Rep Power: 381

I know how to mold the enclosure and everything like that. its just that i can't think of how to make the fiber glass enclosure stronger. I know that you are supposed to use silicot(sp) powder and mix that with the resin to make it more rigid. (i think that the stuff yo uuse to line the bottom of pools before you put the liner in would work but not sure.) But i cannot find it at any home or garden place. Ive look long and hard and have asked many people if they know where i can get it. and no anwsers. So i turn to my fellow 7thgen audio tuners. What can i use to mix with the resin to make the fiberglass stronger.
Here is how i do it
1)tape off trunk where box will be.
2)spray tape with 3m adhesive
3)apply fiber glass badding
4)apply resin to badding with a brush
5)make make frame where i want the sub to be
6)cover frame with stretchable cloth and glue to back side of box
7)resin the colth
8)cut out hole for the sub and boom basically done
im not going detailed becasue those of you who i am asking this question to already know how to do this. so anybody plese help me and tell me what i can use and where to find it. specific names and brands would be very helpgul. and i will rep. thank you. i have my trunk taped off so i really need to get on this.

 
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people use fumed silica to reinforce their sub boxes. It gets mixed in with resin at a 1:1 ratio i believe, but dont quote me on it. Sure it saves time, but its not as strutually sound as adding more layers of fiberglass. After you resin the cloth, layer fiberglass until you cant push in a section of the box with your thumb. Then you have built a strong enough box.

 
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put more bends in it.

 
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thankis looks like im just gonan be adding alot more layers of fiber glass because i can't find silica anywhere. i just wanted to add it so i didn't need as many layers

 
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put more layers of fiber glass. The more layers the stronger. Also if its going to be painted then the body filler should make it a little more rigid.

 
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Also, you can make it stronger by putting in little ribs on the inside, like, glassing some rope or sticking the fiberglass out like little ridges on the inside.

 
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This is the best advice I've seen yet, other than ading layers. This can be done from the inside (in case you've prepped it for paint, of course so can extra layers too). I like to glass rope in there as opposed to the hatched glass pattern ed's describing. Regardless, the resin does little to add actual strength other than hold the fibers together. Strength comes from teh cloth/glass/mat/etc...

 
Rep Power: 283

Build the actual woofer enclosure out of wood, it will probably sound better anyway. Then use fiberglass around that to make it the shape you want.
just my 2 cents

 
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Try a Boat supply store. They have good quality fiberglass repair supplies. They also carry gel coat. I get all my stuff at Boaters World.

 
Rep Power: 381

lol thats actually what i used i used boat grade fiberglass and it turned out really strong.

 
Rep Power: 339

you can also use pieces of wood to reinforce. supports that connect various portions of the box to others, or used to span distances. perfection isnt required, as long as adhesion is good.

the best way to get strength with few layers would be to switch to an epoxy-carbon system rather than a polyester-E-glass system. if you dont have the cash, buy some S-glass rather thna E glass, and really work that resin into the fibers well. youll notice a night and day stiffness increase, layer for layer.