Boat Building Forum

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Same old answers
By:Paul Jacobson
Date: 8/26/1998, 6:16 pm
In Response To: Same old questions one more time (Bruce Everett)

Question one seems to have been answered already, so I'll skip to 2:

> 2) Is there a consensus developing between using multiple layers
> of fiberglass cloth on the outside of the hull rather than one heavier
> layer. If so, what is the "standard" weight cloth being
> used (keeping low wieght in mind).

No consensus yet, but George's argument of using more layer so thinner material may be gaining favor. Just from a matter of material cost, though, since a yard of 3 ounce cloth is much more than half the price of a yard of 6 ounce cloth, you will pay more for two layers of thin fabric versus one layer of thick. Standard weight of cloth seems to be either 4 ounce or 6 ounce. If you use an equal weight of resin and cloth it seems obvious that the 6 ounce cloth will use 50% more resin than the 4 ounce cloth, and the weigh of the boat will be greater. The thicker cloth may give more scratch resistance to the bottom of a hull simply because it is a few thousandths thicker. On the other hand, there have been no complaints about the strength of boats covered with 4 ounce cloth. I got a pretty good price ( I thought) on my cloth from Clark Craft, and the thinnest they had was 6 ounce. I couldn't see spending MORE for 4 ounce.

> 3) I've heard of type of cloth that is extremely wear resistant
> but can't remember the name. It is usually used in narrow widths on
> high wear areas such as the chines.

It would be cheaper to just use the fiberglass scraps you have and put a second layer on the high stress area. If you are doing a stitch and glue, those chines already have a layer or two of fiberglas tape on them already, and are stronger than the surrounding wood. If you are going to be extremely abusive, put on a thin wood rub strip over the top of your fiberglass. a 1/4 inch or 3/16 inch thick strip would be fine. If you sand or plane it to a D shape it shouldn't affect the tracking or act much like a keel or skeg. Hold it on with some epoxy resin and clamps or weights until the glue sets. It can be left unfinished, or you can seal the wood with a coat of resin. when it gets bashed up, sand it off with a belt sander and glue on another.

> 4) Need a good method of filling the gaps between some strips.
> Will standard wood putting create any adhesion problems with the epoxy.
> Is there a benefit mixing your own epoxy/wood blend for this.

Wood putty is okay, but why pay for it? You should have plenty of sawdust around. Use that mixed with the resin. I have seen the suggestion that you measure the proper mix of resin and hardener, but before you mix them, add enough sawdust to the resin to make it thick. After you have the consistency, then mix in the hardener. By adding the sawdust before the hardener the theroy is that you can get it mixed in well, no matter how long you have to stir it. This way you aren't busy mixing while the resin is starting to set. If you can reach under the big cracks, cover the inside with a strip of maskeing tape. Pull the tape off after the resin sets up. This keeps you from forcing a glob through the crack -- and you would then have to sand off that excess.

Hope these ideas help. Paul Jacobson

Messages In This Thread

Same old questions one more time
Bruce Everett -- 8/25/1998, 9:23 pm
Same old answers
Paul Jacobson -- 8/26/1998, 6:16 pm
Re: Same old questions one more time
Guy Wright -- 8/26/1998, 9:46 am
Re: Same old questions one more time
patrick weber -- 9/4/1998, 11:58 am