Inside of hood prep.

ffltstn

Promoted Users
I have a fiberglass hood that has a metal frame.
How do I prep the inside of the fiberglass for epoxy and get up under the frame? (red area)
Also the metal frame was epoxied before it was glued together. I see pitting on it.
Is there a best way to smooth it out? Filler? glazing putty?

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I would hand sand all the red areas with 120,sand the metal with 180 take your time to get in all the pits. Then epoxy and 2K primer,maybe even high build if needed. It should fill those pits.
 
I would hand sand all the red areas with 120,sand the metal with 180 take your time to get in all the pits. Then epoxy and 2K primer,maybe even high build if needed. It should fill those pits.

So just sand back up under the frame as best as I can and call it good?
 
Just sand up in those blind spots the best you can. You will probably be able to sand further than you can spray. You could also brush in epoxy in the hard to reach areas.
 
Unless you're needing show quality and long durability, which would require separating the frame from the glass o_O, I would do as nextgen and Ai said. Make it look good. That metal frame prob telegraphs to the surface of the hood too so you'll have some time invested to make it flat. If it's not a super rare expensive hood I would not take it apart.
 
Just curious what sort of hood has a fiberglass skin on metal structure. Kinda sounds like a replacement skin intended to reuse old structure.
At any rate if I was the one doing the initial bond of fiberglass to metal knowing what I now know, I think I would have used a urethane adhesive so it would have a hint of flex. But if it seems still bonded well I wouldn't take it apart either.

As mentioned above, the inner structure will show thorough to the outside at least somewhat. For sanding the top surface I'd probably have a few coats of high build primer or something like g-2. Then initially block sand it with fresh sharp course paper with very light pressure to avoid issues. If you use much pressure at all with thin fiberglass skin over metal, you WILL create low spots in between the structures.
 
Years ago in the early '90's when I was starting out I used to see some of the fiberglass hood skins that you would bond to a metal inner structure. Never liked them for the reasons stated above. There was a company that advertised in Hot Rod and PHR among others that made them. Super thin and flimsy. 60's Mustangs and Camaro's primarily IIRC.

The pitting is from the rust that was there before the frame was epoxied. As for the backside not alot you can do other than hand sand where you can reach and either spray or even brush some epoxy onto the back. As for the pits, after you epoxy, several coats of 2k urethane will fill them fairly easily.
But is it worth the work for what you will have versus another hood? What type of vehicle is it?
 
The hood is from a '73 AMX, A stock working cowl induction hood.
Can't get a replacement that's functional, and the old ones tend to separate.
They previous owner had been restoring it, his father does restorations and bodywork for a living.
They had separated the metal and fiberglass, worked the metal and epoxied it, then glued the skin back on.
It's going to be a driver, maybe not every day but as often I can. It will not be stock.
I just want it to last another 20 or 30 years till I die.
 
The hood is from a '73 AMX, A stock working cowl induction hood.
Can't get a replacement that's functional, and the old ones tend to separate.
They previous owner had been restoring it, his father does restorations and bodywork for a living.
They had separated the metal and fiberglass, worked the metal and epoxied it, then glued the skin back on.
It's going to be a driver, maybe not every day but as often I can. It will not be stock.
I just want it to last another 20 or 30 years till I die.

Well, to me that sounds like the father knew what he was doing and you can probably feel good that the epoxy is well coated on the inside. I think scuffing and filler would be an answer to not disturb the work that was done if you want it any better. It looks like texture left after the sandblasting to me. I thought I would be run out of here suggesting to split it apart, but it seems it was done already so you can probably expect the back is well protected so dont mess with it anymore.
 
SO much depends on what the final vision is for the vehicle. I think if it was mine, I might just sand and red pad the daylights out of it, and put 3 coats of black epoxy on it and call it good. If the pits and 'glass texture need to be be smoothed more from there, just sand the p*ss out of it again and put another 3 coats on. It's really just a matter of "lather, rinse, repeat" until you achieve the desired look.
 
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