Guidance/Tips on Fiberglassing this box (pic).

[nrgy 10+ year member]

I would like to make a subwoofer enclosure for the rear shelf of my car. I came across this picture on the web, and I want to make my enclosure nearly identical to this one.

I already decided that I will probably use some type of styrofoam to mold the curved edges, but what steps would you guys use to build this box? Also, would you reinforce any areas with wood, such as the middle?

I'm thinking I would probably fiberglass the top and bottom, slide out the mold from the front or back, and then fiberglass the front and back. By the way, the 8" sub would mount in either the left of right side, facing up.

The dimensions would be apprx. 41"L x 9"D x 4"H. I know 4" doesn't leave much for mounting depth, actually the subs mounting depth is exactly 4", hopefully this will be ok.

I would be covering this in black vinly or leather once completed. Any tips or suggestions? This will be my first fiberglassing project. Would this be too difficult for a beginner? I've built custom amp racks out of wood, and wood enclosures so I consider myself somewhat of a DIY and handy man. Thanks in advance.

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[ramos 5,000+ posts]

Let's see here...I would use some form of biaxial woven mat such as kyntex. It won't take but a couple of layers and will be stronger than you could ever need. As for stiffening. Just lay some rope to make some ribs. Simply resin the rope in between the layers of mat. if you plan on the any large panel being flat I would make it out of MDF. it's just easier. Believe me . //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

As for a mold. There are a couple of ways to accomplish what your after. You could use the floral foam. Or you could make a wooden box square that's about an inch larger than your enclosure. Grease the inside of the box with some form of lubricant like vaseline. Then fill the box with great stuff foam insulation (the crap in the can that expands) Then once dry. Pop the block of insulation out of the box. Then carve your mold. Once you have your mold the shape you desire. Start glassing. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[Savant 10+ year member]

I'm not sure you need to have any kind of 'mold' from foam.. I mean, it looks like you have 2 'flat' surfaces (they are the long ones that are flat on the ground and have the curves in them).. if you cut some MDF that's flat on the one side and has the curves to the other side (you would have 2, one for each 'face'), you should just be able to pull the glass tight over that curve while building it up.. I would think a staple or two to hold it tight while the first layer dried would be fine.. and that helps give you maximum volume.. *shrug*

That's just what it looks like to me...

 

[nrgy 10+ year member]

Alright, thanks for the suggestions! I will use some of the techniques you suggested. I plan on using carbon fiber just to see how it looks when I'm finished. But how would you get a nice smooth, shiny carbon fiber finish if you have to layer and then sand smooth? Do you have to polish it or something? And does the nature of the carbon fiber weaves mask any layering?

Also, since it is fibers, when you sand it won't some of the fibers start to fray? Hopefully this question makes sense.

 

[ASDF12345 10+ year member]

hey your in luck..............you dont need fiberglass to build that box. the top piece thats corved can be made by plunge cuting mdf. youll need a plunge router. say your using 3/4 inch mdf, the the plung router to a little less then 3/4. make cuts in parell lines ever 1/4 inch and the mdf will bend. so make the cuts, then fill the grooves with bondo. set the mdf aside and let the bondo dry in the shape you want the panel. to make the sides just trace the top panel and cut side pieces. anymore help, pm me.