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</o:shapelayout></xml><![endif]--></head><body lang=EN-CA link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Film thickness is good – about double what would be on an enamelled (glass powder) steel object (baking pan type thing). The hardness test I always thought was pretty cute as it refers to pencil hardness – the hardness of a pencil that would create a mark and goes up to 9H. 4H is equivalent to an acrylic tub coating and probably most gelcoat fibreglass. Basically powder coating is a paint (polyester and or acrylic resins). It is just applied as a powder and uses heat instead of solvents. The ‘paint’ film with powder coat is stronger because it hasn’t been broken or weakened with solvent holes – does that make sense? Since it is a form of painting the skill of the applicator and how good the shop equipt is becomes important – ask if you can increase the film thickness as that is a good indication of what they can do (typical powder coating is 2-3mil)<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> Impact is blow that would break the film (but typically you have to crush the substrate and this is cast iron) – salt spray test is corrosion and 1000hrs is pretty high for a marine standard but basically meaningless as the tub won’t corrode unless the finish gets totally worn away from obsessive cleaning or scratched or broken. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>So I think you could say that the finish would be roughly equivalent to a fibreglass or acryic tub – not as thick probably but having a cast iron base compensates.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Care would be equivalent to an acrylic or gel coated tub – no abrasive cleansers and waxing/buffing the top and sides is not a bad idea.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><span lang=EN-US style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span lang=EN-US style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> David Bergman [mailto:bergman@cyberg.com] <br><b>Sent:</b> July-28-11 12:11 PM<br><b>To:</b> JOHN SALMEN; 'Green Building'<br><b>Subject:</b> RE: [Greenbuilding] renewing a cast iron tub<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Returning to this question from a week ago, I've determined that the tub can be sandblasted and then powder coated, and that it may make more sense both environmentally and economically to do that rather than replace it with a (good) new one that won't fit as well as this one does. But I'm still trying to work through the durability and hardness question.<br><br>A finisher/powder coater I have worked with previously tells me that the baking temperature is about 400oF and that the finish has these properties:<br><span style='font-size:10.0pt'>Film thickness - 1.5 to 2.5 mil<br>Hardness (ASTM D-3363-92A) 4h<br>Impact 160 in-lbs direct.Salt spray 1000 hrs<br><br></span>Anyone know how to gauge that? What might it compare to?<br><br>Thanks,<br><br><br>At 11:16 PM 7/19/2011, JOHN SALMEN wrote:<br><br><o:p></o:p></p><p class=MsoNormal>I’m sorry I was trying to be humorous (on the dark green side) as well as a bit positive. I like the notion of recycling a tub and the local labour involved. On the practical side I have had to design numerous bathrooms and you have to look at the clients needs and expectations.<br> <br>To be fair to the client I think it depends on the design and the expectations. The tub is an artefact – even if it is renewed it will stand out unless the overall bath design supports it as the old object that it is and for that you need the client to want the old tub. You cannot make an old tub look like a modern tub – it will be shiny but it will still be the old tub. Unless the bathroom design can compensate or make use of ANY potential defects in some imaginable perfection - I would bring in a new tub. If the design and the clients interest can support the old tub I would hazard that the life of an acrylic or fibreglass tub would be equivalent to a renewed powder coated cast iron tub.<br> <br>‘Neatnik’ clients I would further hazard would probably be more comfortable with a new tub. I have had clients that simply were fanatics about old cast iron tubs. I have had clients that have purchased new cast iron tubs that have required significant floor engineering – but these were clients that actually took baths that typically grew up with cast iron tubs and could not be dissuaded . Next to overbuilt v8 heating systems tubs are high on the list of overbuilt and underused items in a home that are part of what I call ‘cultural design environmental failure’ – similar to 3 way switches . <br> <br>Free standing cast iron tubs take a lot of hot water to get to stay at temp. A lot of the people that are addicted to this type of bath run the hot water at a steady flow to keep the tub warm – these are not people that I will design a freestanding tub for (if I have any influence) this person requires a fully enclosed tub designs where you can create a fully foamed enclosure that will retain heat for as long as it takes for them to relax and get out of the tub.<br> <br>So on my checklist for this I would probably have<br>- Client needs – client education/advocacy?<br>- Long term energy considerations (hot water usage will outweigh any other cost if people actually use the bath – but most people don’t take baths and the bath is a decorative object)<br>- Local employment – local supply?<br> <br> <br> <br> <br> <br> <br><b>From:</b> David Bergman [<a href="mailto:bergman@cyberg.com"> mailto:bergman@cyberg.com</a>] <br><b>Sent:</b> July-19-11 7:06 PM<br><b>To:</b> Green Building; terrain@shaw.ca<br><b>Subject:</b> Re: [Greenbuilding] renewing a cast iron tub<br> <br>At 09:37 PM 7/19/2011, JOHN SALMEN wrote:<br><br>Actually there is nothing wrong with an old pitted cast iron tub complete<br>with iron (or blood) stains - it holds water and if I have a bath I am going<br>to either try to read a book (without getting it wet) or stare out the<br>window. It is just not shiny and 'nice' looking.<br><br>I agree in principle, but there are two additional factors at work here. One is that once the rest of the bathroom is renovated, the dulled or pitted old tub is going to stand out (and not in a good way), and the second is that the finish of this tub has become very hard to clean. Even if the clients weren't neatniks (which they are), this would be a problem.<br><br><br>Will it last? Will it be durable? - what are we comparing it to - a stock<br>portfolio?<br><br>I hope not. Stock portfolios have done pretty badly, no?<br><br>More to the point, the conventional in-house recoating treatments -- in many or most cases -- often don't last long at all. Sometimes five years or less. I would be looking for the refinishing to last as long as the bathroom renovation is likely to last. (25 years?) Otherwise, it makes more sense to install a new tub while the walls are open.<br><br><br>David Bergman RA LEED AP<br><b>DAVID BERGMAN</b> ARCHITECT / <b>FIRE & WATER</b> LIGHTING + FURNITURE<br>architecture . interiors . ecodesign . lighting . furniture<br>bergman@cyberg.com <a href="http://www.cyberg.com/">www.cyberg.com</a><u> </u><br>241 Eldridge Street #3R, New York, NY 10002<br>t 212 475 3106 f 212 677 7291 <o:p></o:p></p><p><o:p> </o:p></p></div></body></html>