How to make a THICK acrylic viewing window for a subwoofer box amp rack etc

[caraudiofab]

Hey all! Today I want to walk your through a lesson on how to cut thick acrylic to shape for use in a subwoofer enclosure or other parts of your car audio build. I will show how to custom shape the acrylic, how to make sure it seals well against the wood of the box for an air tight seal and talk about what acrylic to use. Let's get started!

I start with my sheet of acrylic (closest to camera), some MDF, and some Mobile Solutions smart templates that I will use for my shape. You don't have to have templates for this process, but it does make the shapes a lot more precise.



The acrylic is "cast", I find this is best for machining (drilling cutting etc). For small windows 1/2" is thick enough, if you are doing a large window (over 18 or so inches in any direction) I would say step it up to 3/4" thick, this is of course if you are adding it to a sub box, for an amp rack less than 1/2" can work, but probably no less than 1/8"



I position my shape on my panel, this panel is the side of the subwoofer box, once positioned I sketch its shape, rough cut with a jig saw, then stick the shape to the side of the box using double sided template tape:









Over at the router table I have loaded a flush trim router bit, this bit spins and while the bearing rides against the surface on top of the wood it cuts the wood to the same profile below. This gives me a perfect cut.



I copy this to a second piece of wood just because I am doing a deep chamfer on this particular build.

[caraudiofab]

On the back side of the panel I make a rabbet cut 3/4" into the wood and 1/16" deep. This will be used as a guide for where I stick my speaker gasket tape.





Next I do a smaller rabbet cut, and go a little deeper into the wood, this ridge will be used for the vinyl material (or carpet) to wrap around to the back side of the panel, important to do this.





On the front side of the panel I add a chamfer, you could do a roundover or other edge profile, you could also sand this, anything to get rid of the hard edge.



This is not required, but just an idea what the side of my subwoofer box will look like:

[caraudiofab]

Now let's move on to cutting the acrylic. I am going to be shaping the acrylic. Technically you could use your acrylic piece in rectangle form, but I want to show the shaping of it, hope you guys will like that. I start with copying a larger shape to a piece of MDF.



I do this because router cutting acrylic is dangerous, I want to keep my fingers a safe distance from the rotating cutting bit. Here I have rough cut the acrylic, the white strips are template tape that I will use to stick my MDF shape to the acrylic.





MDF stuck to the acrylic:



Now I can stick a router safety shield to this assembly. The MDF is tall enough that I can once again use the flush trim bit to copy the shape and the router bit can pass under my shield.



IMPORTANT: I didn't get pictures of the cutting process, but it is important to see in my video how it was done. You have to step through router bit bearings to cut a little at a time, video here: https://goo.gl/yqjJx3

[caraudiofab]

I place the sheet on the backside of the panel and trace its profile.



In the mean time I have drilled and counter sunk some holes that will be used for my mounting fasteners. IMPORTANT: When doing this for a subwoofer box you want a fastener every 2-3". I only used four because I am just making this project as a demo to help you learn and didn't want to drop any more funds into this expensive how to project. On sub boxes make sure you use lots of fasteners!



Looks like this front:



Fastener secured. To see how I added special threaded inserts into the wood, check out the video: http://goo.gl/4sFjPt



Again! Make sure you use many fasteners! I only used four because this is just a demo to help you learn.



Next I protect the panel with tape and do some upholstery work, the rabbet edges work great for cutting the tape:





Panel is wrapped!

[caraudiofab]

Now here you can really see why I made the rabbet grooves earlier in the process. The gasket rides on one surface, the other allows me to precisely cut the vinyl and wrap it around to the back so you cannot see it from the front.



Here I cut the gasket at an angle, makes it harder for air to leak:

[caraudiofab]

Now all I have left to do is mount the acrylic and remove the backing paper!





To see everything in detail check out the video:



So there you have it, making a acrylic viewing window for a subwoofer box, or whatever you can dream up! Hopefully this helps inspire you guys with some ideas of what you could use this for!

[caraudiofab]

No comments? Come on homies!

[BigAl205]

Sorry, I saw the video, but missed the thread....that turned out awesome. Did you use a standard carbide bit at normal speed, or did it take some adjustment?

[pocket5s]

Same here. Didn't notice the thread. I have always seen them inlaid and bolted in that way. Nice to see a different take on it


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[Glenn]

Damn, that's hotness!