Gal vs Epoxy

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So here's my dilemma.I've made this steel framed window for my very slowly moving bathroom reno.It will go into an external wall which gets a bit of rain, and it will get wet from the shower in the bathroom.The finish will be powdercoated, but I'm thinking about the undercoat.The galvanisers in Sydney are way out on the edge of town and I hate wasting time going there. But I'm assuming the best thing to do would be to get it dipped in hot gal?Yeah, I carry.House keys, wallet, some change, usually a newspaper, maybe a pen.
Reply:Originally Posted by scott brunsdonSo here's my dilemma.I've made this steel framed window for my very slowly moving bathroom reno.It will go into an external wall which gets a bit of rain, and it will get wet from the shower in the bathroom.The finish will be powdercoated, but I'm thinking about the undercoat.The galvanisers in Sydney are way out on the edge of town and I hate wasting time going there. But I'm assuming the best thing to do would be to get it dipped in hot gal?
Reply:im curious on the galv-a-stick. are there inhalation issues with that? we use the spray galv here alot. was wonder if the stick went on thick? just curious thnx!
Reply:I am going to agree with TEK and say that spray galv is your answer.  Originally, I thought of zinc chromate, but researched it to find that it only works with aluminum.  On a side note, zinc chromate can also cause cancer (hexavalent chromium).
Reply:In my experience the sticks are mainly used for touch up.
Reply:From the thread title, I thought you were going to post some pictures of your Mrs. with her hand stuck to something with some 60 second epoxy.      btw, the 60 second epoxy absolutely does set up FAST.  No, neither I nor any one else didn't get 'stuck'.  Spray on galv usually has some sort of binder to get the zinc powder/dust to stick to the part.  The couple of cans/brands I have used had an acrylic binder (acrylic clear paint for all practical purposes).  I do not know the compatibility of powder coating with such a zinc dust and acrylic binder 'undercoating' either from a chemical/coating standpoint or from a thermal standpoint from the powder coat oven curing cycle.Since you pretty much know that a hot-dipped galvanized coating is going to be the 'best', you have to ask yourself what you want to do and how much you want to spend (time and money) and how long you want the steel to last.  Then you can decide on what to do.Trade-offs.  It's all about trade-offs.  The best laid schemes ... Gang oft agley ...
Reply:It was all going so well till Moonrise planted that niggling seed of doubt in my mind.I had never heard of the stick, and I had forgotten about the spray gal.I'm not going to move from this house for a long time and once this window is in, any rust will be impossible to treat. A trip to the hot dip guys it is. Bugger.Thanks all.Yeah, I carry.House keys, wallet, some change, usually a newspaper, maybe a pen.
Reply:We use a product called Dimetcote.  The substrate has to be sand blasted to white metal to provide good adhesion and a good electric bond.  This stuff performs almost as well as any galvanizing process but paint can stick to it.  Dimetcote is a line offered by PPG or Ameron other manufacturers produce similar products.  Most of them are listed as an inorganic zinc primer.
Reply:For a powercoat substrate your going to need to hot dip.I hope your galvenizer is way better than all three of the ones around here.   I shutter to imagine the look of a powder over the locals work.Vantage 500's LN-25's, VI-400's, cobramatics, Miller migs, synch 350 LX, Powcon inverters, XMT's, 250 Ton Acurrpress 12' brake, 1/4" 10' Atlantic shear,Koikie plasma table W/ esab plasmas. marvel & hyd-mech saws, pirrana & metal muncher punches.
Reply:I'm not sure whether our galvanisers would be any better than yours.I'll get it done, though. Might rethink the powder coating.Yeah, I carry.House keys, wallet, some change, usually a newspaper, maybe a pen.
Reply:if they do a good job and shake it well and leave a smooth finish it might not be bad,  but zinc can leave a weird un even surface that will be made to look much worse with a powered coat overlay.Vantage 500's LN-25's, VI-400's, cobramatics, Miller migs, synch 350 LX, Powcon inverters, XMT's, 250 Ton Acurrpress 12' brake, 1/4" 10' Atlantic shear,Koikie plasma table W/ esab plasmas. marvel & hyd-mech saws, pirrana & metal muncher punches.
Reply:If i tell my galvanizers its going in the ground, the put it on real thick and has uneven consistency in places.  If i tell them its to be seen, the put on a nice uniform coat.  Almost looks like a different process.Maybe zinc electroplating might be an option.  I know its not as durable as hot gal, but just might suit the purpose/application.
Reply:but zinc can leave a weird un even surface that will be made to look much worse with a powered coat overlay.
Reply:I'm telling you, look up Dimetcote or a similar product and top coat with a heavy duty epoxy paint.  Epoxy paints will chalk when exposed to UV so if you want it to continue looking good, topcoat with a 2-part polyurethane type paint.Our best paint schedule on our workboats usually starts as a sandblast to white metal, 2 coats of International 300V (one aluminum and one bronze), one coat of International 262, and one coat of International 990.
Reply:I like marine paints - International is a big brand over here. Even though I don't have a boat anymore, I still use them sometimes because they are so easy to paint with and they seem to dry quickly - and with a good finish. They're expensive, but worth it.I'm veering toward dipping just because it's going to protect bits I won't be able to get to with a brush.Yeah, I carry.House keys, wallet, some change, usually a newspaper, maybe a pen.
Reply:scott brunsdon  -  Cold galvanizing, paint or spray, is for repairing highway guard rail.  You can't powder-coat over it; it won't take the bake.  As noted, hot dipped is always chancy; dippers don't want to deal with single item clients of discretion, and their finished product generally ruins fine metal work.  The perfect embodiment is to have your frame zinc [silver] or di-chromate [gold] electroplated and then powder-coated.  Electroplated zinc is reasonably priced, the only problem is finding a plater with a large enough tank [or plate half / flip / plate the other half].  Second option is zinc-chromate powder-coat primer [over a white blast] and than your color coat.   OPUS
Reply:and their finished product generally ruins fine metal work
Reply:Also note if your frame is tube steel they will need to burn holes in it to let the zinc in and the air out.  otherwise it will float in the tank.   You definitely want to put these holes in yourself otherwise you will be very unhappy with the results.Vantage 500's LN-25's, VI-400's, cobramatics, Miller migs, synch 350 LX, Powcon inverters, XMT's, 250 Ton Acurrpress 12' brake, 1/4" 10' Atlantic shear,Koikie plasma table W/ esab plasmas. marvel & hyd-mech saws, pirrana & metal muncher punches.
Reply:Scott,Take your carbon steel frame, look at it very carefully and remember all the steps you did to make it.  Think if there are any design or fabrication changes you would like to make.And then think of that frame as the prototype and then go and make (remake?) the frame out of stainless steel.  No problems with undercoating compatibility or hot-dipped zinc globs telegraphing through the final powdercoat top coat.  Top coat as desired if you want a certain color, or leave as bare stainless if that is the look you want.  Be aware of dissimilar metals (carbon steel and stainless steel) in contact with one another setting up a galvanic couple if you go this route.  If the frame is stainless, then use stainless hardware (nuts, bolts, screws, washers, nails, etc) of the same or compatible alloy as the alloy of the frame.  304 would probably work as an OK alloy for a window frame, 316 would give you a little bit 'better' corrosion resistance to 'wet'.  Neither will hold up to 'nasty' or tough chemical environments (strong bathroom cleaners or lots of atmospheric salt spray come to mind) as they are "stainless" and NOT 'this-stuff-will-never-rust-no-matter-what'.  But they will almost certainly hold up better than carbon steel would.Trade-offs again.  To make a carbon steel part last or hold up in a wet environment takes a wee bit o' work, eh?  It -is- possible to do so (think car panels that are electro-zinc coated and then primed and painted that last 10+ years out in the wet and the sun and so forth).  But also think of all the cars and car parts that are rusty (to varying degrees) also.  The best laid schemes ... Gang oft agley ...
Reply:I suspect it would have been a tad expensive in stainless. The window opening is 700mm x 500mm and the frame is made from 280mm wide x 10mm thick plate. It will look great, trust me. Till it rusts, of course. I'll just have to move house then.Yeah, I carry.House keys, wallet, some change, usually a newspaper, maybe a pen.