How to determine the volume of a fiberglass box?
Printed From: the12volt.com
Forum Name: Fiberglass, Fabrication, and Interiors
Forum Discription: Fiberglass Kick Panels, Subwoofer Enclosures, Plexiglas, Fabrics, Materials, Finishes, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=6937
Printed Date: May 31, 2024 at 8:33 PM
Topic: How to determine the volume of a fiberglass box?
Posted By: brianh
Subject: How to determine the volume of a fiberglass box?
Date Posted: December 20, 2002 at 8:19 PM
I was just wondering. How do these folks that have these huge walls made of fiberglass in their vehicles detemine the volume? Or for any box size when you have sloped fibreglass? I made one for two J L audio tens and it was way too small. Alot of midbass but no low end. Just wondering. Brian
Replies:
Posted By: beerstud136
Date Posted: December 20, 2002 at 9:33 PM
Posted By: capple
Date Posted: December 21, 2002 at 6:05 AM
fill with water,stytofoam peanuts, or anything else you find to fill the enclosure then transplant to a known volume, That is for the non even enclosure imposable to calcualate
Posted By: brianh
Date Posted: December 21, 2002 at 12:09 PM
That is a good idea. But isnt it a quessing game because you have to build it before you can fill it with water? I need at least .75 per woofer for my tens.(thats what JL audio calls for sealed) I just dont see how you can build a good sounding box by guessing. Do you understand what I am trying to say?
Posted By: beerstud136
Date Posted: December 21, 2002 at 2:46 PM
what series are your subs -------------
Posted By: capple
Date Posted: December 21, 2002 at 4:00 PM
Some times when you are using the wheel well or another part of the cars body as the mold for the box there is no way of telling for sure what size your going to have. This way if you go a bit big you know how much and can fill it.
Posted By: brianh
Date Posted: December 21, 2002 at 8:31 PM
My subs are the w1 series. They are about 5 years old and still playing great. I have only built two fiberglass boxes so I dont have a whole lot of practice at it yet. Thanks for all your comments and suggestions. Brian
Posted By: audiomechanic
Date Posted: January 15, 2003 at 6:56 PM
ok here goes....if you are makin the majority out of wood, you can guess pretty close.....just don't put the back on the box and once you have the ring mounted and material streached over the front you can fill it with anything from foam peanuts to water to sand to whatever you can measure. i have a box that is 1 cubic foot that i measured .25, .50..75 and the top is 1 cubic foot to measure the peanuts in.....as for molding it into a side wall that is a little more tricky.....you have to guess more at how much area to glass, but you can still measure it .....glass the area you want, mount your ring to the glassed section, wrap the majority of the front ...just leave a little open and fill it with peanuts..if its too small you can alwasy add more to the base , or move the ring for your sub out more to get more area inside....thats the basic idea ..if you need a more in depth explination let me know
Posted By: brianh
Date Posted: January 15, 2003 at 7:09 PM
Thanks for the comments. I wont be trying a new encloser until I get my new vehicle. Hopefully soon. Thanks again. Brian
Posted By: roadrage
Date Posted: January 25, 2003 at 9:43 PM
simple... i make these all the time. first you need to build a box that has an inside dimension of exactly 12 inches by 12 inches. it should be at least 2 foot deep. this can give you as much as 2 cu. feet of capacity. Take a marks-a-lot marker and mark a line every inch from bottom up on the inside of this box. This is now a perfect measuring cup... go to a store like meijer or wal-mart and buy the styrofoam bb's that go it bean bag chairs. these will be able to fit in the smallest of cavities (and their dirt cheap). estimate and build your enclosure a little bigger than you need. when you have the major structure complete, fill it with the bb's (make sure they reach everywhere, your air will...). Carefully transfer the bb's to your measuring cup, and determine the cu. feet by 12"x 12"x your depth of pellets. figure out how far you are over and add to the inside of the enclosure with cut pieces of 1" thick styrofoam board making sure to recoat over them with more mat and resin. Make sure to remeasure after you are done to be sure everythings right. This is a no fail way so all you can have is fun, good luck. Jim, roadrageaudio (269)684-7570 ------------- you're just mad cause my honda's faster than your v-8
Posted By: brianh
Date Posted: January 26, 2003 at 10:59 AM
Great advice,thanks for the tips. Brian
Posted By: Smooth04
Date Posted: January 31, 2003 at 5:04 PM
The resin won't melt the foam? I have never tried it so I am just curious.
Posted By: POWERSTROKE
Date Posted: February 11, 2003 at 11:49 AM
7.481 gallons of water is equal to one cubic foot of space. Estimating the cubic footage can be done with styrofoam peanuts before you resin the cloth. Move the speaker ring in or out or change the shape a little by braces or whatever until you get the desired amount. If you make it a little bigger, you can always fill it with something to shrink it down to the desired size. after its all glassed, I like to use the water method, this tells me exactly how big it is, and checks my work for leaks. good luck, hope this helps.
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