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General Category => General Discussion => Topic started by: RICH MUISE on 2010-09-29 09:05

Title: moulding in a fiberglass hood scoop
Post by: RICH MUISE on 2010-09-29 09:05
I am puting a wide, low profile cowl induction scoop on my 'custom.I decided against trying to do a steel scoop welded on so I picked up a ford oem fiberglass hood scoop from a '83 mustang GT. I've never used one before, so I need some advise on the right way to mold it in. After removing all the layers of paint I removed the 7 old rusty mounting studs and replaced them with new s.s. ones I epoxied in. I then bolted it to the bare hood using a generous amount of 2 part epoxy around the perimeter of the scoop. I followed with some evercoat kitty hair (similar to body filler but with fiberglass strands) around the perifery to give a solid base to the fiberglass cloth/resin I'll be using next. I rough shaped the kitty hair with some 80 grit paper on a length of 1" plastic pipe to blend it to the hood.
I know I need to start with narrower bands of fiberglass cloth/resin and overlap sucessive layers with wider strips but what I don't know is how many layers I need to do to minimize chances of cracking. Anybody out there done this before? Am I doing this right or do you have any other suggestions thanks Rich
Title: Re: moulding in a fiberglass hood scoop
Post by: Zapato on 2010-09-29 09:39

Think you're on the right track, not sure what kind of epoxy you used I have used "panel adhesive" on a couple of different projects. It appears you have a real crisp line now and probably want to end that way. The more glass you add the harder its going to be to blend it all in and more material to crack. I would talk to guys at your paint supply store and see about a sandable/paintable seam sealer in a tube or some like product that will flex. But also workable so that you don't end up working it all in 2-3 inches out but just a simple smooth bead around your scoop. If they don't have an answer check with the boat repair guys.

Good luck, noticed that you have an attack ready "pug" guarding your perimeter.

Zap-
Title: Re: moulding in a fiberglass hood scoop
Post by: RICH MUISE on 2010-09-29 21:07
since there was no flange area inside the scoop, all I had to epoxy to was the 3/16 or so wall thickness,which is why i went the way I did. The "crisp line" you were mentioning is actually the edge of the 1/2 radius I have all the way around after I blocked the kitty hair with the 80 grit on 1" pvc. It's hard to see in the pic. I did want a soft blend radius around. The epoxy I used is loctite 2 part with a 60 minute set time. I use it when I need additional time to apply the epoxy and set my part in place. It has worked out really well for me so far. In this case I was able to spoon extra epoxy on the inside wall of the scoop knowing that after I set it in place right side up, the extra would have enough time before setting up to run back down to the hood. The attack dog is the chihuawa (sp?) behind the pug. They're my wife's lap dogs, mine outweighs these two by about 50 lbs.(husky husky). I'm thinking of chopping up a cowl vent grille to make a little matching grille for the scoop.
Title: Re: moulding in a fiberglass hood scoop
Post by: Zapato on 2010-09-30 12:38
When I worked for Boeing we had some sealer/bonding epoxies that would be just the thing to use. One could apply them and with brass "spoons" and with a bit of solvent could be shaped to a smooth glass like finish. Unfortunately I've never found anything like it in the aftermarket. It would dry solid but still flex as needed. Several different versions even some used to seal gas tanks. Some versions could be taken apart but others were permanent. All of them accepted primer and paint.Am sure they wouldn't be cheap as nothing used in aircraft ever is.
Title: Re: moulding in a fiberglass hood scoop
Post by: RICH MUISE on 2010-10-12 08:51
got it as close to perfect as I could..hood is all blocked out with high build primer and just waiting for the last coat of high build that will be blocked at paint time. By the way, I ended up with 3 strips of fiberglass cloth over the bead of kitty hair....seemed about right. The first was about 1 1/2", followed by a 2 1/2 and a 4 1/2. A thin coat of evercoat and it blended in to the hood surface really well.   Rich
Title: Re: moulding in a fiberglass hood scoop
Post by: Zapato on 2010-10-12 22:28
Looks great, you going to build some kind of grille for the opening?
Title: Re: moulding in a fiberglass hood scoop
Post by: RICH MUISE on 2010-10-12 23:08
Yeah...just not sure what yet. I haven't been able to get a pic of what the oem came with as a posibility. It's a '83 mustang Gt. the only pics I've found so far are 4...2 of them mounted as ram induction, the other 2 as cowl induction. ...don't know how they came from the factory, and none of the pics showed a grille. I'm thinking also about chopping up a '57 cowl vent grille. The curvature isn't too far off from that of the hood, so I think once I've got the section cut out I may be able to tweek it to the same shape as the hood. The other option is making a s.s. grille from 1/8 x 1/2 bar stock. I did remember to install some clip on nuts( old age again..forget what they're called) before I attached the scoop so I've got attaching points for the grille.
Title: Re: moulding in a fiberglass hood scoop
Post by: JPotter57 on 2010-10-16 20:01
Rich, I dont have a pic of it, but I had an `83 GT ragtop back in the 80s and it is pretty much closed off solid.  It is a little bolt in blockoff plate with 2 or 3 horizontal ribs in it, that run the width of it.  It is finished in matte black like the scoops were.  If you want it functional, best bet is to make it like a billet grille, or something like that, instead of expanded metal or screen, which would look cheezy and cheap.  3 or 4 aluminum bars about 1/8 wide or so would look good, IMO.    :hurricane:
Title: Re: moulding in a fiberglass hood scoop
Post by: RICH MUISE on 2010-10-16 22:50
Thanks for the info. It doesn't sound like the oem was what I was looking for. I'll probably go as you sugested except stainless so I can weld it. It won't be functional - it'll just look that way. Thanks... by the way, was yours ram or cowl induction, as I stated above I've seen them both ways and was curious what oem was.
Title: Re: moulding in a fiberglass hood scoop
Post by: JPotter57 on 2010-10-17 13:49
all 83 GTs had the scoop mounted bacwards, with the opening at rear.  Some owners liked the 82 GT scoop better, which opened at front.  I bought an 84 GT hatchback later that someone had added an 82 scoop to.  To answer your question though, I guess mine was like a cowl scoop, open at back.