#1447870 - 26/07/08 07:17 PM
Stealthbox for a Lancer?
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IamMurph
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JL audio makes some of the best vehicle specific sub woofer enclosures on the planet. Their boxes are not mass produced. Each box is a one off made by hand from custom molds.
I found a box made for the VW Golf that would be perfect in my car.
This box is a perfect fit for the VW. Too bad it won't fit my Lancer. So what can I do? I can make my own box.
I have a little bit of experience with fiberglass. I have made several boxes, amp racks and kick panels. I decided to put this build here on Sound Domain so other can learn with me.
I started off with a gallon of Polyester resin and three packages of fiberglass cloth. The cloth I bought at Wal Mart and the resin came from US composites and West Marine.
Supplies needed:
Latex Gloves
Brushes
Mixing bowls
Acetone for cleaning
MEK
Cooking Oil (Pam)
Painters tape
Aluminum foil
I started off with a nice clean spare tire. This tire has never seen the ground.
Then I started to tape off the tire to create a barrier between the tire and mold area.
After the tape was applies I used spray glue and foil to make another layer of protection for the tire.
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#1447874 - 26/07/08 07:28 PM
Re: Stealthbox for a Lancer?
[Re: IamMurph]
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IamMurph
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Once the tire was foiled I added more tape to protect the sides of the tire. The last thing you want is resin on any surface other than the mold area.
A table would be the best choice for a work area. I used an old Best Buy sign I had in my garage. If you use a table cover it in wax paper. This will protect the table because the resin will not soak through the wax paper.
Add in the MEK per the instructions. Too little MEK will cause a slow curing time. Too much MEK will cause the resin to heat up and dry too fast. The mold can crack and warp.
Mix the resin throughly. It will change color when it's properly mixed.
Spray the surface with the cooking spray. A mold release will work as well. If a release is not used it will be impossible to remove the mold from the tire.
Paint the resin on the mold area and then lay the fiberglass cloth.
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#1447881 - 26/07/08 07:38 PM
Re: Stealthbox for a Lancer?
[Re: IamMurph]
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IamMurph
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48oz of resin was used with two packages of mat.
I then cut a piece of 3/4 mdf the size of the inner tire. This will be where the mounting bolt is added to hold the tire down.
The disc and mold had resin applied to glue the two together.
Then mat was applied over the mdf ring. When the resin dries it will make the MDF and fiberglass
mat into one very solid surface.
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#1447885 - 26/07/08 07:52 PM
Re: Stealthbox for a Lancer?
[Re: IamMurph]
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IamMurph
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The mold needs to dry for 24 hours to set 100%. If you remove it too soon the mold may warp.
If you use more cooking spray then I did you won't have as much foil left in the mold.
The next step in the box building process is the wood frame.
I used a cardboard box to made a template. It's easier to use cardboard then wood. If you cut too much you can alway tape some back on. try doing that with wood.
From there I cut a piece of 5/8 MDF for the bottom of the box.
I did the same process for the top of the box.
The 5/8 MDF was again used for the top.
I used two 1/4 x 3" wood to raise the top and bottom pieces of wood.
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#1447893 - 26/07/08 08:02 PM
Re: Stealthbox for a Lancer?
[Re: IamMurph]
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IamMurph
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I placed the mold on top of the wood box for test fitting.
The tire was laid in place for fitting.
The mold needed to be trimmed to lower the height of the tire.
I used a jigsaw to trim down the edges. Be careful cutting fiberglass. It's sharp and the dust can get glass fibers in your skin. If you get it in your skin take a cold shower to close your pores. Hot water will open the pores and cause the glass fibers to go deeper in your skin.
The next step is to cut the frame down to make room for woofer and rasie it away from the floor.
Bottom
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I trimmed the mold down and it's ready to be attached to the wood frame.
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#1448180 - 27/07/08 03:32 PM
Re: Stealthbox for a Lancer?
[Re: erbgottie]
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IamMurph
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Small update today. It's 100 degrees outside today my working time is very short.
The first thing to do is join the fiberglass mold to the wood. People will argue all day on the best way to do this. More resin, bondo, liquid nail or some other glue. I chose an adhesive that bonds to plastic, wood, ceramic and general construction materials.
I first applied a generous layer of adhesive around the opening of the wood frame.
The inside lip of the mold was filled with more adhesive.
A heavy container was placed on top of the mold to press it in place as the adhesive dried.
The inside panel that was removed earlier was cut for the 10 inch sub woofer. A 3/4 MDF ring was also cut and glues to the back side of the 5/8 MDF. This will make the speaker mounting surface stronger. Two pieces of 3/4 wood were used as mounting brackets to reattach the panel to the wood frame.
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#1448190 - 27/07/08 03:46 PM
Re: Stealthbox for a Lancer?
[Re: IamMurph]
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Thumper26
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looking good man. are you going to add some more fiberglass to help bond the tub to the mdf better?
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#1448197 - 27/07/08 03:59 PM
Re: Stealthbox for a Lancer?
[Re: Thumper26]
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IamMurph
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Yes I will add more fiberglass to not only the mold but the sides will be glasses as well.
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#1448224 - 27/07/08 05:46 PM
Re: Stealthbox for a Lancer?
[Re: IamMurph]
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keep_hope_alive
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SD I chew on Mike Tyson's ear
Registered: 24/04/07
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Loc: Quad Cities, IL
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how much trunk depth will you lose due to this setup?
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#1448243 - 27/07/08 06:33 PM
Re: Stealthbox for a Lancer?
[Re: keep_hope_alive]
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IamMurph
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Remember it's a hatchback and the answer is none. It will all fit under the standard floor.
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#1448250 - 27/07/08 07:26 PM
Re: Stealthbox for a Lancer?
[Re: IamMurph]
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IamMurph
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Did I mention it was hot. Remember when mixing MEK and resin that you take into consideration the temperature outside. Curing times will be accelerated in the heat and slowed in the cold.
The next step is joining the mold and wood with fiberglass and resin.
The adhesive bond is very strong but I want more fiberglass and resin to help if form a stronger bond.
I used up the rest of the cloth mat to start the foundation. Then I switched to chop mat. I prefer cloth because it's not as messy.
With the thicker chop mat I bought at Home Depot I used the soak method. The mat was cut into small squares and dipped into the resin mix. From there it's laid on the mold and pressed down with a paint brush.
I pressed the mat into place with my hands. A fiberglass roller works a lot better but I did not have one on hand.
I used up all the resin I had on hand so the only thing I could do next was prep the gaps with T shirt material.
This old Best Buy shirt worked perfectly. I used a stapler to attach the material and the stretched it into place. The material was again stapled on the other side to hold it in place.
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#1448561 - 28/07/08 10:37 AM
Re: Stealthbox for a Lancer?
[Re: erbgottie]
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SuperJay
I made this!!
SD OG Playa
Registered: 30/08/07
Posts: 21191
Loc: SoCal
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lookin great Murph, can't wait to see it finished
_________________________
more fun than a well oiled midget The best argument against democracy is a five-minute conversation with the average voter." - Winston Churchill i say somethin' stupid everyday, nothin' new  - Flattop 
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#1448787 - 28/07/08 02:42 PM
Re: Stealthbox for a Lancer?
[Re: SuperJay]
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IamMurph
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I picked up another gallon of resin today. Man that stuff jumped in price. $39.99 at West Marine. I also picked up a roller, brushes and some acetone. $85 later and it's over 100 degrees again today. I will change clothes and get to work.
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#1448837 - 28/07/08 03:55 PM
Re: Stealthbox for a Lancer?
[Re: IamMurph]
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IamMurph
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I just took on two different parts at once. The bottom of the box and the inner mold.
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The T shirt material was painted with a thick layer of resin.
 
The panel was flipped over and the pack side was also painted with resin.
Fiberglass mat was added to the back side of the t shirt material for extra support.
The buildup of the inner mold continued with a different method.
Two pieces of mat were submerged into the resin and layed into the mold.
Then I used the roller to press the mat into place.
The inside of the box was coated with a layer of resin to seal all the wood.
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#1449045 - 28/07/08 08:55 PM
Re: Stealthbox for a Lancer?
[Re: IamMurph]
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IamMurph
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Time to put the box back together and attach the material to resin. Normally you would use fleece or cotton. I choose carpet because of the thickness. Getting resin on the inside will be a challenge.
I used a staple gun to attach the carpet to the box frame.
After the carpet was applied I used a razor blade to remove all the excess carpet.
Time for more resin. This carpet takes A LOT of resin.
My 9 year old son doesn't have the camera skills down 100% but you can see what I am doing.
Bottom and sides have the first coat.
Flipped the box over and coated the top and sides.
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#1451019 - 30/07/08 06:15 PM
Re: Stealthbox for a Lancer?
[Re: IamMurph]
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IamMurph
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In order to resin the inside of the box I had to mix a hot batch of resin. I poured 24oz of rein into the box and then rotated it so all inner edges would be coated with resin. This took about 10 minutes of rotation. To avoid doing this yourself, cut the wood frame a little smaller and use a thinner material. That way you can build up to the size needed.
For the next step I have to build up the box and fix some imperfections caused by the carper not being as tight as it could be. For this I used Bondo's version of rage gold. I hate regular Bondo body filler. It's too think and not very forgiving.
After 25 minutes I can go back and sand it down before adding a few more coats.
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#1451053 - 30/07/08 08:10 PM
Re: Stealthbox for a Lancer?
[Re: IamMurph]
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IamMurph
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Resin time
Bottom
Top
After it dries I will do some fine tuning on the sanding. Since it will be carpeted and not painted the finish does not have to be perfect.
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#1451101 - 30/07/08 10:04 PM
Re: Stealthbox for a Lancer?
[Re: IamMurph]
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IamMurph
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Went to take out the trash and the Installer ADD kicked in. I had time to carpet half of the box.
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#1451106 - 30/07/08 10:21 PM
Re: Stealthbox for a Lancer?
[Re: IamMurph]
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keep_hope_alive
Snooch to the Nooch
SD I chew on Mike Tyson's ear
Registered: 24/04/07
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Loc: Quad Cities, IL
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wow. well done. your installer skills are very evident. very nice product. i bet you sleep well tonight.
what does it weigh?
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#1451787 - 31/07/08 06:07 PM
Re: Stealthbox for a Lancer?
[Re: kamikazePSI]
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IamMurph
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Polyfil can add unwanted heat. I will talk to the speaker manufacture and see what he suggests. I could care less what the inside of the box looks like.
The bottom of the box is carpeted. It will be bolted to the car when I am done.
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#1452315 - 01/08/08 12:42 PM
Re: Stealthbox for a Lancer?
[Re: IamMurph]
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IamMurph
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Last bit of carpet went on today. It turned out ok but I may change it before I get the new sub.
All that is left is adding the mounting hardware. Once I get the sub then we will see what fine tuning needs to be done.
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#1452434 - 01/08/08 03:57 PM
Re: Stealthbox for a Lancer?
[Re: IamMurph]
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Thumper26
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Registered: 12/09/04
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wow, very nice job. that's really turning out well! 
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#1452563 - 01/08/08 10:31 PM
Re: Stealthbox for a Lancer?
[Re: Thumper26]
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keep_hope_alive
Snooch to the Nooch
SD I chew on Mike Tyson's ear
Registered: 24/04/07
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that is as stealth as it gets. i hadn't pictured it like that in my head. sweet.
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