Anodize vs Paint Finishes

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Author Message Russell W. Wood Advanced Member Username: woodr5678 Post Number: 5 Registered: 11-2003 Posted on Wednesday, April 28, 2004 - 11:50 am:    Entrances and Storefronts: Which is better, anodized or paint finishes (Esp or powder coat)? Doesn't anodized (show ware) have chemical when in contact with people? Do you know of a website or article to address this issue? Marc C Chavez Senior Member Username: mchavez Post Number: 31 Registered: 07-2002 Posted on Wednesday, April 28, 2004 - 12:24 pm:    The info I've been seeing suggests that high quality Kynar type paint (PVDF) lasts longer, and can be (to some degree) field patched where as anodizing can't. On the other hand the finish has a very differrnt look. check out atofina's web site. (See Division 9 on this site) Nina Dillon Senior Member Username: nina Post Number: 6 Registered: 04-2004 Posted on Wednesday, April 28, 2004 - 02:23 pm:    When deciding on the appropriate finish you would also benefit from considering the exposure the Entrances and Storefront will experience. Powder coating may not be the appropriate finish in a coastal environment, in areas where UV exposure is extreme you may want to be cautious of certain colors of Kynar coating, various "colors" of anodizing also respond to environments in differing ways. (Unregistered Guest) Unregistered guest Posted on Wednesday, April 28, 2004 - 03:33 pm:    Speaking of "coastal environments," I'm specifying a project located in the immediate vicinity of Corpus Christi Bay. In that location, what's the best finish for aluminum windows and storefront - clear anodized? Kynar 500 (PVDF)? Something else? (I recently saw what looked like clear anodized aluminum door hinges on a 16-year-old cruise ship that appeared to have been eaten up by corrosion.) And, in that location, what's the best finish for steel standing seam roof panels - PVDF on Galvalume, siliconized polyester on Galvalume, or something else? Someone just told me that using Kynar within 1500 feet of the seashore invalidates its warranty. Can anyone confirm or refute that? (I'm not sure how close to the shore this project is, but it could be that close.) Thanks. John Bunzick, CCS, CCCA Senior Member Username: bunzick Post Number: 214 Registered: 03-2002 Posted on Wednesday, April 28, 2004 - 04:52 pm:    I believe that 70% Kynar (there's also 50% and 30% versions) finishes will outlast anodized. Anodizing is less-expensive than Kynar, but has a harder finish. You also want to consider the appearance, obviously, since anodized has a look that can't be duplicated in paint. Anodizing will not fade, though most good Kynars won't fade either, or at least not too much, depending on the color. Anodizing can be adversely affected by acidic pollutants in an urban atmoshpere. The warranty you get on a finish will be from the manufacturer of the finished product, who offers it in conjunction with their paint supplier, so limitations, such as being near the shore, depends entirely on that company. Powder coating is not a type of finish, it is a method of application using paint "powder" (not a liquid!) electrostatically applied,followed by heat fusion of the paint to the substrate. Kynar is generally a solvent-applied system (see below), either coil-coated to sheet metal (aluminum or steel) before manufacture into a finshed product, or it is spray-applied to extrusions. Since it is a shop-applied system, applicators are able to control VOC emissions in their plants so VOC compliance is not an issue. Kynar is a brand of resin made by Atofina. Hylar is also PVDF, equivalent to Kynar made by Solvay Solexis (formerly Ausimont). Manufacturers such as PPG and Valspar make the actual paint. Atofina has recently come out with a powder-coat version of Kynar, but I don't know what paint manufacturers are making it, or who is applying it. Anne Whitacre, CCS CSI Senior Member Username: awhitacre Post Number: 87 Registered: 07-2002 Posted on Wednesday, April 28, 2004 - 11:41 pm:    I seldom disagree with Mr. Bunzick, but I consider the Kynar finish to be a "soft " finish and easily damageable in high-contact areas -- like door frames and doors themselves. Anodizing is a permanent finish that simply needs to be cleaned after.. 50 years or so. There are clear anodized finishes that date back to the 1930's and look wonderful today; and the dark bronzes from the 1960's continue to mellow. Back when Kynar was first being used (about 20 -25 years ago) I was told that "they would invent a recoat product by the time the warranty was up." I haven't seen a field applied coating (especially in a metallic finish) that has the even finish that our office finds acceptable and I have made it office policy (as near as anyone can do that in an architectural office) that we will not specify Kynar coatings for doors and door frames. I have no problem with it for areas that are not easily grasped by people. anodizing is a permanent change to the aluminum surface and cannot wear away, rub off or much of anything else. It will eventually get dirty.. and unlike Kynar coatings, anodizing will age. There are two buildings in Seattle that were done within a year of each other: one has silver anodized panels and the exterior is rather nicely mottled now after twenty years; the other is silver kynar and the surface is flat and not as reflective as it was. also in the northwest, Anodizing is comparable in cost to Kynar -- there used to be a 15% cost reduction but not any longer. There is a limitation to the size of the anodizing tanks -- unlike coil coating, and that will determine what can be fabricated from anodized material. Curt Norton, CSI, CCS Senior Member Username: curtn Post Number: 45 Registered: 06-2002 Posted on Thursday, April 29, 2004 - 08:12 am:    A couple years ago I had to do some research on kynar finishes and was told by a product rep I trust that the 70% system is softer but has better chemical resistance (such as in pool areas) and the 50% system is more scratch resistant. If my memory serves me correctly the 70% comes with a 20 (or sometimes 30) year warranty and the 50% comes with a 15 year color and fade warranty. John Bunzick, CCS, CCCA Senior Member Username: bunzick Post Number: 215 Registered: 03-2002 Posted on Thursday, April 29, 2004 - 09:00 am:    Actually, Anne and I don't disagree -- I intended to say that anodized is a harder finish, but my sentence construction could have been more clear. William C. Pegues, FCSI, CCS Senior Member Username: wpegues Post Number: 266 Registered: 10-2002 Posted on Thursday, April 29, 2004 - 10:12 am:    I have worked with anodizing, kynar (and later hylar) based coatings. I agree with the concensus that the resin based coatings are softer than anodizing, but, they are both damagable over time by contact. Anodizing is still just a surface coating, though indeed it does change the surface of the coating. But if you observer people going through doors, unless you have a full height vertical pull, when the first person goes through and the door is still partly open for the next party, they grabe the vertical stile. Its a human nature kind of response, its the closest/easiest part of the door to reach for, and the reach is usually done at close to shoulder height. Its the contact from rings on the hand that wear on either finish. I have seen doors that are coated with both, in exposed (to rain, no overhang), that have no wear on them at all, mostly protected by the vertical full height pull, or doors that don't receive a stream of traffic - 20 years and more. And I have watched doors of both systems degrade after only a few years when they are totally protected internal vestibule doors due to ring contact or movement of large items through the doors. Concerning the hardness of anodized coatings, it depends on the coating classification, and also on the particular finish designation chosen. There is an interior and an exterior classification of anodizing. Unfortunately, NAAMM muddies the information on the interior grade to the point that some try to influence Owners that it is suitable for exterior exposed conditions. Actually, only the higher quality should be used anywhere, interior or exterior, for a commercial application. There are different surface designations and coating designations for anodizing. The more wear resistant are the ones referred to as medium satin and specular. The first is a close example to number 4 stainless steel, the later to number 8 stainless steel in their surface and reflectivity. Unfortunately, one of the most preferred is what is called medium matte etched. This yields a very uniform grey finish, not shiny, not a directional grain. The top surface of this coating can actually be defaced permanently with your fingernail. Well, not some that are soft, but most peoples fingernails can actually put a permanent scratch by simply drawing your nailes over it heavily. Refinishing, unfortunately, anodizing cannot be reanodized in the field. It is an acid bath, the only recourse is to paint it. kynar based products can be refinished in the field. Some of the manufacturer's, such as PPG, provide an ADS (air dry system) version of their Duranar. It has no warranty, and it is not certified by them, though applicators like to act like it is. PPG states its use be limited to recoating. Some like to show up saying that it is used in new installations coating steel or aluminum 'break metal' window stools typically in new construction. Bad choice, they should not be permitted to get away with it - no warranty, no certification for anything including fade from the manufacturer. Another guide is that the darker anodized finish, when scratched, shows silver through it - remember, it is only a surface finish, even it if is integral to the surface, it has a definite thickness and can be farily easily damaged. If you are in a grafitti danger zone - sometimes the chemicals required to remove it will permanently damage the finish, especially if there is a color to the anodizing. Remember, no field touch up, its replace or paint the component. At least with the 'kynar' based painted finishes you can do touchups. Pardon any typos, 'wordos' and gramatical inconsistencies, I typed this on the fly with many interruptions. William Richard Hird (Unregistered Guest) Unregistered guest Posted on Thursday, April 29, 2004 - 10:43 am:    William: Excellent summary. Hope I can remember it the next time I get cornered. The only thing I can to add to this string is that I have seen window frames where the dark anodized finish was gone on the sharp corners of the frame. Since this was during the final check-out, it was the manufacturer's problem, and the effective windows was replaced. I never did understand how it happened, bad process, bad handling? I also wondered if the other windows would eventulally show the bare aluminum. William C. Pegues, FCSI, CCS Senior Member Username: wpegues Post Number: 267 Registered: 10-2002 Posted on Thursday, April 29, 2004 - 10:45 am:    All that said, let me add comments about a newer generation of the resin based coatings. Actually, it is not that new, and has been available for some years. The resin is the next generation of kynar/hylar, it is Lumiflon. Those how walked the exhibit floor may have noticed they had a booth at the CSI Show. Note that this is only the resin, it is not the finish system. Like kynar/hylar, that is not the name of the coating, it is a trade name from the actual coating manufacturer (Duranar in the case of Kynar based coatings from PPG), and the coating trade name from PPG for the Lumiflon based coating is Megaflon. Megaflon is a 100% resin (as opposed to Duranar 70% resin) based coating. Major aesthetic differences are that colors can be brighter. The Lumiflon resin is clear, the kynar/hylar resin is milky. Warranties for Megaflon are 20 years standard. Air dry, field applied or for field fabricated components that need final coating in the field or touch up their system is called Coraflon ADS. This is identical to the spray Megaflon shop coating, still 100% resin, except that it is VOC compliant. Unlike kynar based non-warrantied air dry systems, Coraflon has a 10 year warranty. Unlike the kynar based products which are warranted only for application to an aluminum substrate (though some have put it on other things with no warranty) the lumiflon based prodcut can be put on any substrate to which it can adhere. We routinely specify it on architecturally exposed structural steel, steel space frame components supporting glass atrium skylights, etc. But we have also applied it to mdf board (with recommended preparation and primers from the manufacturer) and we have specified its application to fiberglass gel coated panels for exterior facade components (the adhesion tests just came back on that as acceptable). We used it mostly in minor applications, but about 3 years ago, a client who had us do 3 12+ story buildings in the 1960s that were metal panel and a mixture of porcelain enamel coated panels and dark bronze anodized framing components, came to us for repainting suggestions. We suggested the field coating of the entire facades with the lumiflon product. All 3 buildings were then recoated in the field with the Megaflon ADS coating (prior to its name change to Coraflon by PPG), color was a medium gray. All 3 buildings were completed very quickly, from surface preparation, priming to final coating. There are also a few other existing buildings in downtown locations here in Washington DC where they were recoated with Coraflon by other architects. Again, excuse the grammar/spelling this time around. William Ronald J. Ray, RA, CCS, CCCA Member Username: rjray Post Number: 3 Registered: 04-2004 Posted on Thursday, April 29, 2004 - 10:47 am:    My experience with finishes on high use doors is primary with schools and sports facilities. The typical application is to use PVDF finish on frames (assuming that a “color” finish is desired) and to use clear anodized finish on the doors. Doors are subjected to many potentially damaging occurrences, including damage from keys held by people, finger rings, and items people may be carrying. I have not found any PVDF coating that can resist this kind of abuse. There are formulations of both 70 percent and 50 percent PVDF finishes, such as Valspar Corporation Fluropon Hardcoat and Acrodized Hardcoat, which provide harder finishes that are more abrasive resistant, but in my opinion, do not offer the durability of a Class 1 clear anodized finish. Regarding warranties, spray applied PVDF finishes, which are applicable to aluminum extrusions, typically have a 5 year warranty against chalking and fading. Coil coated PVDF finishes, which are applied to sheet materials, typically have a 20 year warranty. Regarding finishes of roof panels in coastal areas, I recall that “Galvalume” experiences corrosion problems in costal environments. I would suggest contacting a metal roofing manufacture, such as Berriidge Manufacturing Company, to obtain their recommendations. I do know that many metal panel manufacturers do not recommend coating “Galvalume” with PVDF finishes. My recommendation for a metal roof in a coastal area would be Type 316 stainless steel AAMA has several publications on aluminum finishes that may be helpful to read. William C. Pegues, FCSI, CCS Senior Member Username: wpegues Post Number: 268 Registered: 10-2002 Posted on Thursday, April 29, 2004 - 10:50 am:    Richard, I would have to see it to know for sure, but I have seen this myself where the packaging protection for the components being shipped about after coating rubbed the sharp corners. I have also seen it where it was caused by installation of calking and glazing where the contractor did not protect the installed work, but there the wear marks are localized not even across the length of the item. For anodizing, this is an acid bath. Corners can still be a problem, but if it came out of the coating batch process with incorrectly finished edges it could be a problem with that particular anodizers coating process. William William C. Pegues, FCSI, CCS Senior Member Username: wpegues Post Number: 269 Registered: 10-2002 Posted on Thursday, April 29, 2004 - 10:57 am:    With regard to doors of clear anodized finish vs painted doors (regardless of coating type), its definitely the better way to go. But, its not that they don't scratch - its that when they do, which they will fairly easily if you look at it, you just can't see it that easily. When you scratch clear anodized aluminum, its a silvery finish, and the exposed aluminum itself is silvery, so it does not show. But scracth, and esaily if it is keys or rings - yes it will. Its definily the smart way to go though if you have to provide a coated door. William Anne Whitacre, CCS CSI Senior Member Username: awhitacre Post Number: 88 Registered: 07-2002 Posted on Friday, April 30, 2004 - 04:42 pm:    I would also add that our office has used the Megaflon coatings on some large structures (transit shelters and the like) where the pieces were too large to be factory coated. Our results have been mixed -- we're not that satisfied with the coating, but also recognize that for large structural shapes that cannot be shop painted, we don't have a lot of options. We have been very dissatisfied with any metallic coatings that are field applied; somewhat less dissatisfied with the non-metallic colors. Not only is the color not as evenly applied as we would like, but any field touch up... is visible enough that I hear grumbling back at my desk... from across the office. You will need to ask for samples if you are using these coatings, and of course, the samples need to be prepared by the applicators who will be doing your field work. William C. Pegues, FCSI, CCS Senior Member Username: wpegues Post Number: 271 Registered: 10-2002 Posted on Sunday, May 02, 2004 - 01:38 am:    Anne, Its all working with the right applicator. We have never had any problem with either color matching or gloss matching of non-metallic colors - but you have to do your color matching in advance, during submittals, getting and approving samples in advance. As you said, you cannot just show up on the site and start mix and matching. And you have to know there is no way that any field application is ever going to have the consistency of texture that a shop applied spray has. And, if you are trying to match coil coating to field coating - that's not really going to happen - even coil coating to factory spray is different in texture and that creates changes in some colors and definite changes in gloss. For metallics, you are way out on a limb - factory spray again is very consistent, and the stroke of the sprayer is the same direction. In the field, that may not be possible, especially if you are doing an installed piece, you may not be able to spray in the same direction. Direction has everything to do with metallics, it determines the direction in which the particles lie and how they reflect. Coil coating to spray metallics (factory or field) will be very difficult. All the problems related to the flats, plus the coil coating metallics the flakes are oriented totally different than any spray, and the coil coating super smooth surface versus the spray surface - that really changes the character of metallic coatings as well. And that is not just megaflons, that's any generic type of paint. Megaflon has neither more nore less problems than any other kind of paint when trying to match field spray to factory spray to coil coatings. Its going to be a problem, and even more so in metallics. Field touch up - we avoid this as much as possible. We don't want to see it. I specify for the items that will have to take the field spray that the contractor is required to indicate in advance and receive approval for coating them with that system, that we may not approve it, and that unless the item is going to obviously damaged during installation (such as field bolted connections that are intended to be exposed) even though the field coating is to be used, the pieces are to be coated by the applicator at his shop in a shop like condition. That leaves only items that would have damaged the coating to be coated in the field. On top of that, it is specified that any item in this category will be completely coated in the field. It will not be shop coated with the factory coating, nor with the field coating in a shop condition, it will be all coated after installation. How do we get good work? First, we work very closely with the manufacturer. PPG has an excellent group in their field applied Megaflon (now called Coraflon) division. We talk with them about how the parts are intended to be assembled, and they provide input as to which kinds of coatings should be used. They will provide advice on the best matching - perhaps even a panel needs to be field coated because it is running between 2 pieces of field applied structural shapes. If it is necessary, we will provide guidance on the drawings themselves about which type of the coating is used on what components if it is really complex and also really visually important. In addition to that, when the project goes out, PPG will work with the contractor and their approved applicators to make sure the ones with appropriate experience are considered - and they will also work with the applicator during the process to provide as much technical response as possible. And seriously, if I was trying to work with any generic type of coating where it was being color matched across shop spray, shop coil coating and field spray in the same color/sheen - and most especially with the addition of metallics, I would look for the level of input from the coating manufacturer - because its not going to work right with any of them. One of the major problems with color sheen matching of coatings is that we bring all the pieces in the different coating methods together at common intersections. This is a major error. They can come close, but seriously, they can never match. Paints like to try for it, so separation and distance is not commonly provided. We all need to remember the advice of NAAMM in color matching bronze/brass alloys - that they are to be considered as matching in color when they are viewed with the samples 3 feet apart from each other and the viewer at a distance of at leasat 3 feet from the sample. They may fail the match when touching or the viewer is closer, but, they are still considered as matched with the 3 plus 3 criteria. That's the way we should treat paints. Bring dissimilar coating methods closer than 3 feet to each other and then view them at closer than 3 feet - you are going to see irregularities - but then you can't NOT see them when you do that. Its the nature of the coating systems that they are different. Unfortunately, it is the nature of designers to ignore common sense at times too. Do it right and Megaflon/Coraflon will provide equally acceptable color and gloss matching in solid or metallic colors as any other coating system where you have to work with field spray, factory spray and factory coil coatings. William Anonymous   Posted on Monday, May 03, 2004 - 10:52 am:    With all due respect William, just how many hours could you potentially spend on writing the aforementioned storefront section, when you include the discussions with PPG (or whomever)? As you mentioned, a recent project with metallic PVDF coil coated metal panels encountered "different" appearance due to the "direction" of coating application. We did NOT take the design/contract docs time to research/pursue the intracacies of finish variations for the project and now have to accept whatever it is because our docs were not explicit enuf. Even then, our spec dept was criticized for blowing the specs budget...and not by a small amount. BTW - there was also no (or very little) internal const docs coordination review...again, due to what I perceive as "no time" or rather no budget (really lack of foresight in pursuing the public project in the first place) to do so. One would think that historically specifying just the same few colors, would provide the know-how, etc. about the inherent properties, but PM seems to repeatedly take budget shortcut and not take a more proactive approach during CDs...in ALL aspects of project. William C. Pegues, FCSI, CCS Senior Member Username: wpegues Post Number: 272 Registered: 10-2002 Posted on Monday, May 03, 2004 - 12:14 pm:    Anon, For any given new project, less than 30 minutes on the coatings section over the full life (start through completed construction) of the project. There is no significant time needed to review documents for finish directions - I have a checklist interview with the PM and PA for the project. When I see PVDF coatings of any kind, they get a verbal alert in addition to what is written into the checklist - cautioning against creating problems due to panel/extrusion proximity and field vs shop coatings. Given that I have been with them in this capacity for 21+ years, everyone pays attention. The success in doing any effort comes from creating a process. And recording it in my notes to specifiers in the master and in the checklist interview document so that next time through I don't forget. I do both materials reserach as well as specifications. The first interaction I had with megaflon was not project oriented, I thought it was an interesting material that could solve a lot of problems. I did some initial investigation, asked some questions, recorded it for the future. It was 2 years later that the first opportunity came to use the material and suggested its use to the project manager. But I was aware of some, not all, of the different interactions that need to take place. That was probably about an hours worth of initial investigation spread out over time. But its not part of writing the section - I do this for many products, some of which are ultimately never used. Some I do specifically to be aware of why I DON'T want to use a product and be able to substantiate why I recommend against it. That's product research. The first project was the first 'recoat' of 1 of the 3 existing buidlings. The Owner of the buildings wanted to understand the product, so I put him in direct contact with the PPG rep that specifically dealt with recoating. I asked him to specifically go over certain points, and I asked him to contact me with a sumary of what was discussed. I had already learned that in the recoating projects that he was willing to assist the Owner in evaluating the bids, and that he would also contact those coaters in the area to make them aware of the project. Pre-emptive effort to make sure you get what you want with I know the GC has no real knowledge of the system. I guess that took all of 30 minutes in contacting him, and reviewing what was gone over and their recommendations, and various other interactions that included discussions during the construction process. Its really keeping in touch with things. Because this was a recoating project, included in this was an investigation of the surface and condition of the existing building. This would be recorded as part of the develpment of the specification - but then, its the nature of a major recoating. You have to know what is there. That was a 3 hour effort that included travel to and from the site, and going over the building with the PPG rep. Out of that, he went away and then sent me the recommended surface prep, primer, coating system description. I worked that into the specification section and the entire 05080, Metal Coatings section took 20 minutes or so, probably less, to develop. The site trip would be part of that. The other 2 buildings were put into a single project, done together after the success of the first building. I took 15 minutes of exchange with the PPG rep to see if there was anything to be added to what was learned from the first building, and then again, 20 minutes or less to develop the section. The 15 minute discussion was high, but then it was talking about discoveries of coatings over coatings and what really had to be done. The next project after that was a small lobby renovation project. The Owner wanted to keep the metallic coating but on the ceiing which was a complex coffering design, he wanted to see if we could do something with MDF board. I sent an email to the PPG rep, I guess that was 3 minutes. He emailed back to me first a statement that they would have to check, then a couple days later, a surface prep and coating system description. I knew the nature of factory vs field metallic coatings, I took maybe 5 mintues to look at the lobby drawings to assure that there was good separation between the coated surfaces (one storefront, the other the intereior ceiling). There was, and I informed the Project Management team that this is something that needs to be recorded in our design manual - that we always need to have separation if possible. Here we have a system for recording that so that all PMs and Designers are aware - its made part of history. We try to learn from our success as well as our mistakes. Total time on the projects coating section for both metal and mdf board, less than 15 minutes for the life of the project through its completion. Its hard for me to say anything with a section takes less than 15 minutes, basic set up and variuos review printings take that. Now - the process is the same, and for a new major project with lots of potential problems in it, the time to develop the section, including interaction with the PPG representative is less than 30 minutes. The request for color matching samples goes through me, and I got to one person to get color matching requirements for all related coatings (Duranar, Megaflon or Coraflon). He handles all the coordination. Its sending an email that describes the conditions and surfaces and he sends back recommendations. It takes almost no time at all. When I see something that is a potential problem, simply alert the design/production team and tell them they can arrange to see the PPG person to discuss potential problems so there is no surprise. I think my office is simply set up differently than yours. William Anonymous   Posted on Monday, May 03, 2004 - 03:41 pm:    William, I did not expect a minute-by-minute accounting of time. My comment was intended to be self-deprecating, as I most often do not even have the benefit of reviewing drawings...I sometimes believe that they want to spare the expense of plotting and/or think it may take time for me to read them. Obviously your organization understands the value of specifications and is supportive of your process. Russell W. Wood Senior Member Username: woodr5678 Post Number: 12 Registered: 11-2003 Posted on Monday, May 24, 2004 - 01:38 pm:    What is coil painting? I'm not familar with the term. I am familar with paint appilcations such as electrostatic (ESP) or powder coat. Also, I have a spec for baked enamel aluminum window frames, what is application for baked enamel? Anonymous   Posted on Monday, May 24, 2004 - 01:49 pm:    Coil painting, prepainted. Before it is shaped. (Unregistered Guest) Unregistered guest Posted on Monday, May 24, 2004 - 06:22 pm:    Better known, perhaps, as "coil coating"... "Coil-coated" is a familiar industry term, but "coil-painted" is not; coil coating is for things that can be coiled - thin and flexible, such as sheet metal... Ronald L. Geren, RA, CSI, CCS, CCCA Senior Member Username: specman Post Number: 32 Registered: 03-2003 Posted on Monday, May 24, 2004 - 07:10 pm:    I recommend visiting http://www.coilcoating.org/process/. It explains the coil coating process. Russell W. Wood Senior Member Username: woodr5678 Post Number: 13 Registered: 11-2003 Posted on Wednesday, May 26, 2004 - 09:37 am:    I know powder coat is an electrosatic application. Prior to powder coat applications, it was common for solvent-borne paints to be appilied by electrosatic (ESP) method. Are solvent-borne paints still electrostatically applied today? John Bunzick, CCS, CCCA Senior Member Username: bunzick Post Number: 223 Registered: 03-2002 Posted on Wednesday, May 26, 2004 - 01:31 pm:    Both are spray applications. The paint or powder is given an electrostatic charge as it leaves the gun so the droplets are attracted to and adhere to the substrate with more energy. Though I don't know specifically, it would seem likely that solvent-borne systems are still done the same way. Anonymous   Posted on Wednesday, May 26, 2004 - 08:51 pm:    Not exactly, John. Powder coating is a process where powder is propelled toward a metal substrate that is electrically charged. There are no droplets because there is no liquid involved. The powder that doesn't stick is collected at the bottom of the chamber and reused. The charged, coated item is then conveyed into an oven where the powder is heated and melts to form the final coating. There is a new powdercoat product for use with MDF substrates, but instead of being electrially charged, the MDF is first heated to a fairly high temp and the powder sticks to it, as I understand it. John Bunzick, CCS, CCCA Senior Member Username: bunzick Post Number: 224 Registered: 03-2002 Posted on Thursday, May 27, 2004 - 08:37 am:    Anon: True, "droplet" was not the best term to choose to describe the form of the powder particles as they are propelled from the gun. I was trying to make the same point you did--thanks for the clarification. I believe there are processes now where powder coating can be applied to non-metal substates, too. Ronald J. Ray, RA, CCS, CCCA Senior Member Username: rjray Post Number: 11 Registered: 04-2004 Posted on Thursday, May 27, 2004 - 08:48 am:    A.W.P. Wood Products Inc. applies powder coat finishes to a material similar to hardboard. I have specified this process for finishing wood doors provided by demountable wall system manufactures in order to achieve a metallic look. Don Samdahl (Unregistered Guest) Unregistered guest Posted on Friday, January 06, 2006 - 02:43 pm:    My wife and I are building a house which we want to have a glass wall 32' wide and 14' high. We envision a storefront or curtainwall style with each pane in the wall being about 2'x4'. We want the wall to be double paned, low e. We want the wall panes to be aluminum. We would like the aluminum to be a golden color. Would anodizing be a good way to go for this? Could anyone suggest a manufacturer for this type of product or point us in the right direction? Thanks. Richard L Matteo, AIA, CSI, CCS Senior Member Username: rlmat Post Number: 136 Registered: 10-2003 Posted on Friday, January 06, 2006 - 07:01 pm:    Don, First of all - in what part of the country are you located? It also depends on whether you are on the coast or inland. Anodized aluminum has a tendency to pit if near the ocean. William C. Pegues, FCSI, CCS Senior Member Username: wpegues Post Number: 515 Registered: 10-2002 Posted on Saturday, January 07, 2006 - 10:34 am:    Don, Also, it depends upon how 'golden' you want the color to be. Anodizing is limited in range of color for the real durable finishes. There are some bronze tones that simulate various stages of statuary bronze (browns) the lighter of which might be in your direction. Anything other than a brownish tone that tends to golden is going to be a process where they add color to the system. Unfortunately, exposure to direct sunlight these fade out over the years until you are left with the silver finish of natural anodized aluminum - which can look a bit strange as the parts not so exposed keep their color longer. But even interior, these colors do fade. We are talking only 3 to 5 years for an exterior application to be noticable in its fade. There is also no field touchup of anodizing - though it is classified as a coating, it is really a time/temperature acid bath, with or without the dye. The only thing you can do is paint it. The brown 'bronze' colors, if you go that way, don't fade as it is not a dye. And if you get a good quality exterior grade version of the coating, it will last. One of the problems, especially in the coastal environments is that some manufacturers want to give you the lower quality finish telling you its not going to get a lot of abuse so you don't need the heavier quality. Basically that is incorrect. Anything exterior or exposed to a lot of direct light, or that is in contact with being cleaned or touched, and anything in a coastal environment should be the heavier quality. William Dave Metzger Senior Member Username: davemetzger Post Number: 150 Registered: 07-2001 Posted on Sunday, January 08, 2006 - 02:38 pm:    Another consideration that hasn't been discussed above is uniformity and consistency of appearance. Paint coatings will have a uniform appearance, when properly applied. Anodizing, however, can be non-uniform, and this is inherent in the process. This is usually not an issue with stick shapes such as framing for windows, storefront, entrances, curtainwall, and skylights. But it can be noticeable for wider forms such as wall panels and spandrels, especially in the bronze color ranges. This is less an issue with clear anodized and even black anodized, though even there the appearance is not as consistent as with painting. Also, again in particular for the bronze anodized color ranges, is the difference in appearance between different batches. About 25 years ago, we had a project with light bronze anodized storefront, skylights, and flashings, each from a different manufacturer, and ended up with 3 different appearances. All were within the "light bronze" range, but the anodizing process cannot be controlled like the formulation of paint colors can. John Bunzick, CCS, CCCA Senior Member Username: bunzick Post Number: 451 Registered: 03-2002 Posted on Monday, January 09, 2006 - 08:51 am:    Good point, Dave. Along the same theme, I have specified PVDF-painted products from different manufacturers, but required each of them to use the same paint manufacturer and color. One needs to verify during reseach that they each are willing to use the desired manufacturer, but for a reasonably sized job, this may not be a problem. Anne Whitacre, CCS CSI Senior Member Username: awhitacre Post Number: 281 Registered: 07-2002 Posted on Monday, January 09, 2006 - 12:37 pm:    anodizing actually ages -- how I interpret that is that over time, a series of anodized panels will each turn a slightly different color, providing some variation to the surface. we have two buildings in Seattle that were both constructed about 20 years ago. One was of clear anodized panels, the other was silver PVDF panels. The anodized panels have an interesting variation to them; the painted panels all look exactly the same, except that they have gotten rather "flat" looking as the gloss has dissipated. I think the anodizing is more interesting, and oddly enough it seems more "natural" to me.