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I have 2 fiberglass installs under my belt and now I am planning a bigger one.
The first two installs were just kick panels, now I want to try a subwoofer panel. I have saw a few where people make rings out of MDF for the speaker to mount to and then filled the rest in with fiberglass and cloth.
My questions is, when layering the cloth should you let one layer completely harden/cure before laying the second and third etc.. or should you apply the 2nd layer while the first is still tacky?
Thanks for the help!!
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Posts: 76 | From: Calvert City, KY | Registered: Oct 2000
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posted
You should lay up several layers while it's all still tacky, but when you get it about 1/8" thick, let it cure before adding more. Fiberglass gives of heat as it cures, called exotherm.. too much heat can cause the part to shrink or warp and thick lay-ups will give off more heat than thinner ones. Thin lay-ups will take longer to cure as they will produce less heat.
1/8" thick is a good spot to take a break and let it cure, but before you start laminating more 'glass on, sand the surface with 40, 60 or 80 grit sandpaper to give the next layers a good grip.
Here's a tip.. use a biaxial fiberglass cloth.. there's a weave called "knytex" and it's one of the strongest weaves fiberglass reinforcement comes in these days. It's also very thick, you can build up 1/8" thick in 3 layers. It's inexpensive too, runs about $5-$7 per yard (50" x 36"). You'll still need lighter cloths for corner areas, knytex doesnt like tight corners since it is thicker stuff.
------------------ Mike Pipes Digital Illusion Custom Graphics
R POT Designs - Carbon Fiber Watercraft Performance Products
Posts: 431 | From: Lake Havasu, AZ | Registered: Jun 2000
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posted
Thanks for the information Mpipes, I am going to be using 3 8" speaker and dont really expect many tight corners, mostly flowing curves. Where can you get that material? Does any online place carry it?
Thanks
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Posts: 76 | From: Calvert City, KY | Registered: Oct 2000
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posted
you can use polyester Fleece!(get it at a fabric store) then strech it and staple it to your frame , then w/ a 2.5 " brush ,paint the resien on the cloth,let it soak in good.let dry then filp it over and put 2 layers of mat on the back for added strenth!then sand front , smooth with spray bondo,then paint . to see how its done go to..>>
------------------ - ---STEVE COOK<<<3>>>time World Champion----
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Sven, www.shopmaninc.com has the biaxial stuff, but I've never ordered from them so I dont know about their service. You might want to call them instead of going through their site to purchase materials.
Honestly, I would almost stop at 1/8" or 1/4" thick then stop any flexing with bracing inside the enclosure. 1/8" thick knytex weave is wicked strong so it wont bust under pressure, but larger flat expanses will tend to flex which can be remedied by putting bracing in the right spots.
On something like that SPL setup posted above here, I woulda carved that into foam, filled in the rough areas with Duraglass, wax it then lay-up 1/8" of knytex. Once the fiberglass is cured, pull the foam plug out and bond the MDF Rings to the areas the subs screw into. It can be made thin because all those curves in that particular shape make the overall strength very strong.
The reason I would choose carving the foam is it lets you get by with less filling and finishing work because you dont have to fill a large void with body filler and sand it so much.
I could even go a step farther and sand/paint the foam/Duraglass surface til it's slick as snot then pull a negative mold off it and sell reproductions for about.. ohhh... $1500. =)
------------------ Mike Pipes Digital Illusion Custom Graphics
R POT Designs - Carbon Fiber Watercraft Performance Products
Posts: 431 | From: Lake Havasu, AZ | Registered: Jun 2000
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