Hoods are less structural and way easier than fenders . If you are going to blend it in and paint, Getting some surface area at the bonded joint is a big part of what makes it work. Getting some glass fiber across the joint above and below would be about 10 X stronger. Some folks say epoxy won't work well with fiberglas matt ( as apposed to cloth). West systems says this - http://www.westsystem.com/ss/chopped-strand-mat-epoxy/ Epoxy resin bond strength is way stronger than polyester or even vinyl ester resins, but all rely on excellent surface prep to have any bond strength at all. http://www.devcon.com/UserFiles/File/MetalFilled_User_Guide.pdf FWIW some MIL specs say secondary bonding must have some mechanical fastening too.
I just finished doing a cowl scoop on a 65 chevelle. I used a punch flange tool to step the metal down where the scoop rides, body panel epoxy with self tapping screws to temporarily clamp it down, and a skim coat of filler. Hope it holds.
You're on your way Kustom50, I like the bottom flange, it will make blending to steel simpler - maybe. I used plenty of panel adhesive to add a fillet effect on gaps and f'glas renforced filler for initial coats. Some reveal of work in certain light and worry most about Header heat rise after shutting down and the thermal differences seperating glas from hood but looks fine for my needs. Have Fun
I've installed a few scoops on hoods, etc...I always glassed them in with minimal filler work, usually this will keep the cracking to a minimum....and it lasts... I haven't used panel adhesive, but have a buddy who has built several cars and swears by it, and I trust his opinion....not sure if the stuff that comes with the expensive gun is any better, but you could take it to a body shop and have them glue it i suppose if you don't have the equipment.....I think the applicators are about 300 bucks, burt don't quote me on this. Regarding your scoop choice...I believe you should dare to be different....I have a late '60s blue oval that I have a lift off fiberglass hood that uses a Cowl scoop for the clearance needed.....I get all kinds of comments from the Ford guys (wtf did you do that), and also get comments from the Chev guys (at least you have a Chev hood).....hahaha..... Priceless is the looks on their face when I light the car up.... Tom
Thanks for the information and comments guys. I have the 3M adhesive. A buddy has the gun to use it with. I plan on trimming the lip of the scoop in the front to get it to fit the hood better. I will also drill some extra holes in the flange of the scoop for adhesive to come through, Not sure if it will help but it seems it will in my head. Im also thinking some small sheetmetal screws to pull it tight to the hood until it sets up and either fill in the holes or just trim them off even with the hood. This is my first time doing this and as you can tell I over think everything .
When you order the TD make sure that they dont open the screen holes. thats something you can do or not do.
Heres an update, I trimmed the lip up for a better fit yesterday . I also drilled some extra holes in the lip for the epoxy to seep through. I the cleaned the mating surfaces about 10 times to be sure. I drilled 1/8" holes in 10 places on the scoop and hood for sheet metal screw to hold it in place until it was set up. Today I went out and looked at it and it seems to be good. I decided to leave the screws in and cut them off flush with the hood . I trimmed the support for clearance for the air cleaner and tacked everything back in. and primed the center of the hood for now. As my car sits outside I have to work on it in the evenings and weekends at my work. I think it looks ok and will look alot better soon I still need to finish the welding and do the filling on the hood theres no finish work on the hood or scoop in the pics . I got the fit pretty close as you can see
I hate to say this. I removed all self tapping screws out of fear that what was left of the screw would reflect a small crack the size of the screw in the finish later. The metal of the screw will be pretty close to the surface of the filler. The shape of the scoop does look good on there.
Ok heres what I did this weekend.. Nowhere near the caliber of what most of you guys do but im pretty happy with the results. I strpped it down to bare metal. started with fiberglass reinforced putty, fished with some putty. . Blended the hood line into the scoop pretty nice and gave it a couple of coats of etching primer. Looks decent so far
A T-Bolt scoop will be the best looking component on a Chevy. Back in the day, all the dumb kids always put them on backwards! I think its a great idea, seeing how many folks put those nasty GM cowl scoops on every brand of car. To your question, a very high strength epoxy would be good for the "blending" portion of the operation. Putting the scoop up from the underside is an interesting idea. You may lose more scoop height than you think. If I were doing it, I'd gently countersink some holes on the hood, and after a thorough cleaning and scuffing of both surfaces, use a methacrylate adhesive to actually bond the scoop to the hood. This is the adhesive I've used to bond airpans on Pro Stock NHRA car's hood scoops, bonding together Dodge Viper airboxes, as well as Ferrari hood components, and to bond multi-piece body panels on NHRA Pro Stock Bikes, and ADRL Pro Mod bikes as well. It's stout, and it's also what car mfg's use to bond plastic panels together on cars. Plexus is one manufacturer of the adhesive, but there's others out there as well. It is flexible enough to handle the vibration that your car will give it.
They say if you remember the sixties then you didnt live them .... damn I musta slept through that decade but as I recall the teardrop looked good and was acceptable on prettymuch anything ... although I agree ford had a corner on the market , a tri-five with a tube axle and teardrop could make the limpist appendage move! ... that was in San Diego ... in the backwoods! LOL I say go for it ... but expect cracks (both stress cracks and wise cracks) down the road.
Indeed. I learned awhile back on the HAMB that this teardrop shape isn't really a scoop. Sure it provides clearance, but it's for letting air out of the engine compartment. Now you will have to get some dryer duct hose and feed fresh air from the core support some place. Gary
Hi Guys, I am a new member and really enjoy this forum. I had a similiar project but I am having problems. I used the 3m panel adhesive for fiberglass to metal to attach a scoop to my hood. I used the Gold body filler to blend into the hood. I blocked the surface over and over until it was perfect. The problem is now that it is painted and cleared you can see a faint "shadow" line where the edge of the scoop is all the way around. I blocked (wet) sanded the paint and clear but no matter what the line is still visible. I have been told it is because of the two different materials and the rates of expansion. Is there any way to correct this?
Thank you very much , And thank everyone who has givin advice and personal experiances with these products..
I saw a scoop once (glad not twice) of a metal back off a bucket seat.200 ft mark looked cool,you know the rest............................YG
Don't know what you used for primer and how much. Many of the cheaper primers shrink considerably even after they feel dry to the touch. Where perfection is the goal, I have a ten day rule. I won't final wet sand the last coat of primer for ten days to make sure it has fully cured (no more solvent pop) and has shrunk to equilibrium. Assuming the primer is and the polyester is not the problem, thee different rates of expansion could be it.
This may help......when bonding that scoop on the metal hood-did you leave the fiberglass edge of scoop as molded or did you grind the outer edge down [like to a featheredge?] If you did not grind that sharp sqared edge off it will "imprint" where the filler meets that straight edge abruptly [sorta like trying to paint over stripe tape for example....]
I used PPG K36 primer and I feathered the edges of the scoops down to paper thin. They were bonded to the hood with 3M fiberglass to metal adhesive. Sorry, I don't remember the #. The hood probably set for a week before it was sanded. I had the car at a friend's house and worked on it on Saturdays. Prime one and sand the next. The entire body was primed and long blocked a couple of times at least to make sure she was straight. Any ideas to correct this, otherwise I'm going to go back to the original hood. Thanks.
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