77 firebird endura bumper cover restoration

I've put 4 coats on this. I blocked it down. I have a lot of lows yet. I expect to have to do the 4 coats and blocking process another two times. Do I have to re-wipe the bumper cover with 700W&G remover and let sit for 24 hours after sanding down, or can I just blow the bumper cover off with air and start laying more coats down?
 
If you don't touch it with bare hands, and your environment is free from airborn contaminants, you can blow it off and start spraying. If there is any doubt, wipe it and wait. Sun and blowing with air helps the W&G evaporate much quicker.
 
I have my helper wipe everything down each time because he seems to lack conscientiousness about touching things with bare hands or even contaminating a glove then touching the surface. But if you are mindful about getting anything on the part and in a clean environment, skipping the wipe down between primer stages is doable.
 
I have the bumper cover looking good. I did my second session of 4 coats after blocking down the first 4 coats. It looks a ton better. I may have to do one more session, but after blocking what I have now I'll make that determination. What filler should I use over the epoxy on this flexible urethan pieces for very small imperfections? Is evercoat metal glaze ultra ok? I've seen that mentioned on other forums, but it seems odd to use that product in this application. The data sheet to that product has a note under approved substrates that states to use evercoat poly-flex for flexible plastics. Does anyone here have experience using that product over sanded SPI epoxy on a urethane bumper? Again, this will be very thinly applied- maybe .005" - .015" thick. Please link to preferred products as it seems when someone names a product there are still 1,000,000 variants and versions of it.
 
Very thin and small applications would be fine, such as a pinhole or scratch. I have used the polyflex over epoxy, and it sticks great. Just not as easy to sand as regular metal glaze. It has a sticky film on top.
 
texasking said:
Very thin and small applications would be fine, such as a pinhole or scratch. I have used the polyflex over epoxy, and it sticks great. Just not as easy to sand as regular metal glaze. It has a sticky film on top.
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thanks, texas. Are you saying the metal glaze will be ok and so will the polyflex? I looked at the data sheet, and it looks like I need to use the poly flex.
crashtech said:
Any of the flexible poly putties work best with long dry times, for sure.
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you mean let the epoxy dry for a long time?
 
Chris_Hamilton said:
The flexible filler. It takes longer than normal 2 part glaze.
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Chris_Hamilton said:
Metal glaze is OK in small amounts.
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thanks. metal glaze can also be use all over the car too, right? I currently have USC duraglass for covering welds. I've done my best, but I'm no pro. That's how duraglass got brought in to the conversation. Rage ultra will be the majority of what I use. Evercoat metal glaze would be the final filler used on the car body. With poly flex I can fill in the front and rear bumper covers. Does that cover me for the entire car? I'm trying not to end up with 25 different types of filler that each have 1 teaspoon out of them.
 
No need for 25 different fillers. Notice I mentioned very small and thin application. Regular filler or glaze has a certain amount of flexibility, but not as much as Polyflex. The larger and thicker the application, the more flexibility is lost with any polyester. I would much rather sand Rage Ultra than metal glaze or Polyflex. I used to use metal glaze as a final application, but now I use Rage Ultra 99% of the time, even for filling pinholes or small scratches. It doesn't pinhole any worse than Metal Glaze, IMO, if applied properly.
 
You guys can probably spot 1000 flaws just from these pictures without even being in front of the piece, but I am still very proud of this. Thanks to your help and guidance it's a great looking piece now. Tons of hours of work just in this bumper cover. 12 coats of epoxy- the 1st 4 were sanded off almost entirely, the 2nd 4 mainly remain, but there were some spots that sanded through. The last 4 are what you're looking at.

This will probably be in this state for some time. Am I done until whenever I do base coat at which time I'll send with 180, recoat with SPI epoxy, and then base coat within 7 days? Or do I need to coat this with reduced SPI epoxy now to "seal" it? Are there concerns with using urethane-reduced epoxy on this since this is a urethane cover? Is using yourothane reducer in the paint mix a no-no on this?

There is this very tiny small spot that you can barely see that I've highlighted in some of the pictures. There was one or two more of them next to it. It kind of bubbles up. The others have sanded it out, so I would like to think they were just previous layers of easy sand that I did not sufficiently sand down to be flush, but I'm not sure. Would anybody be concerned with this? It will come out with sanding. You can't even feel it with your finger. Here are some pics of the finished piece in general and the small little "boil" or "blister."
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Did you happen to sand through down to the plastic where that blister spot is prior to the last coats of primer? I’ve noticed that with these types of bumpers that when I reprime over a sand through spot it seems like the plastic swells slightly and makes a minor high spot.
 
DavidL said:
Did you happen to sand through down to the plastic where that blister spot is prior to the last coats of primer? I’ve noticed that with these types of bumpers that when I reprime over a sand through spot it seems like the plastic swells slightly and makes a minor high spot.
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ah! Yes, yes I did. In fact, after these last four coats this spot was the only sand through spot. Is it an issue? Like I said, you can't even feel it with your finger. Is this just something that will buff out when I do a little bit of sanding? If so, that goes back to part of the original question; do I let this go for now until I am ready for base coat? At which time I would sand with 180, recoat with epoxy, and then spray base coat?
 
Once that epoxy cures through, subsequent coatings won't be able to penetrate it. So hopefully that issue will go away. Hard to know for sure at this stage.
 
crashtech said:
Once that epoxy cures through, subsequent coatings won't be able to penetrate it. So hopefully that issue will go away. Hard to know for sure at this stage.
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Ok, so even if I sand that down you're saying I should coat it a few more times?
 
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You want to lightly block it flat without breaking through. If you start to faintly see the plastic at that when blocking then stop and reprime. Repeat until the high spot is gone.
 
This is peripheral to the bumper but still involved in the fitment process of the rear end components:

Has anyone added and removed fiberglass on the rear spoilers on these cars at the pointy bases (circled) and/or added/removed material from the front or rear faces so the side pieces were planar with the center piece (planes with the arrows on them in the pic)? These all seem to fit like such crap- especially the bottoms on the side sections. I want it to be tight and come to a rounded point where it terminates at the bumper. They all don't hug the quarters right like they should, and that doesn't look good imo. This pic isn't my car, but it still applies
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No and no. I’ve done a few of these and I find that the planar alignment is done by sliding the two pieces front to back in the mounting holes which effectively rotates them. Sometimes the holes need to be elongated to give enough movement. I also have a vague recollection of adding washer spacers on the studs on the ends to adjust the angle and/or height.

I think modifying them might open a bit of a can of worms.

Don
 
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