Archive through September 09, 2011

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Author Message David Axt, AIA, CCS, CSI Senior Member Username: david_axt Post Number: 1241 Registered: 03-2002 Posted on Thursday, August 25, 2011 - 01:44 pm:    I have a situation where a glulam beam is exposed on the outside of the building and on the inside of the building. How do I handle putting a clear coating the beam? Can I use one paint product instead of an interior and exterior paint product? Mark Gilligan SE, Senior Member Username: mark_gilligan Post Number: 411 Registered: 10-2007 Posted on Thursday, August 25, 2011 - 03:19 pm:    Treat it the same as a piece of sawn lumber David Axt, AIA, CCS, CSI Senior Member Username: david_axt Post Number: 1242 Registered: 03-2002 Posted on Friday, August 26, 2011 - 01:05 pm:    Okay then I guess I will use nitrocellulose lacquer. Thanks! anon (Unregistered Guest) Unregistered guest Posted on Friday, August 26, 2011 - 03:35 pm:    try ZAR by UGL. Dave Metzger Senior Member Username: davemetzger Post Number: 399 Registered: 07-2001 Posted on Friday, August 26, 2011 - 05:16 pm:    I'd be antsy about using nitrocellulose lacquer for exterior use, due to its only moderate water resistance, and also its tendency to yellow as it ages, which shows clearly on light-colored woods. Also, assuming it's field-applied, will there be VOC issues if this is a LEED project? The only exterior clear coating for wood that I've found to be durable is spar varnish--if someone is aware of other clear-coat products with a good track record for exterior use, I'd be glad to hear of it. Again, VOC content could be an issue for interior use of spar varnish. John Regener, AIA, CCS, CCCA, CSI, SCIP Senior Member Username: john_regener Post Number: 539 Registered: 04-2002 Posted on Sunday, August 28, 2011 - 01:54 pm:    Is there a limitation on VOC for the coating? There's an indoor air quality issue that now (at least in California) applies to non-LEED, etc. projects. There are considerations for local air quality management authorities as well as the indoor air quality czars. Anne Whitacre, FCSI CCS Senior Member Username: awhitacre Post Number: 1197 Registered: 07-2002 Posted on Tuesday, August 30, 2011 - 12:09 pm:    I agree with Dave about the Spar varnish for the exterior. Don't forget to have the treatment done after all fastener holes are drilled, so that the inside of the holes gets the treatment, too. This can be shop done, actually with field touch up -- but there shouldn't be any field touch up if all cuts are done in the shop. In the northwest, these coatings work the best if they are shop done and protected until installation is complete. as to Mr. Regener: the Puget Sound Air Quality guys are strict, but its not like California where there are "Washington versions" of various finish projects. You can still get solvent based coatings that actually work. Jim Sliff Senior Member Username: jim_sliff Post Number: 91 Registered: 08-2010 Posted on Wednesday, August 31, 2011 - 06:14 pm:    lacquers and related finishes are a specialty area I deal with daily, a real problem, and tied to both my consulting and hobby - so I'll be happy to provide any info or research you need. This specific subject is a "pet peeve" so I take off the consulting badge (and shove invoices in a bottom drawer) and provide all the advice I possibly can. I'll have a few questions, so if nothing's been decided hopefully I can help. I have to run to an appointment but will post when I get back. Jim Sliff Senior Member Username: jim_sliff Post Number: 92 Registered: 08-2010 Posted on Thursday, September 01, 2011 - 02:11 pm:    OK, I'm WAY late! Anne, we still get solvent based coatings that actually work; it's really the applicators having to re-train themselves every time there's a change that's the problem. Manufacturers do little to notify users of formulation changes and keep the same product name even when the application characteristics are quite different. OK - First, everyone is right about spar varnish on the outside, although it will yellow as much (if not more) than some modern lacquers. It really depends on individual products. As far a "nitrocellose lacquer" goes, I don't like it on any laminated product. Even though almost all modern lacquers are nitro/acrylic blends (whether they say so or not, and an MSDS doesn't tell you either) with improved flexibility they'll still crack eventually. When it comes to lacquers and related finishes, I wear two hats - one my "work" hat, the other refinishing guitars as a hobby. There is a lot of interest in duplicating instruments of the 50's and 60's, especially "relic" finishes, where the finish is artificially aged, worn, discolored, cracked etc. Here's somebody's random example (not one of mine - I don't usually post pics of my work): http://www.josephmind.com/TeleRelic.jpg This has caused a huge resurgence of wood finish debates, overflowing into wood finishing of any kind - furniture, architectural etc. It's also caused a huge amount of confusion and disinformation, some specific to the guitar world (some claiming they can "hear" differences between nitrocellulose lacquer, acrylic lacquer, polyester and polyurethane finishes...which is nonsense) and some applicable here. When you specify "nitrocellulose lacquer" you could end up with pure solvent-type "nitro", acrylic/nitro blend or water based lacquer. Some products labeled "lacquer" are not really lacquers as we think of them, but conversion varnishes or other clear (or in some cases pigmented) coatings. What John mentions regarding VOC's is important almost everywhere, though - because if it says "lacquer" on the label that's how it's classified under air quality regulations. Some jurisdictions have exemptions for 1-liter and smaller containers...some don't. But the general rule is that it's illegal to sell, apply or *specify* products that exceed the upper VOC limit of their classification. And some local rules differentiate between interior and exterior applications. So before you decide *what* to specify, you need to know, of the possible product types you can think of, what the air quality rules are for both the application process(es) and each "candidate". It gets stickier. Shop-applied finishes fall under another set of rules, so if that's a possibility it needs to be considered. To make the pile even higher, if shop application is to be done (or is an option) you need to be sure the system can be touched-up in the field. Then once you have all that info for all possible candidates, you need to know the location of the application(s). You may have a system that can be legally applied in the shop and touched-up in El Paso but if the shop finisher is in Phoenix he may only be able to apply products that can't be touched up in El Paso... Ergo - unless you can control the location of the application you might need to include some language that requires bidders to ensure such products can be used in both locations if necessary. It still may be tangled up in the submittal process but at least the burden is clearly on the contractor to provide a workable solution. And that's without even getting to what's specified vs what's used. Some are very insistent they want "nitrocellulose lacquer" and not "acrylic lacquer", insisting the latter is inferior and that the two are also incompatible (especially when acrylic is applied over nitro). I want to make sure there's a clear understanding of one important fact that seems to cause confusion every other day - "acrylic lacquer" DOES NOT mean it's water-based. The fact is that with a few exceptions sold in small quantities (and not suitable for larger projects) almost every solvent-type lacquer made today (actually in the last 40 years) is a blend of nitro and acrylic. Acrylic resins were added initially to automobile finishes (which were nitro) to improve flexibility - and eventually almost all "lacquer" became "acrylic lacquer". The two are *usually* compatible - there are some highly-pigmented acrylic lacquers (in neon-like colors) that are not compatible with anything but themselves, but those are very isolated conditions not likely to be encountered. But to make this very clear - unless you specify "water-base lacquer"...you'll likely get acrylic lacquer (meaning a blend) or possibly pure "nitro", which is fine too. But there are often problems with submittals of "acrylic lacquer" where "lacquer" is specified. There shouldn't be. I avoid it by specifying "nitrocellulose or acrylic-nitrocellulose blend lacquer". Then things won't get bogged down later on. But I generally go with water-base lacquer in architectural applications as VOC levels are generally lower, chances of early yellowing are lower, they're more apt to be in use by shop finishers and they're usually less expensive while providing performance equal to acrylic lacquer. Most paint reps know far less about lacquers than the woodworking folks; I usually refer to the Woodwork Institute of California's finish systems when I'm looking for a generic type for a specific application - then go to the MPI list for approved products. Hope that helps - If anyone has a specific question shoot me an email! Gerard Sanchis Senior Member Username: gerard_sanchis Post Number: 45 Registered: 10-2009 Posted on Friday, September 02, 2011 - 02:18 pm:    David, Glulam is not the same as a piece of sawn lumber contrary to what Mark advises you to do. Be careful with exterior glulam beams. I don’t know where your project is located, but we had a case where the architect used exposed glulam beams (they were used as beams/railings on bridges between low rise residential towers) on a project located within a stone’s throw of the ocean in SoCal. The glue formulation may have changed since, but at the time it was an organic-based adhesive. It turns out that in a humid environment tiny creatures got in the glue line and ate most of it causing a major failure of the beams/railings. What we had were pieces of unbonded wood and fat bugs. Since then I believe AITC has changed the formulation of the adhesive, but we always recommend a sheet metal cap on glulam beams exposed to the elements to keep most of the water off the beam. As for finishing the members, we specify that a first coat of finish be factory-applied so that even in transit there is some protection against wetting. I dislike spar varnish; it yellows quickly, is a hard finish, and has to be re-applied too often, especially on the West and South exposures, as anyone who’s ever owned a wooden sailboat knows. Sikkens has a good line of exterior finish products with UV inhibitors although they are translucent; their Cetol SRD and Cetol 1 + 23 Plus have worked well for us in the past. You might want to give them a call. Hope this helps. Mark Gilligan SE, Senior Member Username: mark_gilligan Post Number: 414 Registered: 10-2007 Posted on Friday, September 02, 2011 - 03:27 pm:    This is the first time I have heard about bugs eating the glue in glulams in over 38 years dealing with glulams and other engineered wood products. I will offer a couple of facts that might provide another explanation for the reported problems. Any glulam used in an exterior environment or where there is high humidity should be made using exterior glue as opposed to interior glue. If interior glue is exposed to high moisture levels it will loose strength. It is my impression that most manufacturers are now regularly using exterior glue for all glulams but I would still explicitly call out the use of exterior glue for members that will be exposed to moisture. The code requires that glu laminated members that are not shielded from rain be treated or protected by a metal cap. Reference IBC Section 2304.11.3. While the code only addresses this issue for laminated lumber the same problem applies equally to sawn lumber that is similarly exposed. This has nothing to do with the fact that the lumber has been laminated. Because the laminations are not treated before laminating and because of problems associated with treating the members after fabrication the treated wood option is typically not viable for laminated lumber. The wood that you are applying the coating to is the same as a piece of sawn lumber. I will admit to not knowing if the coating will interact with the gluline in some way but I would suspect that if it was a likely problem that we would have heard more comments about this on this thread. Suggest that you contact AITC. Gerard Sanchis Senior Member Username: gerard_sanchis Post Number: 46 Registered: 10-2009 Posted on Friday, September 02, 2011 - 05:56 pm:    Mark, The project I mentioned with the glue eating bugs was designed in 1977 or 1978. AITC standards have changed since then. We asked AITC for advice at the time and their finding was as I stated. Even if the wood is treated, I would recommend a metal cap for beams exposed to the elements. Mark Gilligan SE, Senior Member Username: mark_gilligan Post Number: 415 Registered: 10-2007 Posted on Friday, September 02, 2011 - 07:49 pm:    If you put a metal cap on glulams then do the same for sawn lumber because the issues are the same. I have still not heard anything that causes me to modify my original recommendation that the coating applied to a glulam should be the same as applied to a piece of sawn lumber. In both cases you are interested in protecting the wood from the effects of high moisture content. Richard L Matteo, AIA, CSI, CCS Senior Member Username: rlmat Post Number: 444 Registered: 10-2003 Posted on Monday, September 05, 2011 - 09:55 pm:    Okay, let's end the guess work here. I spoke with a friend of mine who has done glulam projects here in southern California, and near the ocean, with the beams being both interior and exterior. His recommendation based on what he has used is the West Epoxy System, either 105 or 106, with the 207 hardener. The finish is "water clear" This product also complies with SCAQMD (South Coast Air Quality Management District) requirements for VOC's for field application. If you need more info, please e-mail me at richard.matteo@stvinc.com Colin Gilboy Senior Member Username: colin Post Number: 277 Registered: 09-2005 Posted on Monday, September 05, 2011 - 10:01 pm:    West epoxy is by the Gougeon Brothers and is a marine epoxy intended to stand up to marine conditions: http://www.westsystem.com/ I have them listed in the wood repair section and not general coatings. Colin Gilboy Publisher, 4specs.com 435.654.5775 - Utah 800.369.8008 Richard L Matteo, AIA, CSI, CCS Senior Member Username: rlmat Post Number: 445 Registered: 10-2003 Posted on Monday, September 05, 2011 - 10:12 pm:    That may be true, but two of the projects the product was used on were glulams on high end homes, at least one of which is in Laguna Beach, right near the Ocean. It was used as a general coating for glulams on at least 2 projects and there have not been any issues. Gerard Sanchis Senior Member Username: gerard_sanchis Post Number: 47 Registered: 10-2009 Posted on Monday, September 05, 2011 - 11:57 pm:    Richard, I'd like to see the result. How long ago was the epoxy coating applies? We're always looking for compliant products in SoCal. Do you have an address? You can send it to me at the email address below. anon (Unregistered Guest) Unregistered guest Posted on Wednesday, September 07, 2011 - 12:50 pm:    Epoxy coatings will yellow and/or chalk when exposed to direct sunlight/UV. I doubt that westsystems has an epoxy that defies this basic law of resins. Mark Gilligan SE, Senior Member Username: mark_gilligan Post Number: 416 Registered: 10-2007 Posted on Wednesday, September 07, 2011 - 06:05 pm:    Is the epoxy rigid or can it accommodate dimensional change in the wood due to changes in moisture content? While glulams are made of "dry" wood there is still some moisture adjustment that will occur during use especially if the epoxy does not totally encapsulate the member. David Axt, AIA, CCS, CSI Senior Member Username: david_axt Post Number: 1245 Registered: 03-2002 Posted on Wednesday, September 07, 2011 - 06:11 pm:    I agree with anon. I thought that epoxies yellowed very easily. Jim Sliff Senior Member Username: jim_sliff Post Number: 93 Registered: 08-2010 Posted on Wednesday, September 07, 2011 - 06:59 pm:    They do, generally. But there has been quite a bit of progress in epoxy technology in the last 7-10 years. I would agree that most epoxies do yellow under extended UV light exposure - but there are some resin systems (some 100% solids amines and some epoxy/polyester hybrids) that demonstrate on a fraction of the yellowing we encountered consistently 10-15+ years ago. There is, for example, epoxy resin technology used in a large percentage of modern surfboard manufacturing (especially after the demise of the largest foam blank manufacturer, forcing new technology development to fill market need) - Surftech is probably the best known manufacturer, using an epoxy resin to saturate fiberglass over a molded (as opposed to cut/sanded) foam or other synthetic core. Many of the lower-cost boards are plain white (to reduce cost) - I've never seen one turn yellow, and they're subjected to UV light every time they're used. I've also tested samples of a few epoxy floor coatings that have also been touted as having "reduced yellowing qualities", running a UV light curing machine over them (from another technology) that would yellow a "normal" epoxy in minutes and been quite surprised - the yellowing was not completely eliminated but it was very subtle. Part of the rise in floor coating technology (in regards to non or reduced-yellowing epoxies) is due to some reluctance to use polyurethanes as an alternative because of the isocyanate component. With proper controls iso-containing systems like polyurethane or the one really gaining ground, polyurea, are as safe as other coating systems, but many engineers and health officials see "isocyanate" and "have puppies". It's simply a lack of understanding, but the result has been progress in epoxy technology to fill those gaps (whether they're valid or not) and new products that just are not the same "epoxy" we normally think of. They are, however, not as prevalent in the Architectural market as in marine and manufacturing. That's why I'd like to see case histories on West's products. Since one of the sellers is about 4 blocks from me I may just go over and pick some up for a "marine environment architectural test" (My wife HATES the south side of our house - it gets sun but the neighbors can't see it - perfect for test applications!) With enough case history backup I may slip it into my otherwise WIC/MPI based wood finishing specs. anon (Unregistered Guest) Unregistered guest Posted on Thursday, September 08, 2011 - 06:05 pm:    don't forget about the chalking... From Epoxy Paints 101: "The disadvantages of epoxies are that they tend to be brittle, quickly yellow in sunlight (white becomes a creamy color, light blue becomes light green, etc.) and lose their shine in sunlight. The yellowing and loss of gloss (even chalking in some cases) is due to the affect of UV on ALL epoxies (some epoxies will yellow in days, others take weeks but they all do eventually)." http://www.epoxyproducts.com/epoxypaint101.html Jim Sliff Senior Member Username: jim_sliff Post Number: 94 Registered: 08-2010 Posted on Friday, September 09, 2011 - 12:12 am:    I just spent the better part of 90 minutes pouring through "Epoxy 101". Hopefully what I found will prevent others from wasting their time. "Epoxy 101" is a proprietary site put together by one man who does not manufacture epoxies (at least as far as I can tell). He owns a company that distributes several obscure brands. It's a large website that has pages and pages of "value base" epoxies (a term that scares me right off the bat!) apparently manufactured by small blenders (another tidbit I found) and distributed by the owner of Epoxy Paints 101. It's a sales site with difficult-to locate technical specifics. Read on, it gets even more tangled - The MSDS's I located did not disclose clearly the manufacturer; one notes that some components are not disclosed because they're trade secrets. That doesn't fly on an MSDS, so either they're unaware non-hazardous ingredients don't need to be referenced or unaware that full disclosure of hazardous ingredients is required unless a specific waiver is obtained from the federal government for security reasons. There's limited information on the site, no matter how massive they try to make it - and oddly, if you email them they (right at the email link) notify you that contacting them means you agree to all their terms, conditions, safety info and several other conditions that are so restrictive I could never contact them. I've never seen anything like it. The products on the site are totally unfamiliar; personally I've spent the last 18 years with the bulk of my time dedicated to specification, tech support and/or inspection of industrial coatings, and not to blow my own horn...but I would have probably *tripped* over a gallon or two in that time! The products listed on the site are not on the MPI approved products list or any of the popular manufacturer-listed master spec systems. None of the manufacturers I could find buried in the content are Sherwin Williams, Carboline, Tnemec, PPG, Akzo-Nobel, Rust-Oleum, Comex, Benjamin Moore, or any other of the commonly-specified brands. I mention this not to diss the products "anon" may be selling, but to clarify that "Epoxy 101" as linked above is a sales-pitch site tied to small manufacturers. It's NOT a strictly generic technical reference; it also is pushing products outside the realm of commonly-used/supportive manufacturers and, if "anon" really believes his technical comments, uses dated technology in many cases. We all mention brands now and then when they fit specific project needs, but those of us who do (me included) are not connected to any manufacturers. IMO "anon" is a salesman and his "technical information" regarding epoxies is out of date. Many of the major manufacturers have made huge strides to get past the yellowing issues, chalking (not necessarily a defect - in some cases an advantage), and while there's some good information on the *several* linked websites I located there are no specifications nor Architectural-specific project histories. Not to play "forum cop" - but either "anon" is unaware of the basic forum guidelines for product reps or is ignoring them. I just hope I've saved a few folks some valuable time. It didn't bother me - this is the kind of thing I need to know about! anon (Unregistered Guest) Unregistered guest Posted on Friday, September 09, 2011 - 03:20 pm:    Jim, I'm not a product rep. Just a lowly specifier. I agree that the web site is lacking, but the information is consistent with all of the "commonly specified brands" information about epoxy coatings that I have seen. It was not my intention to promote the products on this website, but merely to reinforce the fact that epoxies do not perform well for color, chalk, and fade when exposed to UV light. I called my trusty Carboline rep to ask if there were any new epoxy products on the market suitable for architetcural exterior use that I should know about. "No." he replied - without a moment's hesitation. Carboline's exterior urethanes are tested for color retention, chalking, fading, etc. Epoxies are not. Urethanes are the recommended coatings for durable exterior exposures. Epoxies are not. Opaque or transparent, makes no difference. And this is the same information I have received from Tnemec, Sherwin Williams, and Kelly Moore to name a few. I would be very interested in knowing about new, technologically advanced epoxies that do perform well when exposed to UV, so if you know of any, please share. I am always on the lookout for new, innovative products. Jim Sliff Senior Member Username: jim_sliff Post Number: 95 Registered: 08-2010 Posted on Friday, September 09, 2011 - 05:57 pm:    Well, "anon" - refusing to identify yourself and linking to a sales site centered around one particular person's "opinions" certainly *looks* like a sales push. Your "trusty Carboline Rep" I'm sure is very qualified when it comes to Carboline/RPM's product line, which has a firm foothold on the industrial market. It's just not the call I would have made - there are manufacturers that cover a wider swath of application types; also, there are small manufacturers that sell to nothing but the OEM market that most of the major industrial guys won't be aware of. I will make an assumption (usually a bad idea, but I think right on the money here) and state that from my perspective the Carboline rep answered your question **based on his company's product offerings**. I have worked with (and against, when on the sales/tech side with Tnemec and Rust-Oleum) Carboline many times, and at least in the SoCal market I have not found them to look outside their own loop for cutting edge products - not even within the RPM group (some reps are known for "poaching" accounts that are well-entrenched with their sister RPM companies. "Carboline's exterior urethanes are tested for color retention, chalking, fading, etc. Epoxies are not. " Did he tell you that? Because it's absolutely incorrect. Every one of the epoxy manufacturers I named tests epoxies for color retention, chalking and fading (plus yellowing, which you omitted). "Urethanes are the recommended coatings for durable exterior exposures. Epoxies are not. Opaque or transparent, makes no difference. And this is the same information I have received from Tnemec, Sherwin Williams, and Kelly Moore to name a few." Really? Why are epoxies specified for exterior chemical containment areas that are exposed to UV light and other applications such as anti-skid ramps? Could it be that the abrasion resistance (as a rule) far exceeds most urethanes? Or are you simply wrong? If you check with your SW rep, ask about Epoxy/siloxanes - good color retention and chalk resistance (among other advantages). And Polyamides in some formulations, water based epoxies and hybrids apparently defy your stated "basic law of resins". This is the frustrating part of consulting - convincing folks that historical characteristics, rumors and tales of woe regarding many coatings system no longer apply. One huge disconnect, especially with larger companies (SW, Benjamin Moore, Kelly-Morre etc.) is that not all reps are well-versed in industrial coatings technology - not their own products or those of other manufacturers. Worse, store personnel are rarely, it seems, trained in heavy technical jargon. But here are some simple facts: We've already been given a source by a qualified Specifications Consultant for non-yellowing (I'll fudge and say "reduced" yellowing) epoxies. Here's another - from the website YOU referenced. The link on your site goes to a very generic page stating Bio-Clear 810 yellows in weeks. But here's a statement from a site covering pourable grade epoxies, including specifics on the same product: "When using pourable epoxy, make sure you use a non-yellowing epoxy, such as bio clear 810, by progressive epoxy polymers". To continue my surfboard-industry connection data: "Oceanside CA Jan 2011: After many epoxy resin versions, we introduce the XTR-20 , (20 min. pot life), that will solve all yellowing problems related to epoxy resins in general, This new resin was designed at Epoxy Pro only for surfboard lamination, for those customers who own an Epoxy surfboard that turns yellow this is the ultimate solution." Also note - I don't know exactly what your Kelly-Moore rep told you about epoxies, but if it concerned their water based epoxies those are known for significant reductions in yellowing. If it had to do with KM's solvent-type or 100% solids epoxies - those are buy outs. They don't even make them. I'm not going to belabor this any longer, and simply close with these specifics: 1. Colin posted a source that I'm going to personally check out, verify, and include in specs, as I trust Colin's judgement and experience. 2. My own experience with Sinclair (now Akzo Nobel), Vista, Tnemec, Rust-Oleum/RPM has proven there ARE suitable exterior epoxies, contradicting the "Epoxy 101" website (I would encourage those who have time...and most don't...to look at parts of it, recognize it as a sales agency in disguise with faulty technical information - and not bookmark it!) 3. I've dealt with dozens of other manufacturers as a contractor project manager - with the same progressive results. 4. Far deeper research into performance of epoxies as a project and specifications consultant/inspector (plus coordination work with MPI) has proven time and time again that extensive progress has been made in epoxy technology that disproves the dated claims made on "epoxy 101" and its sister pages. 5. While yellowing/poor UV resistance is an issue with *some* epoxy coatings, any statement tossing all epoxies into a bucket labeled "these products ALL discolor" is absolutely untrue. "anon", if you are truly a "lowly specifier" (I'm not sure if that's a dig, attempt a humor or what) I'll offer some free advice - don't believe what you read on non-technical, haphazard websites. At the very least do some research on your own and perhaps contact a coatings consulting firm in your area and ask for some help, because if you really are not the person behind that website you have been led astray. Good luck in the future. If you want to continue the discussion by email or phone please contact me - but this discussion doesn't belong here.