How To Apply Elephant Hide
Geodesic Airolite Boats (http://www.gaboats.com)
This is a heavy duty additional skin applied over the Dacron for rough duty use. It consists of an 18 Oz. vinyl/Polyester/vinyl triple laminate that is extremely tough and weather proof. While this is not the strongest fabric made; I feel that it is an ideal match for the light weight framework of a Geodesic Airolite hull.
My first thought was to use adhesive all over the Dacron but that proved to be a disaster. Then when I discovered what a strong joint it made bonded to itself, I decided that (like a fitted glove) the vinyl just stuck along the stringers would be the best approach.
The vinyl material is very rip-stop and abrasion resistant. It would be recommended as a treatment for a canoe that is being outfitted to run the Alagash trip in Maine. On the Cricket-12 it is applied from the outer edge of the ply bottom up to the gunwale. On boats without the plywood it could be run from keel to gunwale or even just from keel to the water line. I'll modify that, to do a complete streak that is above the water line amidships. This would run it up quite a bit at the stem which would be desirable anyway.
The first consideration is to deal with the fact that ELEPHANT HIDE does not heat shrink. It has a small degree of stretch but not enough to wrap a hull without cuts and darts. Plan on fitting and cutting the vinyl before the Dacron is applied to the hull, so that you can use the stringer edges as cutting guides. Cut it in strips and apply it lapstrake fashion with joints along each stringer.
Now that’s easier said than done. It cuts easily with a "SNIPPY" razor cutting tool. The "planks" are curved and do nest, sort of, one to the next. The problem lies in the fact that the material starts out 60" wide and is awkward to clamp in place, laying flat on the hull to do the trimming. Start at the gunwale with the boat right side up and work downward.
I hate to say this but you would probably better off to start in by making some sort of jury rig work table to lay out the material flat; then make paper patterns of each strake. Make them just slightly oversize and clamp them in place on the hull for a final trim with a razor knife.
While the "plank" is clamped to the hull for
the final trimming, it is time to incorporate index marks both on the wood frame and on the vinyl. Include a numbering system to get the correct "plank"in the proper place and a center line mark to relocate in the exact position. Roll them up for convenience.
I used acetone on a folded up cotton pad to go over the glue line on the vinyl and clean off any residual crud that might be present. This took off a slight trace of the vinyl color so I felt that it was a good prep for gluing.
The HH66 vinyl cement drys too fast to assemble wet glue lines; however I found that you can brush a glue line along the sides of both pieces to be joined and let dry (just the approximate width of the stringer). With the boat upside down start with the bottom "plank" clamped in place on the hull. Now roll up from one end held with clothes pins so that you can start gluing in the center of the boat.
Now you can assemble the joint then heat and clamp with an iron set at about 170 Deg. Remove the iron and use a roller to squeeze the joint while it is cooling. While doing the above pull the vinyl tight in both directions to prevent any wrinkles or puckers from developing. Practice a little on some scrap while setting the iron temp. It is too hot when the vinyl starts to melt. It is working right when the glue melts and sticks like contact cement. When it is cool the joint holds like it was vulcanized.
WARNING! HH66 is an industrial adhesive with very bad flammable fumes. An industrial strength charcoal respirator should be used. In lieu of protection, work down stream of a healthy fan placed to suck in good fresh air. Doing this in a well ventilated area will keep you out of the small amount of fumes that you are creating, considering the narrow glue lines that are involved.
The Vinyl has a shiny weave texture on one side and an almost smooth matte surface on the other side. It is available in 10 colors including black, white and gray (color and texture varies slightly with each mill run). It is supplied in 60" width along with the vinyl cement from: Goodwin Traders —71 Russell St. Bath. ME 04530 207-443-3072
Associates June 1999
|Copyright 2002 Monfort Associates.|