Should I Make and Sell Cajon Drums?

Recently Chad Wellman asked the Facebook forum ‘Play Cajon’: “I built my own drum and I get asked what brand is it. When I tell them I made it myself I get good reviews. Should I start my own brand of cajon drum and sell them?” Here is the response I wrote to him, although I’ve updated it and will continue to update it as I find out more.

Cajon on a table with other tables selling items at a craft fair.
Firebox Cajon for sale at the Sunnyside Market Craft Fair in Gustavus Alaska

The answer is… yes, but here’s some info to help you understand the economics that will effect your business.

The biggest seller of cajons in the world dominates the market. In the USA just do an Amazon search, you’ll see who they are. Lets call them ‘Big Cajon’. What you won’t see on Amazon are any of the 45+ USA artisanal cajon builders. Big Cajon is so effective at producing, advertising and distributing its cajons that many musicians don’t even know there are other brands.

The 45+ USA artisanal cajon manufacturers fill niche markets. The successful ones seem to focus on several marketing strategies: musicians, churches, custom woodworking/sizes, children/education and ‘local’.

Word of mouth between musicians works: in California drummers talk about Kotz Cajon; in the northeast, Dozzi Cajon; midwest, Lewi Cajon; and in Alaska, Lefty. To use this strategy you’ll need some musician friends or you’ll need to visit with drummers and get your cajons out there. This will take time. Part of the appeal here is that you can build cajons appropriately sized and padded for use as a drummer throne. And USA folks tend to be big, you can size your cajons to fit. (Links to these the builders mentioned above are found at:

Many churches in the USA have music as part of their services and small churches often use cajons for percussion. I think this is a tough strategy to focus on but it has worked for a few cajon builders.

“Custom” is a hot marketing strategy in the music world and is worth keeping in mind. There are many awesome woodworkers making cajons that are works of art, and fantastic instruments.  DayDrums Cajon Co., Moravian Percussion and Custom Cajon Drums come to mind. I’d suggest looking at their websites and products to see if you will fit in that niche.

Custom cajon made in Alaska

Cajons are a great way to teach kids about rhythm, timing and to build coordination and team work. Small cajons for kids is a real market but parents are usually looking for inexpensive options so for the custom cajon maker it’s probably not a the best strategy to focus on.

‘Locally made’ is perhaps the best marketing strategy. For example, “Made in Florida” sounds good and will appeal locally. And there are environmental sell points to locally made cajons: “Sure, you could ship a plywood box full of air half way around the globe, or… you could buy a cajon made in your neighborhood!” Locally made enhances and diversifies the local economy. “You probably can’t buy a locally made cell phone, but you can buy a locally made cajon. It’s nice to support local workers whenever possible.”

Locally sourced wood can also have a big appeal to local buyers. Don’t be fooled by the manufacturers who tout ‘Baltic birch’. Sure it’s a great option but some of the best cajons in the world are made in Peru from solid tropical hardwood. And many cajon builders around the world use local woods with great results. There’s a cajon builder in Costa Rica who advertises his products as made from sustainability grown trees, it’s a sell point that works for him.

There are millions of people in your nearby urban area. The key to success is to get your product known locally. Sell your products at local craft fairs, music festivals and concerts. Donate your ‘extra’ cajons to your local schools, libraries and to small, acoustic music venues. Chat up musicians and leave your business card at local venues. On the internet create a Facebook page devoted to your products. Start a YouTube channel and add good videos demo’ing your cajons. Sell them on and Craigslist.

Big Cajon is owned by a very large musical instrument manufacturer, a big business that plays by the rules of big businesses. Most of their cajons are made in efficient factories in Asia. Their per unit cost for materials and labor is a fraction of what yours will be. They dominate the Internet market and the music store market for cajons. It is unlikely you will ever be able to effectively compete with them on a large scale. But at a local level you should be able to carve a niche, but it may take time and effort.

Don’t expect to get rich overnight building and selling cajons in the USA. Most USA cajon makers are passionate woodworkers/musicians who have found cajon building to be an enjoyable and creative way to supplement their income. However, there’s plenty of opportunity. Cheap factory cajons sell every day online and in music stores. To be a successful cajon maker in the USA you’ve got to appeal locally, appeal as a USA made product, tout your cajons as low carbon gifts and work hard at marketing. If you are seriously thinking of starting a cajon building business you should read this page about How to Sell Cajon Drums

In other parts of the world there are many full time cajon makers. It all depends on local demand, local economics, the quality of the build and the amount of time builders are willing to put into marketing their products.

These links might also be helpful: Cajons Made in the USA and the Best Cajon

Updated 2020-May-13

The Music Shops of Plaza 2 de Mayo – Shopping for a Cajon in Lima Peru

There are over 115 music shops or stalls adjacent to Plaza 2 de Mayo in Lima Peru. Most are small, one room stores with big items stacked to the ceiling and small items multi-layered on glass shelves. Many shops specialize, at least partially. Some cater to brass instruments, others to percussion, keyboards, guitars or Peruvian instruments.

If you are a musician vacationing in Peru and have some extra time it’s a fun couple of hours to wander the streets and stop in a few shops. You never know when you might want to pick up an extra jawbone, zampona, quena or charango. Or a new saxophone, Martin guitar or Korg synthesizer. Almost anything, but look though I did I could not find a kettle drum or a banjo, although there was a healthy selection of sousaphones and harps.

A line of cajons stacked for sale in a music store
Cajons for sale in a music store in Plaza 2 de Mayo, Lima Peru

There are many cajon makers in Peru. The most common cajon in Plaza Mayo shops are the lower-end CPeru cajons which come in many sizes. Most CPeru cajons will sell here for less than 100 soles. They sound good but the joints may appear filled or rough and most are a bit small. Mid-range cajons such as VP Cajons will cost around 150 soles, they sound great and have some beautiful patterns dyed or painted. The high-end PR (Percusion Real) and ATempo cajons will be somewhere between 250 to 350 soles.

Jawbone percussion instruments for sale
Jawbones used as percussion instruments are found in several shops.

Some cajons will include a basic case but you may want to spring for a thickly padded case (100 soles) if you are going to put the instrument through airline baggage handling.  There are a few other cajon ‘brands’ for sale – Peru Percusion, RJ Cajon, ‘Peru’ and Nativ, some of which may be produced by the main manufacturers mentioned above.

Cajons and guitars for sale in Lima Peru
CPeru brand cajons come in many sizes.

Many shops sell CPeru cajons and quite a few have VP Cajons. You’ll have to look harder to find PR and ATempo cajons. In my experience no shop carried all ATempo models. So if you want a specific ATempo model you may have to look around. And some were in better condition than other.

Guitars, violins trumpets in a small music store in Lima Peru
Inside a small music store

The best way to get to the area is to use Uber. Here are two options:

Street view of Av Pierola showing many doors to small music stores
Av. Nicolas de Pierola. Each door is a small music store.

“285 Av Nicolas de Pierola” will drop you in front of a shop with a good selection of PR and ATempo models in excellent condition stored behind glass. From this drop-off walk towards the Plaza 2 de Mayo, there are shops on both sides of the street. At the traffic circle go right.

Entrances to music stores on Jiron Moquegua street

“870 Jiron Moquegua” will drop you more or less in the center of the music store area. The shops around 870 have many cajon brands and models, as do a few shops across the street. Around the corner check out the shops in and around mini-mall ‘Centro Commercial Plaza 2 de Mayo’. The Centro Commercial also has a few local food stalls and a public toilet.

Doorways to small music shops
Entrances to the Centro Commercial Plaza 2 de Mayo, Lima Peru.

Safety: I felt secure here, but this is not Miraflores or San Isidro – you won’t find a police officer on every corner. Your cell phone should stay in an inner pocket. Don’t bring more money than you need or a fancy camera. Keep a low profile. Once you step out of the music store zone the area seems less secure. If you’ve passed more than 2 non-music stores and can’t see an instrument hanging in the doorway of the next shop, turn around. Best to not wander the actual Plaza 2 de Mayo, admire it from the music store zone. Uber out of the area or walk up Av. Nicolas de Pierola to the west, away from the Plaza.

The cajita is a percussion instrument played by snapping the lid closed and by hitting the front or sides with a wooden striker.

There are many other music shops scattered around Lima, most will have cajons. There are also a few shops in Miraflores on Cantuarias street between Pje Tello and Alcanforas. They have a smaller selection of mid and high end cajons and the prices will reflect the location.

Charangos for sale in a glass case
Charangos for sale, Lima Peru

Sousaphone in a music shop window
A great place to pick up that  sousaphone you’ve always wanted.

Saxophones in a glass case for sale
Only a few shops had a wide selection of saxophones. This one is on Av Pierola.

Violins in a glass case for sale
Violins for sale in Plaze 2 de Mayo music store.

Colorful kit drums for sale at Plaza Mayo
Kit Drums for sale in a Plaza 2 de Mayo music store.

Music stores inside the Centro Commercial Plaza 2 del Mayo
Inside the Centro Commercial Plaza 2 del Mayo

Cajon demo in a music store
Store rep plays a cajon in a music store near the Plaza 2 de Mayo, Lima Peru


Managing Your Facebook Group Experience in 2020

Many forums and groups on Facebook are effectively un-moderated. A single stealth-advertiser, like-harvester, spammer or rude person can make these groups/forums unusable or tedious. That smiling, happy guy who seems to have loads of time to post professional level videos once or twice a week… Gee whiz, he’s always using the same global brand…  It’s probably paid-for sponsoring, the post is basically an ad. Facebook probably doesn’t like it, it adds to your advertising burden and they don’t make anything from it but under the cover of a ‘personal post’ there’s not much they can do about it. But you can.

“Stealth advertisers” are persons who promote a company or their products under the guise of a personal account or ‘tutorial’ or ‘review’. They generally don’t acknowledge they are being paid to promote a product.  Stealth advertisers promote products or brands by frequently posting videos or photos that prominently feature the products logo and/or name. They often tout the features in their commentary. In the cajon world these can take the form of ‘grooves of the day’ or ‘unboxings’.  Typically these folks do not acknowledge in their post that they are paid at some level. This is a marketing tactic that should cause folks to question the integrity of the product, as well as the poster. 

Facebook has made it super easy to block stealth advertisers in Groups. Don’t stress about blocking, it’s your time these folks are wasting, do something about it.  Facebook does change it’s menu options frequently so I’ll explain several ways you can block someone and other options below. 

A) Blocking and Reporting Stealth Advertisers on Facebook from Mobile

In groups in Mobile, there are three small gray dots directly to the right of the stealth advertisers name. Click on those and you’ll see some options, one of which is Report to group admins. When you click on this you get a dialogue box with options. Choose Spam and Send to Admins. In the next dialog box that appears you have the option to Block or Hide the offender. Block now to save time, it is unlikely they will change their ways.

B) Blocking without Reporting on Facebook Mobile

On mobile first click the name of the stealth advertiser, then follow examples in the image below or the text description:

  1. Click the big blue “More” Button if it appears.
  2. Click the three dot icon to the right of the Message button. This causes a not very obvious option “View Main Profile” to appear at the very bottom of the screen (it goes away if you scroll or click anywhere else on the page.)
  3. Clicking the View Main Profile button brings up the persons profile.
  4. Then click the three dot icon that appears to the right of “Add Friend”.
  5. Then choose menu option ‘Block‘.
How to block stealth advertisers on Facebook mobile
The basic steps to block a stealth advertiser in Facebook. First click the name of the offender. Note that steps may vary depending on your relationship with the advertiser, and with Facebooks current menu system.
How to block stealth advertisers in Facebook Mobile App
You can also Block from the Setting options on Facebook Mobile

C) Blocking Stealth Advertisers on Facebook from Desktop

Click on the name of the repeat advertiser/spammer/complainer. You should see an option to  ‘View Profile‘ or ‘Visit page“, click it. Then click the small three dot icon to the right of the Follow/Message or Share buttons that are usually to the far right edge of the screen. Then choose menu option ‘Block‘ or ‘Block Page‘. 

How to block a Facebook user from PC Facebook web interface
Blocking a stealth advertiser on Facebook from a desktop interface. Location of the three dot icon will vary with the type of account and the status of the advertiser.

D) Write to Facebook

Screen capture the offending post, send it to Facebook and explain how these kinds of posts are adding to your Facebook advertising burden. Facebook has a carefully controlled advertising program. Companies which circumvent their program add extra advertising load to your experience. They should address it, but it may take time. Here is how to report it as of April 2020. This may change of course:

Follow these steps to report a stealth advertiser to Facebook.
Follow these steps to report a stealth advertiser to Facebook. Choose “Something isn’t Working “and fill out the form, use Groups and upload a screen shot.

E) Write to the Group Admin

You always have the option to write the Group moderator and suggest they contact the stealth advertiser and ask them to reduce the frequency of the posts. Moderation of small groups is a lot of work but if someone is ruining the forum for a lot of people it’s worth a try. To write directly to a group Admin look on the groups home page on the left side list option: “Members”. Admins and moderators are on on the top of the Members list. To simply report the post to a group admin click the three small gray dots that are to the right at the very top of the offending post. Then choose “Report post to group admins” and when the small form appears choose “Spam”.

E) Write a Comment on the Offending Post

There are more and more smiling happy demos and pseudo tutorials by ‘masters’ and ‘experts’ that are basically undocumented, sponsored advertisements. Sometimes there’s actually something good to learn or see, but don’t forget, it’s advertising. Corporate cajon is paying that smiling person to effectively deceive you. All those cajons and percussion instruments in the background… the same brand. It’s an ad to influence your opinion and purchases. If its a good tutorial, just add to the comments: “Nicely done! Thanks for the effort and I understand your need to make a living, it’s tough being a working musician. Of course I always buy local and advocate local. Why support the 1 % when you can contribute to your local economy? I’m sure you’d agree.” And put a link to this page. That will get the message across.

Stealth Advertisers and Like Harvesters Waste Your Time

Don’t stress about blocking someone/some business, it is YOUR time they are wasting. You can unblock at anytime in the future. Facebook provides a list of all blocked users in your ‘Settings’ options. Blocking will not immediately obscure their existing posts, but new posts from the offender will not appear and old posts will not appear after you re-start Facebook. You can also simply “Take a Break” from the offender, which is like blocking them for 30 days. But don’t be fooled. These folks are being paid, it’s a job. It won’t go away in a month.

Companies which sponsor stealth advertisers do so because it works. If the mantra in real estate is ‘Location! Location! Location!, the mantra in advertising is ‘Exposure! Exposure! Exposure!” Saturation exposure keeps that logo and brand name in the back of your mind, that is their aim. Any company that goes to this much effort to fund a video production crew and quality musician to continually produce stealth ads has a lot of extra money on hand. Which should make you question the quality of their products. “Efficient” is not the same as “quality”.

Several years ago I blocked a business that repeatedly posted what I considered to be advertising in Cajon Forum. I recently went back and unblocked them just to see if it was effective. Wow, when viewing the group with the included offender it was almost unusable. I quickly re-blocked them.

Note that the above blocking instructions assumes you are not ‘Friends’ with the offender. If you are Friends your menu options may not be exactly as described above. And if you are Friends then Blocking will un-Friend you. Life is full of choices.

We all get scammed by a stunning photo or a cool sounding name or a smiling friendly player. It is easy to get hoodwinked into liking and friending someone/some page then finding that over time they are really just advertising, promoting themselves or collecting ‘likes’ without providing meaningful content.

It is also possible that the offender is being paid to create negative information about a competitors product while promoting their own product. And sometimes these paid promoters will simply post junk comments or post to distract attention from insightful posts. These folks generally show up over time by their relentless negative opinions or semi-rude comments or a propensity for posts which distract but don’t contribute. Just block them.

It’s your social media experience, control it, or control it not. The choice is yours.  I hope this post helps you maximize your Facebook experience.

And as always: Support your local cajon maker and reduce your carbon footprint. Why support the 1 % when you can support your local artisans instead.

Handmade cajon at a campfire ring
Locally made cajons support your regional economy. And they look super cool around the campfire.

Updated: 06 July 2020

Cajon Design – Downward Facing, Offset Sound Hole

The sound hole on this cajon is on the bottom. Free plans are found here. And most significantly, the front of the sound hole is offset from the back. In theory, because the bottom of the cajon is lower in the back, escaping sound will be focused out the front, and that is what seems to happen.

Firebox Cajon Open Hearth Model showing the large, downward facing, offset sound hole.

Looking into the Firebox Cajon Open Hearth 'bass reflex' port. This is the only sound hole on the cajon.
Looking into the sound hole from the front. This is the only sound hole on the cajon.

Interior of the Open Hearth model showing the bass port bar in front and the lower panel on the bottom towards the back of the cajon.
Interior of the Open Hearth model looking from the front to back showing the bass port bar in front and the lower panel on the bottom in the back of the cajon.


  • As with bass reflex port cajons and ‘busking’ cajons, sound is directed forward, toward the audience.
  • There is greater tapa surface area than a bass reflex cajon of the same height because the bass port bar is lower.
  • Mic’ing the cajon is simple because the bass mic can rest on the floor on a simple foam pad or on the carpet.
  • The large opening means the interior of the cajon is readily available. You could easily pack a small suitcase’s volume of clothing in the cajon.
  • On-off snare assemblies that require access via the sound hole are much easier to access.
  • The cajon may be lighter. The large sound hole uses less wood than a conventional sound hole although the bottom bracket adds weight. Designs with less bottom bracket material are possible.


  • The composition of your floor will effect the tone and loudness of the cajon.  I prefer it on carpet. But on a wooden floor it is louder. In some perspectives this could be listed as a ‘Pro’ – it gives tone and loudness options.
  • As with any bass reflex cajon, the tapa surface area is lower than a standard design.
  • The design is more complicated to make.
  • The design is not traditional.

Construction Tips

There are several ways to build the bottom structure, some of which are much simpler than my preferred method. I like the look of this design, there is a bar of nice wood across the bottom of the side panels.  Also, I’m using western red cedar which is not a strong wood, so I’m reinforcing it.  I’ll show some of the simpler designs in later posts.

Note that the sides of my cajons are ‘right trapezoids’, not rectangles – the box has an inclined front. So while the top of the cajon is 12×12 inch square, the bottom is a 12×14 inch rectangle. The principles would be the same for a square bottom, only the proportions would be different.

View from the back towards the front showing the left side, the bottom bracket and the bottom back panel. The bottom back panel will be glued to the lower portion of the bottom bracket.

Bottom bracket from the back. These channels are easy to rip on a table saw. Or the bottom bracket could be made by gluing 3 separate pieces to produce the same structure.

Back plate on the left, bass port bar on the right. I’ve glued a long block in the front portion of the bracket’s lower channel. This reinforces the bracket and give width for the large rubber feet.

Back to front view with the bass port bar in place on top of the bracket.

Bottom assembly from above. Back is on the bottom of the photo.

I first glue the sides to the bottom bracket,  then glue the rest of the box.

Gluing the top, sides and bottom pieces.

There are a lot of possible ways to build the offset sound hole design.  Please go wild and post some photos in the comments area.

You can hear 2 cajons with these types of sound holes in the YouTube video below. Note that I use polycarbonate for the backs of all my cajons. So the tone and resonance of these cajons will be quite different than most plywood backed boxes.

Please add your comments below.

For updates and new posts just “Like” the Cajons of the World page in Facebook. And/or bookmark this page.

Building Cajons – Attaching the Back Panel Without Clamps

This method is a fast, easy way to get a tight, fully sealed back attached  to your cajon build.  It works well with any back material. No clamps are used. Here’s what you need:

  • camping pad foam material, must be compressible foam of some type, about 1/2 inch (1.3cm) thick
  • a small amount of hot glue or similar to attach the foam to the back plate
  • 12 small blocks of plywood or wood,  (about 4x1x1 inch {10× cm} depending on the thickness of your back material)
  • a drill and screws for screwing down the blocks
  • some heavy objects to weigh down the box, total about 100 lb (45kg)

If you use epoxy, this method works well even with surfaces that are not quite perfectly flat.  Clean-up is minimal. Glancing at the photos below might be enough information to get you going.

In these photos I use polycarbonate for the cajon back but the method is the same for plywood. There’s some polycarbonate specific info at the end of the blog for those of you who want to walk on the wild side.

I cut and sand the back slightly larger than the box by about 1/16 in (1.5mm), then, after it is attached to the box, sand the edges flush.

Hot glue secures foam to edges of polycarbonte used for cajon back.
Foam is hot glued only around the edge of the OUTSIDE surface of the back.

Cut the foam strips to be an 1/8 inch larger than the box side thickness.  Usually about 1/2 inch to 1 inch (1.3 cm to 2.5 cm). Use hot glue to attach narrow strips of camping pad foam along the edge of the OUTSIDE surface of the back.

The camping pad foam strips serves two purposes. It prevents the back from moving and it provides a compressible surface to distribute pressure evenly throughout the attachment zone. Do not use a full sheet of camping pad foam, it will cause the back to bow in the center and you won’t have a ‘stretched’ back. Turn the back over, the back goes face down with 6 small blocks offset from the edges. The foam supports the back. It is the only thing supporting the back.

Mask the inside of the back with tape such that the masking comes within about 1/8th inch of the sides.

Jig to hold cajon showing the first tier of blocks standing off from the polycarbonate back.

Prepare the jig that will hold the cajon box to the back while the adhesive dries. The first tier of blocks must not touch the edges of the back. Leave them back about 3/8ths inch (1 cm). If you use wood blocks you’ll need to pre-drill holes for the screws or the blocks will split. I prefer plywood blocks. The first tier must be high enough that the second tier never touches the adhesive oozing from the joint.

Put the back in the jig foam down and exactly where it will go during the actual glue up. Carefully put the cajon box exactly on the back where you want it to sit when it is glued.  Carefully place and screw down 3 second tier blocks without moving the box, two on one side and one on the top. They should just touch the sides of the cajon. With the 3 second tier blocks screwed down, remove the box.

Jig to hold cajon with 3 blocks having 1st and 2nd tiers of blocks in place.

Prepare your favorite adhesive, in these pictures I’m using clear 2 part epoxy but for a wooden back I’d probably use Titebond III (not hot glue, that’s just for the foam to back temporary bond). I usually take the back out of the jig to put the adhesive on.

Apply a layer of epoxy to the edges of the polycarbonate.
Apply a  layer of adhesive to the edges of the back. This back does not have masking around the inside edge and will require a lot more clean up than a back with masking.

Put the adhesive on the back around the edge where the box will be attached. Once your adhesive is on, put the back in the jig and make sure the back is perfectly lined up with the  appropriate 3 second tier blocks. Turn the box over and carefully place it exactly on the back, with the appropriate side and top against the second tier blocks.

For 5 to 10 seconds, slowly press the box down while slightly shifting its position to spread the adhesive evenly. End with the box pressed tightly against the 3 second tier blocks.

Place about 1/3rd of the weights on the box to keep it stationary. Place and screw down the remaining second tier of blocks. They should be snug against sides. After they are in place the box should not move at all.

The lower tier of blocks is offset so as to not contact the adhesive. The upper tier of blocks hold cajon box in place.
The lower tier of blocks is offset so as to not contact the adhesive. The upper tier of blocks hold the cajon box in place.

Turn the box over and carefully place it exactly on the poly, aligning the edges.
The box and back with the lower and upper tiers of blocks in place.

Once all the blocks are in place add the remaining weight. I use a lot of weight. Some of my early attempts with less weight were less successful.

Using big blocks to weighing down the cajon box while gluing the back on.
Weighing down the box. These are sitka spruce blocks which are fairly light. Total weight is about 110 lbs (50kg)

With the weights in place, reach inside the box, through the sound hole and remove the masking tape. If necessary scrape out the access adhesive that oozes from the joint. Then wipe the area with the appropriate solvent. The more excess adhesive you can remove the easier clean up will be after it has set.

Next day remove the weight and sand the edge to make the back flush. If necessary sand the inside of the back to remove residual adhesive.

The edge of the back sanded flush with the sides and top of the cajon.
The edge of the back sanded flush with the sides and top of the cajon.

A tight box is critical for good sound and durable construction. While building my first cajons I used clamps to attach the back. They worked but it was messy and a bit complicated. I’m sure there are other ways to do this. And plenty of improvements are possible to this method. Please comment below. Thanks, Bill

Firebox Cajon with polycarbonate back, red cedar and yellow cedar sides top and bottom.
Firebox Cajon with polycarbonate back, red cedar and yellow cedar sides, top and bottom. Made in Alaska, USA

Firebox Cajon with luaan tapa, red cedar and yellow cedar sides, top and bottom. Tung oil finish. Made in Alaska, USA
Firebox Cajon with luaan tapa, red cedar and yellow cedar sides, top and bottom. Tung oil finish. Made in Alaska, USA

Attaching polycarbonate as a cajon back:

Polycarbonate gives a cajon a lot of resonance. I cut the poly with a ‘ceramics’ blade on a jig saw which is much, much safer than other methods I’ve tried. Then I sand both sides to ‘frost’ the sheet with either a belt sander or an orbital sander. After cleaning the inside edges with alcohol the polycarbonate it is ready for ‘gluing’ with either 2  part epoxy or AquaSeal as the adhesive.  Critical is an epoxy that is not runny. It needs to be a bit thick to fill and adhere.  If you are using epoxy you must work fast to coat polycarbonate and position the box before the epoxy starts to set. Any end grain must be sealed with a thin layer of epoxy the day before glue up. Many epoxies are heat soluble, if you make a cajon with an epoxied back don’t let it get to hot. And it’s a good idea to put a few screws in to help ensure it stays put.

Updated Feb. 4, 2020