| Author |
Message |
Jerome J. Lazar, RA, CCS, CSI, SCIP
Senior Member
Username: lazarcitec
Post Number: 1084
Registered: 05-2003
| | Posted on Tuesday, April 22, 2014 - 05:53 pm: |    |
A landscape trellis manufacturer has advised us that their stainless steel wire is coated with a powder coat. No explanation of what type of powder coat - any one want to guess? The stainless steel is Type 316L - I didn't know stainless steel could receive a paint coating? Anyone want to tell me how the paint adheres to the stainless steel? |
Wayne Yancey
Senior Member
Username: wayne_yancey
Post Number: 641
Registered: 01-2008
| | Posted on Tuesday, April 22, 2014 - 06:33 pm: | |
Could be Fluoropolymer meeting AAMA 2605.05 for superior UV protection and chalking resistance.
OR
Super Durable Polyester meeting AAMA 2604.05 for excellent UV protectionand chalking resistance
OR
Regular Polyesters meeting AAMA 2603.03 for good UV protection.
OR
Polyester-Urethanes offer very good UV and chalk resistance.
Polyester-Epoxy chalk when exposed to UV. |
Richard L Matteo, AIA, CSI, CCS
Senior Member
Username: rlmat
Post Number: 646
Registered: 10-2003
| | Posted on Tuesday, April 22, 2014 - 07:14 pm: | |
First - Why would anyone want to coat Type 316L stainless steel in the first place?
Secondly, and more importantly - I've researched this in the past and Jerome is correct - you cannot apply any type of paint coating to stainless, especially 316L because it will not adhere to the stainless.
I would be suspect of their claims. |
Jerome J. Lazar, RA, CCS, CSI, SCIP
Senior Member
Username: lazarcitec
Post Number: 1085
Registered: 05-2003
| | Posted on Tuesday, April 22, 2014 - 09:34 pm: | |
Richard, this landscape trellis manufacturer welds their product together to form a 3-dimensional screen to support plant life, they paint the stainless steel to cover the welds - at least that is their explanation.
I don't understand why they have to paint the welds/fabric, according to the Speciality Steel Industry of NA's Stainless Steel Designer Handbook: "Stainless steels are readily welded, and, unlike most other materials, the work
area can be blended for uniformity of
appearance when polished finishes are
used. Spot welding, on the other hand,
has little effect on the surface, and refinishing
is minimized or completely eliminated." - from the 1998 edition - is this not correct?
As you know AAMA requires a pretreatment of aluminum to ensure that the primer and color coat adhere to the aluminum. Without this pretreatment, the coating will fail, I've seen idiots specify aluminum paint without pretreatment, the results are not pretty and very expensive to repair.
It would make sense that stainless steel requires pretreatment as well, but I've never heard of it, nor seen it specified. SSINA does say stainless steel can be 'colorized' - but I've never seen this and I believe the color is not opaque, so the weld imperfections would be visible.
Perhaps this is why the Landscape trellis manufacturer paints their welded product, because to polish the welds and make it uniform in appearance would be very expensive.
Perhaps one of our peers can offer some knowledge here regarding Type 316L SS painting. Although the amount of landscape trellis is small, this is a Ritz Carlton branded condominium project, ripe for future litigation. |
Jerome J. Lazar, RA, CCS, CSI, SCIP
Senior Member
Username: lazarcitec
Post Number: 1086
Registered: 05-2003
| | Posted on Tuesday, April 22, 2014 - 09:40 pm: | |
Wayne, I agree with you, however AAMA standards apply to aluminum only, my query is regarding stainless steel.
BTW, I refuse to specify non-chrome pretreatment as the recent AAMA 2605 recommends. Chrome pretreatment has 30 years of successful history in South Florida. |
Chris Grimm, CSI, CCS, SCIP, LEED AP BD+C, MAI
Senior Member
Username: chris_grimm_ccs_scip
Post Number: 251
Registered: 02-2014
| | Posted on Tuesday, April 22, 2014 - 10:55 pm: | |
The short answer is usually "manufacturer's standard powder coat finish" in a case like this. Ask for color selection and until then add "color and gloss as selected by Architect from manufacturer's full range." Somebody tell us if there is more that a specifier can really do here, but I think this is one of those times we find how far we are from being omniscient.
For a longer answer, yes, in MPI they do have coating systems for stainless steel - sure sounds crazy to me, taking something that would require zero maintenance and then coating it with something that may come off in 10 or 15 years given that it is exterior and a problematic surface to coat. And if you are growing vines on this thing who is going to see the welds unless they do a horrible job on them? As far as if 316L is different then say Type 304 stainless for coating adhesion, I don't know the answer, I need to get my own copy of Zahner's book, one of just a few holes in my library since going independent.
With powder-coating of manufactured items, specifications are often not very specific. Powder-coating is nothing more than an application technique, and yet there are various resins possible. So it is the same level of detail as saying brush-apply a coating system and we don't know or care which type of coating it is. Strikes as a bit odd since normally means and methods are NOT specified. But that's the current state of most specs today on the subject simply because the manufacturers of various coated products do not give any more data themselves about the coating system. Do you want x y or z coating system and that's all they say.
If this trellis mfr recommends coating it, they must have a standard coating system already and factory-apply it, I would hope.
If you are curious to look it up to confirm its existence,
MPI EXT 5.6D:
Prime Coat: MPI #101.
Intermediate and Topcoat: Epoxy, gloss, MPI #77.
for more info: www.paintinfo.com/mpi/guide/fullspecREV.pdf
http://www.specifypaint.com/apl/paintinfo_apl/MpiNumber.asp?ID=101000
http://www.specifypaint.com/apl/paintinfo_apl/MpiNumber.asp?ID=77000
There are many others including pigmented polyurethane. Coating mfr datasheets would be the way to verify suitability for the types of exposure you have. If you ask the trellis mfr they could probably give you this info. I still think it is crazy to coat stainless steel though. Fencing can come with plastic coating but I won't get started tonight on what kind of material that is. |
J. Peter Jordan
Senior Member
Username: jpjordan
Post Number: 721
Registered: 05-2004
| | Posted on Wednesday, April 23, 2014 - 07:35 am: | |
I'm with Everyone about coating stainless steel, nut know that it can be done. And if you can powder coat MDF, you should be able to coat stainless steel. |
Jerome J. Lazar, RA, CCS, CSI, SCIP
Senior Member
Username: lazarcitec
Post Number: 1087
Registered: 05-2003
| | Posted on Thursday, April 24, 2014 - 03:12 pm: | |
Here is the answer from the Landscape Trellis manufacturer:
"After speaking with our factory, the reason we powder coat the stainless steel is for aesthetics only, as there are approx. 3,600 individual welds on a 4’ x 8’ panel, and it’s not practical to grind them smooth. The type of stainless steel we use has an annealed surface and is “.080 dead soft”, which the powder coat does adhere to , and also adds a little more protection as the stainless steel will eventually rust too.
The paint used in our factory is polyester triglycidyl isocyanurate (TGIC) powder."
OK, this sounds viable, still I've not received their specifications for this, and I apparently won't anytime soon, so how do I specify this. The client wants to keep the spec as a competitive spec, not proprietary? |
J. Peter Jordan
Senior Member
Username: jpjordan
Post Number: 722
Registered: 05-2004
| | Posted on Thursday, April 24, 2014 - 03:32 pm: | |
I am assuming you are talking to the Greenscreen people which isn't really a trellis like I would think of if you memtioned the word "trellis." This falls in the category of a manufactured product that is mass produced, not something that is custom fabricated. You would have to find another manufacturer of this 3-D wire grid product; does anyone know of a competitor?
I think part of the reason for doing the powdercoated finish is the idea of a "green screen." While one hopes that this is covered over with green planting in a relatively short time, you can see the trellis/grid. It is more attractive if it is colored green than it is if it is a stainless steel (even if it isn't shiny). Then there is the issue of what it looks like in the winter,,,
Just sat through an informative lunch-n-learn from Tiger Drylac. Aluminum and steel are the materials most often powder coated, but they do powder coat MDF (evidently some of the stuff at IKEA is finished this way), pultruded glass fiber fabrications, plastics, ceramics, and plastics. One of the limitations is the temperature of the ovens in which the poweder is cured (fused and crosslinked into the durable finish).
Resins used in powder coating include fluropolymer, polyester (in different formulations), acrylics, polyester/epoxy, and epoxy. There can be quite a bit of variation in gloss, durability, and chemical resistance.
The powder-coated finish you get on an item as a "standard manufacturer finish" may or may not have the type of powder that you want or need for your job. Getting it powder-coated to your particular specification might be possible, but might also be prohibitively expensive.
If you really look into it, I think you may find that the manufacturer doesn't really know very much about it. I am a little surprised that the company Jerry talked to knew as much about it as they do and were willing to disclose it. |
ken hercenberg
Senior Member
Username: khercenberg
Post Number: 749
Registered: 12-2006
| | Posted on Thursday, April 24, 2014 - 03:32 pm: | |
Working on a project right now with powder coated stainless steel at glass framing. Trying to steer the client away from this option. It is do-able but it rarely makes sense from my perspective.
Jerry, as to your situation, please make sure your client understands that this will look great for the photos taken when construction is complete and it will be a maintenance nightmare in about 5 years. Polyester is an interior coating that has been overused in the exterior world by people who are offering price instead of quality.
Touch base with some of these folks-
http://www.4specs.com/s/07/07-0840.html?zoom_highlight=living+wall
and see if they have anything useful to offer. If possible, perhaps see if they can offer a PVDF coated stainless steel for maximum durability. I presume you're dealing with both salt spray and live plant concerns, both of which are not very friendly to base metal applications. |
Jerome J. Lazar, RA, CCS, CSI, SCIP
Senior Member
Username: lazarcitec
Post Number: 1088
Registered: 05-2003
| | Posted on Thursday, April 24, 2014 - 03:53 pm: | |
Peter, you are correct in your guess, it is GreenScreen...I can be very persuasive, also GreenScreen 'likes' me because they are fabricating another screen for a current job that I was instrumental in specifying their product, so help me god.
BTW - "...Then there is the issue of what it looks like in the winter." Winter, what is winter? this is South Florida, oh yes, I remember winter when I was a young tyke in The Bronx 50+ years ago, that's when it snows instead of rains...we have no winter in South Florida, maybe the best reason to live and work here. |
Jeffrey Wilson CSI CCS
Senior Member
Username: wilsonconsulting
Post Number: 137
Registered: 03-2006
| | Posted on Thursday, April 24, 2014 - 09:36 pm: | |
When I spec Greenscreen, I generally list McNichols "Eco-Mesh" (mcnichols.com) as a comparable product. I'm not aware that they offer stainless-steel. Steel is their standard substrate, with powdercoat finish. |
Lynn Javoroski FCSI CCS LEED® AP SCIP Affiliate
Senior Member
Username: lynn_javoroski
Post Number: 1794
Registered: 07-2002
| | Posted on Friday, April 25, 2014 - 01:03 pm: | |
Jerome, you mean "Liquid snow" right? What is this "rain" you speak of? |
Brett Scarfino (Unregistered Guest)
Unregistered guest
| | Posted on Friday, April 25, 2014 - 11:52 am: | |
Here is a link from the Molybdenum institute on finishes (btw, 316 contains 2% to 3% Mo, 304 does not):
http://www.imoa.info/molybdenum-uses/molybdenum-grade-stainless-steels/architecture/finishes.php
Follow the "Additional Literature" links at the bottom of the page. |
Wayne Yancey
Senior Member
Username: wayne_yancey
Post Number: 642
Registered: 01-2008
| | Posted on Friday, April 25, 2014 - 02:30 pm: | |
Brett,
Thanks for the llink to IMAO.
Wayne |
Jerome J. Lazar, RA, CCS, CSI, SCIP
Senior Member
Username: lazarcitec
Post Number: 1089
Registered: 05-2003
| | Posted on Friday, April 25, 2014 - 02:36 pm: | |
Lynn, I would assume Liquid Snow is cold coming down, Rain in Florida is never cold unless its hail - when it hails in South Florida, all the native Floridians freak out seeing ice hit their cars and houses, of course the ice doesn't last long, but it still manages to make the local news on those rare occasions. |
Lynn Javoroski FCSI CCS LEED® AP SCIP Affiliate
Senior Member
Username: lynn_javoroski
Post Number: 1795
Registered: 07-2002
| | Posted on Friday, April 25, 2014 - 05:27 pm: | |
"liquid snow" is, I think, what you guys call "rain" - grin |
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