glass scoop/metal hood

[kmcanally]

I am sick...long story short: I bought an original steel hood with a glass scoop already bonded to it. This after buying and reselling two different pos all glass hoods. Apparently the guy that bonded the scoop to the hood used resin instead of filler to blend the scoop to the hood. Now that the hood is painted there are raised lines showing through in some areas. These lines are more pronounced when the hood is out in the sun where it gets hot. It makes me sick because I got almost $2k in this hood. In hindsight I should have bought a new repro hood and glass scoop and had my painter bond it so that I know it was done right (and for less $) but it is too late for that now. Anybody familar with this problem and know how to fix it? The painter first saw the lines when he wiped it down with wax and grease remover prior to shooting the color on. So we recovered the hood in polyester primer in an attempt to seal in this problem but it obviously did not work. When we saw it in the paint we though we could sand them out when we cut and buffed it. But today I went and looked at it after it was buffed and they are still there. HELP!

[paul67]

To me it sounds like it not having time to cure properly before the paint is put on and is shrinking . Your best bet is to contact the resin company to see how long it should cure for and also the filler company then rip it back to let it cure. When i had a hood done it was resined then filled but left it about a week for the resin then used a flexy filler, then left a week ,used stone chip as the pimer filler as its flexes then put a drop of paint addative that used for painting plastic bumpers in the top coat. This used to be a common fault on fibreglass street rods over here in the uk.

[kmcanally]

Thanks Paul...Actually the scoop was attached to the hood almost two years ago and it was just now painted. I bought it on eBay over a year ago from a guy in Phoenix. It was advertised as "professionally bonded" and "ready to paint". I had the hood pin holes filled and smoothed on both sides plus we built up one side of the glass scoop (67 Shelby) so the contours matched. We also ground/weld/filled all of the holes and hardware used to hold the scoop in place while it was bonded. Something is reacting, we thought the polyester primer would cover it up. So now I don't have enough paint left over to paint it again. The paint is Glasurit (line?) bought over 10 years ago so I am not sure how well we are going to get a match (GM Polo Green). So I might go back with gloss black on the middle of the hood after we grind it all down and start over. A black hood would probably look ok with dark green and black wheels.

[Rick D]

Do you have a picture? What kind of scoop do you have bonded to the hood? Fiberglass to metal almost never works. I would think that the lines that you are seeing are the step for the scoop down to the hood. Is the scoop sitting on top of the hood or is bonded from the bottom? 3M make a very good product to bond fiberglass to metal and then you can use fiberglass resin and matting to finish the contour. But as I have seen in 20 years of body shop ***** it will almost always fail at some point if not right away. Did you bake the finish after painting it or did it air dry? After striping it down and rebonding and glassing it again bake it in a booth or with an IR heat lamp will take out a solivent. All so if you paint was mixed correctly and you didn't change it up then they should beable to remix it the same again. Just blend the color in to the fenders and it will look great unless you want the black.

Rick

[kmcanally]

No pictures yet but I will get some. The line are raised, random and a little web like. Being raised you wopuld think you could wet sand them flat but apparently they just come back. Another thing is that there are some 6" to 8" from the scoop? We baked it before paint after they initially found the lines and then baked the final finish. We also pit it out in the sun before and after paint. For now we are going to let it sit for a couple of weeks before another cut and buff...who knows maybe they won't come back.

Thanks for the info and I will get some pics next week.

[Jim Nilsen]

The correct way to bond fiberglass to metal is with a 2 part epoxy. VFN sells fiberglass patch panels that I put on a 67 Camaro years ago. I did one side with resin and then a guy who came to look at the car told me it would fall off eventually and gave the last of the epoxy he used to bond all of his glass to metal on the car he was modifying. The resin side lasted a long time before it started to have problems but the epoxy side was on forever and was easy to do in comparison to the glass resin which wanted to have pin hile air pockets in it.

VFN verified that the epoxy was the better way to go when I called them to make sure. The epoxy cost as much as the panels back then but it is the way to go when putting glass on steel. I was told the expansion/contraction rate of the epoxy was closer to the rate of the steel making it not crack as easily as glass does.

Jim Nilsen

[ProTouring442]

Anyone know what they use on the Eleanor clones? I know they bond on a lot of fiberglass parts when making one. Anyone know someone at Unique Performance?

Shiny Side Up!
Bill

The correct way to bond fiberglass to metal is with a 2 part epoxy. VFN sells fiberglass patch panels that I put on a 67 Camaro years ago. I did one side with resin and then a guy who came to look at the car told me it would fall off eventually and gave the last of the epoxy he used to bond all of his glass to metal on the car he was modifying. The resin side lasted a long time before it started to have problems but the epoxy side was on forever and was easy to do in comparison to the glass resin which wanted to have pin hile air pockets in it.

VFN verified that the epoxy was the better way to go when I called them to make sure. The epoxy cost as much as the panels back then but it is the way to go when putting glass on steel. I was told the expansion/contraction rate of the epoxy was closer to the rate of the steel making it not crack as easily as glass does.

Jim Nilsen

[paul67]

if the paint is 10 yrs old that could be the prob as paint goes off after a few months

[paul67]

Just thought, a friend of mine repairs corvettes and will only use the GM bonders for the panels , and as we live in the uk he could skip to another product over here but knows this does do not crack or shrink.

[kmcanally]

if the paint is 10 yrs old that could be the prob as paint goes off after a few months

I thought about that too but the painter said it should be ok. Plus the lines were first noticed in the final primer coat prior to paint...we just thought we had contained them with polyester primer since it, like the resin, is made with polyester.

[paul67]

noted that you notice when its in the sun or under a lot of heat , is your house got ac if so can you put in a place to see if it goes when the hood is not so hot if it does go its the shrink diff between the panels ,how to cure that without removing i cannot help but you would a least know what causing it.