Need some help with endura bumper repair
 

My GTO is at the paint and body shop now. The guy is doing an excellent job and has gotten a lot done in only a week. I've seen the guys work and I'm confident I made the right choice. My only concern is the endura bumper on my car. I want to ensure that he does it correctly because I'm not so sure how much experience he has on working on the endura bumper. I've gone through a few threads here and it seems 3M use to make a product used to fill in some imperfections but I see 3M does not make it anymore. Any recommendations? I also saw a video somewhere that said to NOT use primer on the bumper because it will crack through the paint....anyone heard of that? Can someone post a video or article that shows a "step by step" in repairing and paint the bumber.

never heard of the no primer thing
I use SPI epoxy and (fingers crossed) havent had an issue

I used the flexible SEMWELD 39708 product on my 72 endure nose, its a 2 part like the 3m but comes in tubes that dont need a special gun, applies & sands smooth and has lasted almost 10 years with no signs of cracking or failure. Works great on other flexible materials too like later 1978 noses.

After repairing cracks, most guys spray with SPI brand epoxy primer, epoxy primer wont crack like normal primers so that is what you probably heard about using normal primers. Then you apply the base/clear over the epoxy primer following the time frames SPI states to apply a top coat. I used another brand of epoxy primer that worked good too.

This was posted by a member here (PaulatFast) who was always posting great information, too bad he is gone, as I always read his posts to learn something,

Hope this helps




To sum up the system we use, I submit the following. Brands are named, not to aid those brands in sales, but just for reference because they work for us.

First we sand blast the endura bumper, not soda blast, not sand with a DA...

I have found that ANY brand of flexible epoxy repair product seems to adhere well, sand easily and last as long we've had them out there. 3M, Medallian, some french canadian product we have right now... same smell, working time, etc.

After repairing the issues we fit the bumper to the car.
This procedure involves bending, twisting, jumping on and sometimes beating the bumper with a5 lb sledge hammer. It involves trimming and/or building the edges with the 2 part epoxy. The bumper brackets and the frame horns usually need the slots welded up and ground back down, smetimes the lower front of the frame horn needs trimmed to allow the bumper to go back far enough to achieve nice gaps. Remember, the factory gaps sucked most of the time, as evidenced by the GM photo's from back in the day. What is a nice gap? 1/16" to 1/8" on a 68-9, and 1/32" to 3/32" on a 70. NO TOUCHING!

After the nose fit is perfect, or good enough for you, we spray several coats of SPI Epoxy primer, it sands easily, sticks to the endura and the epoxy repair material. This is where I feel brands are inportant. Some epoxy primers simply do not sand well, ever! The SPI does, so we use it! Others may work, I don't know. We use no other primer, no 2k, nothing but the SPI epoxy. We recoat and block as needed. We sand the epoxy through 600.

We use the same SPI epoxy and sealer before basecoat or single stage. We have used flex agent in the base in the past, never caused an issue. We don't any longer, after researching what the flex agents actually are... simply retarding agents that prevent fully curing.

We have sprayed many bases without issue, Nason, Omni, Dupont Chroma-Base, PPG DBC, Pro-Spray, Zenith and our current mix station, PPG Global. or the record, avoid Napa, Martin Senior CrossFire on anything. Horror stories too numerous for this thread...

We spray SPI Universal High Solids Clear, it sands and buffs well, doesn't yellow and sticks to anyone's base. The following is totally my observation and opinion. Good, Quality, High solids Clears don't harden and become brittle like cheap clears do. We have sprayed Dupont 7900 in the past, it is pretty good but i've repaired noses that were sprayed in 7900 14 years earlier, and the clear was very brittle. That said, there are probably numerous clears that meet this criteria. I use what is proven and works for me.

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Paul
FAST Automotive -The Pontiac restoration shop, not the fuel injection guys! I had the name first.

My site... needs updated-
www.fastrestorations.com

Cammer-6,
Is this what I need to buy? and how much do I buy? https://www.southernpolyurethanes.com/epoxy-primer

78w72,
I looked around and it looks like they don't sell SEMWELD 39708 anymore. Not even at Summit!

Yes that’s what PaulatFast was referring to. It mixes 1:1 with activator so you’d end up with 1/2 gallon sprayable. More than enough for the endura bumper. Use it for the metal backing and brackets too. Great epoxy at an affordable price. Can also be use as a wet on wet sealer when mixed with reducer. Their forum has many helpful folks if you have any questions about their products and their uses.

Looks like it may be discontinued... im sure sem or other brands make something that will work. Heres a recent thread that mentions some other options.

https://forums.maxperformanceinc.com...d.php?t=871172

3M 05887 works great but you need the special gun. I have lent it to others in this forum so I’ll extend that offer to you as well. PM me if you think you’ll need it.
Dave

My guy who's doing my 'bird asked about the endura, and I gave him Paul@ FAST number. He called and Paul was very helpful, my body guy appreciated it.

Paul is the guy to ask, he's done 100s & 100s of them.


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I think the no primer thing is being confused with the no flex agent thing. Honestly, it kind of doesn't matter if you use flex agent, as long as you give it time to fully cure.

That can take some time though, depending.

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Hey all.