The Best Wood for a Cajon Drum
I've answered a couple of Facebook posts about wood for cajon construction. Below is my answer. I'll update it as I have more insight and information.
What's the best wood to use to make a cajon? There are three considerations: the cajon box, the back panel and the tapa-the playing surface.
Wood for the Cajon Box: Top, Sides and Bottom
Many artesanal cajón builders around the world make cajons from locally sourced, solid hardwood. Many people in Europe prefer Baltic birch plywood. Cajon makers in Asia use plywood and solid wood from tropical hardwoods. Cajon businesses in South America often use local tropical hardwood or locally available plywood. I have made great sounding cajons from USA Doug-fir based cabinet grade plywood and birch cabinet grade plywood. I have also made great sounding cajons from solid softwood - Sitka spruce and western red cedar. The point of these examples is: There is no magic 'best' wood for a cajon. However, there are some guidelines:
Solid Wood Cajon Boxes
Cajon builders generally recommend harder, denser solid wood, wenge, padouk, walnut, oak, maple etc. However, it's not a hard and fast rule, I've successfully used Sitka spruce and western red cedar, both considered tone woods. Many solid wood cajons are made from several to many smaller pieces glued together to make a composite panel, see the photo of the ATempo cajon to the right.
Plywood Cajon Boxes
Many cajon builders recommend hardwood plywood with more plys and without airspaces. Marine plywood, often from Indonesia, is available in coastal areas around the world and is dense with many plys, but is often very expensive. My recommendation is to use locally made plywood, the harder and denser, the better. The nicer the finished side of the plywood the better. Cabinet grade plywood probably produces a better looking and sounding cajon than construction grade plywood. Your choice of wood will probably be influenced by what is available locally and how much you are willing to spend.
TL;DR: If you can get it and work with it, solid dense hardwood will make an awesome cajon. If you use plywood, try for hardwood plywood with more plys and fewer airspaces. Marine plywood or cabinet grade plywood should produce a nicer looking, better sounding cajon than construction grade plywood. Recommended thickness would be between 12mm and 20mm (1/2 inch to 3/4 inch).
Wood for the Cajon Back Panel
The back panels of many cajons made in Peru are often the same material as the sides, with the same thickness as the side panels. Whereas many commercial cajon manufacturers around the world use thinner wood or thinner plywood, plywood as thin as 4 mm. Commercial manufacturers try to minimize their raw material expenses and try to minimize shipping weigh. For beginning cajon makers I would suggest using the same wood you use for the sides. It will make a heavier cajon but should have good sound. If you are concerned with the weight of the final product, try a slightly thinner back.
Wood for a Cajon Tapa
Most cajón builders use plywood for the tapa, 2.5 to 3mm thick. 4mm is sometimes recommended but I think that's a bit thick unless the box is bigger than usual. 5-ply hardwood plywood is often recommended but I've made great sounding tapas from 3-ply tropical plywood. Again I would look to see what is available locally. 3mm, 3-ply plywood is sometimes available in local hardwood stores, but you may have to look at specialty hardware stores and not national chains. I've recycled old hollow doors using the 'door skin' as the tapa. 2.5 to 3mm thick 5-ply birch plywood is available on the Internet, often listed as 'aircraft plywood. Because the tapa is screwed on, you can make and try several as you find or order different materials. Some cajon builders make stunning tapas by using bookmatched veneers from exotic woods on the face of the tapa. (Beware that some commercial cajons have reproductions of exotic woods on the face of the tapa! It is fairly easy to tell the difference, real wood veneer tapa faces are each unique whereas printed tapa faces are identical.) Solid wood, carbon fiber, acrylic and lexan are other options for a tapa but they will give very different sound. Thin solid wood must be reinforced with bracing or it will probably crack.
Some additional thoughts
- For me, as important, or even more important than the wood used for the box, are the joints holding the box together. The box needs to be glued tight. A few nails or a little weight or a couple of straps is not enough. In my opinion, many YT videos show inadequate clamping/weight. Heavy weights (>50kg) or many clamps with box joints, rabbeted joints, dovetails or corner braces will make a strong, tight box that resonates. Let the glue dry overnight or better two nights, and don't stress the box until the back is glued on and the tapa is screwed on. Some of the loudest drums in the world are carved from a single piece of wood. As I'm building a cajon I like to vision that I am trying to weld the panels into a solid piece to maximize loudness and resonance. Perfectly cut joint edges, glued tightly together is the objective.
- Some of the best commercial cajons have plywood back panels so tight they seem as if they were stretched on, but, they are glued. How do they do it? I don't know. But one of these days a few days before glueup, I am going to store my back panel in a much hotter place than the cajon box. After glue up perhaps it will shrink a little and make a tighter fit. If anyone can come up with a way to get the back panel on really tightly, please let me know!
- All cajons sound different. Even an experienced cajon maker using the same plans and woods used in previous builds will sit on a newly finished cajon wondering what it will sound like. Factory made cajons use consistent materials and exacting construction methods, yet cajons from the same model will often have somewhat different sound.
- Plywood is made in many countries from local wood, some hardwoods, some softwoods. Some use many layers, called plys, some have minimal numbers of plys. Plywoods are designed for specific uses, including airplane production, exterior use, general use and marine use. Different plywoods will have different acoustic properties.
- There are differences in construction techniques used when making a solid wood vs plywood cajon. Solid wood will expand and contract with changes in moisture. Hence "solid wood" cajons typically are made from several pieces glued side-to-side. This adds time and expense. Major cajon manufacturers may prefer plywood, in part, because it is simpler and cheaper to use and gives consistent results.