How do you attach a fiberglass hood scoop?

DissFigured

New Member

Apr 26, 2005

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Dallas, TX

Nov 2, 2007

#1

• Nov 2, 2007

• #1

I got my hood scoop today, and I am going to paint it but I am not sure how to attach it.

Is it totally Ghetto to epoxy it to the hood?

 

CraigMBA

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Mar 24, 2007

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Orange, CA

Nov 2, 2007

#2

• Nov 2, 2007

• #2

3" drywall screws?

 

valley82

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May 16, 2005

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San Diega, Ca.

Nov 2, 2007

#3

• Nov 2, 2007

• #3

In the eighties the product I used to attach fiberglass to bare metal was called "cathair" it was a body filler with fine strands of fiberglass mixed into it, you mixed it like bodyfiller with a tube of hardener. It worked well and bonded the two very well.
There maybe better products around nowadays, checkout eastwood.com I'm sure others will chime in as well.

 

C

chromedog

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Jan 13, 2006

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worlds center for speed

Nov 3, 2007

#4

• Nov 3, 2007

• #4

epoxy will hold just fine, just roughen up both surfaces before you glue it down, and give it PLENTY of time to cure... if the glue says 12 hours at 70 degrees, give it 16 hours or so to be sure it is stuck...

 

rbohm

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Apr 12, 2002

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tucson,az

Nov 3, 2007

#5

• Nov 3, 2007

• #5

since you have the bond on type of scoop, there are two good ways to bond it to the hood. first prep the surfaces properly. the first way you use epoxy to bond the scoop to the hood, then when the epoxy has set up, you smooth the excess epoxy off, then go over the seam with body filler, the cat hair stuff works great. smooth that down until you are satisfied with the effect.

the second way you set the scoop in place, and drill several small holes for pop rivits, then after the rivits are installed, you go over the seam with body filler again to smooth everything out.

you can also use rivits with epoxy and body filler if you like. remember you dont want the hood scoop coming off while diving down the road.

 

ratio411

Founding Member

Apr 21, 2002

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Pensacola FL

Nov 3, 2007

#6

• Nov 3, 2007

• #6

Best way is to get a scoop that is made to bolt on.

Though you can bond fiber to a steel hood, most professional custom body guys won't do it.
I know a man that builds 6 figure rods and he refuses to mate fiber and steel by bonding them. He says it WILL crack and warp. His reputation is worth far more than anyone can pay him to do this. Vibration and weather react differently with fiber and steel, so to put the two together will crack/break the bonding medium... no matter if this is epoxy or tigerhair or whatever.

So, bolt it on, or don't do it is what the pros say.

Edit:
If you have a fiber hood, that is a different story!
Bond on scoops are made specifically for fiber hoods.

 

C

chromedog

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Jan 13, 2006

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worlds center for speed

Nov 3, 2007

#7

• Nov 3, 2007

• #7

there are automotive epoxies made that are oem approved for bonding plastics (fiberglass falls into this catagory) to metal. when you come right down to it, using polyester fillers on metal is the same as bonding plastic to metal, they both expand at different rates, right?

 

ratio411

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Apr 21, 2002

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Pensacola FL

Nov 3, 2007

#8

• Nov 3, 2007

• #8

chromedog said:

when you come right down to it, using polyester fillers on metal is the same as bonding plastic to metal, they both expand at different rates, right?

Click to expand...

You mean Bondo...

I see cars all the time with Bondo falling off under the paint.
My son's car has a bondo repair on the rear quarter, just behind the driver's door that is all jacked up under the paint. Looks nasty, just like it does when the bonded on hood scoop cracks up the paint and gets all jacked up the same.

I am sure everyone here has seen Bondo under cracked paint, well every bonded on scoop I have seen is like that too. (unless it was just done, or a garage/trailer queen)


Edit:
I am not going to get into a pissing match with pro-bondo folks.
Just pointing out the obvious, and now I am done.
Do it the way you like.

 

DissFigured

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Apr 26, 2005

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Dallas, TX

Nov 3, 2007

#9

• Nov 3, 2007

• #9

OK,

First, I am totally not above using elmers glue on this If you recall, I am one of the "Paint your car your self w/ rollers for $100" guys. (Worked great by the way)

so I placed the scoop on the hood traced it w/ a marker
took a dremel and all around the inside of my trace line, I cut little 1 cm lines into the paint to the metal so it looked like a dotted line tracing the scoop.

Ran a thick bead of epoxy around the dotted line ensuring that it got in to those dremel crevices real good. Put the scoop down and put weights all over the thing.

I just added some body filler to the seam. I think it is going to look good. Not going for a show car here just a car that sits in my garage and only cruise around the neighborhood a couple times a year.

Now I got to get the rollers and rustoleum back out and re work the hood a bit.

 

ratio411

Founding Member

Apr 21, 2002

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Pensacola FL

Nov 4, 2007

#10

• Nov 4, 2007

• #10

DissFigured said:

I am one of the "Paint your car your self w/ rollers for $100" guys.

Click to expand...

I actually thought that method was a good idea!
Just plenty of elbow grease to save thousands of dollars...

 

S

SCameron

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Jan 28, 2004

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Zanesville, Ohio

Nov 4, 2007

#11

• Nov 4, 2007

• #11

good luck bonding it with durglas, epoxy, bondo, seam sealer, or what ever. i have never seen a scoop applied this way and not crack over time. heat from the motor and opening and shutting the hood will create a crack.

 

dennis112

15 Year Member

May 15, 2005

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Amish Wonderland of Central PA.

Nov 5, 2007

#12

• Nov 5, 2007

• #12

I did kitty hair, rivets, a layer of fiberglass mesh and then a bondo treatment to bond and smooth a Shelby fiberglass scoop to my metal hood in 1978. After thousands of miles (local and cross country) and 80 or so drag runs this year, it still has yet to crack. My engine bay gets quite hot with the 1 3/4" headers on the windsor.

The hood is very, very heavy though. . . . . .

With a roll on paint job, I wouldn't think twice about adding the scoop as touch ups are well within your capability.

 

DissFigured

New Member

Apr 26, 2005

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Dallas, TX

Dec 7, 2007

#13

• Dec 7, 2007

• #13

HA HA HA HA


Guess what....

The damn thing cracked.


I will be removing it and re applying it w/ some sort of fastener this time.

 

M

my68stang

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Dec 3, 2007

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Dec 7, 2007

#14

• Dec 7, 2007

• #14

3m

i just used a product by 3m called duramix $37 for a epoxy it takes a special gun to use it but the gun was free to rent were i got it. worked great sets up really quick. Within a hour i could pic up my hood by grabbing the fiberglass scoop.

check out pics on page3 of my cardomain site


http://members.cardomain.com/my68stang