I recall an article in the magazine Corvette Fever in which they replaced the old urethane bumpers with rigid fiberglass ones, junked the metal/rubber/plastic bumper substructures and epoxied the covers straight to the body. No heavy bumper substructure, no PITA bumper fasteners, and no lines to tell the bumper from the rest of the car.

The article covered the possible pitfalls of eliminating the bumper substructures (ie, collision) but it made for a real slick look, saved weight, and sounded a lot easier than working around the substructure and fooling with those lousy bumper cover fasteners.

Two years ago I replaced the front bumper with a tru-flex bumper which fit much better than the replacement urethane bumper which the previous owner sold with the car after removing the factory bumper which did not fair well the hazards posed by parking lots.

Eager to get some body work experiance, i did all the necessary prep work and painted the bumper to match the rest of the car. It looked good enough that i drove it the following year without any weekend projects or repairs, just a fun summer of driving.

But, the back bumper needs replaced. In fact, I just got done removing it and have found that the Tru-flex bumper which I ordered for the back (from the same company, at the same time as the front bumper) does not fit nearly as well as the front did. Due to this, I am once again considering gutting both bumpers and epoxy-ing them straight to the body.

Has anybody else heard of doing this? And does it work with tru-flex bumpers or do they have to be the rigid fiberglass ones used in the article?

Also, do you think it would be worth the hassle of removing the newly replaced and repainted front bumper to do the same?

 

From what I have seen in my research of this topic, it is best to use the fiberglass bumpers. This way, you are bonding 2 "like" materials with similar flex and vibration characteristics. This will ensure your bonded bumper seem won't crack and look bad.
Also, with the full fiberglass bumpers, there is some wiggle room inside that will allow you to clearance them to fit well over the crash structure. IMHO, I would not remove this structure as your insurance policy will likely be voided, not just thinking of the car, here... I'm thinking of your major medical liability. We can get in a car crash in our Vettes just as easily as we could in our daily drivers. I have seen some people actually remove a little material off their crash pads to get a good fit. This would be a compromise position.
If you want to blend the bumpers the bullet points are: affix the bumper so body lines are consistent and even. Cut a V groove along the seam and fill with kitty hair and epoxy. Sand the seam smooth and level. Apply a feather coat of good (evercoat makes one) filler. Sand again for smoothness, prime, sand, prime and paint and sand and paint and wet sand and polish and...
It's a process. It's also a GREAT look! One day I hope to do this when I redo the body. Look at forum member ONAQWST car for a great example of that smooooooooth look.

 

Truflex is fiberglass. It just has a flex agent added to it.

Danny

 

My front bumper is fiberglass and my rear bumper is Flex-glass. I bonded both to the fenders about 10 years ago. I have a hairline crack on once side of the joint in the rear (Flex-glass), but that may not have been related to the materials (rigid vs. flex).

Front (rigid):



Rear (Flex):



Either way, I would definitely bond the bumpers to the fenders again.

 

I recognize that... it does however not "act" the same as the surrounding material, which according to the research I have done on this and other forums, leads to problems.

 

I also remember an article about bonding glass bumpers to the body, but they stressed the importance of "keying" the two surfaces together to avoid cracks. They basically used a dovetail type joint between the bumper and body before glassing.

Its one of those things that looks great without knowing what was done, and if I ever get around to replacing the wavy urethane on my '79 I would sure like to do it.

 

Lets say after you have it all done and it looks like crap what then.
I would work on the back bumper and get it better lined up, I would use Flex fit or true fit. Use the re-tainers paint the bumper and call it a day.Clean the body ground while doing the back bumper.JMO