| Author |
Message |
Nathan Woods, CCCA, LEED AP
Senior Member
Username: nwoods
Post Number: 344
Registered: 08-2005
| | Posted on Friday, October 08, 2010 - 12:34 pm: |    |
I have a corrogated metal panel system specified inside a govermental institutional facility that is specified to receive a baked-on polyester paint coating, in a custom color. My quanity of panel required is small (400 sf), and as typical, the contractor is now trying to back out of it, saying that he needs to order 4500 sf of material to get this color. Instead, he wants to use a polyuerathane, presumably sprayed on in his shop.
I'm not a chemist. I'm only worried about durability, color and finish.
What do you reccommend? What should I watch out for? |
Richard Gonser AIA CSI CCCA
Senior Member
Username: rich_gonser
Post Number: 7
Registered: 11-2008
| | Posted on Friday, October 08, 2010 - 12:43 pm: | |
Hi Nathan,
What manufacturer's product? Is it a custom color? It sounds a like a bid bust regarding price not an availability problem. |
Nathan Woods, CCCA, LEED AP
Senior Member
Username: nwoods
Post Number: 345
Registered: 08-2005
| | Posted on Friday, October 08, 2010 - 12:52 pm: | |
It's always a bid bust. That is what I am trying to solve, rather than insisting on the spec and jeopardizing an already tenuous situation (hugely political project).
What I am looking for is technical comparison information between Polyester finishes and polyurethane finishes. |
Dave Metzger
Senior Member
Username: davemetzger
Post Number: 374
Registered: 07-2001
| | Posted on Friday, October 08, 2010 - 01:13 pm: | |
The contractor's reason sounds legitimate. Usually sheet metal panels are coil-coated, which means the whole coil needs to be ordered with the custom color.
We specify polyurethane paint for exterior use frequently, though typically it's been for components such as on-site railings or framing rather than metal panels.
You can see properties of their polyurethanes by looking up data sheets for Tnemec paints (Series 73 Endura-Shield, or Series 1074 or 1075 Endura-Shield II, all of which are aliphatic acrylic polyurethanes) on their website, www.tnemec.com Click on "Resources", then "PDS", then "Performance Criteria". You'll need to log-in in order to to download performance criteria, which is a pain. |
Paul Gerber
Senior Member
Username: paulgerber
Post Number: 30
Registered: 04-2010
| | Posted on Friday, October 08, 2010 - 04:54 pm: | |
Another alternative would be a site or shop-applied electrostatic finish.
In a previous life I worked in the construction and development department of a large grocery retailer. A great number of the stores had prefinished, premanufactured aluminum panels at the entrances (Alucobond/Kanalco/Alpolic). When there was a change in corporate branding with new colours, we had a painting contractor who came on site and electrostatically painted all the existing panels in place and you couldn't tell they weren't factory prefinished! Part of the success of this method was the fact that the paint they used was about $160/gal...but that is still cheaper than buying an entire coil of steel for 400 s.f.
Ride it like you stole it!!! |
Anne Whitacre, FCSI CCS
Senior Member
Username: awhitacre
Post Number: 1027
Registered: 07-2002
| | Posted on Friday, October 08, 2010 - 06:28 pm: | |
You don't say where the coated material will be installed (other than inside); the polyurethane may actually be more durable and hold up better under handling. The coil coated finishes do tend to be a bit soft and will mar and scrape; the polyurethanes can come in formulations that are much harder to the touch.
use one system of products (pretreatment, primer, coating) and have it done in controlled shop conditions as recommended by the coating manufacturer. You can get as good appearing installation as what you specified. I agree with David about the Tnemec paints -- they are my standard for interior high performance steel frames and other interior metals that will be subject to some abuse. |
(Unregistered Guest)
Unregistered guest
| | Posted on Friday, October 08, 2010 - 06:41 pm: | |
Thanks guys!
(why isn't my log-in info persistent?) |
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