Doing a hood scoop.. need a little advice

[Conner]

I have a red '95 Jeep Grand Cherokee Laredo that I'm putting a Ram Air scoop on. I eventually want to make it functional, but for now, I don't plan on cutting a hole in the hood until I get things situated with the cold air intake. I can post pics if it'll help anyone to know what I'm working with. Anyway, right now I have the scoop centered and marked. Well, nothing is marked now, 'cause I have the holes drilled for rivets and all I have to do is line them up. Took the scoop off, removed all the tape and tried sanding down to the metal. It took forever just to get past the clear coat. The sun is now down and my weekend is over. No time to do anything through the week 'cause of my job, and the fact that my Jeep is my main vehicle. A few questions I have for anyone who knows what they're talking about..

Do I have to sand down to the metal to get a better stick with the fiberglass and body filler, or can I just go down to the primer?

If I accidentally go past the primer to the metal (if I decide to keep the existing primer), do I just spray primer in those spots, or use body filler, sand it and then primer?

Is 3M Bondo Fiberglass Resin any good?

Is it ok to put the scoop on after I primer, or put the scoop on bare metal and then primer? I imagine that's a stupid question, but I'm pretty new at all this and it's my first project.

Is there any easier way to take it down to bare metal without having to sand? And if not, what grit should I use?

I'm sure I'm forgetting something, but I'll ask as I remember.

I'm eventually going to take it to a shop to get painted, but I just want to put the scoop on myself to save on cost. Got some spray on primer to keep the metal from rusting until I can get it to a shop when I have the funds.

Any help would be greatly appreciated.

95jgcscoop.jpg

Update 7/30/12

I just finished putting it on. Still not finished sanding, but had to primer it with a cheap primer until I can find the time to finish it. Maybe next weekend. There are still a lot of high spots that may not be noticeable in the pics, but very noticeable in broad daylight. At least it's on and not budging for a while (or at least I hope).

And an extra thanks to Len for all the help and solving any issues I had. You don't find customer service like that anywhere else. It's unheard of any more. THANK YOU! And sorry it took so long getting the pics up.. here you go.

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[Len]

If you want the seam between the scoop and the hood to last and NOT crack you need to make everything between them flexible including the adhesive, the filler, the primer and the paint.

We do this by using Fusor Cross Bonding Adhesive two part epoxy to bond the scoop to the hood then use flexible filler to finish the leveling process. Once the filler work is finished we prime using urethane primer that has a flex additive then guide coat and block sand the primer. All of the paint products that have a hardener added also need a flex additive. Yes, you need to start with bare metal and bare fiberglass where they are glued together.

Position the scoop and screw it in place then trace outline onto the hood, remove the scoop then grind off the paint. Apply adhesive to the hood and scoop edge by pressing it into the scratches then put the two together and re-insert the screws. Try not to squeeze out all of the adhesive because that is where your bonding strength is located.

Fusor 116b Link



Flexible Filler Link

[Conner]

Thank you very much. Getting ready for work now, but I'll reply with any questions I have when I get off. Seems pretty straight forward and possibly easy enough for me to figure out. Patience seems to be the biggest thing here.

[Conner]

So if I'm going down to bare metal, adding adhesive to the hood and scoop and attaching the two, how do I primer the part of the hood under the scoop? I'm eventually going to cut a diamond shape out of the middle, but what about the rest of the hood that is going to be left under the scoop? I imagine I could just mark where the scoop will meet the hood with painters tape and primer the middle of the hood (what would be under the scoop). Then leave the rest bare for adhesive, filler and fiberglass. Then finish with primer on the rest.

One way I imagine it.. I could sand to bare metal, lay the scoop on and position it with the holes I've already drilled, outline with masking tape, remove the scoop and figure in how many inches of the scoop will meet with the hood, trace inside the masking tape outline with painters tape, spray primer inside of that, let dry, remove tape, glue the scoop, fiberglass, sand, primer. Would that work? I'm just trying to get a better understanding of the whole process. Figured I could leave the rest of the hood bare to leave myself room for fiberglass.

Sorry for any confusion. Long night at work.

Also, if you sell everything I need, such as the adhesive and filler, what about the primer you were talking about? Does that come in a spray can. I don't have any guns, so I'm limited to using cans. Which is why I bought some enamel primer in a can.

[Len]

So if I'm going down to bare metal, adding adhesive to the hood and scoop and attaching the two, how do I primer the part of the hood under the scoop? I'm eventually going to cut a diamond shape out of the middle, but what about the rest of the hood that is going to be left under the scoop? I imagine I could just mark where the scoop will meet the hood with painters tape and primer the middle of the hood (what would be under the scoop). Then leave the rest bare for adhesive, filler and fiberglass. Then finish with primer on the rest.

One way I imagine it.. I could sand to bare metal, lay the scoop on and position it with the holes I've already drilled, outline with masking tape, remove the scoop and figure in how many inches of the scoop will meet with the hood, trace inside the masking tape outline with painters tape, spray primer inside of that, let dry, remove tape, glue the scoop, fiberglass, sand, primer. Would that work? I'm just trying to get a better understanding of the whole process. Figured I could leave the rest of the hood bare to leave myself room for fiberglass.

Sorry for any confusion. Long night at work.

Also, if you sell everything I need, such as the adhesive and filler, what about the primer you were talking about? Does that come in a spray can. I don't have any guns, so I'm limited to using cans. Which is why I bought some enamel primer in a can.

Position and screw down the scoop and draw a line all the way around and remove the scoop. Use a grinder to remove the paint only where the scoop makes contact with the hood and leave the paint elsewhere if you can't prime it. If you don't have the right tools it's difficult (if not impossible) to do the job properly. If you have a compressor you can use a grinder like the one below or (without a grinder) you can use a drill with sandpaper with the pad below.

Primer Link


Grinder Link


Use this with a drill and sandpaper if you don't have a compressor.
LINK

[Conner]

I think I get what you're saying. Position scoop, mark around it, remove scoop, grind down to bare metal where contact will be made, keep existing paint in the middle of hood, apply adhesive to hood and scoop, rivet into place, use filler and then fiberglass, or the other way around, and then primer? If that's correct, then I only have 2 more questions. Do I use filler and then fiberglass or fiberglass and then filler to make it seamless? And can I primer over existing paint if all is smooth and level?

[Len]

I think I get what you're saying. Position scoop, mark around it, remove scoop, grind down to bare metal where contact will be made, keep existing paint in the middle of hood, apply adhesive to hood and scoop, rivet into place, use filler and then fiberglass, or the other way around, and then primer? If that's correct, then I only have 2 more questions. Do I use filler and then fiberglass or fiberglass and then filler to make it seamless? And can I primer over existing paint if all is smooth and level?

Wouldn't use fiberglass because it will crack. The metal hood and the scoop will tend to expand and contract at different rates as the temperature changes and the joint between the two needs to remain flexible to absorb this difference. Flexible adhesive, flexible fillers, flexible primers and flexible paint will help insure a long lasting repair. I think the only place I may use fiberglass filler is to cover the screw holes after the scoop is glued in place.

[Conner]

Sounds good. I've never messed with the stuff anyway, and I'm not sure if I want to get into it yet until I start making my custom bumpers. Can I primer over existing paint for the rest of the hood after the scoop is finished?

[Len]

Sounds good. I've never messed with the stuff anyway, and I'm not sure if I want to get into it yet until I start making my custom bumpers. Can I primer over existing paint for the rest of the hood after the scoop is finished?

As long as the existing paint isn't cracked or peeling you can prime or paint over it but remember that the thicker the primer and paint is the easier the paint will chip and the larger the chips will be.

[Conner]

I ordered the products you listed a little over 24 hours ago and the order history says it's still pending. Have they been shipped yet?

[Len]

I ordered the products you listed a little over 24 hours ago and the order history says it's still pending. Have they been shipped yet?

Yes, they shipped yesterday. The order history doesn't change.

[another2centsworth]

It won't take long Conner. Len is good getting it to the customer...

[Conner]

From the help and advice he's given so far, I don't doubt it. This is the only place I've been able to ask for help and not get ridiculed for what I'm trying to do to it.

[Conner]

Just updated the first post with new pics. Still gotta sand the high spots out and shape the points to be even in the front. And I noticed the passenger side hump all the way in the back by the windshield is more rounded than the driver side. Looks like the one who made the scoop didn't get it quite even.