Making a Layered plywood HiFi unit.

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Youtube supplemental.

This is a supplemental article to accompany my you tube video “Making a layered plywood HiFi unit” and will hopefully answer some questions and fill in information gaps in the video. I have also written an article about how I got started making layered plywood furniture.

Layered plywood HiFi unit

Tools.

Don’t be put off a project like this when you see it being made in a fairly well equipped workshop. I made my first few pieces of layered plywood furniture using only my basic site work power tools; these consisted of a jigsaw, a router and a Belt sander and orbital sander for power tools and a few clamps, as well as the basic hand tools. The hardwood layer could be bought as planed all round timber to avoid the need for a planer and nailing the layers can be done by hand.

By far the hardest and most time consuming part of the process is sanding the assembled unit, the routing leaves a rough and slightly uneven surface and due to the built up layering process; any routing errors early on can lead to some fairly large peaks to sand away. A belt sander makes fairly short work of this, starting with fairly coarse p60 grit belts. The belt sander can also be mounted on a bench and used to sand the initial profile template.

Here is a list of ideal tools in order of how necessary they are.

  • Jigsaw
  • Router (with 1/2″ flush trim cutter)
  • Belt sander with p60 and p120 grit belts
  • Orbital sander with p120 and p240 discs
  • Drill/screw driver
  • Gloss paint roller for applying the glue
  • clamps
  • Other basic hand tools, hammer, block planer etc.

Materials.

The main material used is obviously birch plywood, I used around one and a half sheets of 24mm (1″) plywood for the main body (around two thirds of the layers are made up several pieces in order to use up all the off cuts) and 12mm (1/2″) plywood for the back. Latvian or Finish birch plywoods are the best as they have far fewer voids inside, Russian birch can be a bit hit or miss on the quality.

The fancy hardwood on the front is Bocote (Cordia elaeagnoides, Cordia gerascanthus). In the past my go to timber for the hardwood layers was usually Rosewood as I like the colour contrast against the plywood. Either way it is a good idea to use dense exotic hardwoods for this as they tend to have a low coefficient of expansion making it more suitable for gluing to the face of the plywood.

The finish used was ‘Bona Mega One’ water based flooring lacquer. Water based lacquers seem to work really well with the birch plywood end grain as it remains a nice pale beige colour, whereas poly or cellulose types will turn it yellow. Being a flooring lacquer it is very hard wearing and has a nice satin finish.

Adhesives.

The adhesive used for the plywood layers was Titebond 50 but this is no longer available. Titebond 2 or3 should be a good alternative. Avoid using cheaper white PVA as this tends to react with the finish and after time you will feel ridges where the glue has expanded out of the joint.

Epoxy was used to glue the Bocote to the plywood. Bocote has a very high natural oil content and feels really waxy and so can be quite tricky to glue, normal wood glues rely on the ability to penetrate the fibres of the wood and the oils will inhibit this. Epoxy grabs hold of any surface deviations so scuffing up the surface with a coarse abrasive will give a good hold for the Epoxy.

Epoxy and wood glue

The brackets.

I was also asked several questions about the metal brackets I used to connect the shelf to the main body including; “why didn’t you use a hidden dovetail” and “wont it rust” “it looks ugly” etc. Firstly, given the weight of this type of furniture it is really useful to have the shelf section removable, I cant imagine try to lug something like this up stairs! And by the way; the subject of this video was a relatively small unit, the longest I made In this style was over 8 foot long! The heaviest was probably a 3 foot deep by 7 foot long desk.

The brackets I use to connect the shelf are designed to allow expansion/contraction in the plywood which can be more than 6mm (1/4″) over the 2 foot depth of this unit, (the movement will be in the thickness of the plywood) so the brackets are kept as short as possble while the bolt holes are over sized to allow movement. The brackets also do not bottom out so are under tension and can be tightened if they become loose.

For hidden dovetails to work they need to be tight fitting and very accurate. Due to the nature of how the layered plywood units are made, particularly how the surfaces are prepared it is difficult to ensure a flat on the underside face for the dovetail to run on, plywood end grain is difficult enough to sand smooth let alone sand perfectly level so the dovetail method just is not practical in this case.

Plans.

HiFi unit plans
Hifi unit plans

I have included a download of a plan in sketchup below as a guide. While I hope this is useful I implore anyone interested in making their own layered plywood furniture to start with a sheet of MDF and draw out their own design, nothing is more satisfying than making and finishing a piece of furniture you have designed yourself.

Included in the skeptchup file is a full profile which could be printed out to full size (there are guides on the net and Youtube showing how to do this) as well as a half profile which could be used to either save on paper or to draw out a longer version using one half at a time and then filling in the gap. Also included is a 3D model of the unit with dimensions for visual reference.

Please also note if you do intend to replicate this piece then these plans are for single use only, not for redistribution as plans or for commercial manufacture of the design.

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