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Re: fiberglass chopper gun
In Response To: Re: fiberglass chopper gun ()

> Yes I had thought about doing a hand lay up but with a chopper gun i could
> do the hull with out some dring to fast and have a soild hull. if it was
> going to be a small boat i may but i am looking at building a 65' hull.

Have you considered using ferro-concrete instead of fiberglass? For a hull of that size concrete could be a real advantage in both construction time and costs. There would be no form 'cutting' or mold making (time consuming and costly) as the iron framework is easily and quickly bent to shape, wired together, and plastered with concrete. I've seen one really good book on the subject and know that there must be several others. I got the impression that building sailboat hulls from ferro-concrete was much more popular in Australia than in New England, so you may want to look for references from 'down under'.

Fibreglast (www.fibreglast.com) sells NEW chopper guns and has the necessary materials to feed them. They also have video instruction tapes on many fiberglass construction techniques. For the modest difference in price you might want to start with new tools. You might save a couple hundred dollars in a multi thousand dollar project, but having a used one break down in mid-project could be a bummer.

Copied from the Fibreglast ( yes, they DO spell it that way!) website are these descriptions of chopper and 'cup' guns.

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Quick Glass Build Up Chopper Gun

A hand held, variable speed air powered chopper gun for coating molds or parts with glass reinforcement. Continuous glass roving is fed into the rear of the gun. The gun then chops the roving into short pieces and deposits them onto the mold. Resin is then applied by brush, roller or sprayed on using a cup gun. The length of the fibers can be varied from 4" down to 5/16". This gun will deposit the equivalent of one layer of 1 oz mat onto a vertical surface without fall-off before wet-out. Ideally suited to quick mold or part build-up once the first layer or two are in place. Use a saturation roller to remove trapped air. Works with #522 Gun Roving or #292 Graphite Tow

171-A Each...............................................................$ 279.95

Gel Coat Cup Gun

An inexpensive gel coat gun for spraying small to medium size molds. Avoids the high cost of catalyst injector systems and at the same time avoids the pitfalls of a regular spray gun. The resin and catalyst are mixed in the disposable paper cups, the lid and nozzle assembly are pressed on, and the cup is then placed on the gun. With the paper cup in a level position, depress the trigger and the air stream picks up the gel coat and provides a uniform, high velocity spray pattern. To clean up, merely remove the cup form the gun, and just clean the lid and nozzle. Requires 60-100psi of air. Cup capacity is one quart. We ship the gun with a 3/16" ID nozzle, but others are available (see below).

120-A Each................................................................... $ 139.95

Catalyst Mixes While You Spray External Mix Cup Gun

Also an inexpensive gel coat gun for spraying small to medium size parts and molds, but with external mix for the catalyst. This added feature means less wasted material because there is no need to pre-catalyze. This gun uses the same paper or plastic cups and the same nine different nozzles as the #120-A. There are seven different nozzles for the catalyst side of the gun for a wide variety of catalyzation rates. There is an angular adjustment to set the spray patterns for full catalyzation, no matter which nozzle or viscosity of material is sprayed. Separate flow controls for gel coat and catalyst can be adjusted to desired material flow and atomization rates. An excellent gun when numerous color changes are done.

836-A Each.................................................................$ 269.95

Save time and waste less resin

Cup Gun Gravity Feed Attachment An easy-to-use attachment, this assembly replaces the one-quart cup when spraying larger projects. The hose provided easily attaches to either our #120-A Gel Coat Cup Gun or our #836-A External Mix Cup Gun. The large bucket allows up to 8 quarts of resin or gel coat to be mixed and sprayed at one time. Use this assembly to spray larger projects in a fast, easy manner instead of mixing several smaller batches or using more expensive equipment. This product lets you spend less time mixing and wasting resin, and cleans up easily with acetone to be used over and over.

1213-A Each.............................................................$ 59.95

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Years ago I saw tools that mixed resin, catalyst, and glass strands and sprayed the mixture. These seem to spray either glass, or resin. First you spray on a coating of glass fibers, then you cover it with a coat of resin. I'm not too impressed with the ability to put on a layer equal to 1 ounce mat. Hand layups of heavier glass cloth (say 20 ounce cloth or similar mat) might be faster. You could spray on the resin to saturate the fabric, and roll out the excess. The cup guns mentioned above, with the bulk feed attachment would let you do batches of up to 8 quarts ( two gallons) at a time. That would cover a pretty good area! And, you could whip up a fresh batch in a few minutes and keep going -- working out from a wet edge before the first batch sets up.

Just a few thoughts. Building boats that big is really beyond my field of expertise -- I read about them but I don't actually work on such a scale, so take these ideas with at least a few grains of salt.

Paul G. Jacobson