SterTheDer Posted July 15, 2014 Report Share Posted July 15, 2014 Thats right, i am building my subwoofer box out of Fiberglass + Foam composite.I got designs for a box for 2x SQ HDC3 12"s, and it was supposed to be built from 3/4" mdf, and would have weighted over 250 pounds.HELL NOPE... Too damn heavy for my lil 2.2 i4 engine... so.... i am building a boat. 3/4" Pink insulation foam (3 sheets 4'x8') (Yep, from menards, for house insulation) 7.5oz fiberglass cloth (20yards) 2 gallons of Epoxy resin (because vinal and polyester resin eat foam) 5.7oz carbon fiber (2yards) Now, before the flood of people hating on foam+ fiberglass chime in... if you have not worked with compostie materials then please go try it first, you will be pleasantly surprised Ok, here we go: I cut my pieces of foam down to the proper sizes for my box, the same as if it was MDF.Once i had all my pieces cut, i layed up TWO layers of 7.5oz glass (15oz total) and as little epoxy resin as i could. When that cured, i did the same to the backside.Holy buckets you have no idea how freaking strong this stuff is!I am able to support a Diamond d9 12d4 (roughly 30 or so lbs) on a 15.5"x28"x3.75" piece of foam with 30oz of fiberglass, with ~1/16" deflection.(the 30lb sub was aproximatly 1ft from the table, so 30lb/ft of force caused less than 1/16" deflection) Assembling the fiberglass pannels is easy as well, i simply epoxyed the joints, and reinforced with 2" fiberglass tape.Thusfar my box is under 40lbs, and is freaking strong. The only wood in my box is the front baffle, 3/4" pine, due to me f*** my holes the first time (i needed 11" diameter, i cut 11.25" so none of my screw holes would work), the top and bottom of the inner box (due to my need to have separate assembly pieces, i used 1/4" plywood to hold the inner ports together), and the mounting flanges on the edges of the box (because i cant screw every angle when it is in my trunk)Videos of this project are posted to my youtube page: https://www.youtube.com/user/sterthederSo far, in all my two months of searching.. it appears that i am the only person IN THE WORLD to be using a foam subwoofer box....Plenty of all fiberglass builds, plenty of fiberglassed mdf/plywood, very few carbon fiber/mdf boxes.. but absolutly nobody but me is using foam for my composite! one in a million? PSHH... one in a billion? hell no, JUST ME! (unless you know somone else with a foam box?)Fiberglass foam composite is used heavily in the boat industry, they construct boat hulls with it!It is also in the aerospace industry, for aircraft wings!Surfboards are foam/fiberglass! Very very few pro audio monitor cabs have been made with this technique, and it is quite successfull.Common "You shouldnt do that because XXXX":resonance: "the low mass means it will resonate!" Well.. yes... but no... the fs of the box is several hundred htz, due to the low mass pannels, and it doesnt flex due to the stiffness of the composite.I dont understand why nobody else is doing this.... does anyone hear have any exp? Rough conclusion: Fiberglass/foam composite box is 3x the price, 3x the work, and 1/5th the weight. Link to comment Share on other sites More sharing options...
Broke_Audio_Addict Posted July 15, 2014 Report Share Posted July 15, 2014 So is it finished and playing yet? That being said a lot of people's definition of "music" is a clipped 30 hz sine wave with some 80 IQ knuckle head grunting about committing crimes and his genitals. Link to comment Share on other sites More sharing options...
harlemn8ive Posted July 15, 2014 Report Share Posted July 15, 2014 Postem up!! Check out my build slow but... slow and steady wins the race http://www.stevemeadedesigns.com/board/topic/185561-1st-build-budget-toyota-mark-2/ Link to comment Share on other sites More sharing options...
Skullz Posted July 15, 2014 Report Share Posted July 15, 2014 People generally don't think outside the box. pun intended I have been into many hobbies and building radio control airplanes will teach you a lot about improvising and coming up with ways to shave weight off an airplane as you build it, and it will also teach you ways to shape and mold things you never thought were possible. 01 Ford focus ZX3 Pioneer AVH-X491BHS PPI PC 4800.2 Morel Maximo 6.5" x2 Link to comment Share on other sites More sharing options...
hispls Posted July 15, 2014 Report Share Posted July 15, 2014 I wonder if 2 layers of weave is enough on larger panels? I've played with carbon fiber and epoxy and it's very strong so this seems very promising when weight is priority over coast and hassle. Link to comment Share on other sites More sharing options...
Karkov Posted July 15, 2014 Report Share Posted July 15, 2014 post up some pics. and vids. on this site please. 2007 Chevy Tahoe (SOLD) 12 ~ FI Audio X series 10" w/BP option 2 ~ DC Audio 5.0K @0.67 3 ~ DC Audio 5.0K @1.0 2 ~ PPI 3 way sets (not installed yet) 1 ~ RF T400-4, 1 ~ RF T600-2, 1 ~ RF T600-4 4 ~ CT Sounds 5.25" Strato comps (rear fill only) 1 ~ XS Power D4800 1 ~ XS Power D3400 8 ~ XS Power XP3000 160 stock alt, Mechman 370 Elite, 185 DC Power 320+ Sq. Ft. Sound Deadener Pioneer AVH-X5500BHS Youtube: https://www.youtube.com/user/knfjdkghjudfhsgkjdhf/videos?sort=dd&view=0&shelf_id=0 Link to comment Share on other sites More sharing options...
Aj11 Posted July 16, 2014 Report Share Posted July 16, 2014 how big was the original box for 2 12s that it would be 250lbs? one sheet is like 55lbs. so you needed 5 sheets for a box for 2 12s? i don't understand... jvc deck stinger 1800 front hc 2000 kinetic rear 2 runs of 1/0g big 3/4 ct 60.4 2 ct 1400.1 ct EXO 15 d1 lots of deadner type r comps front stage 6 kicker tweets rear stage lots of great stuff coming soon ho alt more bats ct comps for front stage more deadner sweet amp rack lots of L.E.D lights new deck (thinking 80 prs, or flip out) Link to comment Share on other sites More sharing options...
REH Posted July 16, 2014 Report Share Posted July 16, 2014 how big was the original box for 2 12s that it would be 250lbs? one sheet is like 55lbs. so you needed 5 sheets for a box for 2 12s? i don't understand... A sheet of MDF is more like 90lbs. Even with that said, had to be double thickness all around? Link to comment Share on other sites More sharing options...
Tecomah Posted July 16, 2014 Report Share Posted July 16, 2014 750??! Yeah, fuck that. Fuck this website, fuck SMD, fuck Steve, fuck all of his butt buddy mods, and their couches.^ DON'T BE A DICK LIKE THIS GUY Team Subsonic Lows Link to comment Share on other sites More sharing options...
Noel989 Posted July 16, 2014 Report Share Posted July 16, 2014 Build Log - http://www.stevemead...-cruiser-el-pt/ Link to comment Share on other sites More sharing options...
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