Friday, January 7, 2011

Scratch Built 1:12 Peterboro Canoe Conclusion

The hull is now surprisingly strong for its light weight and will get even stronger once the internal frames are added. Start by milling strips that are 1/16 by 1/32 inch in cross section. 

These are soaked and bent over the approximate strongback frames. This will prevent them from kinking when inserted into the hull.

They are placed into the hull while damp and thin CA is used to glue them in place.

A strip of plastic works as a spacer and the frames are glued into place the whole length of the hull.

Once all are in place, trim the ends and sand flush with the sheer plank. 

Thwarts of cherry were used on this model. I have a jig for making the decorative bevels in these thwarts or a rounded file can be used instead.

The frames are marked where the thwarts are to be installed and a section of the frame is removed and the thwart is glued in place.

Floor boards are milled from a contrasting colored wood (cherry in this case). Since I build many of these canoes, I have a jig for getting the proper rounding of the floor board ends.

The floor boards are glued into place and the interior of the hull is finished off. A coating of thin CA can be used over the entire interior surface to even out the tones wood finish.

The kit comes with deck boards that are undersized in my opinion. I make replacements that are oversized so that an even overlap can be made in both the cap rail and decks.

Three short segments of strip are used to finish off the planking of the stem and stern and a gentle curve is carved and sanded into these strips. The stem and stern pieces are trimmed down and a crown is made into the tops of these.

The decks are glued in place with a slight separation between the deck pieces at the far ends of these. This will be covered by a cap on top and a false keel at the ends.

As can be seen in this photo, there is plenty of excess material for forming the overhang on the hull. 

Cap rails are cut and installed between the ends of the decks.

The interface between the cap rails and the decks are cleaned up and a gentle camber is sanded into the tops of the decks.

An even overhang is shaped in the cap rails and decks.

Deck caps are installed and trimmed to size.

Here is a very effective method for soaking wood that works well if you don’t want to get a large container out to hold the planks. If the wood is very stiff and doesn't want to bend well, the water soaked plank/paper towel assembly can be micro-waved to steam the wood. I've used this technique several time with uniformly good success.

The false keel is bent to shape and installed onto the hull using rubber bands attached to the thwarts to hold it in place while the glue dries. 

The cockpit combings are formed using a bending jig made of MDF and then are installed into place.

Trim and profile the combings once they are attached to the canoe. 

Paddles can be made to accent the canoe display. For this particular canoe I chose traditional otter tail paddles. First find a pattern that you like and size the paddles to an appropriate length. In this case they end up being around 5 inches long. The various stages of production are shown here.

Make a pattern and trace out on basswood, cut out using a new and sharp knife. Use a plane or other tool to thin out the blade of the paddle.

Since I turn out the shafts on a drill press I carve a round section to insert into the drill press chuck. Turn the shaft.

Finish off the hand grip and smooth off the interfaces between the handle, shaft and blade.

 Here is a photo of the completed canoes. The one in front has mahogany trim and the one in back cherry. The presentation plate has been placed on the first canoe while the second is still awaiting a suitable event for presentation. I hope that you've enjoyed following along.

Thursday, January 6, 2011

Scratch Built 1:12 Peterboro Canoe Part 1

Midwest offers a kit of this canoe for around $30. The canoe is built on a strongback and once the kit is completed the strongback can be reused as many times as you like. The cost for scratch building this kit is around $7 per canoe. I've built four of these thus far and I thought I'd pass along what I've learned and what seems to work for me.

Start by milling 3/32 inch thick basswood boards into 3/32 x 1/16 inch thick strips. Using 3/32 inch thick material assures a clean top and bottom surface for the strips. Any minor surface irregularities made during the milling process will be removed when the completed hull is sanded. Two contrasting strips of a dark colored wood will be used for the third planks from the sheer. I’ve used mahogany and cherry for this but you can select any wood that you like. I prefer woods with little grain and figure to them because of the scale but this is a matter of personal preference. If you are making several canoes, try to buy several sheets of basswood of differing color tones to add interest to the planking of the hull. 

Bow and stern pieces are cut out following the pattern in the kit. Mark the location of the sheer plank on both of these. A keel strip is glued onto the both end pieces and they in turn are temporarily glued onto the strongback base. The plans call for marking the locations of the cross braces on this strip but this is not necessary. The ends of the sheer plank are beveled and glued at the previously marked location on the bow and stern pieces. Alligator clamps work well to keep the sheer in good position.

The first several strips require no beveling along their length, only beveling of the ends where they glue to the stem and stern. Thin CA glue is used to gluing the strips on to the canoe. The thin CA flows by capillary action between the planks. This will be explained better later.

Once the hull begins to make a turn (tumblehome), bevels must be made to the edges of the strips. This can be done by sanding or planning. I use a plane because it makes less mess and dust. A jig that consists of a groove made into a piece of wood that will accept a strip is shown below.

Once the strip is secured, the plane is held at an angle and is run end to end to make the proper bevel.  A sanding block is used to bevel one end of the strip for attachment to the stem.

Once in place thin CA is run between the strips. A needle with the bevel ground off works well to accurately place the CA.  Once glued, a short time of holding the planks together allows for a firm bond.  

Work down the hull until about 4 inches from the end. Place the plank into final position and mark the end of the strip.

Use a nail clipper or other cutting device to trim the strip to length. I find that nail clippers leave a nice clean cut.

Pull the strip away from the strongback and sand the bevel into the stern end of the strip.

Glue the strip down to the stern.


Continue down the hull until the turn of the bilge. The last strip before the hull becomes flat on the bottom is the hardest in the whole canoe. Once this is in place it becomes much easier. I find that rubber bands work well to keep the canoe in good contact with the strongback. I should also add that I use small pins at the sheer to keep the sheer strake in contact with the strongback.

When the turn of the bilge is reached, the strips change from attaching to the stem/stern and instead attach to the keel. Since the floor of the canoe is essentially flat in cross section, there is no need to bevel the long edges of the strips. To cut these strips, place one in position and mark the location of the end of the bevel with a small tic as shown.

I also mark the keel so that there is perfect symmetry in the bottom planking. Use a straight edge to cut the bevel and place the end of the strip into the canoe.

Repeat the process on the other end on the strip. Glue the strip in place using thin CA.

Sunday, January 2, 2011

Miniature Stratocaster Pinewood Derby Car

Here is the car that I built for last year's pinewood derby.

It is a miniature Stratocaster Guitar mounted on a chassis that is shaped like a guitar case.  I never raced the car because of fears of destruction as it ran down the track, but it sure looked good!  It is made with a basswood body and maple neck.  A photo of a stratocaster was downloaded from the Internet and scaled to the proper size on the computer before being printed out.  The printed copy was cut up into neck and body sections and pasted onto wood to allow for exact cutouts to be made.  I used grinders, files, sandpaper and other tools to shape the body and neck and then individual fret lines were incised into the finger board with an x-acto knife.  Some 0.25mm wire was glued into each of these fret slots to make actual metal frets and even finer wire was used for the strings of the guitar.  Some scrap sprue from plastic model kits was turned to make the knobs and sheet styrene was used for the finger guard.  Lastly, copper wire and brass tubing were used to make the cable and 1/4 inch jacks to finish out the project.  The body is painted with flaming red lacquer with clear coat over the top.  Here are a couple of other photos of the finished project.