11 Feb 22:
Placed the first garboard plank on the building jig to check the shape. Used one of our lap clamps to hold the plank in place at the mid frame while we checked the fit.
Then we dry fit the bow and the stern to make sure we had proper overlap of the bottom plank and that the upper edge of the plank (when the boat is upright) came all the way to the knuckle in the transom, where the next plank will overlap. Stern shown below. When the fit was right we drilled a pilot hole and counterbore for a #8 x1 inch silicon bronze screw, that will be our alignment hole when we permanantly install the plank with thickened epoxy.
Checked the bow fit. A good tip is to make some pencil marks for where the transom are and also mark which edge of the dry plank gets adhesive. Otherwise one may lose track of which edge to apply the adhesive to...ask me how I know...
Next we took the dry plank off and applied THIXO thickened epoxy adhesives to the bottom plank lap and the garboard plank faying surface (contact points). Right about now is a good time to lay some plastic film over the molds, so that the planks do not glue themselves to the molds.The plank is permanently screwed to the transoms and frame. We used deck screws and fender washers as temporary fasteners while the epoxy dries. Think of them as clamps. Once the epoxy is dry the screws are removed and the holes are filled with thickened epoxy.
Used this folding rule to mark 6 inch spacing for the temporary fasteners.
After the planks are clamped, rech inside and clean off any excess epoxy.
Our friend Richard has built 4 Nutshell Prams, and he offered a tip to use blocks of signmaker's PVC foam board as backer blocks for the screws. The PVC will not get glued to the boat like a wood block will. We found a product at our local sign shop called Palight and it worked great.
Trimmed the planke end with a crosscut saw.
The bow end takes some creative cutting. We used our DeWALT oscillating multitool to make a plunge cut directly down to the centerline of the forekeel. then cleaned up the cut with a chisel. For the opposite side garboard we dry fit the plank, marked the centerline with pencil, took the plank off and rough cut the line with a jigsaw. Then we dry fit the plank again and tuned the cut with a hand plane.
You'll end up with a small gap along the forekeel that is filled with thickened epoxy. the plank edges will be filed flat later and a brass or bronze protective rub strip will run along the keel and cover the garboard plank seam.
TotalBoat THIXO thickened epoxy adhesive used for the seams. It has excellent gap filling qualities, which we need :) It comes it 2 part single tubes with 185ml of product, and on this build we have been trying out the 2 tube (resin and thickened hardener) THIXO Pro system and dedicated Pro gun. The Pro tubes hold 460 ml of product, 2 1/2 times more. If you plan to use more than 3 tubes of the smaller THIXO tubes, this would be the better route to go. The Pro gun is around $80, but it is High Thrust 26:1 ratio caulk gun that makes it easier to dispense the thick product, compared to the bottom of the line standard 7:1 ratio caulk gun. This makes the job easier, especially when the product is cool and harder to dispense. And while the THIXO costs a little more than hand mixing resin, hardener and filler, there is no guesswork involved with THIXO as to how much resin and hardener to mix, how much filler to add and time saved standing around stirring a pot of epoxy in a cloud of filler dust. The THIXO system is also applied in a very precise manner, which limits waste. FMI: https://www.totalboat.com/product/thixo-pro-21-epoxy-system-2/
End of day. All stop. SCUPPERS has the watch.
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