Topic: Question Regarding Prepping Underside of Metal Framed GT500 Hood for Painting

[kkupec02]

While the hood is off waiting for the rebuild of the brake system components and I replace the steering column wiring harness, I wanted to get the underside of the hood ready for body color and paint it. Right now it has an after market trunk type paint on it. The hood pin plates have been moved a little due to some cracking. I will address that when I get to the topside. My plan is to wire brush/sand the metal frame down to bare metal to remove the light surface rust. The fiberglass area will be lightly plastic brushed to remove loose paint but not enough to wreck the grain. I don't think fiberglass will stand up to any paint remover. I have two questions. First, I would of course primer the metal frame. But I am thinking no primer on the fiberglass to avoid filling in too much of the grain? I was thinking color only on the fiberglass. Second, the fiberglass is separating from the metal frame in a few of the wrap around areas. Should I use paintable body caulk or seam sealer on those joints to avoid debris and moisture from separating it further? Thanks all. 

[Bob Gaines]

While the hood is off waiting for the rebuild of the brake system components and I replace the steering column wiring harness, I wanted to get the underside of the hood ready for body color and paint it. Right now it has an after market trunk type paint on it. The hood pin plates have been moved a little due to some cracking. I will address that when I get to the topside. My plan is to wire brush/sand the metal frame down to bare metal to remove the light surface rust. The fiberglass area will be lightly plastic brushed to remove loose paint but not enough to wreck the grain. I don't think fiberglass will stand up to any paint remover. I have two questions. First, I would of course primer the metal frame. But I am thinking no primer on the fiberglass to avoid filling in too much of the grain? I was thinking color only on the fiberglass. Second, the fiberglass is separating from the metal frame in a few of the wrap around areas. Should I use paintable body caulk or seam sealer on those joints to avoid debris and moisture from separating it further? Thanks all.

I believe the underside had a light primer coat when shipped to SA from the mfg.Assuming you are concerned about a factory look what ever sealer you use try to blend it in given it may not appear factory if you are not careful .

[J_Speegle]

Most concerned along the edge where rust appears to have made it way under the fiberglass transition. Without disturbing that fiberglass you will likely need to address that chemically with a rust neutralizer. At that point and after the rest of the undersides are prep-ed you can choose to lay some fiber glass under that later to seal and support that edge from breaking or cracking since your choosing to do this as a DYI project

Kill and remove the rest of the surface rust. Get all of the Zonatone off the surface. Mask and spray away on a nice day - guessing you don't have a booth.

[kkupec02]

Thanks. I have done body work and painted whole cars before with success albeit it one stage lacquer. I can get rid of the bad rust spot, treat chemically with rust mort and paint with a shell type rust sealer like POR-15 and then body color. I am not familiar with fiberglass not having worked with it before. I guess I can check around to having that done by a pro. I assume you would tuck the fiberglass under the separated edge for support and then feather the fiberglass into the center of the hood?

[Bossbill]

I hate POR-15.

The last time I used that stuff was on the trunk of my 65 street car.
It got between the the inner and outer structure and expanded.
My painter cussed me out for a week trying to straighten out that mess.

[carlite65]

i just used it on the inside of my mailbox. it was rusty.

[J_Speegle]

Thanks. I have done body work and painted whole cars before with success albeit it one stage lacquer. I can get rid of the bad rust spot, treat chemically with rust mort and paint with a shell type rust sealer like POR-15 and then body color.

Like others would not suggest POR, Rust Shield on any similar products. You will likely have issues with over coatings sticking to the products, IMHO kill/convert the rust then treat it like your typically would on the exterior of a car. where you would apply filler. In the repair area especially you need a surface with will allow the fiberglass repair to stick to al the surfaces

I am not familiar with fiberglass not having worked with it before. I guess I can check around to having that done by a pro. I assume you would tuck the fiberglass under the separated edge for support and then feather the fiberglass into the center of the hood?

Your only addressing the small edge of the bonding of the fiberglass top panel to the steel frame. Would not feather the repair the repair any further than need to make it look "natural You can test and see how much effort that raised edge will move back towards the metal frame to help with this and in turn less fill or material between the two. Don't think you want to produce allot of tension as it will only stress the repair and possibly create cracking somewhere else. 

[kkupec02]

Thanks. I won't use POR-15. I'll check with a body shop.