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Old 06-18-2009, 05:00 PM
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Default Fiberglassing 101-Materials, tools, etc.

Fiberglassing 101 - Materials, supplies and misc. info.

There are several kinds of fiberglass available on the market. I will discuss 2 kinds here, chopmat (CSM) and woven roving (wr).

Chopmat is randomly oriented strands of chopped fiberglass that are held together with a resin soluble bonding agent. CSM comes in a variety of thickness', or weights. The most common for small jobs are .75 oz and 1.5 oz mat.

*HINT* If you buy 1.5 oz mat, you can actually peel the layers apart and get 2 layers of .75 oz mat. Considering 1.5 oz mat isn't twice as expensive as .75 oz, you can actually save some money this way. .75 oz csm will conform to contours better than 1.5 oz, so if your project has some contours to it, .75 might be a good idea.

Woven Roving is made from continuous glass fibers that are woven, like you would normally expect to see. One over, one under, one over, one under, etc. These are also offered in a variety of weights. WR is generally used for building thickness and rigidity quickly. It does NOT contour well.

Resins: There are 2 flavors of resin, polyester and epoxy. Polyester resin is what is most widely used in basic fabrication and layup. Epoxy resin I am not real familiar with but I know it is used for carbon fiber work. Resin requires a catalyst agent in order to harden (kick). In the case of polyester resin it is called MEKP, methyl ethyl ketone peroxide. It is mixed at about 10 drops per ounce of resin. You can choose to mix less (1-3 drops) to get a longer working time, or if it is really hot out. If you mix any less you will lengthen the amount of time it takes the resin to kick. If you use too little, it wont every kick and you will have to start over. If you add too much MEKP you greatly reduce your working time (5 minutes) and you can possibly start a fire or damage your project.

If you want to get SUPER NERDY , check this out: http://www.derakane.com/downloadServlet?docPath=DPAPP1.asco.ashland.com\Da ta\ascc\ecomdocsasc.nsf\359C8E53D541AD8E85256FD400 51F3D7\$FILE\DRKFabTipsFullVersion.pdf

Tools and supplies(as seen on fiberglassforums.com)
Dust masks or hydrocarbon mask: Helps you keep from getting “high” off resin fumes as well as preventing you from getting lung cancer while sanding later in the process.

Polyester resin w/ cataylst: The main ingredient for fiberglassing. Used with catalyst to bond the strong fibers of glass to one another. The resin alone is not strong and rather brittle when dried. It is the glass fibers or carbon fiber that produce the strength. Obtained at boat repair stores, hardware stores, and online. Ranges in quality priced at $30-50 a gallon.

Fiberglass mat: This produces the strength when “wetted out” with resin. Comes in various weights per area. A denser mat allows for strength to be produced quicker but is harder to use on curves of a structure. Obtained at boat repair stores, hardware stores, and online. Varies in price: Look online (not expensive compared to resin).

Fleece: Used to produce a structure shape over the MDF skeleton in order to allow the initial coat of resin to dry and thus be strengthened via more mat and resin. Obtained at local fabric stores. ~$4 a yard.

Latex gloves: To protect your hands.

2-3” chip brush: Best for applying resin to your creation. Leave it in the cup to dry that way any extra resin pulls out with the cup allowing you to reuse the cup. Don't spend a lot of money on these. They are 1-3 use only brushes.

Fiberglass roller: Best item in order to roll bubbles out of the mat after it has been “wetted” out with resin.

Acetone: Used to clean resin off things it shouldn’t be on, always keep around just in case. In case you get resin on your skin, have a container of Replacetone handy. Acetone can be very BAD for you.

Sandpaper 40-220 grits:
Use to sand to a satisfactory smoothness in order to allow for paint or wrapping of covering materials like suede or vinyl.

More information and supplies can be found here:
Fiberglass Supply (Surfboards, Windsurfers, Kayaks, Canoes, Boats , Autos and more)
Fiberglass , Epoxy , Composites, Carbon Fiber - U.S. Composites, Inc.
TAP Plastics

Fiberglass Forums - Powered by vBulletin - A GREAT site and wealth of knowledge. Just make sure you search first before asking any questions... they're touchy about that. Read the sticky notes inside each section. They contain TONS of useful info.

Some "How-to" videos:
YouTube - fibreglast's Channel
YouTube - tapplastics's Channel

This is by NO means the end-all be-all of information about fiberglass material, resins or other related materials and tools. This is simply my attempt at communicating what I know about these things from working with and reading about them. I highly encourage anyone thinking about doing fiberglass work for the first time to do lots of research and reading. The links given are those that "I" suggest. Some of the information listed above was taken from the sites that are linked. Additionally, this article was not and is not endorsed by the owners/operators/patrons of this site.
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Old 07-13-2009, 02:54 AM
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In the navy we use bagging film and a vacuum pump to pull atmospheric pressure on the patch, or repair were making. It makes a near hard as nails repair as it draws all the layers of glass down together in a tight matrix.

the vacuum pump I use for home projects is a pump used for pulling a vac on car A/C systems. It cost about 20 bucks on ebay.

We also use pre-preg glass.

basically lay out your bagging film, glass, then apply resin, lay a top layer of bagging film on it and use the roller to press the resin into the glass cloth. when fully saturated the glass will appear nearly transparent.

roll it up, and place in a freezer (no food in the freezer) this will last for hours, sometimes even days

then pull it out when rad to use, thaw it, and apply it, by pull one layer of bagging film off, laying it down and rolling all the air bubbles out of it.

once cured just peel off the excess bagging film on top, and its nice and glossy, low residual sanding is needed. you can vacuum this too. using this method as well.

Last edited by ydeardorff; 07-13-2009 at 02:56 AM.
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