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  • Mistakes with fibreglass

    Ok so here goes. I'm trying to make twin FG sub enclosures in the back of my 2001 daewoo lanos (don't laugh!) to house a pair of reverse mounted Audiobahn 12" subs. its my 1st attempt at fibreglassing the problem that i have at the moment is as follows:

    I put the 1st layer of fibreglass matting in with no problems at all, as in all smooth with no bubbles etc, however when i added the second layer in (still working in the boot as the glass would not be anywhere near strong enough not to warp if i removed it) i ended up with a shed-load of bubbles in it, that i only noticed once it had dried. I want to know if there is a way i can fix this, with out pulling the whole lot out and starting again? any advice on this would be greatly appreciated!

    also are there any pitfalls i sould look out for when mounting the speakers the way i want to? man i should research a lot more before i do all this!!!

    cheers, AJ<br /><br />
    East Coast Audio UK

    Daewoo Lanos "Woo of Doom" Show Car

    Fabrication 4%
    Bodywork 0%
    carputer 1%
    Finish Line - not even in sight!
    TOTAL SPENT SO FAR 250

  • #2
    Granted, I'm no expert, but I would say: Get to sanding!

    Good luck!

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    • #3
      hi guys

      figured the best thing to do would be to rip the lot out and start again - could not be bothered to do all of that sanding!!! - came across a wicked little tool to guard against all of the bubbling problems that i had before - a paddle roller - haven't seen a lot mentioned on the site, but its taken all of the hassle out of the removing of bubbles stage.

      my next question is i am failing to see how to do the volume measurements on the install, as the negative i have is only 3 sided..... woes of biulding one in such a pitifully small boot (or trunk). if anyone has some ideas on how to do this that would be very appreciated - i'll whack some pics up of my work in progress soon so you can all critique away!

      nice 1

      AJ
      East Coast Audio UK

      Daewoo Lanos "Woo of Doom" Show Car

      Fabrication 4%
      Bodywork 0%
      carputer 1%
      Finish Line - not even in sight!
      TOTAL SPENT SO FAR 250

      Comment


      • #4
        You're going to have to build up braces with speaker rings to hold the speakers. Once you have the base of your mold in the trunk, you can attach this brace/speaker ring system, and then you can wrap fleece around this to give the curvature you want. Cut out the holes where the rings are, and then sand like crazy and paint

        Another trick to get bubbles out is to really keep an eye on it, if you see bubbles forming, take a paintbrush (I'm assuming you're applying with a brush) and just dab the bubbles, they will come out.
        - Chris Williamson
        Interior Technology
        '02 Ford Ranger
        '68 InvaderGT - Custom Kit Car

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        • #5
          a fiberglass roller will work really well, but on a curved surface they may not work 100%, you can get different shaped ones but sometimes it can be difficult.

          something else you can try that may help is coating the surface u are applying the glass to with a coat of resin then apply the glass, then work more resin thru from the top. this will ensure that there is resin on the back side, as that what causes alot of the bubbles.

          also try chopping ur paint brush down to about 1" long so its alot more stiff and not so much like a paint brush as u want to dab the resin with a stipling motion (?make sense) and try not to paint it on as this wont work it thru the weave,

          Are you going to cover the box with anything when you done??
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          • #6
            usually people use fiberglass rollers. Also, if you're letting it completely kick before the next layer you're going to end up with bubbles no matter what. This is because the fiber drys in irregular shapes. You cannot lay the fiber back down flat because of this. This is one reason to lay it a few layers at a time and to use a roller where possible. Else, you will always have bubbles to some extent unless you use a rather expensive vacuum tool. This is part of learning to work with glass, learning how to deal with these issues.

            btw - thread moved to the fabrication forum.
            Jan Bennett
            FS: VW MKIV Bezel for 8" Lilliput - 95% Finished

            Please post on the forums! Chances are, someone else has or will have the same questions as you!

            Comment


            • #7
              thanks guys, a lot of useful tips there, it's actually about 99% bubble free, maybe due to the fact i'm using some really heavy matting and working with a small area.

              anyway i'll get the pics up and you guys can judge for yourself.

              peace out

              AJ

              East Coast Audio UK

              Daewoo Lanos "Woo of Doom" Show Car

              Fabrication 4%
              Bodywork 0%
              carputer 1%
              Finish Line - not even in sight!
              TOTAL SPENT SO FAR 250

              Comment


              • #8
                oh btw am going for the OEM look and covering boxes in the stock boot carpet that i'm getting from a junk yard. also matching the false floor and flushed amps. sound fun so far? lol

                AJ
                East Coast Audio UK

                Daewoo Lanos "Woo of Doom" Show Car

                Fabrication 4%
                Bodywork 0%
                carputer 1%
                Finish Line - not even in sight!
                TOTAL SPENT SO FAR 250

                Comment


                • #9
                  ARGH! new question now! - i really need to know how many layers of 650 mat i need to put in for my negative before i can pop it out of the trunk of my car without warping, and how many it is gonna need to be strong enough to support the vibes from my 500w sub. also any advice on powercaps would be majorly appreciated, as i kinda know i need one, but don't really understand why.

                  the greatest irony is that the fabrication is the easiest bit! its just making sure i dont mess it up aloong the way! great forum by the way people - more info that the rainman with an encyclopedia...

                  until the next time

                  AJ
                  East Coast Audio UK

                  Daewoo Lanos "Woo of Doom" Show Car

                  Fabrication 4%
                  Bodywork 0%
                  carputer 1%
                  Finish Line - not even in sight!
                  TOTAL SPENT SO FAR 250

                  Comment


                  • #10
                    regarding caps - I'd suggest you do a quick search in car audio for 'capacitors' as this subject has been beat into pulp.

                    As to how thick you need it for a 500watt sub...not that thick for only a 500watt peak power sub. Also, your sub is not a 500watt sub. It's peak power handling might be 500 watts, but you're referring to it in an incorrect manner. When referrign to how much power you have you might want to refer to the amplifier and how much RMS (NOT peak) power it's capable of producing.
                    Jan Bennett
                    FS: VW MKIV Bezel for 8" Lilliput - 95% Finished

                    Please post on the forums! Chances are, someone else has or will have the same questions as you!

                    Comment


                    • #11
                      sorry should have been more clear - its a 1000w peak, 500w RMS as far as i am aware - its an Audiobahn AWC12T running through a stealth 500w amp. bought them as a package so i think its all good! the 1st shot i had at this i put in 2 layers, and could jump on it without it breaking, and that had heaps of air bubbles in it! as i said before, the actual making of it seems easy enough, its just making sure its gonna last more than 30 seconds when its done!

                      thanks man

                      AJ
                      East Coast Audio UK

                      Daewoo Lanos "Woo of Doom" Show Car

                      Fabrication 4%
                      Bodywork 0%
                      carputer 1%
                      Finish Line - not even in sight!
                      TOTAL SPENT SO FAR 250

                      Comment


                      • #12
                        Originally posted by AJ3000 View Post
                        ARGH! new question now! - i really need to know how many layers of 650 mat i need to put in for my negative before i can pop it out of the trunk of my car without warping, and how many it is gonna need to be strong enough to support the vibes from my 500w sub. also any advice on powercaps would be majorly appreciated, as i kinda know i need one, but don't really understand why.

                        the greatest irony is that the fabrication is the easiest bit! its just making sure i dont mess it up aloong the way! great forum by the way people - more info that the rainman with an encyclopedia...

                        until the next time

                        AJ
                        650g mating is a very heavy grade, this would be the reason for the bubbles. 650 is for boat hulls not wooferboxes, its harder to wet out smooth. Get yourself a metallic roller, they are a godsend. I would recommend a much lighter matting on your next purchase, 100-300g is plenty for automotive. You will only need 2-3 layers of 650 to keep its shape.

                        For further layers of the 650 try splitting it up. 650 will be made up of many smaller grades, you can peel it back to form two 325 sheets, you will find it easier to apply it.
                        Continued Worklog... Upgrades in progress:
                        *15.4" WXGA LED backlight touchscreen upgrade
                        *Custom fiberglass dash bezel

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                        • #13
                          BiGGy you are a genius! i noticed the layering when i was layering it out. i got me a paddle roller, and you're right they do rock something chronic. i got 650 matting as i live by the sea, and we have a lot of boat shops but not much else! if 2 layes is enough to keep shape, will it be enough to not blow up when i put the sub in? or should i whack another on or 2 on just to be sure?

                          nice one

                          AJ
                          East Coast Audio UK

                          Daewoo Lanos "Woo of Doom" Show Car

                          Fabrication 4%
                          Bodywork 0%
                          carputer 1%
                          Finish Line - not even in sight!
                          TOTAL SPENT SO FAR 250

                          Comment


                          • #14
                            Yeah I would thicken it up allot after you get the whole enclosure together. I would put 6 or more 650 layers total to finish it. When using heavy matting on curves scrunch it up like a newspaper and rough it up a bit, it loosens up the strands and makes it even easier to apply. If you have any other fb questions you can pm me.
                            Continued Worklog... Upgrades in progress:
                            *15.4" WXGA LED backlight touchscreen upgrade
                            *Custom fiberglass dash bezel

                            Comment


                            • #15
                              ok so i'll slam some pics and some descriptions if need be. i have also put in pics of my false floor amp install to see what you all think of that. its the original boot carpet used, which will be the same as what i cover the sub boxes in.

                              ok so in order - 2 pics of one of my 2 stealth amps flushed into the false floor

                              next pic is my masking ready to glass - there is 2 layers of tape criss crossed, (1st top to bottom, second side to side) and there uis a layer of tin foil below just in case.

                              ok now the glassing. we come in here at the 3rd layer of 650 grade matting. pics below are some close ups of some of the bubbles that i have. they are in the tightest crevice in the corner of the car, and acually are about 85% glass, with only a bit of bubble in it. i guess i'll sand it out and kitty-hair it to make it strong though?

                              I think it is going ok so far. more pics to follow.

                              cheers dudes and dudettes

                              AJ
                              Attached Files
                              East Coast Audio UK

                              Daewoo Lanos "Woo of Doom" Show Car

                              Fabrication 4%
                              Bodywork 0%
                              carputer 1%
                              Finish Line - not even in sight!
                              TOTAL SPENT SO FAR 250

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