[rasilverbird]

I know we've had numerous Endura paint threads, but I can't find any details on primer.

It's been recommended to use a flex agent when painting an Endura bumper, and to use a flexible 2k primer...but what about the base primer?

I'm going to be spraying epoxy on my car soon and want to know what to do with the bumper. I reached out to the manufacturer and they said that their epoxy was NOT designed to use with a flex agent. Do I just spray it without? Do I use another type of primer for the bumper?

[dataway]

SPI is what people are going to recommend, and I would too. No additives ... shoot, sand, shoot sand, shoot sand etc.

[n20ta2]

I used the spi epoxy but limited it too 2 light coats. Followed by 2 coats finish. No flex agents needed, keep the finish coats to a minimum with as little build up as possible and you won't have any cracking. It's been finished for 10 months now and I can flex the bumper with no issues

[dhutton]

SPI epoxy is flexible and requires no flex agent etc. Just shoot it.

Flex agents are not widely used any longer afaik.

Don

[tjs72lemans]

Yes, SPI primer is the only way to go. It will be flexible enough to keep from cracking. Even multiple layers built up work. Your paint will also be a bit forgiving with that base so it won't crack. So, no flex agents needed for top coats either.

[HoovDaddy]

You didn't mention what you are painting over and whether or not there are any cracks?

Don't use any solvent cleaners prior to priming, solvents can damage the plastic easily after all these years. Use the SPI Waterborne Wax & Grease Remover, dry it, and let set for a few hours or next day. These bumpers can absorb solvents as well as the first coat of primer. You'll likely need more than 2 coats of SPI Epoxy to have enough to sand. You want enough to sand but don't want to sand through.

Have you test fitted the bumper? After priming you can use TRANSTAR Plasto-Mend or 3M 5887 to fill cracks and panel match.

[MUSLCAH]

Spray with any epoxy …let dry 24 hours ..then without sanding you can apply some SEM “ Bumper Bite “ ..which is a flexible ( Body Filler ) type of glaze …for cracks and voids…gouges…then more epoxy over that.

[rasilverbird]

Thanks for all the replies.

Originally Posted by HoovDaddy

You didn't mention what you are painting over and whether or not there are any cracks?

Don't use any solvent cleaners prior to priming, solvents can damage the plastic easily after all these years. Use the SPI Waterborne Wax & Grease Remover, dry it, and let set for a few hours or next day. These bumpers can absorb solvents as well as the first coat of primer. You'll likely need more than 2 coats of SPI Epoxy to have enough to sand. You want enough to sand but don't want to sand through.

Have you test fitted the bumper? After priming you can use TRANSTAR Plasto-Mend or 3M 5887 to fill cracks and panel match.

Painting over raw rubber. I have already patched all of the cracks, and have test fit the bumper.

[rasilverbird]

Originally Posted by tjs72lemans

So, no flex agents needed for top coats either.

Really? Everything I've read the last couple of years has said to add it to the paint and clear.

This is my second time painting this car. The first time (back in the '90's) the bumper paint cracked in all of the corners. I want to avoid that this time.

[MUSLCAH]

Originally Posted by rasilverbird

Really? Everything I've read the last couple of years has said to add it to the paint and clear.

This is my second time painting this car. The first time (back in the '90's) the bumper paint cracked in all of the corners. I want to avoid that this time.

Paint has changed a lot ovah the last 30 years…just like knee replacements and cancer treatments

[tjs72lemans]

I would say if you use regular epoxy primer (like in the old school days) rather than SPI, everything else on top of that will crack like your old one. The foundation is most important.

[HoovDaddy]

Originally Posted by rasilverbird

Really? Everything I've read the last couple of years has said to add it to the paint and clear.

This is my second time painting this car. The first time (back in the '90's) the bumper paint cracked in all of the corners. I want to avoid that this time.

I thought of an idea for you. Contact Transtar Auto Body Technologies on their website https://www.tat-co.com/

They have a few automotive specialty primers for different kinds of plastics. I've used these and other products for many years, good stuff and priced below the big guys. I've used their waterbase Hydroflex primer on urethane bumpers without fail. They will tell you if its compatible with your bumper.

Tell them what you have and see what they come up with.

[tjs72lemans]

I don't believe SPI was out back when you last painted, so again I don't think you'll find a more flexible, forgiving primer than that and will not crack.

[mrennie]

Originally Posted by MUSLCAH

Spray with any epoxy

I would not recommend this. SPI epoxy is known as the "go to" for Endura repairs and using another brand may cause problems. Brands of flexible epoxy repair material are less of an issue, but the primer is super important to ensure a crack free result.

Personal experience: I blasted my Endura bumper and sprayed 2 coats of RM EP589 epoxy on the inner surfaces, and was keeping the SPI epoxy for the exterior work. When I was working on the bumper a few months later, any area where I had flexed the bumper (most notably the upper edge where it meets the hood), the RM primer had cracked and spider webbed. A review of the PDS clearly said it was not to be used on flexible surfaces. This was OK as all I wanted to do on the inside was get it a uniform colour, but if it had been the outside, it would have been a bad end result.

Second example: Sprayed 5 coats of SPI epoxy (1 hour between coats) in preparation for blocking. Left bumper on work stand for several weeks then went back one day and got it ready to work on next morning. Next morning, go in garage and found it had slipped off the work stand and was laying on the floor face down . Put it back on the stand, not a crack to be found, just a few scrape marks. Processed to block sand and all was good.

I am not saying that SPI Epoxy is the only epoxy flexible enough for Endura repair/repaint, but I am saying I am not convinced "any" epoxy primer is flexible enough for Endura repair/repaint.

Regarding flex additives, just for some interesting info: I always keep a few 1/4" to 3/8" discs of the hardened leftover material I mix in the paint cups, and the disc of single stage urethane I sprayed 2 years ago is still very flexible, almost like a dog's flexible chew toy. I also have a 4-5 year old disc of SPI epoxy and it is still able to be flexed, but it much stiffer than the urethane. You can bend it without breaking, and it will slowly return to its previous shape. A similar disc from urethane primer/surfacer is brittle and will not flex at all without cracking.

[rasilverbird]

I've just spent about all day today reading on the SPI forums, and now I'm convinced that I will just primer the bumper with SPI...no 2k and no flex agent. Thanks for all the SPI recommendations!

[MUSLCAH]

Originally Posted by mrennie

I would not recommend this. SPI epoxy is known as the "go to" for Endura repairs and using another brand may cause problems. Brands of flexible epoxy repair material are less of an issue, but the primer is super important to ensure a crack free result.

Personal experience: I blasted my Endura bumper and sprayed 2 coats of RM EP589 epoxy on the inner surfaces, and was keeping the SPI epoxy for the exterior work. When I was working on the bumper a few months later, any area where I had flexed the bumper (most notably the upper edge where it meets the hood), the RM primer had cracked and spider webbed. A review of the PDS clearly said it was not to be used on flexible surfaces. This was OK as all I wanted to do on the inside was get it a uniform colour, but if it had been the outside, it would have been a bad end result.

Second example: Sprayed 5 coats of SPI epoxy (1 hour between coats) in preparation for blocking. Left bumper on work stand for several weeks then went back one day and got it ready to work on next morning. Next morning, go in garage and found it had slipped off the work stand and was laying on the floor face down . Put it back on the stand, not a crack to be found, just a few scrape marks. Processed to block sand and all was good.

I am not saying that SPI Epoxy is the only epoxy flexible enough for Endura repair/repaint, but I am saying I am not convinced "any" epoxy primer is flexible enough for Endura repair/repaint.

Regarding flex additives, just for some interesting info: I always keep a few 1/4" to 3/8" discs of the hardened leftover material I mix in the paint cups, and the disc of single stage urethane I sprayed 2 years ago is still very flexible, almost like a dog's flexible chew toy. I also have a 4-5 year old disc of SPI epoxy and it is still able to be flexed, but it much stiffer than the urethane. You can bend it without breaking, and it will slowly return to its previous shape. A similar disc from urethane primer/surfacer is brittle and will not flex at all without cracking.

And…how long have you been a paint rep ?

[dhutton]

Originally Posted by MUSLCAH

And…how long have you been a paint rep ?

Muslcah, Try it, you’ll like it….

Don

[n20ta2]

It is pretty nice stuff. There are other flexible epoxy options available that would work as well but the spi does sand really nice. It's the first one I have used that sands as easy as 2k. I would like to try there clear as well, I have heard it sands really nice too.

[MUSLCAH]

Originally Posted by n20ta2

It is pretty nice stuff. There are other flexible epoxy options available that would work as well but the spi does sand really nice. It's the first one I have used that sands as easy as 2k. I would like to try there clear as well, I have heard it sands really nice too.

Do you think SPI is a true epoxy primer ? Why is SPI sandable …While the other Epoxy from PPG , DuPont, RM, Ditzler, Spees, Nexa Autocolor, Diamond, Sherwin Williams, HB, glassurith (sp)…are not easy to sand . Is talc in the SPI ?? Maybe all you guys that carry the SPI flag …can educate me.

[dhutton]

Originally Posted by MUSLCAH

Do you think SPI is a true epoxy primer ? Why is SPI sandable …While the other Epoxy from PPG , DuPont, RM, Ditzler, Spees, Nexa Autocolor, Diamond, Sherwin Williams, HB, glassurith (sp)…are not easy to sand . Is talc in the SPI ?? Maybe all you guys that carry the SPI flag …can educate me.

Ask your question on the SPI forum and you will get an honest answer. Or call Barry on the tech line and ask him. He will gladly answer all your questions. And yes, I believe it is a true epoxy. There is no talc in it, of that I am certain.

SPI has experienced huge sales growth so it seems that most open minded folks who try it make the change and spread the word.

Just don’t hammer in the first coat. Medium wet first coat then hammer away…

Don