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Old 12-28-2006, 01:42 PM
4th Gear
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Join Date: Apr 2006
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Default F/G Box DIY

Fiberglass Box

*First off I hold no responsibility to any damage or unfortunate mishaps caused by the use of this information. Fiberglass is in a sense an art form, and each artist has there own technique. This is the way I chose to build my box but does not mean that you have to do it this way too.

What you will need:

1 gallon of fiberglass resin
3 pk. of fiberglass matting (may need more or less depending on 3 pk. of fiberglass cloth the volume needed)
At least 10 cheap 2” paint brushes (should be about .49 cent each)
Thick plastic containers (I use paint mixing cups because there thick and have measurements on them already)
1-roll of masking tape
1-roll of blue masking tape
1-can of spray adhesive
Enough stretchy material to cover the front of the enclosure
(Fleece is popular but most any stretchy material will work)
Wood for speaker rings (I use MDF and double it up so the sub is Foil flush mounted)
Box of latex gloves
Respirator or at least a dust mask unless you like to get high on resin fumes.

Dremel tool or something of the sort
Wood cutting tools (what ever you use for cutting rings unless you buy them)
Socket set for removing the metal basket

Ok now let’s get started! First thing I did was take measurements of the space available (11 ½” x 13) and decided on using a 10” sub (Memphis 15-PR104D). Then I cut the 2 speaker rings out of MDF and glued them together. I wanted a flush mount appearance so I cut the top ring a 1/2” larger then needed so I can round off the outside of the ring and notch out the inner part for the speaker. If you don’t want the flush mount then you only need 1 ring.

Remove the basket for the tool box/cd changer with a 10mm ratchet. Now it’s your choice on what “you” want to do here. The opening is odd shaped so you can cut the opening for a perfect square or build around it. I chose to cut the opening because it’s easier and gives me a little more air space. Besides the door will cover it up if I take out the sub.

Now its time to build a frame, I built mine out of poster board and hot glue. I used this because it’s sturdy enough to hold the shape for the mold and easy to cut to shape. Another option is to make a base out of wood then attach the f/g to that.

After the frame is built its time to prep it for f/g. You do this by putting a layer of white masking tape down then a layer of blue tape on the frame and all surrounding areas of this enclosure. YOU DO NOT WANT TO SKIMP ON THIS STEP RESIN WILL RUIN EVERYTHING IT TOUCHS. After the area is taped off you can lay your foil over the tape and start your mold. (foil allows you to remove the mold easier) I just f/g over the tape since my frame can just be broken apart.

*Make sure that you where gloves for this next part f/g and skin don’t mix.
Gather your resin, f/g cloth, mixing cup, paint brush and scissors. Cut all f/g cloth to manageable sizes needed for the mold. (2” wide strips are what I work with) I arrange my pieces according to length so I’m not fumbling with sticky hands for a certain length. Then mix enough resin for the first coat. (Between 4-8oz)

*It’s a good idea to double or triple up your gloves so you can just take one layer off when it gets sticky.

Paint the resin onto the frame/foil and stick the strips on making sure there are no bubbles. Layer a thin coat of resin on top of the cloth also so it does not appear white any more and let it cure. I lay down a 2-3 layer’s just to make sure that the structure is strong enough to pull off the frame. I also lay this layer in opposite directions of the 1st because it seems like it should be stronger this way. Once the mold is formed and cured, its time to remove it from the frame by prying it off or disassembling the frame.

Gather your materials from the last step but instead of f/g cloth you will need the f/g matting. Don’t cut but pull the matting apart in manageable pieces. Mix your resin and apply just like the last step being sure not to leave bubbles behind. If you see bubbles then you must get rid of them with a razor or other cutting tool. Concentrate on large flat areas since these are the weak spots. (If you can flex it with your finger it’s too weak) Once the mold is solid without flex points test fit it and trim the outer edge with a cutting tool. Remember to compensate for the fleece when trimming it’s going to add (1/8 to 1/4in.) to the total size. Also if your box is going to be wrapped in carpet you will need to compensate for this now.

It’s time to mount your speaker ring. You will need wood dowels or MDF, & hot glue. Place the speaker ring in the position you would like it to be, cut the supports and hot glue or staple them into place. This must be strong enough to hold against the pressure of the stretched material.

*Test with packing peanuts to make sure you have the correct volume. You do this by getting a 12x12x12 box and filling it to the correct volume then adding it to your enclosure, then make adjustments accordingly.

If your box is the correct volume attach the stretchy material. I start by stapling the fleece to the inner part of the speaker ring. Then I stretch the fleece over a lip of the box adhering it with spray adhesive. I cut triangles out where I get folds so it lays flat. (stretch the fleece tight so you don’t get any sagging)

Once I’m happy with the way things are I put a layer of resin down. Mix about 10oz. of resin because fleece is very absorbent, also make sure to keep it as smooth as possible to make sanding easier. I strengthen from the inside of the box to avoid making the box larger and to keep it as smooth as possible for sanding. Once the face is strengthened I mix a 5:1 ratio of body filler/resin. I use this to add strength and make sanding easier, paint this on and let it cure.

Start with 80 grit sand paper taking down the high spots, then switch to 100 grit, then 220 grit making a nice smooth even surface. Spot putty any pits or pin holes then sand smooth with 330 grit sand paper. Spray high build primer on the face of the box and look for any imperfections using spot putty to correct them. If everything looks good you can spray your primer and paint or cover with whatever material you desire. DO NOT paint the box if you think there is more sanding to be done. The paint will peel up when you try sanding it and give you a lot more work to do.

You can spray rubberized sound dampener or put dyno-matt on for better sound quality. Pre-drill your speaker holes and drill a hole just large enough for your speaker wire in the side of the box. You can mount a speaker terminal but it may be a pita since the f/g is not flat. Run your wire through the box and seal with silicone. (Make sure to let this fully cure before introducing your sub to the box because silicone and its fumes can ruin a speaker) I am mounting the box in place with 3/8 threaded rod some big metal and rubber washers. I used the bracket that holds the horn since it already has holes in it. I also hot glued some wood to this part (pic) and zipped a screw in through the top so the bottom doesn’t move around.

Finished box
Old 12-28-2006, 02:08 PM
AWDaholic's Avatar
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Join Date: Feb 2005
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Default RE: F/G Box DIY

Old 12-28-2006, 02:13 PM
Join Date: Aug 2008
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Old 12-28-2006, 02:21 PM
4th Gear
Thread Starter
Join Date: Apr 2006
Posts: 3,396
Default RE: F/G Box DIY

Yea i didn't read the DIY rules. I thought it gets posted here and if the it then they put it in the DIY. That's how I see it done before.

So if an admin. see's this post can you delete it from of.

Old 12-28-2006, 02:28 PM
AWDaholic's Avatar
Senior Administrator
Join Date: Feb 2005
Location: Lotsa places, currently Metro D.C., USA
Posts: 13,574
Default RE: F/G Box DIY

you can STILL PM it to Amanda, AND leave it here. I'z jus fcukN witchu
Old 12-28-2006, 02:38 PM
4th Gear
Thread Starter
Join Date: Apr 2006
Posts: 3,396
Default RE: F/G Box DIY

I pm'd her.
Old 12-29-2006, 02:06 AM
5th Gear
Join Date: Sep 2005
Location: New Orleans, La
Posts: 9,133
Default RE: F/G Box DIY

nice man did you get everything running yet

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