how to get a flat hood?

roger1

roger1

Master Mechanic
Aug 23, 2010
400
93
San Angelo, TX
Is the sheet metal distorted at all? If it is, get a NEW hood. If not, you could use autootive spray foam. NOT the stuff they sell at Home Depot. Thats what it looks like they’ve been using any more at the factory on attaching large sheet metal to inner structures of all the vans at work. I used it for my station wagon roof.
Agree.
Even for a seasoned metal man, repairing a distorted hood skin is extremely difficult.
If the metal is to be worked, it should be separated from the inner structure first by drilling out all the spot welds at the perimeter.

Btw, this is the proper stuff for what goes in between the inner structure and skin:
https://www.lord.com/products-and-solutions/adhesives/fusor-231234-sound-dampening-material
 
  • Like
Reactions: You Know!
84 El Camino 231

84 El Camino 231

Apprentice
Nov 16, 2018
69
8
I noticed a ripple in my hood one day and decided the cause was the ribbed reinforcement beneath had caused it. Long story short, I made the ripple worse while attempting to correct the issue but me and sheet metal never got along well.
 
  • Like
Reactions: You Know!
5

57 Handyman

Not-quite-so-new-guy
Feb 6, 2017
33
8
It is hard to diagnose anything without being able to examine and see what is going on and where. What is the history of the vehicle? How many times has it been painted? Unfortunately, the hood is what we as a driver see the most and because of the large surface in front of us, we tend to focus of it.

Before cutting loose the surface metal front the support structure, I would take/strip off most, if not all the paint, and find the root cause(s) of your distortion. Also, do not use a die grinder or a heavy type of grinder with aggressive grit sandpaper, such as 36 grit. It is too easy to cut into the metal...before you know it you will be thinning the metal. Be very patient, go slow and keep moving your dual action sander across the surface. If your car has been painted several times, I would start with 180 or 220grit until you begin to see a different layer of paint across the hood...definitely stop before you hit the primer. Be mindful of how much your sandpaper is cutting and replace the disc when you notice it isn't cutting easily. Biggest mistake is to apply more pressure; also, you do NOT want to create any heat! As for sanding your hood, or any large flat sheet metal, just guide the sander...place your fingers around the base and not on top. At some point in your sanding, you will begin to see evidence/patterns of the high and low spots. When this happens, you will have to decide whether to continue removing more paint/layers.

The next step is to address and resolve the wavy surface with high build primer and proper sanding. Application of two layers of high build primer is what I would recommend...let dry thoroughly. Then, apply some guide coat and begin sanding with 320grit and progressively switch to 400 then 600 grit. Again, as you sand, just guide the sander and use cross hatching patterns. Once the guide coat is gone, move to the next area. I like to work in 3x3 foot sections.

Hopefully, you will not need to mess with disconnecting the hood from the support structure. The engineers designed this feature to provide a sound foundation for the large sheet metal.

As one last bit of encouragement...be patient and once you finish, you will be very proud of the work you performed to get your ride to this beautiful condition!
 
  • Like
Reactions: You Know!
You Know!

You Know!

Not-quite-so-new-guy
Apr 3, 2019
12
3
Thank you so much for the info, I am taking a break from the hood rite now because it is not going well, focusing on some easier things for now. I will update when I get back to it, thanks again this forum has helped me so much I really appreciate it!
 
D

DocG

Not-quite-so-new-guy
Aug 29, 2017
39
18
so doing body work and repaint on a 1979 monte carlo but I can not get the hood flat because of the glue they used to join the hood at the factory, has anyone else had this problem.
So I just finished the hood on my 84 Calais. The problem as others have commented is the bonding adhesive that dries out and either separates from the hood outer skin and allows the outer skin to "OilCan " or, shrinks up and creates a low spot in it. I have separated these problem adhesive spots with a hacksaw blade and reglued the panels together with 3m bonding adhesive. When the hood outer panel is loose and moves up and down when pressure is applied such as block sanding, I bonded paint sticks between the reinforcement and hood panel . I will then spray urethane coating over the area to hide and sound deadin it. When repairing any large flat panel I recommend doing so in areas that are defined by factory style lines one at a time. I also suggest that you invest in a good Long Flat sanding board and I like to use 100- 120 grit paper as they cut well yet are fine enough to prime over. Lastly I always use spray Guide Coat to check the straightness of my work as I go. I have attached a few pics of my hood and wish you Good Luck !
 

Attachments

  • Like
Reactions: You Know!

Please support GBodyForum Sponsors

Classic Truck ConsolesDixie Restoration DepotMike's MontesP-S-TSouthside Machine PerformanceUMI Performance

contact[email protected]for info on becoming a sponsor