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Old 01-21-2019, 01:52 PM   #1
sick472
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In Lieu of the Hood Brace Pads?

I am looking for ideas to add support to the 1/2 acre of sheet metal that we call a hood.

My hood has a tendency to oil can easily (on both sides), but has good shape when in the outward oil can position. The braces are not the same distance from the hood sheet metal from front to back (or sides to side) which means the replacement pads will only help at one end which leaves me worried that the hood will become a noise maker at highway speeds. I am currently preparing to do the skim putty work and would also like the extra support so that I do not exercise the oil can effect while block sanding.

I know I can cut rubber/foam material strips of different thickness and apply them as necessary (step the thickness up as the brace gets further from the sheet metal).

I do not want to try and bend the braces to improve the gap consistance for fear of permantly warping the hood.

I am currently toying with the idea of intalling jackbolts (#10 machine screws or similay) in the braces which would allow me to apply the "proper" pressure along the braces. These jackbolts would be backed by a strip of shetmetal that could be extra wide for extra support and be glued to the underside of the hood as well. This concept may also help adjust out any slight warpage prior to skim putty.

What's everybody doing with regards to hood support?
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Old 01-21-2019, 04:39 PM   #2
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Re: In Lieu of the Hood Brace Pads?

I have seen on this forum where a member put a cross brace between the two that run front to back. Basically making an H pattern and reinforcing the currently unsupported middle. He made it from the original brace material from a donor hood. It looked good
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Old 01-21-2019, 05:23 PM   #3
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Re: In Lieu of the Hood Brace Pads?

spray foam insulation
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Old 01-22-2019, 04:12 AM   #4
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Re: In Lieu of the Hood Brace Pads?

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Originally Posted by tinkerdad View Post
spray foam insulation
Spray foam insulation will hold moisture . Lay a clean bead of windshield urethane between the hood and braces let it set up over night and your done, it will also sound better when you close the hood .
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Old 01-22-2019, 09:20 AM   #5
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Re: In Lieu of the Hood Brace Pads?

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Spray foam insulation will hold moisture . Lay a clean bead of windshield urethane between the hood and braces let it set up over night and your done, it will also sound better when you close the hood .
^^^^^^^^^^^^^^^^This^^^^^^^^^^^^^^^^^^^^^^^^
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Old 01-22-2019, 02:51 PM   #6
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Re: In Lieu of the Hood Brace Pads?

I like the urethane caulk plan and the extra bracing as a back up. I still might tinker with the jack bolt/screws to fine tune the pre-puttied contours, but once the urethane is in place, remove the screws. I assume urethane dries pretty stiff unlike silicone that cures with a fair amount of sponge to it?

I considered the foam approach, but felt like the foaming action could push out on the hood too much as it expanded. I did not think about it holding moisture.

I am still open to any alternate ideas as I will not get to this work until next week, but, at least, I have a comfortable plan.
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Old 01-22-2019, 03:21 PM   #7
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Re: In Lieu of the Hood Brace Pads?

Don't glue the braces to the skin. When the hood skin warms in the sun, it expands. Where it is glued to the braces, it will not, and be low spot, looking like a dent. I use the hood bracing material. And bend the braces as necessary, if the gap is too large.
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Old 01-22-2019, 04:28 PM   #8
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Re: In Lieu of the Hood Brace Pads?

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Originally Posted by turp mcspray View Post
Don't glue the braces to the skin. When the hood skin warms in the sun, it expands. Where it is glued to the braces, it will not, and be low spot, looking like a dent. I use the hood bracing material. And bend the braces as necessary, if the gap is too large.
I would like to hear more about the bending techniques please. I imagine twisting or torqueing the rear brace and/or the rear skin while trying to equalize the brace to hood spacing. I have thought about blocking up the hood at the rear and along the front and pushing down on the braces so that the larger gap at the rear could be reduced, but I think the rear brace would want to twist as well.

My real fear is that, typically, when I put my weight into a body panel to "fix it"...It ends up getting worse rather than better.
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Old 01-23-2019, 09:41 AM   #9
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Re: In Lieu of the Hood Brace Pads?

Quote:
Originally Posted by turp mcspray View Post
Don't glue the braces to the skin. When the hood skin warms in the sun, it expands. Where it is glued to the braces, it will not, and be low spot, looking like a dent. I use the hood bracing material. And bend the braces as necessary, if the gap is too large.
I've used it before and it worked for me , YMMV , So answering the op's question "In Lieu of the Hood Brace Pads? " I suggested urethane , There are products available today just for this purpose but they are 2 part and pricey ( $ 20.00 - $50.00 ) requiring a 200 ml gun ($50.00) and urethane is cheap ($8.00 ) and just about everyone has a caulking gun . Without a picture to see just exactly what's bent anything that's cheap and fast and permanent may be better than time consuming jack bolts or adding extra bracing ? The op said "I do not want to try and bend the braces to improve the gap consistance for fear of permantly warping the hood ".

Reduces Noise, Vibration and Harshness in Vehicles

For collision repair jobs where minimizing NVH (noise, vibration and harshness) is important, the 3M NVH Dampening Material is an excellent complement to flexible or pillar foams and factory dampening materials. This two-component material applies smoothly and easily between roof skins and roof bows, door skins, door intrusion beams or other areas using non-structural type foam materials. Unlike many seam sealers, this material goes in soft yet remains very sturdy, allowing for expansion and contraction of automotive sheet metal. Yet it has no solvents so it won’t shrink and pull the metal in after installation. It minimizes application time and cleanup – it applies right from the cartridge without added mixing time, and provides up to a 1” thick layer of flexible material on vertical and overhead surfaces.


http://www.tcpglobal.com/FUS124.html

https://www.amazon.com/3M-04274-NVH-.../dp/B005IU2IPM
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Old 01-22-2019, 09:31 PM   #10
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Re: In Lieu of the Hood Brace Pads?

On the braces that run front to back, I just set a 2x4 against the brace, and smack with a big hammer. Do as needed, until the bracing pads hold the skin up. The back brace has a much wider gap. Menards has different sizes of weatherstrip. I put it all the way across the back. It really helps stiffen up the skin.
Hope this helps.
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Old 01-23-2019, 12:17 PM   #11
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Re: In Lieu of the Hood Brace Pads?

I am probably overthinking the step of my build, but that's what I do. So, I appreciate everyone's input to no end. Anything that make me think is a bonus.

I have attached a photo from before much of the de-rusting that best shows the gap changes from front to back. It's a bit hard to see, but the gap is much narrower towards the front. I did some pushing around on the braces last night and I think I can improve the gaps with some muscle without jeopardizing the niceness of the outer surface.

Part of me says...get the brace to hood gaps (center and front and back) supported with something like padding, weather-strip, edging or urethane, then do the outer finish work accordingly. There is slight waviness to the outer skin, slight, which would require the usual putty work. Now, part of me wants to add temporary shims to finely wet sand the primer to get a shine going on (it's remarkable how much shine you can get from primer by wet sanding with 600 to 1000 grit which makes body waves stick out like a fat thumb - just dont forget to rough the primer back up, paint does not like to stick to shiny primer - don't ask how I know that), then add the jack-bolts to compensate for some of the wave. Adding urethane at this point holds the finessed shape hence reducing the putty work. I am also thinking that I could wrap the braces with a heavy plastic before the urethane is applied and then trimmed away afterwards leaving the outer skin to be free to move independently.

I will argue that the efforts of all this may be about the same as other more common approaches...maybe I'm in this for the journey more than the results. Anyhow, I appreciate the conversation just the same.
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Old 01-23-2019, 02:10 PM   #12
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Re: In Lieu of the Hood Brace Pads?

I had the same problem when I started to block sand my hood.

I used SEM 39357 flexable urethane foam and bought one of those special caulk guns Grumpy mentioned off of ebay. It worked well.
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Old 01-23-2019, 02:29 PM   #13
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Re: In Lieu of the Hood Brace Pads?

The windshield urethane idea sure sounds like a winner to me.
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Old 01-24-2019, 06:37 PM   #14
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Re: In Lieu of the Hood Brace Pads?

Just ran across this, thought I'd share. Putting a regulator in a 2010 Expedition, I'm guessing these little balls are similar to the anti-flutter foam that Grumpy posted a link to.

http://www.tcpglobal.com/FUS124.html#.XEo8rFVKjIU
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Old 02-11-2019, 10:45 AM   #15
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Re: In Lieu of the Hood Brace Pads?

I have another thread in the Paint and Bodywork section that inquires about filler putty and the hood's low spots where I show my attempts at siffening up the hood, but thought it best to add to this one as well for those interested. The bodywork thread is here if you want to get into the discussions revolving around laqcuer primer and filler options...

http://67-72chevytrucks.com/vboard/s...d.php?t=780912

Anyhoo,

I put 3/16” x ¾” bar stock at the side supports, drilled and tapped for #10-32 screws every 5 inches with matching holes in the support. The bar stock gives the screws something to push on and the aluminum flats (about 0.060" thick by 5 or 6" wide) protect the under side of the hood from the screws and evens out the pressure. The center support was made from ½” x 1” x 1/8” thick channel, drilled and tapped for the same screws.
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Old 02-11-2019, 10:46 AM   #16
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Re: In Lieu of the Hood Brace Pads?

I will be applying widow urethane tube caulk through the holes (Red Arrows) in the braces to create supports about every 5 inches along ALL the supports, front, back, sides and center, and the jack screws will be removed. The urethane will adhere to the aluminum and keep in in place once the machine screws are removed. (you can not see it, but there is a thin strip of aluminum under the center channel brace) The aluminum is not glued to the underside of the hood. This should allow for some shifting between the two if any shrinking and expansion should occur. The long machine screws in the side braces used for "jacking" the hood will be replaced with shorter ones to keep the bar stock in place which will serve as additonal siffeners for those braces. The first and last screws on the center brace will also be relaced with shorter screws to hold the channel in permantly. Then the final sanding and filling will be performed.
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Old 02-11-2019, 10:54 AM   #17
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Re: In Lieu of the Hood Brace Pads?

SIDE NOTE: I measured the widest rear width of the hood to be 71-1/2” before the addition of the supports and jack screws. Once the hood was “jacked” the 71-1/2” dimension remained, meaning the hood kept its form…thank goodness!

The picture below shows the problems I was dealing with before the stiffeners...

I'll explain the situation: The outer-most high parts (OUTER BLUE LINES) of the waves are directly above the two supports that run front to back on either side. As if the hood was once supported well with the foam spacer pads at the metal supports (I removed the foam pads and they were loose as you would expect, but not by much). It appears as if the center section (with the front-to-back ridge) and the outermost sections have "flopped in the wind” long enough to stretch the metal. The ridge is high, like it's supposed to be, then it dips down (RED AREAS), then back up (over the supports), then back down (OUTER RED AREAS) until it evens out and approaches the side of the hood where it bends down to make the sides. Most of the wave is towards the front. Using a straight edge, (and my imagination because its all curved one direction or another) it appears to only need that 1/16” of fill maybe a bit more.
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Old 02-11-2019, 10:56 AM   #18
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Re: In Lieu of the Hood Brace Pads?

The results of adding the stiffeners are show below…the Green Stripes represent what used to be low areas that are now flat. I can see no light between the hood and a straight edge. I still have some low spots (Red Circles) to deal with. These areas are associated with the dings that have been hammered out. These areas will require some filler, but minimal, I hope.
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Old 02-11-2019, 11:11 AM   #19
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Re: In Lieu of the Hood Brace Pads?

I feel like this work has beefed up the hood a great deal. The sides beyond the side supports are still bit unstable, but much improved over stock. I hope that the epansion and contraction of the hood panel from sun heat does not come back and bite me.

I will likely be wet sanding the acylic enamel paint job down to a dull finish when it's all said and done so any slight warping will be masked due to its lack of shine. I am going for a old oxidized look as if the truck has been sitting, unused, since 1972. Kinda like Gringoloco did, but without the sand-through to the prmer (hopefully)...Look at post #363...

http://67-72chevytrucks.com/vboard/s...444746&page=15

Thanks for all the ideas and concerns so far!
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