# 07 Trailblazer SS, fiberglass sub box-last piece



## papabearsc (Oct 2, 2010)

Well, finally got the front stage and rear fill done in the Trailblazer SS, and got amps and subs worked out so it was time to build my new box. Full build post coming soon....... Never messed with fiberglass before, but it was time to learn, so here we go. Advice wanted, even though I've already dove balls deep into this.............

Bought this awesome spandex type fabric (had bad experience with fleece last time I helped someone with glasswork) from Walmart, and even made an old lady mad that I bought the last of it, LOL. Want the box to fit full width of my cargo area, and match the angle of the back seat of the SS. I also wanted to leave the ends kind of "dead" space to utilize the factory cargo anchors in the floor of the truck. Looks like a huge box, but lower the back seats and the ends are empty space, using the space to bolt the box to the floor, as well as house distribution block and battery and the like. 

Anyway, here's how it started....2 hour quick box to house the older model RE Audio SE 12's...the ones with the spoked aluminum basket.









Started by making the base, tight to the back seat and snug between the wheel well humps in the carpet. Back piece is angled with the back seat, to sit snug. I then cut 5 pieces to make "studs" in the base and back piece. Two for the ends, two for the outsides of the airspace part of the box, and one to divide the subs. I then went in with a pencil, and just freehanded a curve for the front of it. 



















I had already made and assembled the speaker rings with T-nuts already installed, so I heated the hot glue gun up and got to visualizing....beer helped.


























Got the one in a pretty good spot (more of a guess than anything), so I glued her in. Put the other side in and tried our damndest to get the second to match. Glued them in with dowel rods and hot glue, sturdy as hell. 

Then we wrapped it with the oh-so-stylish spandex crap from Walmart and it began to take shape. Three coats of resin on the material (30 ounces total) got the shape done. VERY symmetrical, but if you look hard enough you could probably find a defect somewhere. 


































Then time for chopped mat and cloth for reinforcement in the INSIDE of the speakers' airspace. All corners and joints of fabric and speaker rings were lined with cloth and then packed with chopped mat. Of course, PILES of resin were used for all of this.


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## papabearsc (Oct 2, 2010)

Tomorrow we get more resin inside, then I can start with binding posts for speaker wire, and cut out the speaker rings and mount subs.


































Anybody got a suggestion of how to strenthen this part? Where the fabric/resin meets the edge of MDF speaker ring? Is it 0strong enough?


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## Mless5 (Aug 21, 2006)

Sweet spandex! Can't wait to see the finish!


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## mattyjman (Aug 6, 2009)

are you reinforcing the ring from the back with glass? if so, then you should be fine. if not, then i would make sure you put a few layers back there, bonding the back of the ring to the front of the mold


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## papabearsc (Oct 2, 2010)

Yeah trying to reinforce from the back, such a pain in the ass, glad no one will ever see the inside, LOL!

She feels real strong, and I do want to overbuild it, just in case. With 20 degree temps, hardener sure goes quick!

The bond on the rings is my only concern...









Think it'll be okay though. This is from inside....


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## papabearsc (Oct 2, 2010)

Think I'm gonna "texture" paint this one, just to get ready for a show, then re do it smooth for leather and suede wrap to match seats. Will this be "wrappable"??


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## rcurley55 (Jul 6, 2005)

cut large holes on one side of the enclosure off (back or bottom). Then you can cleanly apply all glass to the rear of the mold fabric. Screw/glue/seal a new back/bottom to the box and you now have now cut a ton of time off of sanding/cleaning up the front an don't have to worry about delamination issues - that's how I've done it.


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## nineball (Jan 17, 2008)

forget that. grab a gallon of duraglass and fill up the gap behind the rings with it. way easier to do.

shots from the inside looking out




















here you can see the green under the glass around the ring on the inside.


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## rcurley55 (Jul 6, 2005)

nineball said:


> forget that. grab a gallon of duraglass and fill up the gap behind the rings with it. way easier to do.
> 
> shots from the inside looking out
> 
> here you can see the green under the glass around the ring on the inside.


That works if you are just looking to strengthen that interface (I've done the same), but it doesn't alleviate the need to reinforce the mold fabric across the entire front of the box. Doing that reinforcement from the rear with proper matt/cloth + resin layup will save time when it comes to doing the bodywork on the front in my experience. Just providing a different option


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## nineball (Jan 17, 2008)

rcurley55 said:


> That works if you are just looking to strengthen that interface (I've done the same), but it doesn't alleviate the need to reinforce the mold fabric across the entire front of the box. Doing that reinforcement from the rear with proper matt/cloth + resin layup will save time when it comes to doing the bodywork on the front in my experience. Just providing a different option


isn't that what the glass is for?

-edit-

just re-read and noticed the OP has not glassed the outside yet. i assumed he was going to, but if not then filling the rear won't help nearly as much.


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## rcurley55 (Jul 6, 2005)

nineball said:


> isn't that what the glass is for?


I don't want to get into a fabrication debate on this guy's build log, but let me explain myself further (just to make sure we are on the same page, I'll be pretty explicit)

For a fiberglass enclosure with a lot of curves (well, you wouldn't really want to build a flat sided 'glass enclosure anyway), you typically stretch mold fabric over a frame to get your shape, then wet out that fabric with resin. This gives you a hard but brittle form to build from.

At this point, you have to reinforce the resin-coated mold fabric for it to work as a subwoofer enclosure. IMO, the only way to correctly do this is to add additional layers of fiberglass cloth/mat with associated resin.

You can either add that material to the front of your mold fabric (the show side), or the back of the fabric (the inside of the box). 

If you add to the front:
-You have better access to the box
-You have to (arguably) do more bodywork to smooth out the fiberglass in prep for paint/covering

If you add to the back:
-Your access suck
-You save a ton of body work

My argument is that if you plan ahead, you can leave an access hole on the rear of the enclosure and then just seal it back up after you are done reinforcing the box.

<----hates body work

As always, there is more than one way to skin a cat!

Great start on the box btw, looks like it will be cool when all is said and done!


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## nineball (Jan 17, 2008)

see my edited message above yours before you posted. i've built more than my fair share of glass enclosures.


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## papabearsc (Oct 2, 2010)

Ugh.... Access is so limited that I think I have underbuilt the enclosure.....so do I add resin/cloth to front, or trust that I did it well enough inside?

I'm tired of screwing with it, and don't want it super smooth, so I'm gonna hi-build real heavy and texture paint this ***** and hope the RE's don't blow it apart......


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## TimesCaptured (Jan 6, 2011)

Can't wait to see the finished product.


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## kizz (Jun 22, 2009)

Looks like a good start. Could you have rounded the corners of the frame in the front to make it smoother. i see the corners pointing out on the top and bottom in front.


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## papabearsc (Oct 2, 2010)

The points weren't planned for, but when sitting in the truck, they look pretty cool, so I proceeded. 

This bein my first experiment with glass, and the perfectionist I am, I will probably redo this in a week anyway, learned so much already, next time ought to be way better....


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## kizz (Jun 22, 2009)

gotcha. it looks good regardless to me. i have never done fiberglassing cuz frankly im just scared.


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## papabearsc (Oct 2, 2010)

When u get frustrated and run out of patience, what do u do? Call in reinforcements and buy them some beer!


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## TimesCaptured (Jan 6, 2011)

Corna and Bud Light - Both Great Choices. 

Oh Crap I just noticed a Sub Box in this picture. 

Standing By!


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## papabearsc (Oct 2, 2010)

Well, had a problem with this box. At first, I wanted to not have it smooth. I wanted it textured like the interior panels of the truck, so resin was sanded "semi-smooth" and primed. Then paint was applied. Turned out looking like ****. 

So, sanded the paint and primer REALLY good, almost took it all off. Then applied filler over the entire box. BAD IDEA! Apparently the hardener in the filler had a reaction with the little bit of paint left on the box and the paint turned into jelly....thus lifting all the filler off. What a pain in the ass.

So....back to sanding. Got it all the way back down to straight resin. Applied a few more coats of resin to outside, and let it all dry up. Then one of my buddies came by last night and informed me of a mixture of body filler and fiberglass resin. He mixed it up and we "floated" it on the entire box. That **** is AWESOME!

It has been sanded all the way to 220. Got some Evercoat Easy Sand glazing putty from an automotive paint shop. Guy swears by it, so gonna coat it in that and go to town sanding again. 

For someone with as little patience as myself, I can't believe this is happening. Good thing a friend of mine who is currently unemployed LOVES to sand. So while I'm at work, he's at the house sanding......for beer and cigarettes. More to come tonight.


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## DJSPANKY (Dec 15, 2009)

Box looks great so far- can't wait to see the updates with the resin/hardener mix.


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## TimesCaptured (Jan 6, 2011)

I meed unemployed friends......


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## papabearsc (Oct 2, 2010)

Glazing putty....works wonders!


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## papabearsc (Oct 2, 2010)

So CmK sanded his ass off today until his fingers bled. Glazed it, sanded 100, 150, 220, 320, then hibuild primer and that's how she sits now. Ready for a few spots to be filled / sanded again an primed once more. 

Should be painted and installed by the weekend....







































And CmK and his war face....


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## eviling (Apr 14, 2010)

all those things on the same table are such a bad idea XD


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## papabearsc (Oct 2, 2010)

No man...that's sanding fuel...


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## Dodge4L1fe (Jun 5, 2009)

Nice box... and awesome SS


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## papabearsc (Oct 2, 2010)

Here ya go! Flat black Krylon, four coats.


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## steffanan (Dec 9, 2010)

woah im doing a fiberglass box in my trailblazer, and im totally going with flat black krylon too! thanks for the direction!


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## iasca judge (Jan 5, 2010)

Box looks good. doesn't sanding suck though??? Great job


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## papabearsc (Oct 2, 2010)

I hate sanding. Like I said in an earlier post (I think i did anyway), I had an unemployed friend at the time, so all I had to do was provide him a pack of cigarettes a day, sandpaper, and a 12 pack every couple of days and he sanded while I was working. I got off, did more filling, and he sanded the next day.

Worked out well for me.

Thanks guys....too bad this one's gettin scrapped real soon


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