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Thread: Epoxy or Urethane primer over mixed finish frame?

  1. #1
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    Question Epoxy or Urethane primer over mixed finish frame?

    I have a '65 Impala frame that I rattle canned about 13 years ago with enamel and the finish remains in quite good condition, no rust (wasn't rusty back then either). Since I'm now doing a suspension rebuild I decided on a urethane upgrade while she's fully disassembled (engine and sheet metal are also removed). Not sure what my prep was back then but since the finish looked quite solid I just took a wire wheel to it and the paint come off relatively easy but a very sturdy red(ish) primer (oxide?, OEM?) underneath remained mostly intact. Figured it's so well adhered why remove more than necessary.

    Question now is -- Since wheeling it had me exposing only a few small spots of bare metal should I switch to a urethane primer or remain with my original intent to epoxy it prior to a urethane top coat. I have no need to sand between coats since a non-massaged OEM look is what I'm after. Maybe epoxy for the sealing properties since I'm unsure of the coating that remains? I'm just brainwashed by having heard so many times "epoxy over bare metal only" that I can't help to question epoxy over any other surface despite application labels.

    Thanks!

  2. #2
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    Quote Originally Posted by aurecom View Post
    I have a '65 Impala frame that I rattle canned about 13 years ago with enamel and the finish remains in quite good condition, no rust (wasn't rusty back then either). Since I'm now doing a suspension rebuild I decided on a urethane upgrade while she's fully disassembled (engine and sheet metal are also removed). Not sure what my prep was back then but since the finish looked quite solid I just took a wire wheel to it and the paint come off relatively easy but a very sturdy red(ish) primer (oxide?, OEM?) underneath remained mostly intact. Figured it's so well adhered why remove more than necessary.

    Question now is -- Since wheeling it had me exposing only a few small spots of bare metal should I switch to a urethane primer or remain with my original intent to epoxy it prior to a urethane top coat. I have no need to sand between coats since a non-massaged OEM look is what I'm after. Maybe epoxy for the sealing properties since I'm unsure of the coating that remains? I'm just brainwashed by having heard so many times "epoxy over bare metal only" that I can't help to question epoxy over any other surface despite application labels.

    Thanks!
    Since you have some bare metal spots I'd recommend you apply a "direct to metal" (DTM) product first. We use a lot of Zero Rust on frames and under vehicles, it's not expensive, looks good and is easy to apply.


  3. #3
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    Quote Originally Posted by aurecom View Post
    I have a '65 Impala frame that I rattle canned about 13 years ago with enamel and the finish remains in quite good condition, no rust (wasn't rusty back then either). Since I'm now doing a suspension rebuild I decided on a urethane upgrade while she's fully disassembled (engine and sheet metal are also removed). Not sure what my prep was back then but since the finish looked quite solid I just took a wire wheel to it and the paint come off relatively easy but a very sturdy red(ish) primer (oxide?, OEM?) underneath remained mostly intact. Figured it's so well adhered why remove more than necessary.

    Question now is -- Since wheeling it had me exposing only a few small spots of bare metal should I switch to a urethane primer or remain with my original intent to epoxy it prior to a urethane top coat. I have no need to sand between coats since a non-massaged OEM look is what I'm after. Maybe epoxy for the sealing properties since I'm unsure of the coating that remains? I'm just brainwashed by having heard so many times "epoxy over bare metal only" that I can't help to question epoxy over any other surface despite application labels.

    Thanks!
    if you're dead set on a 2k product i'd use epoxy as the first coating over what you have. i think it's less likely to have issues with the substrate as it is. but really, the product len suggests is a fantastic coating for the undercarriage. it's easy to apply, looks like a factory coating, and is easy to touch up when you get the inevitable chip. i've sprayed, brushed and rolled it on with great results.
    b marler

  4. #4
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    Appreciate the replies!

    Zero Rust would make life easier especially considering I just raised the body off-frame today, something I wasn't really intending to do aside from replacing body mounts. I now have a fair bit more frame to address and, while it's not heavily rusty (especially topside), ZR would allow a little less prep.

    So the question has to be asked -- What sheen does Zero Rust's black offer? I'm looking for a satin. It seems 10 to 1 with 1.4-1.6 is suggested for spray? Any preferred thinner and...possibly a hardener?

    *EDIT* -- Just found the following "A reduction of 15-20% with xylene is typical. Recommended thinners are xylene, lacquer thinner, acetone, and acrylic enamel reducer. Do not use mineral spirits or VMP Naptha for thinning."

  5. #5
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    Quote Originally Posted by aurecom View Post
    Appreciate the replies!

    Zero Rust would make life easier especially considering I just raised the body off-frame today, something I wasn't really intending to do aside from replacing body mounts. I now have a fair bit more frame to address and, while it's not heavily rusty (especially topside), ZR would allow a little less prep.

    So the question has to be asked -- What sheen does Zero Rust's black offer? I'm looking for a satin. It seems 10 to 1 with 1.4-1.6 is suggested for spray? Any preferred thinner and...possibly a hardener?

    *EDIT* -- Just found the following "A reduction of 15-20% with xylene is typical. Recommended thinners are xylene, lacquer thinner, acetone, and acrylic enamel reducer. Do not use mineral spirits or VMP Naptha for thinning."
    zero rust has very little sheen, maybe slightly less than satin. i reduce it with xylene to spray, 1,3 tip conventional gravity feed gun. no hardener. on other one part paints i've experimented using acrylic enamel hardener with very good results, but i haven't tried it with the zero rust. really though, the fact that it's not a hardened paint is one of the things that make it so easy to touch up when you do get a chip in it. a little scuff with a pad and you can recoat it with hardly any prep.

    oh yeah, the spray can has exactly the same paint in it, just a little more reduced. get a can and paint something so you can see for yourself how it looks.
    b marler

  6. #6
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    Quote Originally Posted by bmarler View Post
    zero rust has very little sheen, maybe slightly less than satin. i reduce it with xylene to spray, 1,3 tip conventional gravity feed gun. no hardener. on other one part paints i've experimented using acrylic enamel hardener with very good results, but i haven't tried it with the zero rust. really though, the fact that it's not a hardened paint is one of the things that make it so easy to touch up when you do get a chip in it. a little scuff with a pad and you can recoat it with hardly any prep.

    oh yeah, the spray can has exactly the same paint in it, just a little more reduced. get a can and paint something so you can see for yourself how it looks.
    I apologize for being MIA. Definitely want to thank you for the insight!

    Now I have a couple more questions and the first pertains to the following quotes I dug up in this forum while researching.

    Zero Rust is an excellent product over bare metal but not over rust.
    If I understood correctly, Zero Rust can be applied to bare metal (sand blasted), wire brushed, or any risidual paint and/or rust providing the surface is scuffed and cleaned. Correct?
    That's correct except I would treat/convert the rust before applying the ZR.
    This is making ZR appropriateness (in the real world) over even de-scaled and de-powered rust not recommended.

    The second question would be -- Does ZR black flash satin enough that a second coat of the same black's coverage can be easily determined? My project now is a frame and underside for which I expect a gallon would be enough for 2-3 coats. I was contemplating contrasting coats (red oxide/black) but leery of excess waste if another project doesn't come around in time.

  7. #7
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    Quote Originally Posted by aurecom View Post
    I apologize for being MIA. Definitely want to thank you for the insight!

    Now I have a couple more questions and the first pertains to the following quotes I dug up in this forum while researching.




    This is making ZR appropriateness (in the real world) over even de-scaled and de-powered rust not recommended.

    The second question would be -- Does ZR black flash satin enough that a second coat of the same black's coverage can be easily determined? My project now is a frame and underside for which I expect a gallon would be enough for 2-3 coats. I was contemplating contrasting coats (red oxide/black) but leery of excess waste if another project doesn't come around in time.
    I normally recommend at least two coats and if you apply them carefully you can probably get away with just black but it's usually easier to see which surfaces need the additional coats when a different color is applied first. You can spray it in sections so that it's easier to count the number of coats in those areas.

  8. #8
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    Quote Originally Posted by aurecom View Post
    I apologize for being MIA. Definitely want to thank you for the insight!

    Now I have a couple more questions and the first pertains to the following quotes I dug up in this forum while researching.




    This is making ZR appropriateness (in the real world) over even de-scaled and de-powered rust not recommended.

    The second question would be -- Does ZR black flash satin enough that a second coat of the same black's coverage can be easily determined? My project now is a frame and underside for which I expect a gallon would be enough for 2-3 coats. I was contemplating contrasting coats (red oxide/black) but leery of excess waste if another project doesn't come around in time.
    zero rust is able to be applied over de-scaled rust directly, but we always recommend to treat the rusted surface first as an extra bit of protection.
    you will be able to tell the difference in sheen between cured and fresh. i always let it sit overnight before re-coating.
    b marler

  9. #9
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    Appreciate the replies Len and bmarler.

    As with most every coating I'm sure ZR can only benefit from "best practices". Since the description reads as an encapsulator it's not dependent on a rust conversion process for adhesion thus every bit of mitigation should be a positive.

    Thanks!

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