Basic material

[jrbeall]

I found out early on that using solid wood for clock construction presented  problems.  It expands and contracts with changes in humidity and it is weak where the grain runs accross.  It is true that early American wooden clocks used solid wood and they worked pretty well.  They were  crude however allowing plenty of slop in their fit.  I have been interested in making my movements as small and precision as possible and needed better material.  I tried Baltic birch and aircraft birch, which is gereally a little better,  but found them to be less than perfectly flat and of an uninteresting color.  I tried making my own plywood then and using a variety of different veneers, and was able to make beatutiful material of any thickness and of excellent strength.

Homemade plywood is very easy to make.  All that is needed is good veneer, eboxy glue and a simple vacuum press.  Veneer is not very expensive but eposxy is a little pricey. I Use West System products which are excellent.  The 105 resin and 205 hardener mix in a 5 to 1 ratio but the containers come with pumps which automatically meter out the correct volume.  The glue will harden in 2-3 hours at room temperature but a little heat will speed that up considerably.  I use a flood light in winter or the sun in the summer time.  

When you lay up the laminations, of course, every other layer has the grain at 90 degrees to the last.  This is what gives the material its strength.  Since the eoxy is waterproof, and the veneer is so thin,  the plywood is absolutly stable.  For vacuum, I have used an electric pump, but now am using the "Thin Air" press which is simply a heavy poly bag with a valve and a small hand pump.  It is available from Lee Valley Tools.  You will need a hard, smooth flat platten and a piece of window screen to spread the vacuum.  I also place the glue-up in a plastic bag to keep the squeeze out from getting on the platten. I usually make pieces which are about 10 inches square, [limilted by the width of the veneer] and 5 to 7 plys thick

I have tried using yellow glue for plywood but the moisture in the glue causes the veneer to buckle and bubble and produce bad lumpy reults.

[JayRay_Hughes]

For my first gears I was thinking about 3 plies with the center ply 8 or 12 pieces quarter sawn, grain running center to edge. The other 2 turned 90degrees to each other. Should I use more plies?

I like the escape wheel in the monograph you posted. I was thinking about doing mine this way also.

Have you tried something like this? Will 3 plies be stable enough?

[jrbeall]

Harrison used center to edge solid oak strips for his large wheels.  I think he may have sandwiched them between brass disks.

  I have made very large escape wheels in that way but for small ones it is hard to get them accurate.

3 plys is not enough.  It is just as easy to glue up 5 or more once you have got all the stuff together.

[JayRay_Hughes]

roger on the 5 plies

[PatrickToomey]

I just joined this forum since I'd like to try making a wooden clock on my CNC router. I noticed this message about making plywoods and I wanted to recommend a brand of epoxy that I've used in the past, MAS. You can find them at http://www.masepoxies.com/products.htm  Two great things about this brand is that you only need vinegar or alchohol for cleanup and they have no VOC's so you won't have to worry about developing an alergy to them like you can with other epoxies.  It's really nice stuff to work with as well. As mentioned earlier, it's not cheap but you really don't need much for this kind of application so it's well worth it.

[Merl]

I think I'm ready to try making my own plywood from veneer.

Are there recommendations for sources of veneer?

Thanks

Merl

[bobledoux]

Hardwood stores generally carry veneer.

Several mail order suppliers sell it.

For example:

http://www.grizzly.com/products/searchresults.aspx?q=veneer

http://www.grizzly.com/products/h9802

[Chipped Tooth]

Have any of you used a product called Azek? This is a foam plastic board material used in house construction. It is low density and easy to machine. I’ve used it very successfully building RC aircraft. It machines and handles much like hard balsa wood, but without any grain. It will float in water, but is completely waterproof. It is used in home construction to replace wood that maybe damage by exposure to exterior driven water. It comes in mill stock of many shapes and sized, flat being the shape I buy, but sheet stock is available too.

The material takes stains and paint extremely well. The fact that it has low mass plays well for gear making since it would have little inertia. I think it would wear okay, but testing would need to run on a set of gears on the workbench before commitment to a clock.

I suppose a non-wood product like this may not be of interest to some since this forum is about “Wooden Clocks” for the most part, but I thought I toss this suggestion out for others to evaluate.

I love to machine this material. I cut and shape it into many shapes and the lack of grain makes it ideal for things like gears that must not swell, or warp due to moisture ingression.

Here is the Azek web site, take a look around and you'll see sheet stock and the Mill Board sizes. It glues up using standard PVC cement. Laminations are simple and easy, as well as re-sawing to thin boards; I use a band saw for this task.

I purchase this material a Home Depot and other large hardware stores, it appear to be a very common product for trim/flat stock material. I've not seen sheet stock (i.e. 4 x 8 ft panels) yet. The cost of this material is modest.

One last comment: this material is "foamed PVC plastic". It is much lighter and easier to machine than PVC sheet or plastic PVC fittings used in plumbing. It sands down very smooth and appears to have modest friction associated with the polished surfaces.

Azek on the Web: http://azek.com/viewProduct.php?id=12

Chipped Tooth……..

[Byncnada73]

Thanks for starting this You guys are so great to share all this information--and basic is just what I need