For me it's easiest to do my original drawing at 1":1' scale. A 7 foot board would be 7" long on paper. I've also used an enlarging function on a copy machine to adjust size. Plot dots on your template material (Masonite) every foot. I also place dots at 6" and 3" at each end.
Plot dots at every inch on your drawing (1/2" and 1/4" at the ends.)
Measure across your drawing at each dot and do the math (1/2" = 6", 1/4" = 3" and so forth.) Plot the enlarged measurements on your Masonite at the corresponding dots and use a fiberglass rod, batten or strip of wood to connect the dots.
Using a skinny lead pencil and keeping your lines crisp on your drawings will aid in accuracy. Once you have your curves drawn, cut out the template, shave bumps with a mini-plane and smooth it with sandpaper. With a little practice you should be able to get pretty close to the curves in your drawings. Any slight discrepancies can be adjusted by shifting your template around to fit your desired dimensions.
I’ve watched videos and noticed some shapers seem to take a blank, pin-point the center of the board and use two different masonite templates (one for the bottom half and the other for the top half of board). What is the advantage of that type of template.
Here is an example (attached image I found online). You can see from the pencil lines he’s used two different templates one for the back and one for the front.
Yes, Huckleberry got the spin template right. For those I usually draw up my full size pattern on paper before transfering to masonite one end at a time.
One tip is to taper the width at each end of the spin template so it is easier to get them to overlap properly if you decide to extend the length of the board. You will usually be bumping the width out a notch or two depending on the extension of the length. The tapering width at each end of the spin template allows you to fudge a little.
Now when you’re working the curves, even if you plot a dot every 3" or so how do you obtain that smooth round edge, it seems to me it would have a little connect the dot feel. Do you use a flexible ruler or something as a guide?
By taper I assume you mean just leave some additional length incase you decide to create a similar board but longer.
One other question reguarding spin templates, one end is the nose and the other end is the tail how do you properly line the template up with the stringer? or is the answer you dont. You line up the nose with the stringer, then measure out from the stringer at your mid point (example 20" and place a dot) and use that as a guide for the spin template?
How do you draw up your template full size on paper? same method as mentioned above, dots?
I have a fiberglass 'whip' that was part of a bicycle trailer safety flag. It works perfect to connect dots. I tape down one end along the center of my outline template curve and flex the tip to fit the nose and tail curves. I have to flip it around to do each end.
For the paper pattern - yes, I use one edge of the paper as a centerline and plot my dots accordingly. It helps to tape the paper down on a hard floor. Once you have the full curve laid out on paper it is easy to swap the ends to make a spin template with the nose on one side and tail on the other.
It is also easy to extend the length a bit and slightly taper the width where the center point on each side will be. That way you can bump the length and the width with a simple shift in template position.
The stringer can be used to help lay out your dimensions but the outer edge of the template only needs to hit a couple of dots. I.E. measure across the blank and plot your width, nose and tail dimensions, then line up the outer edge of the template with those points. The end of the template can cross over the stringer. The template doesn't need a straight edge down one side to line up with a stringer. With a spin template there isn't a straight edge anyway... one side is the center to nose curve and the other is the center to tail curve. The end of the template can line up with the stringer but doesn't necessarily have to line up with anything.
The main thing is keeping track of how far you shift things around so you can do the same on the other side. I often have little marks along the edge of my templates where I've crossed the stringer line with the template. I make sure to use the same mark when i flip it over to do the other side.
Some of my outlines were done with templates that were an inch or so from the stringer or center line. In those cases I just use a relatively flat section of the curve to fill in the gap.
Don't hesitate to get creative. It's just a pattern you'll be using to trace an outline. It's YOUR curve. Don't be afraid to tweak it.
In this image I show the ends with a "stringer line" - that's just to better understand the spin template concept.