3/4" Plexi & MDF Box
3/4" Plexi & MDF Box
A Canadian forum, awesome! This is my first post here, looks like a useful spot!
Now onto my situation, I'm going to be incorporating 3/4" plexi into an all 3/4" MDF box I'm building.
The box will be sealed, low powered, around 200W RMS, dual chamber, with a pair of prototype 10s (100W RMS per sub).
I have experience in the field, just none with plexi. I've got everything planned out, except how to attach the plexi to the MDF. So what type of seal should I use, I was thinking something like the foam weatherseal type stuff inbetween the joints, and then 2" #6 drywall screws through predrilled holes in the plexi and MDF to attach it to the MDF. Or should I be using something else, like a silicone sealent in the joint?
Whatever is used has to be slightly attractive since you'll be able to see it through the plexi.
The plexi is being used for just the face panel of the box, so it will have the subs mounted to it as well, so I was wondering if anyone has mounted subs to plexi, and what they did. I was thinking of using again, the weather seal to seal the sub to the plexi. And then also bolts with nuts; with some kind of rubber washer on the inside of the plexi to minimize any possible vibrations. The nuts will of course also be loc-tited in place.
The construction materials, and plans won't be changing, so I just need input on the optimal way to seal and attach the plexi preferably from people who have past experience working with plexiglass.
Thanks for any input!
Now onto my situation, I'm going to be incorporating 3/4" plexi into an all 3/4" MDF box I'm building.
The box will be sealed, low powered, around 200W RMS, dual chamber, with a pair of prototype 10s (100W RMS per sub).
I have experience in the field, just none with plexi. I've got everything planned out, except how to attach the plexi to the MDF. So what type of seal should I use, I was thinking something like the foam weatherseal type stuff inbetween the joints, and then 2" #6 drywall screws through predrilled holes in the plexi and MDF to attach it to the MDF. Or should I be using something else, like a silicone sealent in the joint?
Whatever is used has to be slightly attractive since you'll be able to see it through the plexi.
The plexi is being used for just the face panel of the box, so it will have the subs mounted to it as well, so I was wondering if anyone has mounted subs to plexi, and what they did. I was thinking of using again, the weather seal to seal the sub to the plexi. And then also bolts with nuts; with some kind of rubber washer on the inside of the plexi to minimize any possible vibrations. The nuts will of course also be loc-tited in place.
The construction materials, and plans won't be changing, so I just need input on the optimal way to seal and attach the plexi preferably from people who have past experience working with plexiglass.
Thanks for any input!
Originally Posted by Kinslayr
Here's a question for ya. Did you take into consideration the strength of the plexi after you cut 2 10" holes in it and hang 2 10" woofers on it?
I'm making a point of leaving as much surface area as possible by decreasing the depth of the box in order to allow for the incrased area on the face.
The plexi will have support in the center from the chamber seperating panel.
I'm currently planning an overall width of 39" and a height of 12.5" or 13". These figures are based on the maximum allowable dimension given the trunk space I'm working with.
Originally Posted by Kinslayr
You will want as little amount of plexi on the same plane as possible, unless there is adequate bracing. More plexi = more flexi.
So given those maximum dimensions, and the fact I'm using 10s, what would you say would be good face dimensions?
You can also change to some other type of stronger acrylic. I have mounted Eclipse Titanium 12's to acrylic before, powered them up with 1000w rms to each in a sealed box with **** issues. I have some old crappy pics somewhere that I can e-mail to you if you want to see them. I lost all of my good build up pics on this vehicle (computer virus).
Currently I am building a box that will again use 1" clear acrylic, nice and strong and this time we will be mounting 2 Focal quad coil 18's in them. To ensure a good mount, like the Eclipse subs we did previous, I am machining a 1/4" steel or aluminum ring that is the exact outside and mounting diameter of the sub. This ring goes on the inside of the box and sandwiches the acrylic between the sub and the ring. I then run a blot through the sub, through the acrylic and finally the ring and attach a nyloc nut to secure the whole assembly together. Then I attach the predrill acrylic (with now mounted subs) to the box. I used a common 3/4" glass window foam tape to seal the box to the acrylic and used the same tape, be it a smaller width between the sub and the acrylic. Hope this helps you out.
Currently I am building a box that will again use 1" clear acrylic, nice and strong and this time we will be mounting 2 Focal quad coil 18's in them. To ensure a good mount, like the Eclipse subs we did previous, I am machining a 1/4" steel or aluminum ring that is the exact outside and mounting diameter of the sub. This ring goes on the inside of the box and sandwiches the acrylic between the sub and the ring. I then run a blot through the sub, through the acrylic and finally the ring and attach a nyloc nut to secure the whole assembly together. Then I attach the predrill acrylic (with now mounted subs) to the box. I used a common 3/4" glass window foam tape to seal the box to the acrylic and used the same tape, be it a smaller width between the sub and the acrylic. Hope this helps you out.
Originally Posted by MR2NR
You can also change to some other type of stronger acrylic. I have mounted Eclipse Titanium 12's to acrylic before, powered them up with 1000w rms to each in a sealed box with **** issues. I have some old crappy pics somewhere that I can e-mail to you if you want to see them. I lost all of my good build up pics on this vehicle (computer virus).
Currently I am building a box that will again use 1" clear acrylic, nice and strong and this time we will be mounting 2 Focal quad coil 18's in them. To ensure a good mount, like the Eclipse subs we did previous, I am machining a 1/4" steel or aluminum ring that is the exact outside and mounting diameter of the sub. This ring goes on the inside of the box and sandwiches the acrylic between the sub and the ring. I then run a blot through the sub, through the acrylic and finally the ring and attach a nyloc nut to secure the whole assembly together. Then I attach the predrill acrylic (with now mounted subs) to the box. I used a common 3/4" glass window foam tape to seal the box to the acrylic and used the same tape, be it a smaller width between the sub and the acrylic. Hope this helps you out.
Currently I am building a box that will again use 1" clear acrylic, nice and strong and this time we will be mounting 2 Focal quad coil 18's in them. To ensure a good mount, like the Eclipse subs we did previous, I am machining a 1/4" steel or aluminum ring that is the exact outside and mounting diameter of the sub. This ring goes on the inside of the box and sandwiches the acrylic between the sub and the ring. I then run a blot through the sub, through the acrylic and finally the ring and attach a nyloc nut to secure the whole assembly together. Then I attach the predrill acrylic (with now mounted subs) to the box. I used a common 3/4" glass window foam tape to seal the box to the acrylic and used the same tape, be it a smaller width between the sub and the acrylic. Hope this helps you out.
These 10s aren't very heavy, and as stated above won't have a huge amount of power, because I don't have the ability to machine an internal ring, do you think that just using a large rubber/plastic washer on the inside with a nylon nut over that would be sufficient? I can provide pics of the 10s, and possibly get an approximate weight, but because they're prototypes I dont' have any details currently.
If you do have any pics of your previous setup, and it isn't too much trouble to forward them to me that would be amazing, bradgoldring@hotmail.com
Also, what do you think about what I was discussing with Kinslayr, will I be able to safely go with the 39"x12.5" dimesions for the face, with the chamber seperater as a center brace to the plexi?
Thanks again.
I don't anticipate any issues with the size of the baffle that you are building provided that there is a center brace. Just make sure that you drill the plexi properly and use the proper screws on it. Do not let the screws bind on the plexi at all. As far as the ring goes, a sub is an object in motion. When you apply power to it, energy is made in the form of sound on the inner and outer stroke. Well, this means that at the same time the sub wants to go in exactly the opposite direction. With nothing to bind to like in mdf, you are now placing all of the stress on the nyloc nut on the back side of plexi. Not exactly a good idea. Plexi when stressed will ultimately crack. At the cost of that sheet of plexi, make the ring as it will distribute the load across a much larger surface area. Head into a metal shop with a case of beer. Tell them that you have a case of beer to trade for the guy who can whip up some steel rings. They will mark them out to the inner and outer dimensions that you should provide. Make the ring the same size as the inner and outer mounting dimensions of the sub. After they cut it out with their torch, take it away and if you have a angle grinder, time to clean it up. Sand it down nice and clean and slap some Tremclad rust paint on it, whatever color you like or have it powdercoated.
The rings I am making this week will be 1/4" steel, trimmed perfectly and then chrome plated. Bling bling bling.
The rings I am making this week will be 1/4" steel, trimmed perfectly and then chrome plated. Bling bling bling.
Last edited by MR2NR; Jun 24, 2006 at 02:09 AM.
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Alrighty. First of all, 3/4" acrylic is plenty strong. There will be no problems. And while I appreciate MR2NRs approach to mounting, most cars will not need such an advanced mounting procedure. Regular bolts with nyloc nuts and a simple washer have always worked fine for me.
For mounting the acrylic to the enclosure, try to avoid screws with flush fit heads. They distribute the load diagonally across the material and may crack or chip the acrylic. Use something with a flat pan head OR if you want something that looks nice use these:
Courtesy of: http://www.leevalley.com/hardware/pa...75&cat=3,41306
Specifically Item A or B goes into the wood as an anchor and then Item F is the actual fastener. Expect to pay about a buck per anchor/bolt combo at Rona, Home Depot, etc. If you want to save some $$ you can use regular bolts with the anchors but these bolts are nice with the large heads - often no washers needed.
For mounting the acrylic to the enclosure, try to avoid screws with flush fit heads. They distribute the load diagonally across the material and may crack or chip the acrylic. Use something with a flat pan head OR if you want something that looks nice use these:
Courtesy of: http://www.leevalley.com/hardware/pa...75&cat=3,41306
Specifically Item A or B goes into the wood as an anchor and then Item F is the actual fastener. Expect to pay about a buck per anchor/bolt combo at Rona, Home Depot, etc. If you want to save some $$ you can use regular bolts with the anchors but these bolts are nice with the large heads - often no washers needed.
