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  • Questions for the chrome shooters...

    For those of you who have shot a variety of "chrome" powders, I have a couple of questions and a request for advice.

    First of all, let me explain that this is a hobby for me. I use an Eastwood Hot Coat gun because it was inexpensive and I had no plans to do more than a few parts for myself. I simply cannot justify the cost of an adjustable or corona discharge type gun; this is not a revenue stream for me. I am willing to accept that as a limitation; should the answer to my questions boil down to "get a better gun" then I'm prepared to send my parts elsewhere to get the results I'm after.

    All my questions are in reference to chrome powders and their post-treatment; if you have no experience with these powders, I'm not really interested in hearing from you. (No offense meant; you're simply not the target of this question in this is public forum.)

    1) The two chrome powders I've used may be the same; they look identical to me once cured. One is Eastwood's "reflective chrome" and the other is PBTP "ultimate chrome." Both of these products claim to require a clear coat and three types of clear I've tried severely "darken" the finish.(*) Is this normal? (The clears I've tried are Eastwood's "ultra clear low-temp," PBTB's "super durable high-gloss crystal clear" and "diamond acrylic clear.")

    2) I'm very happy with the look of the chrome powders after application; every part I've done comes out highly reflective, very smooth and I was initially impressed with the powders. It's close enough to the real thing that it's difficult to tell in photos that it's not real chrome and as I said, I'm very happy with the results. I've read elsewhere that the PBTP "bonded chrome" does not require a clear coat, but is suggested for UV protection and "mar resistance." What is your experience with this powder? Is it as "bright" as the ultimate chrome? Does it truly need a clear-coat in low-duty applications?

    Finally, my request for advice; I'm prepared to hear that I'm just being too demanding of these products. I understand these powders are on the forefront of the technology and this process simply isn't going to duplicate true chromium plating. I don't expect it to and again, I'm happy with the pre-clear coated parts. Please help me understand, from your customer's satisfaction with your preferred "chroming" method, how I can get the best results with the equipment I have.

    You may recall my earlier issues with clear powders; I have overcome these issues with a new IR gun and some confidence in my oven and the powders themselves; I believe I was "checking" my parts too often, preventing the parts from ever coming up to temperature and my IR gun simply wasn't up to the task.

    Thank you in advance for your consideration and your advice. Please be honest; I have no disillusions that I may well not be equipped or prepared to get the results I want.

    -Deek

    (*) By "darkening" the part I mean that the parts are still reflective, shiny on the surface, but the quality of the reflection is flawed... see the images below that illustrates the reflection in two parts that have been chromed identically, and one clear-coated with PBTP's acrylic clear. (My favorite clear so far)

    [EDIT] Edited to add email notification. [/EDIT]

  • #2
    Re: Questions for the chrome shooters...

    I've shot quite a bit of the assorted chrome powders. PBTP's Bonded Chrome is very similar to Eastwood's Single Stage Chrome, both in looks and durability. All of the other reflective chromes will need a clear or they will tarnish and discolor very quickly. The single stages will also discolor after a year or so unless they are exposed to direct sunlight and/or chemicals, in which case they may discolor much sooner. Unfortunately, any clear over the reflective chromes will dull them. There is no getting around it...yet. They do end up looking more like shiny silver after clearing. Hopefully the technology will be there in the near future to produce a chrome-looking powder that will maintain its shine after clearing, but we're not there yet.

    Best of luck.
    Dan
    sigpic

    I carry a gun because I'm too young to die, and too old to take an ass-whoopin'!

    Comment


    • #3
      Re: Questions for the chrome shooters...

      I agree with Wise. Long story short, you want chrome or polished aluminum, you need to start polishing or sending stuff out to the chromer. Chrome powder WILL NOT resemble the reflective chrome you want to see after it is cleared. PERIOD.

      I see this question more than any other, and as much as people say, try this, and try that, I have yet to be able to do it myself, more importantly have never seen it replicated anywhere.

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      • #4
        Re: Questions for the chrome shooters...

        I have been playing with chrome at the moment
        [attachment=1:14kytlu5]mail-4.jpeg[/attachment:14kytlu5]
        [attachment=0:14kytlu5]mail-3.jpeg[/attachment:14kytlu5]

        I wont say who's but it is quite good
        I lacquered with a 2k iso lacquer on this one and it came out quite good and retained the reflective quality of chrome
        not perfect but as close as i have got
        Mike

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        • #5
          Re: Questions for the chrome shooters...

          I've used the Eastwood chrome with the hobby gun and was pleased with the results. Unfortunately the clear destroyed the finish. Mine turned grey not silver. I'm not sure how to get a 'light' coat of clear on the part. How do you control the amount of clear coming out of the gun and laying on the part when there are no controls, other than air pressure, to control the coverage? Lower the pressure and nothing comes out...
          Lower the powder level and the window of perfection comes and goes like a fart in a windstorm...

          I'll use the chrome again but until I step up and get a good gun I'll pass on clearing.

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          • #6
            Re: Questions for the chrome shooters...

            Originally posted by Doogles
            I've used the Eastwood chrome with the hobby gun and was pleased with the results. Unfortunately the clear destroyed the finish.
            I'm in the same boat!

            Originally posted by Doogles
            Mine turned grey not silver. I'm not sure how to get a 'light' coat of clear on the part. How do you control the amount of clear coming out of the gun and laying on the part when there are no controls, other than air pressure, to control the coverage? Lower the pressure and nothing comes out...
            Lower the powder level and the window of perfection comes and goes like a fart in a windstorm...
            This is what I was eluding to in my original post. I initially thought this to be a result of poor equipment or a mismatch of raw materials. Since then, through the posts here and research elsewhere, I've found that a large percentage (most) photographs of "chrome" parts are pre-clear coat! I wouldn't call my parts "gray" because they do shine in the sunlight, but under low lighting they do have a decidedly "dull" or "dark" appearance.

            As for controlling the clear coat; the Eastwood clear and the Super Durable... clear go on very nicely for me; the acrylic clear is another story. The key for the first two is getting a good ground. I haven't found any tricks yet for the acrylic. What seems to work best for me is to use moderate pressure (around 7 lbs) and back off the part quite a bit. When I get too close, areas that are covered get uncovered... it's odd; almost as if the gun is pulling the powder off the part. (Which I suppose is possible; the powder will go wherever the charge potential is greatest and if the powder has "flipped" then the gun would have higher potential.) I notice that I have to clean off the tip of my gun much more often; I'll do 2 or 3 passes and blow off the tip, 2 or 3 more, etc...

            Originally posted by Doogles
            I'll use the chrome again but until I step up and get a good gun I'll pass on clearing.
            I can't be sure, because I don't manufacture the powder, but my impression is that the clear is required to prevent oxidizing. I hear talk of "tarnishing" and discoloration and this would indicate to me that the metal or metalioid in the powder that provides the reflectivity has some moderate level of reactivity. Again, I can't be sure, but I would be surprised if the metaloid weren't a silicone or aluminum alloy. If that were the case, I would expect the finish to dull or discolor in a very short time. (less than a year indoors, much faster if exposed to the elements)

            We do high-speed vacuum evaporation (sputter) here at work and the un-cleared chrome looks very much like our aluminized layers prior to laquer application.

            -Deek

            P.S. Thanks to everyone for their posts. I've learned a lot these last few days and I'll just say this: I'm ready to be done with chrome, but I'm ready to start on candies!

            Comment


            • #7
              Re: Questions for the chrome shooters...

              Originally posted by Smartway
              I have been playing with chrome at the moment
              [attachment=0:119iyp8l]mail-3.jpeg[/attachment:119iyp8l]

              I wont say who's but it is quite good
              I lacquered with a 2k iso lacquer on this one and it came out quite good and retained the reflective quality of chrome
              not perfect but as close as i have got
              Mike
              So that part is "chromed" with powder coating then clear-coated with lacquer?

              Interesting mix of materials there; I'm surprised the solvent in the lacquer didn't discolor the chrome when sprayed. Do you mind saying what extender you used in the lacquer?

              I wiped a part with lacquer thinner and it turned it into primer gray!

              -Deek

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              • #8
                Re: Questions for the chrome shooters...

                So that part is "chromed" with powder coating then clear-coated with lacquer?

                Interesting mix of materials there; I'm surprised the solvent in the lacquer didn't discolor the chrome when sprayed. Do you mind saying what extender you used in the lacquer?

                I wiped a part with lacquer thinner and it turned it into primer gray!

                -Deek

                Yes Chrome powder remove from the oven and let it cool down ( not totally )
                It needs to be just warm to the touch, ( if you let it cool down totally the lacquer clouds at first but apply heat it clears}
                The lacquer did not cloud when the part was warm

                you cannot touch the chrome with any products before applying the clear , thats why a lacquered it warm to get adhesion

                The main problem I had was the part was blasted and I went straight on with the chrome which due to the age of the part left it slightly orange peel and that spoiled it somewhat

                The Lacquer is a 2k iso anti scratch clear this mixes 2 parts lacquer yo one part activator and is not really classed as a solvent more a polymer so is less likely to attack the chrome

                The next one i am going to powder high gloss black first and try to get it as flat as possible this should help the chrome to be more reflective

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                • #9
                  Re: Questions for the chrome shooters...

                  Not strictly Powdercoating related, but "chrome effects" certainly...

                  I recently coated a part with Alsa Corp's "Killer Cans" Killer Chrome kit.

                  Wow.

                  Durability is laughable as compared to powder coated parts, but it's as close to real chrome as I've ever seen.

                  I'm going to see if I can use mirror black powder, their chrome spray, and a powder clear. (Just to compare results)

                  -Deek

                  Comment


                  • #10
                    Re: Questions for the chrome shooters...

                    Sorry FirstYearDeek for the late reply, but i had to freshen up my _Chrome-powder_ knowledge.

                    The darkening/dulling of the chrome-powder you see with a clear coat is a well known effect for all chrome powder coatings. Since you are not using real Cr-24, but rather a pigment which looks like it, you will never have the chrome look.

                    The effect is caused by leafing (or better in your case: de-leafing) of the pigments.
                    The pigment used in all chrome powder coatings is aluminium, they are shaped in a sequin form and very small, close to 5-6 microns in diameter but 2 dimensional.
                    Most of them are treated with some form of stearic acid, which helps it to make the bond to the polar/unpolar chain of carbon atoms. Al(III) by itself would not bond, it is not bipolar enough.

                    During curing, the alu-pigment floats to the surface, it will organize itself in a perfect parallel to the surface pattern, kind of staged if you look from the side. By doing this it creates a perfect, continous layer of little mirrors -> gloss and refelction 100%

                    Unfortunately, aluminum pigments react with water, air humidity is enough. Over time the alu will oxidize and the effect is gone. Alu is also a very weak/soft pigment and you can scratch the surface very easy.

                    The biggest problem in/with leafing pigments is its color change when you try to double coat it with a clear. By applying the second coat and curing it, you melt the surface with the perfect paralllel sequins, light will be scattered and diffused -> perfection gone.
                    Your eyes pick that up as dull or gray looking or just darker.
                    [ A broken mirror is always darker at the rift compared to an even surface, light is absorbed]

                    Up to now there is no known way to stop the dissolvage of the important leafing layer.
                    Big german/austrian companys are working on this. They add inhibitors to the resin system and coat the alu pigments with inhibitors also in order to make it a single coat system which doesn't have this effect.
                    They are fighting many physical problems: Has to be a leafing pigment which is reactive, scratch and mar resistance, overall durability and most important: Cheaper then real croming.

                    Right now, there is just no way to protect the pigment layer for outdoor usage without a clear coat on top, this will cause the dullness and darker look.

                    Some people, like you, try to cold coat the second clear layer, but you still add another layer of broken reflection and this takes away the briliance of the first coat.

                    Trust me, if i knew a way to make it happen, i would not type this but be on my way to Milwaukee and knock on the door in Juneau Avenue.

                    B

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                    • #11
                      Re: Questions for the chrome shooters...

                      Originally posted by benwish
                      Trust me, if i knew a way to make it happen, i would not type this but be on my way to Milwaukee and knock on the door in Juneau Avenue.

                      B

                      Whats in MKE on Juneau?

                      Comment


                      • #12
                        Re: Questions for the chrome shooters...

                        B,

                        Thank you for your very detailed and technical explanation.

                        I'll report back on the Alsa chrome product, though I'm not sure I expect better results, now that I've read this.

                        The one advantage their chrome layer may have over a powder layer is that it's thinner and bonded; that is it won't be suspended again when cured.

                        If that's the case, we may have a winner on our hands.

                        Another interesting thought was that of smartway... a topcoat that is not thermo-set but still protects the layer from oxidation but with a minimum of scatter might be the best bet for low-duty (decorative) applications.

                        The luggage racks I've been agonizing over this past week really do require the durability inherent, so I'm hoping the Alsa product pans out.

                        Thanks again!

                        -Deek

                        Comment


                        • #13
                          Re: Questions for the chrome shooters...

                          Another interesting thought was that of smartway... a topcoat that is not thermo-set but still protects the layer from oxidation but with a minimum of scatter might be the best bet for low-duty (decorative) applications.

                          Just to add the lacquer I use is a high solids iso lacquer used on cars like Mercedes so is a very tuff and durable finnish
                          it will flat ant polish to a very good if not perfect finish.

                          I am going to do some more test pieces like this and also some in pc top coat
                          I will post pics when done if you like or

                          "if I get them right is more likely"

                          Comment


                          • #14
                            Re: Questions for the chrome shooters...

                            Anyone try laying down the chrome and clear powder and then curing? I know a while back I did a test sample with some trans powder and it turned out pretty good.
                            http://i73.photobucket.com/albums/i210/a426fan/dan2.jpg

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                            • #15
                              Re: Questions for the chrome shooters...

                              Originally posted by X-Link
                              Anyone try laying down the chrome and clear powder and then curing? I know a while back I did a test sample with some trans powder and it turned out pretty good.
                              I did some little metal spacers last night using this method; I used the Ultimate Chrome and Acrylic clear.

                              It looks (to my eye) exactly like the two-step process.

                              May work better with a different clear, I don't know, but it sure saved me some time!

                              -Deek

                              Comment

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