Hand Lay Up Guide

Polyester Resin with Wax (non-air inhibited), or without Wax (air inhibited)

Polyester Resin will not cure in the presence of air. To get around this problem, a very small amount of paraffin wax is mixed in solution with the resin. In the curing process, the wax rises to the surface in a very thin film and excludes the air from coming in contact with the resin, allowing it to cure very hard on the surface. Waxed resin will cure with a satin finish. This means it will not alow for a good bond for the next coat of resin.

Waxed resin is used for one coat glasswork, or for the last coat of resin in a laminating schedule, or for any layer in a laminate that has to be sanded. As long as the waxed surface has been sanded, there will be good bond for the next layer. Waxed resin can be used for multiple layer work as long as each layer is applied on top of a wet layer. Waxed resin is often referred to as Finishing Resin.

Resin without wax cures hard, but remains slightly tacky and gummy on the surface. This surface cannot be sanded but makes for very good adhesion for other coats of resin and glass. This is the type of resin used most in fiberglass construction. For a hard, final finish, a coat of resin or gelcoat with wax can be applied over the no wax layer. No wax resin is often referred to as Laminating Resin.

Pitfalls of using Surfacing Agent (wax)

• Surfacing Agent must be clear. Not cloudy or lumpy. It can be warmed in HOT WATER, to clear it up. NO FLAME OR HOT PLATE as fire is possible
• Resin or Gelcoat must be over 70°F before surfacing agent can be added; this can also be warmed in hot water bath.
• Surfacing Agent may not work if laminate gelcoat is done in direct sun on hot days.
• Styrene fumes may accumulate in low areas, such as swimming pools, and can prevent Surfacing Agent (wax) from working.
• Over catalization may cause the gel to happen so quickly that Surfacing Agent will be unable to work.

Glasses

Fiberglass Cloth

This is lightweight, woven fiberglass and is available in many different weights, the most common being 6 ounce and 10 ounce (this is the weight of the cloth per square yard). Fiberglass cloth is used mainly as a waterproof covering over small boat hulls, canoes, cabin tops, engine boxes, etc., where great strength, impact, and abrasion resistance is not required. Cloth is also used as a final finishing layer over previous lay ups, such as mat. This is the E-Glass type of fiberglass cloth.

One important fact to remember when using fiberglass cloth is that it does not lend itself to hard angles very well. Whenever possible, break hard angles with a plane sandpaper, or radius inside angles with hull and deck putty or body putty. this, in many cases, is desirable for a good-looking job, anyway. One gallon of resin will saturate or "wet out" approximately 6 square yards of 10-ounce cloth. More resin will, of course, be required to finish the glass job or to fill up the weave of the cloth until it is smooth.

Fiberglass Mat

Mat is the most versatile and widely used form of fiberglass for the hand lay up procedure. Mat is made up of short, individual fiberglass that can be hand laid in place. We stock Mat in tow weights. ¾ oz. and 1 ½oz. per square foot. Mat is used in applications where strength and durability are required, such as, on work decks for commercial and sport fishing boats, cabin tops, all sorts of tanks, washboards, battery boxes, decks and balconies on houses, and auto body repair work.

Mat will conform nicely to hard angles and tuck in close to places where woven fiberglass will not. When layered or combined with woven roving, very strong, rugged glass laminates can be built. Because of the amount of resin it absorbs, Mat is not used in applications where maintaining it extremely lightweight is important. Mat leaves a fairly rough texture, which is an advantage in areas where a non-slip surface is desired. The choice of either ¾ oz. or 1 ½ oz. Mat depends upon the strength required or the complexity of the surface to be glassed. The ¾ oz. will lay down over or into angles and curves with less work than the thicker 1 ½ oz. Two layers of ¾ oz. could be laid to equal the strength and thickness of one layer 1 ½ oz. Mat will not de-laminate or peel off as easily as woven fiberglass. If it were to be removed, Mat would tend to break off in pieces where woven fiberglass would peel off in sheets. Always use short nap paint roller to apply the resin to the Mat. Never apply the resin with a brush or squeegee. This would mop the fiberglass hairs around into piles and the finished product would have a very lumpy texture, making sanding and finishing a nightmare. Of course, it may be necessary to dab with a brush in hard angles or corners, but never stroke the surface back and forth. Always apply dry Mat to the surface you wish to cover and then apply the resin. In most cases the resin can actually be poured onto the surface from the mixing can and then spread around with the paint roller. One gallon of resin will wet out approximately 3 square yards of 1 ½ oz. Mat. When using Mat, a laminating roller should be used to massage out excess resin and the air that becomes entrapped in the laminate while it is still wet.

Roving Woven

We Stock 24 oz. and 18 oz. (per sq. yd.) Woven Roving. Roving is woven like cloth but is much heavier and thicker. It is used for reinforcement where much strength is required, as in the construction of boat hulls, tanks, swimming pools, etc... Also for smaller jobs such as glassing bulkheads and engine beds into glass hulls.

Roving should always have at least one layer of Mat applied first under it and between any further layers. Never apply Roving directly to Roving. Again, a pint roller is the best tool to use to apply the resin due to the large amounts of resin needed to wet out the Roving. Approximately 3 square yards of 24 oz. Roving can be wet out with a gallon of resin.