[PSUBS-MAILIST] Fiberglass

Tue May 5 00:09:04 EDT 2015

Hugh,  I really think you want to use some type of epoxy.

http://protective.sherwin-williams.com/pdf/Epoxy%20Coatings%20Guide.pdf

The fact that the two parts create cross linked bonds is something that a one part coating can't achieve.  But I have heard some good things about the vinyl ester and I'm sure it will work.

brian

--- personal_submersibles at psubs.org wrote:

From: Hugh Fulton via Personal_Submersibles <personal_submersibles at psubs.org>
To: "'Personal Submersibles General Discussion'" <personal_submersibles at psubs.org>
Subject: Re: [PSUBS-MAILIST] Fiberglass
Date: Tue, 5 May 2015 10:05:55 +1200

Just put in my penny's worth. I had professional advice as I don't know
squat about resins. 
I understand there are 3 choices of fibreglass resin.  Poly-ester, Epoxy and
Vinyl ester.
I was advised to use vinyl ester as it has less absorption of water when in
a pressurised (deep submerged) situation.
My concern was that the absorption would alter the buoyancy of the
fibreglass if there is any reasonable amount used.
Cheers, Hugh

-----Original Message-----
From: Personal_Submersibles [mailto:personal_submersibles-bounces at psubs.org]
On Behalf Of hank pronk via Personal_Submersibles
Sent: Tuesday, 5 May 2015 9:52 a.m.
To: Personal Submersibles General Discussion
Subject: Re: [PSUBS-MAILIST] Fiberglass

Alan,
Oh I misunderstood, I hate fiberglass! :-)
Hank--------------------------------------------
On Mon, 5/4/15, Alan James via Personal_Submersibles
<personal_submersibles at psubs.org> wrote:

 Subject: Re: [PSUBS-MAILIST] Fiberglass
 To: "Personal Submersibles General Discussion"
<personal_submersibles at psubs.org>
 Received: Monday, May 4, 2015, 5:38 PM

 Hank,I mean
 when the fiberglass has cured & just the surface is  tacky.It is  meant to
be like this to form a chemical bond with the next  layer.If you  wait for
the surface to dry (in time) then the next layer  doesn't adhere as well.I
used  clear cast polyester resin in art works, & you had to  add paraphin
wax inliquid  form to stop the surface becomming tacky.There are two general
types  of polyester resin used for repair. Laminating or Bonding  resin
which cure to a tacky surface and Fiberglass or Marine  Finish resin which
cures to a non-tacky  surface.Laminating  resin (Evercoat # 100560, 100561)
is used for initial coats on wood or for multiple  applications with
fiberglass cloth or mat. This resin is  air-inhibited which means it will
cure to a tacky finish and  does not require sanding between coats. This is
desirable in  laminating because the layers adhere to each other better.
 This product should not be used as a final coat unless  measures are taken
to seal out the air during the curing  process.Marine and Fiberglass
resin (Evercoat # 100553, 100552,  100554, 100517, 100518, 105499, 105498,
105500, and 105501)  is non air-inhibited or waxed  resin. It is for the
final coat. This resin cures  with a hard non-tacky surface. When the
catalyzed resin is  applied as a final coat to the laminate coats of resin,
the  wax rises to the top, sealing off the air and allows the  resin to cure
to a hard finish, which can then be sanded,  painted or gel coated.NOTE:
Cannot be used with  aluminum, redwood and/or close-grained woods like oak
or  cedar. Do not use with Styrofoam.Alan

   From: hank pronk via
 Personal_Submersibles
 <personal_submersibles at psubs.org>

 To: Personal
 Submersibles General Discussion
 <personal_submersibles at psubs.org> 

 Sent: Tuesday,
 May 5, 2015 9:14 AM
  Subject: Re:
 [PSUBS-MAILIST] Fiberglass

 Alan,
 Tacky
 means weak hardener ratio or poor mix.  Tricky stuff!
 Hank--------------------------------------------
 On Mon, 5/4/15, Alec Smyth via
 Personal_Submersibles <personal_submersibles at psubs.org>
 wrote:

  Subject: Re:
 [PSUBS-MAILIST] Fiberglass
  To:
 "Personal Submersibles General Discussion"
<personal_submersibles at psubs.org>
  Received: Monday, May 4, 2015, 5:11 PM

  Hi
  Alan,
  Interesting comment
  about the
 polyester being designed for one shot. The

 polyester resin I used is from 3M and the instructions  say
  that it you restart the job on a cured  layer you should sand
  it lightly first - so
 that's what I did, since it took
  about
 a month to get the desired number of layers on. It
  didn't seem to have any bonding issues  with layers
  applied on cured material. This
 particular 3M polyester
  cures fully in 2
 hours, and didn't feel tacky after

 that, so perhaps this is brand specific.
  Good point about the sections

 helping make the mirror versions of the MBTs. I made
  templates out of thin particle board to cut  out the foam
  sections, and by flipping the
 templates was able to make
  mirror image
 tanks. 

  Best,

  Alec
  On
 Mon, May 4, 2015 at 4:33
  PM, Alan James via
 Personal_Submersibles <personal_submersibles at psubs.org>
  wrote:
  Hi

 Scott,some great ideas
  from Alec there.I
 like his
  idea of using sandwiches of
 thinner sheets of
  polystyrene.You should
 be
  able to trace a shape on one sheet, cut  it out,
  thencopy around it on to
  the corresponding sheet of the mirror
 imageballast tank, to get two tanks that are
  identical.When I did mine
  I
 marked the hull with a felt pen as to where

 theballast tank was going
  to fit against
 it. I covered this area with
  plasticfood
 wrap. I then
  draped glass mat over
 it & epoxied about 3
  layers over
 this. Polyester resin will
  disolve the
 plastic food wrap. This approach may be a

 problemon vertical walls & there
  may be
 a similar appoach that works better.You need to embed this  shape in to the
polystyrene
  section by wire
 brushingout the
  polystyrene untill it's
 a good fit. Because of shrinkage
  of the
 fiberglass& warping it
  won't
 nessecarily be a perfect match & may require
  additional work.Once you have the
  polystyrene shape done you cover it with  fiberglass & go
  overthe area you formed
 against the
  hull.I used epoxy because it
 can go
  straight on to the polystyrene (test
 it first)
  &you can spend a month
 slowly
  building it up, whereas polyester
 resin is
  designedto be laminated in one
 shot. It
  is air inhibited & remains
 tacky on the outersurface unless it has a wax additive.I  once made a 1/4
size ambulance out of

 polystyrene using mainly achain saw.
  Great
 fun but one hell of a mess.Alan

  From: Alec
  Smyth via
 Personal_Submersibles <personal_submersibles at psubs.org>
   To: Personal
  Submersibles
 General Discussion <personal_submersibles at psubs.org>

   Sent: Tuesday, May 5,
  2015 3:33 AM
   Subject:
 Re:
  [PSUBS-MAILIST] Fiberglass

  Hi
 Scott,
  Coincidentally your timing is
 really
  good, because I just finished four
 rather complex-shaped
  MBTs for the new sub.
 Since my sub is a one-off rather than
  a
 series production item, I used the method of glassing  foam
  plugs that are then dissolved, rather
 than making molds. To
  summarize:
  - The plugs
  are a sandwich of
 many layers of pink home insulation foam

 from HomeDepot. When I did Snoopy's saddle tanks I  cut
  out the sections with a hot wire, but
 this time I realized
  my jig saw does the
 job in about a tenth the time. Step one
  is
 to cut a whole bunch of sections and glue them together.
  If I weren't so tight-fisted, the ideal  solution here
  would be to mill a single
 block of foam using CNC equipment,
  but I
 get by with what I have on hand if it'll save
  money - and a milling job would probably take  quite a lot of
  it.
  - The
 glued
  sections are only a rough draft of
 the final form. Next you
  have to shape them
 until the steps between sections are gone

 and everything is nice and smooth. I use three tools to  go
  from the draft to the final product, in  this
  order:1) A plain old wood saw2) A
  Stanley Surform shaver, with flat and or  rounded blade
  fitted depending on the
 surface. This thing is absolutely
  essential
 and I use it for 99% of the job. See
http://www.stanleytools.com/default.asp?CATEGORY=SURFORM+TOOLS+AND+BLADES&TY
PE=PRODUCT&PARTNUMBER=21-296&SDesc=Surform%26%23174%3B+Plane+Type+%96+Regula
r+Cut+Blade3)
  Sand paper
  I'm
  afraid I have no scientific answer to ensuring  symmetry. I
  just put the plugs side by side
 and do a bunch walking in
  circles, taking
 measurements, and using a level. The plugs

 won't come out identical, but close enough to be
  functional. This part is more sculpture  than
  science.
  - Next,
 paint
  the plugs with several coats of
 water-based paint. This is
  to prevent the
 resin from dissolving them. Water-based

 because if not you run the risk of the paint dissolving  the
  foam.
  - Now apply
  layer after layer of wetted fiberglass cloth.
 I don't
  mean all in one sitting, I mean
 iteratively for about a
  month. There are
 two main considerations then, cloth and

 resin.
  I can't
  give
 you a specific recipe for cloth or the cost for cloth,
  because I used a combination of material I  already had on
  hand and new stuff. I have
 purchased from http://www.fibreglast.com
  in the past, but this time found lower prices  on eBay for
  what turned out to be perfectly
 good material. Mostly I used
  6.5 oz (quite
 light) cloth so that it would drape better,

 but that depends on the shape of your tanks. For  instance,
  on the inside face that goes
 against the hull, you can get
  away with
 much heavier material since its a gentle curve in
  just one plane, and the same goes for any flat  surfaces. But
  if you have compound curves
 or tight curves its way more
  challenging to
 drape cloth without forming air bubbles. I

 make the walls that go against the hull thinner, since  they
  aren't going to be banging against
 things like the outer
  or upper faces will.
 On average I probably put down ten to

 fifteen layers of cloth. The pros use vacuum bagging to
  prevent bubbles. With my caveman fiberglass  skills I just
  try to avoid them in the
 first place by selecting
  better-draping
 cloth, and when I get a bubble I remove it

 with a flap wheel before putting down the next layer. In  the
  middle of my layup I put down several
 layers of Kevlar. This
  material is trickier
 to work with than fiberglass, it
  can't
 be sanded and once cured you can only really go
  through it with carbide tools. The idea is to  increase
  survivability by making the MBTs
 puncture resistant. If I
  hit a rock or a
 dock I still expect the resin might crack,

 but it should be quite hard to put a hole in the Kevlar.
 You
  might think this hard layer should go
 on the outside, but I
  put it mid-schedule
 so I could sand imperfections out of the

 fiberglass layers above it.
  This job (new
 sub, not Snoopy's
  tanks) took ten
 gallons of resin. Everyone will tell you

 epoxy is stronger than polyester resin. However, epoxy is
  $76 per gallon vs. $34 for polyester, and  Snoopy's
  polyester tanks have held up
 perfectly well for years. So,
  for me, this
 is a case of cheaper-is-sufficient and I went
  with polyester.
  -
  Iteratively sand and fix imperfections with a  fairing
  compound. I used West Marine's
 #410 fairing filler
(http://www.westmarine.com/buy/west-system---410-microlight-filler--P004_120
_004_016).
  You can do this with Bondo as well, but #410  is easier to
  sand.
  -
 Dissolve the
  plugs. When I made
 Snoopy's saddle tanks the pink foam

 dissolved instantly with gasoline. This time, despite  being
  the same brand foam it was somehow
 gasoline resistant, but
  acetone did the
 job.  

  Best,
  Alec
  On
  Mon,
 May 4, 2015 at 9:22 AM, via Personal_Submersibles
<personal_submersibles at psubs.org>
  wrote:

  Alec,

  I
 was curious if you could go into details about the
  making of your saddle tanks?

  *Where did you get the foam and
 fiberglass and what
  types did you use
  *How did you shape the foam to ensure symmetry

  *Was there any difficulty or anything you  would do
  differently

  Thanks,

 Scott Waters

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