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Tutorial: How to make the mold for the curvy legs on the little table

June 22, 2010 By

I received several requests to show how to make the mold to create the bent laminations that became the curvy legs on a small table I built recently. Get some coffee, and enjoy!

Background:

It starts with a full-size drawing on a piece of 1/4-inch plywood – doing so allows you to adjust the arch radius, etc.:

Laying out the curves for the full-size drawing was interesting – but I found an easy way to zero in on the trammel length I would need. First, large calipers, to get the curves to look “right”:

Then I made a simple trammel with a hole large enough to allow the pencil tip draw two lines, the rough outline of the leg and stretcher thickness:

Using the trammel set for the radius in the full-size drawing, I drew the curves on a piece of 1/2″ thick MDF, and cut the curve on the band saw – THIS will become the “master”, from which all curves will derive:

Before continuing, it was necessary to smooth the edges, to finish the MDF boards with these “master” curves – I made a flexible sanding block, and sanded until happy with the curvature:

The other side of the master mold receives the same treatment:

After transferring the smooth outlines to 3/4″ MDF, I cut close to the line, and used a pattern router bit to make exact duplicates of the “master” curves:

The first set of curves on the 3/4-inch MDF becomes the pattern from which all others are made. It took several copies to make the mold to create the curves, but I was finally ready to use the mold – here is one-half of the mold, as I prepare to apply cork and tape over the cork – each new piece is screwed on to the previous one, to keep all pieces perfectly aligned – they are stacked and screwed to the previous one, then the edge is smoothed at the router table, until the desired width is obtained:

Cork is required to smooth the slightest imperfections in the curve:

Pressure is applied to smooth the glued cork on the mold halves:

Tape is then applied on top of the cork, to allow the glue to release from the mold without damaging either the mold or the work piece:

Now that the mold halves are done, it is time to resaw the pieces to be laminated:

Mix, and apply Unibond 800 on the surfaces to be laminated – this glue has a long open time, which makes very nice for this, and for veneering applications:

NOW is the time to use the mold simply insert the pieces that will become the bent lamination:

Allow the glue to cure under clamp pressure, and remove from the mold after allowing the glue to cure overnight:

After cleaning one edge, and maybe even running one edge over the jointer blades, clean up the other edge on the band saw:

It will be necessary to use a block plane (or YOUR favorite tool) to do a final clean-up of the edges:

Cleaning up the edges.

Thanks for staying with me for the entire process – enjoy! And please let me know if I goofed up something in the process.

— Al Navas

Filed Under: Blog, Design, Jigs, Layout, Tutorial Tagged With: , ,

Drawer guides for the stand-up desk

March 31, 2010 By

Few things can be more annoying than stuck drawers; however, I find sloppy-fitting drawers quite annoying, too. As a result, this desk gets hefty drawer guides, to keep the drawers moving straight and without much sideways slop. This is accomplished with drawer guides attached to the dust cover.

For each drawer I size the guide a bit at a time, using a hand plane:

Tweaking the width with a hand plane.

To prevent binding at the drawer opening, some hand work is required to taper the guide near the entry point:

A smooth taper is essential.

Installed, the guide allow lateral movement of only a few thousands of an inch. As the drawer bottoms are oriented such that long grains runs the width of the drawer, this tight fit should be good – if not, a few thin shavings from the sides of the drawer will fine-tune the fit quickly:

One guide screwed firmly in place.

Up close and personal, this is the drawer’s view of the guide in place. The taper is key to allow easy drawer entry into the space:

View from the opening.

Sometimes the spacing between drawers is narrow; in this instance, the two drawers share one guide:

One guide shared by two drawers.

With the guides in place, it is possible to continue to place the drawer stops; only then can the final fit of the drawer fronts be done, to ensure good appearance on the front apron. While this appears tedious, it is actually rewarding work; the details do count!

— Al Navas

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Filed Under: Blog, Design, furniture, Tutorial

Sanding – gotta love it

February 17, 2010 By

Like so many other woodworkers, I used to hate sanding. In fact, many years ago, it was typical for me to spend many hours working on a project, only to get near the abyss of ruining a project by sloppy sanding, followed by applying a sloppy finish. The outcome: a sloppy project, and nowhere nearly as nice as it could have been — in other words, frustrating at best, and ugly at its worst. This was due to ignorance on my part — ignorance about what to do, how to do it, and what to use to do it well. In the end I learned better ways, and I now like the process about as much as doing anything else in the shop. It sounds crazy, right?

It is not that crazy, if you think about it; for it is the looks of the project that ultimately invite touching and feeling the wonderful surfaces, the nice curves and edges… But before I get sidetracked, I can word it better: Learn to sand properly, and the finished quality of your projects will jump to a new level! And by learning to sand properly, you will also gain appreciation for the careful sanding steps required between layers of topcoat you apply to your project. Ultimately, your dyes, your lacquer, your poly, etc., all your finishing materials will thank you, too.

The rule I now apply to my finishing projects is quite simple. If I take 100 hours to build a project, I allocate at least another 50 hours to the finishing process. This time includes sanding the wood, in preparation for the required sealing shellac wash coats, for example; then carefully sanding each layer of finish until I feel nothing but a smooth surface on the entire piece. The process is the same whether I am finishing a lid for small jewelry box, the box itself, of a huge dust cover for a large furniture piece.

The biggest discovery I made in tackling the proper finishing of a project, was finding the proper sanding paper. But not just any sanding paper. I finally, reluctantly, bought some of 3M’s 216U Fre-Cut™ Gold, 600-grit sandpaper; and now I buy it in sleeves of 50 sheets, from Homestead Finishing Products (Owner: Jeff Jewitt, the famous finishing guru). This paper is my secret weapon in a successful finishing process:

216U sanding paper.

As I mentioned, I buy the paper in 9″ X 11″ sheets, and then cut them to fit my sanding pads — each sheet gives me four pieces — I have never made a sandpaper cutting jig, as I find this method is quite simple:

Measuring to cut - not fancy.

I think that the edge of my 36-inch metal rule works great for cutting the paper to size. If you decide to do it this way, make sure the abrasive faces down, or your rule’s edge will be slowly worn away and you will no longer have a straight edge:

Cut with abrasive facing down.

After I finish applying a layer of coating, and the coating has cured or dried properly, I use the 600-grit paper on the sanding block to lightly sand all surfaces; the 216U is a long-lasting paper, and resists clogging with finish better than anything else I have used in the past:

Sanding thoroughly.

After sanding I then vacuum as much of the sanding dust as possible, and follow it with a thorough wipe-down using a moist paper towel or lint-free cloth:

Cleaning sanding dust.

This next step is crucial, and guaranteed to result in the smoothest finish on the project. Your fingers are extremely sensitive to imperfections on a surface; therefore, use them well, for they will reveal even the tiniest of bumps on the wood:

Feeling for the slightest "bump".

If needed, I will again sand the areas where “bumps” or imperfections still exist. By going through this entire process, I guarantee myself the best finished surface possible on my projects. If I can do it, I know YOU can, too! Take your time, and you will soon get wonderful results by sanding carefully, and patiently. And you will be happier with your projects.

Disclosure: I am a happy customer of Homestead Finishing. I have no interest in the company, other than their continued success.

— Al Navas

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Filed Under: Blog, Education, Finishing, Tutorial Tagged With: , ,

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