Could you tell me about the fiberglass process using resins (raw
materials)and perhaps something about pricing, maybe spot market
prices.  I would like to learn as much as possible about the
fiberglass process in making fiberglass tubs and showers

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Clarification of Question by 1camera1-ga on 15 Jul 2005 10:43 PDT

I am looking for more detailed info, like what are unsaturated
polyesters resins?  What part does benzene and styrene play?  What are
polymers?  Etc.

Hello  1camera1-ga 

         

 Difficulty associated with answering  this question has to do that it is asking
about chemistry of a material which is not well defined chemically.

 Word resin has two meanings, 1) sap of a tree

 and 2) a compound which looks like sap, and which chemically can be
almost anything:

 thermoplastic materials such as polyvinyl, polystyrene, and polyethylene and
 thermosetting materials such as polyesters, epoxies, and silicones

  http://www.answers.com/resin&r=67

All of the above are polymers -(with different chemical formulas)
 and there is a reason for similarity between these compounds.

. We will get to the question

"What is a polymer", and why polymers have high viscosity like sap, soon.

 First, to clarify the complication further, the term 

 'Fiberglass resin' aka 'boat resin' is a trade name for a product
used in construction trade:



 Polyester Resins are styrene based products used in all types of
composite construction. Commonly referred to as fiberglass resin or
boat resin. An economical alternative to using epoxy resins. New Vinyl
Ester resins are becoming more popular as an alternative to epoxies as
well.

http://www.shopmaninc.com/resins.html

  For this products, typical retail pricing is
   
 1 Quart  $10.45
http://www.shopmaninc.com/polyesters.html
http://www.fiberglasswarehouse.com/polyester_resin.asp


 Now to the chemistry of  polymers  
 (Unlike polymers resins are not a well defined scientific term,
  they could be considered a sub-class of polymers, perhaps synonym to oligomers.

OK  

 
What is
 Monomer, Oligomer, Polymer  ?

polymer  chemical compound with high molecular weight consisting of a
number of structural units linked together by covalent bonds (see
chemical bond). The simple molecules that may become structural units
are themselves called monomers; two monomers combine to form a dimer,
and three monomers, a trimer.
http://www.answers.com/polymer&r=67

Here is more on polymer
polymer
http://en.wikipedia.org/wiki/Polymer

and example of particular polymer compound

polystyrene
http://en.wikipedia.org/wiki/Polystyrene


actual chemistry - role of benzene

 Other suitable solvents may include

 carbon tetrachloride, ethyl chloride, methylene dichloride,

 
http://www.cheresources.com/polystyzz.shtml


Hedgie

I can tell you specifics about laying fiberglass because I have done
quite a bit of it. Do you have specific questions.

Fiberglass items are typically made by forming over a mold, or plug. 
The plug should represent the finished surface of the object -- for a
bathtub, this would be the inside of the tub, and the tub side facing
out into the bathroom.

First, the plug is treated with a mold release, which is a spray or
wax that keeps the plastic resins from sticking to the surface of the
plug.

Second, a gel coat is applied to the plug.  The gel coat is a resin
material that gives the finished part a smooth, hard finish.  The
final color of the item is usually created by adding dyes or pigments
to the gel coat.

Next, one or more layers of a fabric composed of glass fibers (glass
mat) are draped over the plug, and are cut to size.  After each layer
of mat is placed, resin is applied until it "wets out" or saturates
the mat.  This process is repeated for each layer of mat.

Many kinds of mat can be used -- mats made of glass, kevlar, carbon
fiber; mats that are woven, knitted, or just random strands mashed
together into a sheet and held together with a binder.

In an alternate process, the part thickness can be built up by
spraying a mixture of resin and glass fiber pieces using a "chop gun".
 This generates a tell-tale stucco-like texture on the back side of
the piece.  The chop gun process builds thickness much more quickly
than hand lay-up, and the raw material fiber is much cheaper.  On the
down side, the strength-to-weight ratio is nowhere near as good as for
hand lay-up (this is not a big issue for bulky stationary items like
tubs).

The thickness, weight, and strength of the resulting piece are largely
determined by the "layup" -- the details of how many layers of mat are
used and what kind of mat they are.  The strength of fiberglass comes
from the high tensile strength of the fibers, so in high performance
items, the orientation of the different layers is chosen very
carefully to maximize strength and minimize weight.

Fiberglass Supply (http://www.fiberglasssupply.com) offers a variety
of materials for home fiberglass projects.  Prices range from $1 per
square yard for chopped mat to $30 or more per square yard for carbon
fiber mat.  Resins run about $30 per gallon.  I'm sure that you could
get much lower prices for larger quantities.  In addition, for bathtub
or shower mass production, I'm pretty sure you would make heavy use of
a chop gun for speed of assembly and low materials costs.

fiber glass is for instelation and for sound blocking

Yes, it can be used for insulation and soundblocking as stated in the
last comment, but there are many more uses such as composite
fabrication and molds, which pertains to this question.

The most valuable resource I could possibly offer would be the forums
at Fibre Glast, a Canadian company specializing in all things
composite, from the hobbyist to the manufacturer.

http://www.fibreglast.com/ (click on the FibreTalk link for the forum)

That may arguably be the best source for any information regarding
this subject. The members of the forum are knowledgable, and the site
itself has a library of information to get anyone started. Videos and
books are also available there.

I hope that helps your search for answers.