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FRP vs Glass/carbon fiber

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  • #76
    The main problem I'd not the latch busting that I've seen, just it coming loose from the hood itself. Just put a few layers of fiberglas around it and it'll be fine.

    Btw, I again STRONGLY recommend a little bit of fiberglass reinforcement on at least the area where your hood pins/latches are going to be. The mat used is really weak, and very suseptible to cracking. 15 mins spent before you mount your pins night just keep the hood from breaking apart in the future.
    '18 Chevrolet Volt - Electric fun hatch for DD duty!


    DefSport Koni Sleeve and Spring Perch Buy!!!
    http://www.nissanroadracing.com/showthread.php?t=5902

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    • #77
      Why not ask them to modify the hoods more to fit our requirements like you did with shreding the weight.
      "hexa-dodecahedron-triple-threaded-super-eleventy-way-adjustment-spec" dampers. -Def

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      • #78
        Originally posted by a_ahmed View Post
        Why not ask them to modify the hoods more to fit our requirements like you did with shreding the weight.
        It took them two tries just to get a lighter hood with no CF layer as it was... I'd hate to see how many tries it would take to meet additional requests, lol. For a $250 hood I'm not complaining a bit.

        Def, guess I'll have to do a little research on laying fiberglass as I've never done it before...
        -Monty

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        • #79
          ya i have no clue or space or tools to do what def described... would love to but im in an appartment... as with wanting to learn welding (if you recall)... the odours/smell whatever probably will be icky to deal with heh... ah well
          "hexa-dodecahedron-triple-threaded-super-eleventy-way-adjustment-spec" dampers. -Def

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          • #80
            Fiberglass is eeaaaaasy if you don't mind making a mess.

            you can buy it by the quart/gallon at Lowes/ HD/ / Wal Mart/ auto parts store.. To reinforce the spots Def's describing, you'll only need a partial 1qt can.

            Get some of the chopped mat, not the woven stuff- chopped is stronger in multiple planes than mat.

            Sand the area you want to apply it to, plus a couple inches for good measure. the rougher the better.

            Then grab a cool whip bowl, some stir sticks, and a paintbrush (wear some thick kitchen type rubber gloves too. regular latex/nitrile gloves will melt through!)

            pour a bit of resin in the bowl and mix w/ hardener per instructions. stir well until you see the color change on the resin. stir a little bit more for grins.

            then what I do is brush/roll some resin onto the area to apply a thin layer of resin to the surface. brushing does well to remove the small bubbles on the surface that really weaken the bond between layers.
            then take small strips/patches of the mat and dunk it into the resin, or place it on a sheet of plastic and pour some resin on to it. using the sticks/brush/whatever, work the resin into the mat until it's saturated. this is visibly obvious when it's done.
            then simply lay the mat out onto the part and work the bubbles out. If you want to do multiple layers, you can add 2-3-4-5 layers at a time and then let it harden as per instructions- some brands you can use a heat lamp to cure faster, some you can't.

            when it's hardened, rough sand and add additional layers, or finish sand and paint...

            If the bottom of the hood isn't painted, I'd recommend shooting it with something to keep oil and grease from impregnating into the glass. it shouldn't have any issues with that, but it never hurts to give it a layer or two of gloss black to make things look nice and protect against oil & grease.
            Originally posted by SoSideways
            I don't care what color they are as long as they are LONG AND HARD.
            '04 G35 Sedan 6MT- The DD
            '96 240SX- The Track Toy

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            • #81
              Great instructions. Glassing is really easy-peazy, I'm sure it's tough to get a nice smooth finish but if you're just reinforcing things structurally or making parts that would be tough to produce otherwise, it's definitely worth the minimal effort, mess, and fumes.

              Ahmed, if you try glassing inside your apt, you're gonna be sleeping in the car for a while.
              ~1992 240SX, SR20/Koni track day car
              ~2016 M3, daily driver

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              • #82
                I would say go with woven glass in the ~6 oz size vs. mat. Mat is good for building up bulk for cheap, but woven will pretty much always beat it out for strength vs. weight.

                You can buy Bondo brand polyester resin and woven fiberglass at Wal-Mart in the auto section if you're just doing a small project like this. High markup, but you're only dealing with a little bit of stuff so it helps to not pay for shipping. Expect about $10-12 for the resin and glass. Get some 60 grit sandpaper while you're there to rough stuff up.

                It's super easy to apply, just follow the directions and mix up a little resin at a time(not more than you can do in about 2 mins), and cut the glass out before you mix the resin.

                Cut the glass at a 90 degree bias to the strands(i.e. perpendicular), and lay them in lines you'd like to reinforce about 4-5" wide.
                '18 Chevrolet Volt - Electric fun hatch for DD duty!


                DefSport Koni Sleeve and Spring Perch Buy!!!
                http://www.nissanroadracing.com/showthread.php?t=5902

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                • #83
                  my bro has made a mould for a CF bonnet that we hope will come out at about 7-8lb, but at the moment getting the resin infusion technique down is proving pretty tricky. We would quite like to try some pre-preg but this mould isn't designed to take the heat required to cure so we'll have to stave off trying that.

                  13lb for a glass bonnet is a good effort, and provided you can get the additional support in the required places to achieve the strength then that is very good value for money.

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                  • #84
                    Took off the wood and it dropped to 12.5#.

                    It fits pretty good. Doesn't look like it will take much to get it all right except for the latch. The latch bar on the hood doesn't go down nearly far enough to latch into the car latch. I ordered hood pins and think I will remove the stock latch completely.

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                    • #85
                      Originally posted by logr View Post
                      Took off the wood and it dropped to 12.5#.

                      It fits pretty good. Doesn't look like it will take much to get it all right except for the latch. The latch bar on the hood doesn't go down nearly far enough to latch into the car latch. I ordered hood pins and think I will remove the stock latch completely.
                      Good to know on the latch bar and I'll probably remove it too.. I wasn't really liking it anyways, looked like it would fail on the first trip down the front straight of SRP!
                      -Monty

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                      • #86
                        Umm yeah. I never rely on latches on anything but OEM hoods- especially if you're doing 100+ in a draft. damn near shook the hood hinges off the car when I was drafting a guy at 115.. I'd hate to see what happens with a cheap hood latch.
                        Originally posted by SoSideways
                        I don't care what color they are as long as they are LONG AND HARD.
                        '04 G35 Sedan 6MT- The DD
                        '96 240SX- The Track Toy

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                        • #87
                          Originally posted by Matt93SE View Post
                          Umm yeah. I never rely on latches on anything but OEM hoods- especially if you're doing 100+ in a draft. damn near shook the hood hinges off the car when I was drafting a guy at 115.. I'd hate to see what happens with a cheap hood latch.
                          I thought about using the latch in combination with the hood pins, but after actually taking a good look at them, I figured it was best to not even consider that. They look like they will pull out with very little force... even if you did use fiberglass to strengthen the area.

                          We have a big bump at the end of the front straight that can put your head into the roof if your going fast enough... I'm sure that would be enough to pop a weak latch, lol.
                          -Monty

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                          • #88
                            Friend of mine hit that bump at around 140 at the last track day in a Porsche. Rear tire blew out about then. He said it was very exciting for a while but the story has a good ending. Nothing and nobody got hurt. Not sure he will be doing many more track days though.

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                            • #89
                              I use the latch + hoodpins. Just adjust the pins so they have a little tension when closed.

                              The latch is enough to keep someone from casually "checking out" your engine. Not that the flimsy hood would stop them if they really wanted to, but I imagine at that point your car is going to get molested anyway.
                              '18 Chevrolet Volt - Electric fun hatch for DD duty!


                              DefSport Koni Sleeve and Spring Perch Buy!!!
                              http://www.nissanroadracing.com/showthread.php?t=5902

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                              • #90
                                That's why mine doens't sleep outside.
                                Originally posted by SoSideways
                                I don't care what color they are as long as they are LONG AND HARD.
                                '04 G35 Sedan 6MT- The DD
                                '96 240SX- The Track Toy

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