I cut a hole in my MK4 hood last night....

[NAVYDUDE]

Gentlemen,

Well i measured about 629 times and just had a wierd feeling about what i was coming up with and decided to add an inch on all sides to the FFR recommended hood cut out (so the hole be smaller and I could trim out)

It seems the outer and inner hood AREN'T bonded at all..., there is about a 1/8 gap all the way around the cutout.

What am I supposed to 'bond' the two pieces with? rage gold, build it up w fiberglass/,... something else??


My daughter actually walked into the garage and said "awesome!! the hood is on...why did you cut a hole there..."

Thanks very much guys.
Jeff

[Bob Taylor]

cool you aint scared ! boats are fibergass and I hear the product of choice is 5200 . I believe it's Dupont. Unsure if it's paintable. Also there are all sorts of super adhesive agents for body shops stop by a local or ask a builder here on the forum . Hope this helps a little Bob

[Cone Basher]

I have done a fair amount of fiberglass work on Corvettes over the years and I used a product called Duraglass (NAPA has it), I also used it during my Coupe build. This product has glass fibers mixed with it and once mixed with the hardner it is fairly easy to apply. It hardens fairly fast so mix it in small batches. Rough up both surfaces and blow glean, apply the dura glass with a plastic spreading tool (NAPA also) forcing it between the panels you wish to bond. The dura glass after it hardens can be worked smooth with sander 80 grit works for me, then go finer if you wish to paint.
This is what I've used and it works for me.
HTH
CB

[Laser Stan]

What you found is not unusual for the Mk4 hood. I've had two of them, and both have had missing adhesive where the scoop cut-out goes.

What you do with it will depend on how you want to attach the scoop. If you're planning to bolt it on, then the gap would be squeezed shut by the bolts, resulting in sloped margins around the top and bottom perimeter of the hood cut out. This would mean more bondo, just to get the proper hood shape back again. If you want to avoid this, you can cut some strips from the hood cut-out and bond them into the gap. Fiberglass resin seemed to work well for this. At least it did for me.

If you're going for the flush look with the scoop, you can remove a border from the upper perimeter of the cut-out and bond the scoop onto the lower layer. I used an epoxy from Lord (via McMaster) for this. It all seemed to work quite well.

[JKleiner]

Yep, only bonded at the perimeter.





I mixed up some 3M HSRF and packed it in between the two at the opening:



After it cured I cleaned it up with the DA then used Rage to smooth and round it over.

Cheers,
Jeff

[Fastcars]

Bonding inner panels at the perimeter only is normal fiberglass practice even for older Corvettes. Bonding inner panels to an outer panel will print through eventually at the point of bond and show up in the paint finish reflection. Bonding the immediate area of the hood cutout won't cause a problem however because now the hole is just another perimeter area.

[SeanHM]

Originally Posted by Cone Basher

I have done a fair amount of fiberglass work on Corvettes over the years and I used a product called Duraglass (NAPA has it), I also used it during my Coupe build. This product has glass fibers mixed with it and once mixed with the hardner it is fairly easy to apply. It hardens fairly fast so mix it in small batches. Rough up both surfaces and blow glean, apply the dura glass with a plastic spreading tool (NAPA also) forcing it between the panels you wish to bond. The dura glass after it hardens can be worked smooth with sander 80 grit works for me, then go finer if you wish to paint.
This is what I've used and it works for me.
HTH
CB

Would the Duraglass be good for bonding my scoop on as well?
Hoodscoop.jpg picture by Front58 - Photobucket
I was probably going to use Duramix, but I've honestly never used it on anything that needed to last more than a few races and wasn't concerned about painting over the union. The Duraglass sounds like a better alternative for 'glass work and for prepping for paint. I've also got to add some cloth the backside of the V and fill in that gap. What's the cost like?

[j.miller]

Backfill with Rage Gold, when the #8 button heads are in it holds everything together without distortion. da Bat

[Cone Basher]

SeanM: Yes it will work fine just be sure to rough up both surfaces and clean before you apply it. Not expensive you can check your local NAPA but I think a quart wth the hardned is around $15. I like this because it has the fibers in it. I have also used used it to fill larger openings by taping some hard plastic (antifreeze container) cut to overlap the opening and after grinding the opening to a 45 degree angle and applying it works fine. The Duraglass and oher Fiberglass repair materials do not stick to hard plastic plastic, I built a set of fender flares for my old Corvette using the hard plastic under the wheel well and filling the opening with fiberglass mat and cloth on the bottom side (all NAPA items) and they have been on there for 30 years. This is good stuff if you do not like it just cut or grind it off and start over.
HTH
CB

[bob c]

I envy you guys with the flat hoods. I have a MK2 and would love NOT to have a scoop. Bob

[SeanHM]

Thanks CB! Sounds like a trip to NAPA is in my future.

[NAVYDUDE]

Thank you guys very much- I have a friend who does alot of fiberglass work with surfboards, but I do like the bonding the cut out pieces in place as well. Thanks again fellas- your the goods.