Help with perfecting board outline

I have a problem may be someone can help me. I have read all the archives about truing a blank and have tried all the techniques, but I still find areas on my out lines that aren’t perfect; where the arch may be a little flat or something. When I draw my outline the outline looks good but after I have cut it out and trued it up I notice Imperfection in the flow of the rails. Nobody else sees it in my boards as I have done about 17; is it possible to get a truly perfect out line, is the blank and my eyes playing tricks on me.

Here’s a kind of different approach that may me helpful. I’ve been doing this for almost 30 years and it works pretty well. The “bumps” may be from drawing your templates on a flat surface rather than the gradual curve of the blank’s rocker. Try designing right on the blank. To get the overall curve/concept use narrow masking tape rather than drawing all over your blank. This allows trial and error without a lot of mess. Set the blank up against the wall and stare at it. Focus on the outer edge of the masking tape line. Lay the blank on the floor and stare at it. Set the blank on your shaping rack and sight it down. By sighting it down, I mean holding the nose/tail up to your face and check for bumps. You can carefully re-lift a section of tape with a blade and re-set it, or you can just cut it out and replace it. After a lot of looking you can decide if you like the left or right side better (this almost always happens). That will be the side you trace with a pencil and cut out. Trace/sketch right up against the tape. You can pull the tape and cut the ONE rail. Clean up this rail outline, again, sighting it down from all perspectives, then take your template material (door skin ply, plastic, etc.)(pre-cut one foot wide strip for ease of handling) and clamp it to the blank so you can trace this new outline. I do this with the blank vertically on rail in the shaping rack so my pencil doesn’t slip. Cut out the template and AGAIN sight it down to make it nice. Compare the new template with the cut outline. If you are a good craftsman you should be darn close and you can “update” the cut blank if you need to… …then just do the other side. Shape.

That makes sense about how or why I get flat spots, I will try that out. I have drawn on my garage floor using my templates and they look fine, archs look good, even when they are drawn on my blanks they look good ( I will double check next time really look from all angles). After I have cut them out and trued up I usually take them out side lay the blank down and look really caerfully top and bottom and then up against a wall and that’s when I see the problem areas.

You can spend a lot of time checking your templates and it’s time well spent. Using paper templates that you took off another board can be problematic as it’s difficult to cut a clean curve with scissors even if you did a perfect tracing. Transfer to masonite or whatever and spend some time truing it up. I put mine on their side in the crutch of my shaping rack and look along the edge for any dips, bumps or straight spots. Clean up your blank before tracing the outline and use pencil for a nice thin line. Try and follow the line with a long sanding block or electric planer to get a 90 degree edge - I sometimes trace an outline on the deck as well as the bottom as a reference. When shaping your rails, blend the deck and bottom together at the edge and no further. Getting carried away with shaping screen or sandpaper along the edge will distort your outline.

One thing that ive found that helps is after you have cut your outline use your surform and only true up the bottom rail once you have got the bottom rail true take you squre and with the board on its side push your squre in the rail untill it is sitting flat on the rail this will show you how much foam needs to come off the top railthen take your surform and even the top and bottom rails up thats something that works for me after you have done that take your planner with 0 cut and go along the outine,the planner will ride on the low spots and take out the high spots hope this helps

                                                                                                        Cain

It takes a while to where you can shape both sides of the board equally let alone SEE the dips and doodles. I lay the cardboard on the blank bottom and make the template with the curve of the blank. Proceed with cutting the outline until you get the board to where you have both sides outlined and smoothed. Then do the foil. NOW go back to checking out the outline. Believe it or not a 1/16" flat spot will make a huge difference in flow of the outline curve. I then roll out a long sheet of white paper and tape at the stringer on the “winner” side. I take a single edge razor blade and cut the paper out in the shape of the outline by running the blade right up against the foam edge. Then un-tape and flip over the paper template and see how the other side matches up. If it’s shy - figure out how much you need to take off on the original side. Next take a big fat black marker and trace over the edge of the paper outline onto the blank. Flip and do the same to other side. Now use your surform or sanding block to take away only the black edge and you will have TWO matching sides with a curve that looks good to the eye!

To get perfect symetrical outlines and flowing templates. 1) use full templates, 2) True them with a planer from nose to tail, this will smooth out the high & low spots in your shape 3) cut the shape out with a router leaving a 1/8th inch template guide buffer, or for the hand saw guys…the pencil line. 4) Put the blank in the saddle rail up, and true up rails with a planer to the pencil line. 5) Throw away your surform, or better yet put the surform in the glassing box, and use it to cut down bumpy laps. Use the planer for everything. it wont lie to you. Surforms are liars.

-Jay

Thanks, Jay…I should have added this disclaimer:

I am a backyard shaper and use mostly hand tools after the foil is roughed in.

Be sure and replace the blade that “lies” with the microplane surform blade. It works well and takes a much finer cut.

The 5.5" Microplane Surform Blades have proven to be a great blade replacement option for the Stanley Surform Planer. These blades have a shaving effect on both wood and foam. They are smooth enough to be used for flattening and finishing and do not cause chipping when working against the grain of the wood stringer. 5-1/5"x1-11/16"

…the problem is in the templates. bad or not even curves provides impossible to true up outlines…

…the BEST method for build templates is with a cnc router.

Fernando

Today I taught my robot to be a shaping machine,

he said he had seen one in the Surfer magazine.

And NOW you complain about no “human” touch,

while I drink coffee when he mows and such,

but look at my fingers on keyboard and mouse,

come on over and see my new car and house.

Up on the screen my shape is so cool,

it really doesn’t matter the buyers the fool…

My template(s) are made of a thick cardboard stock. This will lay on the blank quite closely.

I draw the outline with pencil, darkening in the excess blank outside of the template line.

I true the blank by eye, repeatedly checking it against the template.

I think that the eye is/has to be the final judge. It has to “look” right. I lean it upright against the wall, stand back and admire/agonize. Often what seems to be perfect on the shaping stand and in my hands, shows those imperfections. Very frustrating, especially if one is a perfectionist!

On the other hand, I think that small imperfections are of relatively minor importance. Why?

Consider this: when riding a wave, basically only one rail at a time is engaged (the exception being the tail, but this represents at most maybe 20% of the rail outline).

So strive for perfection, especially in that tail section, but don’t stress out. The biggest danger is obsessing and overshaping.

It is vitally important, of course, that each rail be as perfectly flowing as possible, but is it even possible that each rail be 100% the same? (This is actually an impossibility on a micro-level.)