blackbalt sport

I'm building a fiberglass sub box for my 08 Cobalt Sport but I'm kind of confused of what to do now?

I've got all the fiberglass mat and resin done and used body filler today to fill in the cracks. However, after I sanded some of it down (with 120 grit cuz thats all I had laying around) I found that there was still grooves and bumps. Do I get some 80 grit sand paper and sand everything down till its smooth or keep applying body filler?

First time with fiberglass so it wasn't to pretty at the start
https://www.cobaltss.net/gallery/fil...06_08_1719.jpg

Where I am now
https://www.cobaltss.net/gallery/fil...06_08_2018.jpg

This is the view of the side of it and shows how there is still rough patches
https://www.cobaltss.net/gallery/fil...06_08_2019.jpg

I am planning on carpeting the back and bottom but I am not sure about the sides.

EmperorJJ1

iTrader: (5)

woah theres tons of air bubbles in the fiberglass. ur gonna want to fill those holes in the 3d pic with filler and sand smooth again. Hit up impulse buyer for more info. hes the expert with fiberglass ive just seen it done

fmxr47

i made a box for one of my 10's before and it is not a quick job, you need to apply more filler sand it, then there will be more air bubles so apply more and sand it and you have to repeat this proccess until you fill in every little hole and then go finer and finer on the sand paper, and trust me if you dont take the time to smooth it out it looks like **** when painted

-the.k.w.c-

wow!!!!!!! dude thats horrible most of that glass isnt pushed down and bubbled up and its supper ruff and pokey ....if u plan on carpeting it, then just sand all the super ruff stuff down and put the carpet on it ...carpet hides everything cause its so thick.

but by the looks of things that box is horrible in design too and is going to look kinda funny setting in the trunk

EXsoccer1921

iTrader: (14)

i'm gonna guess this is your first time glassing? did you do any research before hand, cause i'm guess not. no offense, but you may just want to call it a loss and trash it and start over, or just carpet the whole thing

ls1fbody

sandpaper is your new best friend. don't give up, everybody has to start someplace. maybe you picked a job that was a tad to ambitious for your skill level. kudos man, i wouldn't have had the ***** to just launch into such an intense project.

blue06

wow, you're gonna need a lot of sanding if you want to paint the box, but you might want to go with vinyl or carpet

JRANGER

OK it is MILKSHAKE TIME......You will want to fill all the bubbles and the easiest way to do the whole body filler thing is the milkshake. You take your body filler and add about resin to it.. 4:1 ration. Then add your filler hardner and mix it until it is about the consistensy of a milkshake. Paint it on the box with a brush and then sand after it dries. It should make it a little easier because it wont be all spoty and goes on smoother. This is what I did and it helped alot. You will want to hand sand it and be careful and patient

Also RAGE GOLD is an awesome body filler and easier to sand then say bondo

dont let people get you down on it.....

Here is my box build thread...similar things happened
https://www.cobaltss.net/forums/electronics-audio-video-49/jranger-starts-his-fiberglass-sub-box-69020/

fmxr47

yeah, dont give up on it, it took me a whole weekend to do my box and it takes a lot of time, sanding and bodyfiller

EXsoccer1921

iTrader: (14)

i've done a painted finberglass box for a single 10" and i spent so much time sanding and bondo, sanding and bondo, it's rediculous. i'll get some pictures up of it

https://www.cobaltss.net/forums/show...48#post2431448

theres the box that i did. all sides painted

blackbalt sport

Thanks to all for your help! Its greatly appreciated. And for all you other losers ya its my first time and I don't care. I wanted to try something new and I'll just work on it till its done. No, the design isn't the greatest but I wanted to start with a more basic design and didn't want it to take up my whole trunk. I think you all will be surprised by the end product and if it don't turn out big deal, it was worth it learning how to do this stuff.

Turbo06Sedan

My first time glassing, i had semi similar results. However, I loaded on the filler/glassed the **** out of it, then sanded ALOT.

impulseballer

all i gotta say is you need to invest in a good random orbital sander and sand paper bc you have a **** load of sanding to do. keep it up tho man. if you can if u didn't already you want to sand out those air bubbles. they will weaken your box.

Switt23

iTrader: (7)

That is why with the box I did (after seeing others do it), make the base structue then cut a whole on the bottom of the box big enough to get your hands in. Stretch the fabric over it all and glass from the inside ...

Then when your done, cut out another base board and attach to the bottom. Saves on a lot, i mean a lot of sanding

blackbalt sport

Ya I got the bubbles out. Everything's good now but I just can't get it smooth enough for paint. Does that painting thing with filler/resin work if my body filler has the fiber strands in it?

impulseballer

dude after sand most of it down. you want to add a light weight body filler to fill the low spots. bondo sucks ***** but if its the only thing you got then wutev. try and buy some rage gold its the best out there and sands real easy. after you sand everything flat with the filler in you might want to milkshake it to fill in any pinholes etc. milkshake is the same as when you mix up the filler you just add some polyester resin to thin it out. you paint it on with a brush. you just have to do alot of sanding man.

blackbalt sport

Ok ok so here's another question. How would it look if I carpeted the whole box lol... But seriously?

impulseballer

don't do it bro. if anything use pleather or something. it looks so ghetto if you carpet the whole thing.

blackbalt sport

Alright I'm stickin to paint... The box is startin to look a bit better now after a round of spot putty to fill in the holes left from that bondo fiberglass strand garbage. Here it is and even though it looks really patchy its actually gettin smooth. Just looks like that from how much crap i've had to fill in. But its gettin there. I'm still thinking of carpeting the back and bottom. What is the best way to do this so that I have nice edges where carpet meets fiberglass. Does it work to wrap the carpet underneath itself a few inches to give it a smoother finish?

https://www.cobaltss.net/gallery/sho...hp?i=37925&c=3

-the.k.w.c-

dont stick with paint dude really that boxs will still need a ton of bondo and sanding befor paint i can tell by looking at it that there are a ton of high and low spots and u will see every one of them with paint ...carpet will hide everything that bo is showing

impulseballer

is this ur first fiberglass piece? if so i highly recommend carpeting it. or if you get the sanding done decently to where there's no low and high spots use a truck liner type of spray. it's a textured look that will hide some imperfections also.

JRANGER

you just need to be patient man...It takes alot of time and Impulse helped me out with my build. After I sell mine I will be back at it again starting a smaller system build

blackbalt sport

No it ain't gonna be anything close to perfect and ya obviously its my first box. I'll post another pic once its done. What kind of spray are you talkin about? Like line x or something? Whats the cost of that stuff?

JRANGER

Its textured bed liner spray...You can get it at autozone and what not.

blackbalt sport

I'll think about it... probably stick to paint tho lol.