68 bonding adhesive

[Ed P.]

Looking for bonding adheasive for headlight support bar in nose ( boomerang) the original compound was a white or off white color and felxable. All I can find is black. Any suggestions.

[Mark E.]

Re: 68 bonding adhesive

In 2015 the surround panel on my '70 separated from its metal support just behind each of the headlamp doors. This caused the surround to raise just enough to rub against the headlight doors when actuated.

If this is your issue and the panels are currently installed, here's what I did...

I used 3M Structural Adhesive #08101. It's a two component system- the base is white while the accelerator is beige. I don't recall the resulting color of the mix (it's covered by the panels) but it's probably light beige.

Instead of removing panels or headlamp doors, I worked through the valance and grille openings to spread the failed bond a bit using plastic scrapers as spacers (wood shims should work too). I then cleaned the bonding surfaces by carefully spraying acetone (a super fast drying solvent with no residue) into the gap, which was a bit nerve racking since I didn't want to harm the lacquer finish. I let it dry 24 hours and then squeezed the adhesive into the opened gap the best I could. To press the panels together while drying, I covered the surround with clean towels then placed six 35 pound boxes of kitty litter on the surround. As I recall, I jacked up the front of the car to provide a level surface for the boxes. This stuff reaches full strength after eight hours so I left it alone overnight.

My cat was thankful for all the fresh litter, but alternatively you can use clamps if the headlamp doors are removed.

This approach avoided a lot of disassembly and protected the finish. The repair remains solid after nine years, but obviously this short cut won't work if there's significant corrosion in this area.

[Paul S.]

Re: 68 bonding adhesive

lord fusor 100ez ez plastic body repair adhesive (heat-set), 7.1 oz.
lord fusor 100ez ez plastic body repair adhesive (heat-set), 7.1 oz.

[Patrick B.]

[Mark E.]

Re: 68 bonding adhesive

Mark— Was it the bonding strip riveted to the metal support that was coming loose loose from the surround, or was your metal support bonded directly to the surround like a 73?

With my '70, the bonding strip is riveted to the metal support. That connection was okay. The issue with my car was the bonding strip came loose from the surround.

To your point, if the rivets are failing (usually due to corrosion) this short cut does not apply.

I didn't know that for 1973, the metal support is bonded directly to the surround. Does this mean there's no bonding strip or rivets?

[Patrick B.]

Re: 68 bonding adhesive

Yes, I believe 73 was the first year that the bonding strip, rivets and risk of bumps were eliminated. The steel was bonded to the surround with the Lord Fusor adhesive that Paul mentioned.

[Patrick H.]

Re: 68 bonding adhesive

Yes, I believe 73 was the first year that the bonding strip, rivets and risk of bumps were eliminated. The steel was bonded to the surround with the Lord Fusor adhesive that Paul mentioned.

Correct.

Anyone know the best way to "fake" the rivets on a pre-73 if you want to have it judged, but use the 73-later style of bonding?
Can you seal the rivet tops to prevent future fiberglass bumps?

[Patrick B.]

Re: 68 bonding adhesive

I would think you would remove the steel bar leaving the bonding strip in place, remove the rest of the rivet by cutting thru the bonding strip with a hole saw-like cutter without cutting into the surround. Next you would glue the steel bar to the bonding strip with Lord Fusor. Finally you would glue pieces of aluminum shaped like rivet heads to the places on the bar where the real rivet heads once were. Since the aluminum rivets are gone, the bumps cannot form again.

I have developed tools to do the first two steps. I tested them on a nose piece cut off a wrecked car, but I have not used them on a good car yet.

[Mark E.]

Re: 68 bonding adhesive

I would think you would remove the steel bar leaving the bonding strip in place, remove the rest of the rivet by cutting thru the bonding strip with a hole saw-like cutter without cutting into the surround. Next you would glue the steel bar to the bonding strip with Lord Fusor. Finally you would glue pieces of aluminum shaped like rivet heads to the places on the bar where the real rivet heads once were. Since the aluminum rivets are gone, the bumps cannot form again.

I have developed tools to do the first two steps. I tested them on a nose piece cut off a wrecked car, but I have not used them on a good car yet.

My understanding is you said for '73 and newer, the metal frame is directly bonded to the surround. If so, then why is the bonding strip kept in this modification? To avoid removing it from the surround?

[Patrick B.]

Re: 68 bonding adhesive

My understanding is you said for '73 and newer, the metal frame is directly bonded to the surround. If so, then why is the bonding strip kept in this modification? To avoid removing it from the surround?

I think the idea was to retain the appearance of the pre-73 arrangement which would change by removing the bonding strip. Removing the bonding strip would also risk damage to the surround and certainly to the paint. It might also cause the headlamp doors to be lower than the surround.