65air_coupe

When I stripped and painted it 30 years ago, I attempted to rejoin the hood to the underside structure with 5 min epoxy. That didn't hold and now that it's apart again, I'm wondering what to use. There are some dynamite adhesives in the marine world that would work, what did GM use in the first place and has anyone had to re-bond theirs?

Kid_Again

dynaglass that you can get from any automotive paint supply jobber

wombvette

It is only bonded around the outside edge. Do not bond it on the interior edges or the cross braces.

quahog

i have a 66 and the hood was unbonded when i bought the car. when that project came up i used 3m 5200 its a marine adheasive that looks like the original bonding agent and holds great its been on the car for @ 2 years now no problem.

65air_coupe

I puzzled, it appears as tho it was originally bonded there and I can't imagine having those surfaces in contact without either bonding or insulating them. Otherwise, there's going to be vibration and wear. The hood obviously flexes in the center with the surface joined as well, wouldn't think that's desireable.

Grizzly

When I asked that question some time ago, I also got differing opinions. What I do know is there already is something there and it is not glue but more of a putty that has hardened.

The one important thing I didn't think about that was brought up is that some epoxies generate a good deal of heat when they cure and that might be bad for the paint.

I'll keep watching for a definitive answer...............

Kid_Again

"I'll keep watching for a definitive answer..............."

you may be watching for a long time...all i can say is that for my cars and the midyears that i've worked on, the big block hoods have no central brace, the small blocks do, the small block braces have molded-in pads and everyone of those pads had dried adhesive between the pad and the hood - i cleaned out all of that crap and used dynaglass with great success

65air_coupe

That's really all the answer I was looking for, thanks kid.

Update: did a little research and found dynaglass, duraglass, tigerhair, are all structural fillers, not really adhesives per se. This is a spot that can't be cleaned spotless so I think I'm going to use a true adhesive like the 3M 5200. I used it alot for maine applications and it's as permanent a bond as you can get in plastics.


[Modified by 65air_coupe, 8:17 PM 7/2/2004]

quahog

on where to bond. i also bonded the center section of my hood as it was originally bonded to the hood skin in the center i cleaned out the old and put 3m 5200 with no problems this is a one part adheasive that comes in a squeeze tube it does not generate heat and becomes hard but not brittle the car had new paint on it when i did this with no oll effects. no mix no fuss hardens like hockey pucks i would pay attention to the curve of the hood when you do this job as how it is clamped when drying can effect the curve i blocked the hood on its sides and put a weight in the center to press the brace and the skin together worked like a charm good luck jeff

JohnZ

The inner panel cross-bracing wasn't "bonded" to the inside of the outer panel; the material you see there is a panel deadener, commonly referred to in body/paint supply shops as "gumdrops". The only actual fiberglass resin bonding material between the inner and outer hood panel is around the outer periphery of the panel.

Using aggressive resin bonding material on the cross-braces can result in "bond burn" distortion on the flat surfaces of the hood outer panel - that's why those areas weren't "bonded" to begin with.


[Modified by JohnZ, 5:20 PM 7/2/2004]

wombvette

Thanks John for the confirmation. As usual they take no heed from knowledge and experience and follow the false prophet.

BayRay

JohnZ,

Where do you get the gum drop stuff??

BayRay

Happy 4th of July to all!!

JohnZ

At any automotive body & paint supply store - just tell them you want "hood gumdrop" adhesive.

65air_coupe

"Thanks John for the confirmation. As usual they take no heed from knowledge and experience and follow the false prophet."

Phrase it how you like, I specifically asked as to how it was done by GM. I also said it should be either bonded or insulated, the relative motion and vibration between the surfaces was/is unacceptable. Just telling me don't glue it doesn't resolve the problem.

I have no way of differentiating 'false prophets' from misinformed, do you? I suspect most of us just try to find the commonality in the sea of opinions.




[Modified by 65air_coupe, 11:22 PM 7/2/2004]

LouieM

I'm told by the body shop that's working on my 67's hood that by this time nearly all midyear hoods need to have the inner hood brace re-gum dropped. Maybe so. They ground away the old gum drops, propped the hood and inner brace apart with paint stirring sticks, squirted in gum drops where the factory had originally, then removed the sticks. They repainted the inner hood. May as well do it right while the hood's off.

65air_coupe

I think I'll follow your example and let the painters take care of before painting.

John 65

For what its worth, I used Liquid nails, the one that is formulated for fiberglass, says it right on the tube, and its worked great for years.

Cmacsvette

Well spoken.

Craig

wombvette

Well, it was stated that y`all wanted a definitive answer and we have you one. I understand that it is hard to determine the wheat from the chaff around here, but hang around a little and you will learn.

soppeng

Wombvette, what's your thoughts on using a silocone caulk for those who don't have to have it exactly as the factory, but don't want to bond the hood to the braces and risk distortion?