smoothing the hood

[55chevylover]

When leaving off the hood bird what is the best way to finish the flat spot?

[567chevys]

Hi 55chevylover


Cold shrink the emboss down with a hammer and dolly carefully and then stretch the center out to extend the peak. It really goes well if you are careful.


Sid

[markm]

I molded the bird mount on my 55 into the tip of a teardrop scoop.

[Rick_L]

A 55 has no raised embossing under the bird, but a 56 does. So no shrinking is required on a 55.

There are two ways to do it.

#1 - stretch the flat area and raise it up into a peak that matches the peak that runs the length of the hood. There is a fellow that goes by "MP&C" that has detailed that on several forums - a google search may find it.

#2 - form a cap piece from sheet metal to extend the ridge shape forward. Then tig weld it to the hood.

Either way is about the same amount of work, and #1 is a bit "cleaner".

You'll also need to weld all the holes up.

Doing a 56 would be similar after you shrink the embossed area.

[MP&C]

Here's the method Rick mentioned above... Having done it this way, and as prone as these hoods are to oil canning, I would recommend this over any welding. Video at the end shows the lack of oil canning..


One of the tasks on the 55 in the shop is to de-bird the hood and bring the peak forward.







I know I can cut a strip out of the middle and duplicate a replacement with this little jewel...



.....but this hood is relatively straight and rust free, so I'd like to keep it intact (without all that welding) if at all possible. I tried my hand at some manual "punch and die" tooling to see how well it might work, and all in all, it wasn't too bad although it will take some clean up afterwards:









Results from the "start line"




The pad, or "plateau" where the bird rested seems to have a nice crease around the perimeter.



We started with using the crowned body hammer off dolly to knock the sharpness down a bit.



After that we needed something that more closely matched the inside radius. This would work if it weren't for that flat spot on the bottom of the hammer....



...but after about 5 minutes with the grinder it had a more conforming radius..



Kept working and working (and more use of the "Punch and Die" as well).....





and this is what we ended up with....









It still has some fine tuning to go, holes to fill, some shrinking in the "valley" down both sides towards the front and some tweaking here and there to make the peak more uniform front to back. But overall I'm real pleased with how it turned out.


Backing up a second, a few more details.....


The plastic is a black delrin, it is some pricey stuff so if you know anyone who uses it try to latch on to any scraps for just such an occasion, but this stuff came from McMaster Carr. I have also used it for making a non-marring "punch" for persuading some stainless moulding into moving where I wanted it to. It was made using the Dewalt, two passes at about 1/4" deep. The rest of the shape was using an 80grit 3" roloc. Shape, test fit, repeat. (Until it matched the peak on the rear part of the hood)





An alignment mark was located on the delrin "die" and also down the center of the hood, including the underside for keeping the punch in line. Very much a two person operation, good thing my nephew Chris needed some money for a transmission (dang Honda's) or this might have been a weld caper.


The Delrin, although a hard plastic, tends to absorb the "blow" much more than if made of metal, so it will tend to do more shaping rather than stretching had it been a metal dolly. The 2" round stock in the photos (above post) was merely to keep the delrin from bouncing around. Also working in your favor using the punch and die arrangement, after having knocked down the sharp edge of the plateau, as seen in the next picture, operation of the punch (red arrow) will tend to draw the hood in from the sides (green arrows), which should re-form some of the excess metal from the plateau. All in all there should be minimal if any stretching of the panel.



Here are comparisons of the delrin at the rear (factory peak), middle and front of the hood.













You can see the hood gains more crown toward the front, but the peak also seems to still have more altitude there. It's here where I'll use the shrinking tip on the dent puller to shrink the "valley" a bit more to try for better consistency out to the front.


Now to fill in some bird mounting holes... Using my Roper Whitney hand punch to make some plugs for the holes, but the punch part has the locating center point, which will tend to distort the plugs. I found the correct size and ground off the point.





Plug held in place with a couple strips of tape on the bottom, long enough to tack in place....








Welded in place and welds dressed....








And here is the video that shows a bit more detail, and the lack of oil canning....


http://s5.photobucket.com/user/rmcca...5Hood.mp4.html

[smooth 56]

MP&C good to see you here. That is awesome work you are the man.

[chevynut]

Awesome work and documentation Robert! Glad to see you posting here.

[Rick_L]

Robert's work is amazing, and even more amazing are his posts on how to do it.

[DoubleNickle]

Very nice work. I just can't understand why anybody would remove the best looking part of a 55. To each his own I guess.