will note that the infused
single-skin is lowest in cost, this is due to less materials being used and a
quicker turn around on the mold. Labor costs are actually higher than is
depicted here as all the materials have to be pre-cut and carefully
prepositioned prior to the infusion process (the labor is more expensive due to
requiring greater experience in the lay-up crew). While you might use the
ballast tanks as an infusion process learning exercise, you expenses on the few
runs that will be made for others will never amortize your costs.
The real benefit of the infusion
process is building a lighter, stronger structure that allows greater speeds in
surface vessels. They have computer programs that model the infusion
progression and even these then have to have trial runs to get the bonding and
strength that was designed. R/Jay Resepectfully, Jay K.
Jeffries Andros
Is., Bahamas Save the whales,
collect the whole set. From:
owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org] On Behalf Of Brent
Hartwig Jay, Your speaking of the
laminating resins that doesn't have the wax in it. Your data looks good to me.
The powder and PVA trick was first mentioned to me in regards to my issues with
bondo taking forever and a day to cure out, and still being some what gummy
after weeks. If I put more resin in the mix, I would have even less time to work
with it, and it was still gummy on the surface. I don't like to have to
put on really thick coats, just so I can remove the outer later with a grader.
I've not worked with the wax type resin yet. But I wonder if it is just easier
to wash off baby powder or PVA, then dissolve
wax. I coated most the outer
surface of my bow MBT with polyester resin the other day, to fill in all
the bubble holes and voids from the part never having been gel coated in the
mold to begin with. Once done and when the resin firmed up, I just brushed on
the PVA in less then a minute. Then the next day I just washed it off and
sanded with no trouble. My earlier testing runs, showed that was what I
should expect. The infusion
molding I've watched at the Aerocet plant makes be believe there is a fair bit
less labor when you consider they can lay up all the layers in advance at a nice
even pace, with out having to wait between some layers being put up with
resin. I watch one float being infused that took less then a half an hour
to infuse. It's sorta like painting the outside of a house with a sprayer vs, a
brush and roller. In that the sprayer in quicker doing the actual painting, but
there is more prep work to do first. The advantage I like
most of all during the fabrication process is not having to deal with all the
fumes you have with hand layup. Also there are some added expenses
with the flow mat, runners, tubing, release cloth, sealing cover, edge sealing
means, etc. It is a little
more work to make a mold for infusion molding. Once you know how the resin
flows, and how to make the proper flanges on the edges of your molds, I can see
it as being reasonably easy to make a mold for infusion molding and use it. You
don't want to have to pull the resin more then 28 inches across a area. So this
means for longer runs you have to install more coiled runners and/or the very
open foam type runners, to allow the resin to start another 28 inch section. For
many one off parts it's best to just hand lay up. If I get a nice new
capped pair of MBT's, then I might as well make the molds so they can be
infusion molded, so I can practice the art, and produce some nice tanks for
other Subdudes if they wish. Regards, Brent | ||||||||||||||||||||||||||||