[Greg Reid]

Is that a complete no-no or can I apply a coat and sand most of it away without inviting cracks later?
I already have a coat of epoxy in place but I can see lots of blemishes...Some are very small cracks, others sanding marks etc. Looks good until in the bright sun. I know they're gonna show with paint on it.
I feel like I'm trying to round up a room full of cats chasing the sanding marks and cracks on this thing.

[fbrown]

I don't know if you saw this post, but I have basically followed Paul's recommendation for how to prime the bumper, the only change I made was to spray 4 coats rather than 3 since I know I'm not as experienced as someone who does this for a living. Paul's instructions work very well and leaves a very smooth surface. I can add that you will need a flexible sanding pad when working all the curved surfaces . I found that a Motor Guard Memory Block for Contour Sanding worked well. (Part Number - MCMB-1)

http://forums.maxperformanceinc.com/...d.php?t=692686

[Greg Reid]

Thanks for the link. I had missed that one.

After looking at it yesterday, I could see that most of my problem is in the portions of old primer that I did NOT get completely off of the endura before priming. That's where the cracks were. I had already repaired the knicks, etc. with a two-part-epoxy rubber bumper repair.
I re-sanded last night with 80 to get the old primer completly gone or smooth, then went to a 120. After that, I used one of those 3m sanding 'sponges' on the finest side to remove the fuzz. The epoxy I'm using sands very nicely for what it is.
I was planning on one coat of epoxy thinking that the thickness might be the reason for later cracking. After reading that, I'll go with at least 2.
Going out to re-shoot it this morning.

[fbrown]

I don't think you will find the thickness of the epoxy primer as the problem with cracking. While repairing my bumper, I jumped on it, bent it with 2x4's, even broke a 2x4 while bending the bumper. The paint got messed up pretty bad but to my surprise when I sanded off the BC/CC off the primer underneath was not damaged. It turned out that all I needed to to to my bumper was to strip the color, but since I didn't know anything about the history of my bumper I sanded to bare rubber. In the process I ended up redoing all the repairs that had already been done to the bumper. In any case I suggest that you spray at least 3 coats of primer if not four. You will end up sanding most of it off by the time you sand with 320, 400 and 600 in the final step of the surface repair. I ending up sanding through it a couple of spots and and shooting a couple of more coats in the areas I sanded through. I still think you could do a better job with a flexible sanding block. The bumper is murder to sand smooth will all of it's curved surfaces. I didn't think 3M sanding blocks got as fine a 600 grit. The final step with 600 girt is what got my bumper perfectly smooth.

BTW I used a dry guide coat, after initial sanding the bumper looked good, but then I applied a dry guide coat and the guide coat showed plenty of flaws.

[Greg Reid]

The 3m block is one of about 8 or 10 different things I use as sanding blocks. Everything from rubber hose to aluminum channel.
I resprayed today and it looks much better. Still has some flaws....Kinda like a beautiful woman in direct sunlight. Still looks nice but you can see the blemishes here and there.
I'll sand it tomorrow and and keep respraying as long as I need to. Looks MUCH better today though.

Here's what it looked like after the first spray-




MOSTLY looks like this now-




Still have a FEW spots like this though....

[1978 T/A]

I don't see why you couldn't use a surface primer. Epoxy primer/sealer lays out a lot thinner than a surface primer and is really intended for filling light sand scratches before you shoot a base coat.

What kind of sanding sponges are you using?

I would reprime the whole bumper with at least 3 coats and sand from there. If you're not going to apply a final coat of sealer before paint you need to wet sand the bumper with 600.

This is the process I generally go through in repair:
Filler if needed.
3 coats of surface primer.
Guide coat and sand with either dry 320 DA paper or wet 600.
Lay down 2 coats of sealer.
Lay down base coat & clear.

[Greg Reid]

You know, I forgot to follow up on this thread. I finally did get a nice, smooth finish on my bumper using only epoxy. It will fill but it just takes quite a few coats with sanding in between to get the filling effect.
From what I understand, the problem with the surfacing primer on Endura is that it is not as flexible as the epoxy...which is why Epoxy tends to sand poorly.
Here's where we are right now...I'm satisfied with it. Took about 6 coats, 90% probably sanded off....

[Cammer-6]

I like it!
it took me several coats and some fusor to get the millions of hairline cracks filled.
A time consuming process but just imagine if you had a chrome bumper that looked as bad,how much work would it be?

[Greg Reid]

Thanks Cammer. It's back on the car now.
One correction to my previous post..I stated "only epoxy". I should mention that I also used a 3M two-part epoxy rubber bumper repair kit. I bought it right off the shelf at Auto Zone. It's about 6 bucks.
I sprayed, sanded, blew the dust off, skimmed the bumper repair on over any cracks and pores I could see, sanded again, blew/wiped the dust off from the repair, sprayed again and repeated everything until it was smooth. I used a combination of blocks, sanding sponges, rubber hoses with sandpaper stuck on and straight paper in my hand, depending on the shape of the area.
Between the epoxy and repair kit, everything was eventually filled. Yes, it was time consuming...

[hobi]

Originally Posted by Greg Reid

You know, I forgot to follow up on this thread. I finally did get a nice, smooth finish on my bumper using only epoxy. It will fill but it just takes quite a few coats with sanding in between to get the filling effect.
From what I understand, the problem with the surfacing primer on Endura is that it is not as flexible as the epoxy...which is why Epoxy tends to sand poorly.
Here's where we are right now...I'm satisfied with it. Took about 6 coats, 90% probably sanded off....

Your bumper looks great the cracking in the previous pictures really gets you down after all the prep work than you go to prime and that happens but it looks like the system you are using is working very well nice job looks great.

I went to a local GTO Club members house to help him with his Endurallema and what I saw is very common. The bumper was not on the car as a matter of fact the whole front clip was off. The first thing I do on a Endura bumper car is make sure the whole car as far as the body goes is not only on the car but alighned as best as possible.

So if you are changing any parts hood hinges fenders whatever do all that first, than aline all the sheetmetal as best you can, than I lay the bumper up and get it to fit as best I can, AND THEY ALL NEED SOMETHING EVEN NOS ONES IF YOU ARE EVER THAT LUCKY. Sometimes I have to pull the Endura off put in a hydralic press and straiten, than I strip the fenders to bare metal and the bumper is sandblasted, than I use the rubber repair kit and over build the bumper about one eighth of a inch. Than I file the bumper with 80 grit till it meets the fenders and hood. After that its EPOXY PRIMER TIME NO FILLER PRIMERS NO FLEX AGENTS. Paul at FAST Automotive has the best system in the world and he says EPOXY ONLY and my system is similar and have had great results but I am not in the body business I am in the construction business I am a very serious hobbist and very very fussy and have had great results with my system but I read all the post from Paul and nobody I have talked to knows more HIS SYSTEM WORKS.

[Greg Reid]

Thanks hobi, I appreciate the words of wisdom....and I like that- "Enduralemma"...lol
As for fitting everything first...I agree. I thought of that when I was midway on my bumper. That's why I stopped everything, mounted the bumper and everything else. Got it to fitting pretty good, pulled it back off and sprayed it. It still has a couple of fit issues but not too bad. Haven't decided if I'll pull it back off or not at this point. Gap needs closing just a bit on the driver's side....and I'll probably do it.
Just took these pics a few minutes ago in fact....

[1978 T/A]

Looks real good Greg! Glad everything worked out for you.

[Cammer-6]

right now your code K car looks about the same as mine
cut in and ready for final blocking and shoot
keep up the good work and youll probably complete before me

[webfoot]

Greg did you mix the epoxy with any kind of a reducer or is this just mixed straight up?

[Greg Reid]

78TA, thanks!

Cammer,
I'm curious about your K code car. Any pics? Interior color? Vinyl top? You know the drill...

Jeremy,
Out of all the coats I applied and sanded, I did reduce a couple of the applications a bit....more or less experimenting. Didn't hurt any and layed down a bit smoother on the surface of the bumper. I reduced one as much as 20% or so. Mainly, I just added a dash of reducer directly to the cup.
All in all though, I found my early problems with rough finish was caused because I wasn't adjusting the mixture on the gun quite heavy enough. Kinda like the airborne particles were partially drying in the air and causing a slightly 'grainy' finish on the surface.
Once I got the gun adjusted right, I probably didn't even need any reducer.

[1978 T/A]

Webfoot- As far as reducing, look at the back of the paint can and it will give a mixing ration of 4:1, 1:1 etc. I would stay with the mixing ratio on the can. I would only add more reducer if you find that the primer is starting to harden in the gun between coats. More reducer will prolong your overall dry time too so keep that in mind as well.

[Cammer-6]

68 Bird Sprint
black custom trim(deluxe knit weave)
no vinyl top

I parted one that was custom trim deluxe no knit weave
turquoise in and out 4 speed 1 bbl(very rare)
But it was very rusty from the anal owner keeping it covered with a tarp.
Still have some of the body parts left and they buff out to look like new(no repaint)

[Greg Reid]

Sounds like a nice 'Bird Cammer. Good luck with it. Mine came with black vinyl top and Turquoise interior. Haven't found any pics of one just like it as every black vinyl top K code car I see has a black interior.