[PaulatFast]

Actually, I SAND blast all of my noses! The sand strips the paint and bounces of the endura. It leaves a very good surface behind for either the epoxy or the repair material. Of course they are blasted with care from a distance, but it works great. We use to hand sand them, but that takes forever and you still remove rubber with the sand paper. On some really dried out noses the blasting actually removes the crusty rubber down to still resiliant material.

The paint curing process sounds like a winner.

What all do you think we should test?

-The SPI epoxy in varying thicknesses.
-I also have some dp90 epoxy.
-A freind of mine swears by a Rubber Seal flexable 2K, he'd spray a panel.
-Maybe some standard 2K with and without a flex additive just for fun?

That's six samples, anything else? or anyone else have suggestions!

[Formula8]

I think we need to back track a bit to make this as scientific of a test as possible. I think the premise is that the factory did not have the same problems of paint cracking with the origninal finish as we do now when the endura has been properly refinished with modern materials. That being the case, the process to test this would be to refinsh endura with a series of modern materials and compare those against the factory original paint job. We have neither an original bumper or the original paint job so to begin somewhere, we are going to have to duplicate that or alternatively, test the best performing option out there and see how it compares to alternative products.

Paul has a system that works for him. I suggest we use that as the control for the others to be compared against. I think if the testing is limited to primers, we are missing out on an opportunity to find out what effect the clear has on the cracking as well. I also think if we limit the testing to metal, we will be missing something as I don't think anyone is having cracking issues on metal. I went ahead and ordered 2 sheets of SBR rubber (http://en.wikipedia.org/wiki/Styrene-butadiene) that are 4" wide by 36" long and 1/2" thick with a durometer of 70. This is a little harder than most tire rubber which typically varies between 40-60 and significantly thicker than most of the endura areas where we are seeing cracking. If my order was processed correctly, these should be drop shipped to Paul's place sometime in the next week or so. I can't say that I have ever ordered rubber before but I hope this approximates the endura.

My thought is that these would need to be cut into multiple strips and refinished along the lines Paul has suggested above. I really would like to see these strips prepped and primered with the materials above but also top coated. Maybe one single stage and another with BC/CC. I would definately want to see a rubber strip with the SPI epoxy and a BC/CC combo Paul typically uses. If that combo does not crack under the type of bending expected, I would be sold. If Paul happened to have some PPG BC/CC, I would have to run down there and give him a big fat kiss for doing this.

Paintguy, I am thinking the rubber strips could be tested the same way as the metal test panels. If so, maybe after Paul has worked his magic, he could send them to you to be tested.

[paint guy]

I also think that testing should be done on paint systems,not just primer.Panels(whether steel,rubber,or a cut-up endura bumper)should be painted in as close a manner as possible to how a restored car would be painted.This includes film thickness,time between coats,any sanding to the primer/clearcoat,buffing,etc.All in favor of running a couple of different film thicknesses(I can check total DFT,but not the film thickness of each individual product once it recieves a subsequent coat)on one or more of the systems.I can run adhesion on the rubber strips,and also stone-chip for a comparative study.I will need 2 panels(steel,that i will mail to you)of each system,and one rubber panel of each for testing.We have to careful in what exactly we want to test,as it is very easy for these things to grow from just a couple of panels to a large number.My suggestion would be this:6 panels of the SPI at normal(low) film thickness,2 with heavier film.Then coat 2 SPI with Rubber SEal 2K,two more using your std procedure(these will be the controls)and 2 more with no flex in the topcoat.At the same time you're spraying the controls,you can coat the 2 SPI heavy DFT primer panels,and also spray your 2K on a couple of DP90 panels.That gives us 10 panels,5 variations,and if you spray the rubber at the same time,15 data points.What do you guys think?

[PaulatFast]

Just let me know what you want.

[Formula8]

Buffing and sanding seems like a lot of work for Paul. I think we can assume that a higher film thickness would increase the likelyhood of cracking. For my purposes and to keep it simple, I'm primarily interested in 4 rubber strips:

1) SPI epoxy/BC/CC
2) SPI epoxy/single stage
3) DP/BC/CC
4) Rubber seal 2K/BC/CC

[PaulatFast]

OK, I received the 1/2" rubber via UPS today. It is 4" in width, there are two peices 24" long. What do you guys think? Sample size? Products tested? Give me some direction.

[FLYNLOW]

FWIW, I've had good results using the 3M two part, SEM Flexible Primer and DBC base coats...

[Formula8]

Thanks Paul, I didn't think they got it right but it least it got there. To minimize the hassle on your end. I am focusing on four panels. The first being exactly what you are using and have been successful with. The SPI epoxy primer and whatever you are using for BC/CC. The second would be the SPI epoxy an a single stage topcoat to see what effect the clear has on flexibility. The third would be a PPG DP epoxy with their 401 catalyst. (http://forums.maxperformanceinc.com/...ght=endura+ppg). Finally, just to mix it up a bit would be your buddy's Rubber seal 2K with whatever BC/CC you used on panel #1.

Panel 1 and 2 compares 2 stage vs. single stage.
Panel 3 compares PPG's recommendation vs. Paul's.
Panel 4 compares the Rubber seal primer vs. both SPI and PPG's epoxy.

procedurally, I would prep the strips, cut them into smaller 6 X 4 strips which should give you 8 strips. Of the 8, I would clean and lay down SPI on two of them, PPG on one and Rubber seal primer on the last one. Save the other 4 strips for future use or whatever you want to try. I would then lay a base coat/CC on panels 1,3 and 4. Either a single stage if you have it or just BC on panel 2. You probably want to select a top coat color that contrasts with the rubber. Assuming the rubber is black, white is probably the best bet and the least expensive. I am kinda' torn on the flex additive as they are said to be temporary. I am afraid that might result in something that passes the test now but in 6 months would just crack.

As far as the testing goes, I don't know. Do you want to send the strips on to Paint guy or just put like 10 degrees of flex in at a time an see which one holds up best??

[Formula8]

Originally Posted by FLYNLOW

FWIW, I've had good results using the 3M two part, SEM Flexible Primer and DBC base coats...

What is DBC and is it single stage or BC/CC? I assume PPG Deltron. Good to hear as that was the basecoat I had intended to use.

[paint guy]

Originally Posted by Formula8

Thanks Paul, I didn't think they got it right but it least it got there. To minimize the hassle on your end. I am focusing on four panels. The first being exactly what you are using and have been successful with. The SPI epoxy primer and whatever you are using for BC/CC. The second would be the SPI epoxy an a single stage topcoat to see what effect the clear has on flexibility. The third would be a PPG DP epoxy with their 401 catalyst. (http://forums.maxperformanceinc.com/...ght=endura+ppg). Finally, just to mix it up a bit would be your buddy's Rubber seal 2K with whatever BC/CC you used on panel #1.

Panel 1 and 2 compares 2 stage vs. single stage.
Panel 3 compares PPG's recommendation vs. Paul's.
Panel 4 compares the Rubber seal primer vs. both SPI and PPG's epoxy.

procedurally, I would prep the strips, cut them into smaller 6 X 4 strips which should give you 8 strips. Of the 8, I would clean and lay down SPI on two of them, PPG on one and Rubber seal primer on the last one. Save the other 4 strips for future use or whatever you want to try. I would then lay a base coat/CC on panels 1,3 and 4. Either a single stage if you have it or just BC on panel 2. You probably want to select a top coat color that contrasts with the rubber. Assuming the rubber is black, white is probably the best bet and the least expensive. I am kinda' torn on the flex additive as they are said to be temporary. I am afraid that might result in something that passes the test now but in 6 months would just crack.

As far as the testing goes, I don't know. Do you want to send the strips on to Paint guy or just put like 10 degrees of flex in at a time an see which one holds up best??

That sounds like a plan to me.I'll send you at least 8 4"x6" std test panels(steel)in the mail tomorrow so you can paint everything at once.If you don,t want to send the rubber strips to me,that's fine,but I figure if you have 4"x6" rubber panels,you could cut them down to approx 4x4",keep the remainder to do your own flexing,and I'll take the 4x4",mount them to a steel panel(like the ones I'm sending you)and run them in a gravel-o-meter,which will throw a measured amount of std. size stones at the panels at 60 MPH.(IMO,a good,real world comparative test.)Then I'll bend the steel ones in a Mandrel bend(another good comparision of flexibility)and send them back to you for your evaluation and you can post the results on here with pictures ,if you like.

[FLYNLOW]

Originally Posted by Formula8

What is DBC and is it single stage or BC/CC? I assume PPG Deltron. Good to hear as that was the basecoat I had intended to use.

Yep, Deltron. FWIW, I used DCD 35 clear over it, but I believe thats just a California Compliant clear...

[Formula8]

FlyN, any flex additive?

Paint guy, if Paul is up to all of this, I'm cool with your plan.

[PaulatFast]

Get me the metal!

[FLYNLOW]

Originally Posted by Formula8

FlyN, any flex additive?

Paint guy, if Paul is up to all of this, I'm cool with your plan.

Nope, no flex additive. As I understand it, the stuff just evaporates in a reasonably short period of time anyway. Its just meant to keep things flexible during reassembly.

[Musclerodz]

We have our Formula nose in primer now ready for sealer and color. I talked with both PPG and Dupont reps, and decided they were idiots since they kept referring back to painting urethane bumpers.

It has been sitting about 2 weeks now as a part of a little experiment. Another business I own is restoring vintage aircraft. The tube structure of many antiques is fabric covered and the paint must be flexible enough not to crack. One of the primers we use is a flexible pure polyurethane primer that when applied to the fabric I can fold it back on itself without it cracking.

Once the nose was completely stripped, I ground out any bad stress cracks and repaired them with 3m automix heavy body seam sealer, worked perfect. After that I wiped the entire nose with it to reinforce any light stress cracks. Scuffed the nose up and applied the aircraft fabric primer. So far I have seen no signs of cracking when I bend the edges and appears to be well adhered. It does not sand quite slick enough to seal over so we applied a thin coat of 2K primer with flex agent, most of which would be sanded off. I tried SEM flexible primer but it cracked after 2-3 days. So far I am happy with the results. I will see about taking a pic tommorrow of me forcing a bend to show the flexability of the product.

[niceta]

I have less than 0 exp when it comes to paint but thought this might be helpfull to someone doing a nose. I beleive this is a member here?? Cant remember where I got the link from but looks like he has experience in endura. Uses PPG for the most part.
http://www.goatsgarage.com/bumpfrm1.html

[PaulatFast]

Originally Posted by niceta

I have less than 0 exp when it comes to paint but thought this might be helpfull to someone doing a nose. I beleive this is a member here?? Cant remember where I got the link from but looks like he has experience in endura. Uses PPG for the most part.
http://www.goatsgarage.com/bumpfrm1.html

That must be at least 15 years old. He says an NOS endura bumper can fetch as much as 600.00! Later he says the NEW BC/CC systems may require a flex additive. He refers to using laquer thinner in the primer. The pictures of the cans date the whole article as well. I doubt many of those products are still available.

Thanks for the link, always looking for more information. I'm sure at one time that article helped several guys!

[Formula8]

Paul or Paint guy. How are we doing on this? I am going to start preping my bumper this weekend.

[paint guy]

I'll be able to report results within 1-2 days after reciept of the panels,provided they have enough cure time on them,otherwise it will take some time in a force-cure oven(48-72 hrs@.120F)before testing.please keep in mind that the most time-consuming aspect of this project is the spraying of the panels,which Paul is doing.Quite sure the info won,t be available before this weekend.

[70 One Owner GTO]

I have been following this thread with great interest, and I'm sure many more are too. Have not heard anything for a month, is test still ongoing, any results? Not trying to be pushy but very curious.