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| Catalyzed Poly brush application? http://www-.luthiersforum.com/forum/viewtopic.php?f=10102&t=7508 |
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| Author: | Alain Desforges [ Fri Jul 14, 2006 1:22 am ] |
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I've always thought that catalyzed poly was so nasty that you had to apply it in the safety of a paint booth and that a forced air respirator was needed. Is it possible to apply poly with a brush? Has anyone tried/done this? Just how dangerous is this stuff? What kind of safety precautions are needed? Secondly, where can I get some without having to buy a 5 gallon pail? Thanks in advance. Regards, Alain |
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| Author: | Robbie O'Brien [ Fri Jul 14, 2006 1:46 am ] |
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Alain, Yes, it is possible to apply cat urethane with a brush and I have done it many times. Remember that this stuff builds in layers instead of melting into the previous coat. It is therefore very important that you get a nice soft brush to apply it with and get it as level as possible. You should wear a respirator for solvents and eye protection. Do it outside or in a well ventilated area with no spark hazard (pilot lights etc.) You can get cat urethane at IC&S ( 717-391-6250 ) Get a quart of TP 60 - Clear polyurethane gloss and a quart of TX 75 - Hardener and one quart of the appropriate thinner. It costs about 35 bucks but the haz mat shipping costs put it up to around 65 or 70 bucks. If you need more info on how to apply it when you get it, let me know. Happy finishing! |
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| Author: | Mario [ Fri Jul 14, 2006 1:57 am ] |
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polyurethane or polyester, Alain? Big difference.... |
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| Author: | Alain Desforges [ Fri Jul 14, 2006 2:51 am ] |
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Thanks Robbie for the info. Much appreciated. Mario, that's avery good question. I'm thinking about the 'newer' finish that's 100% solids and won't shrink back. Is that Polyester? Thanks. |
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| Author: | Mario [ Fri Jul 14, 2006 2:57 am ] |
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Polyester's about 90% solids, and yes, doesn't shrink back. |
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| Author: | Alain Desforges [ Fri Jul 14, 2006 3:03 am ] |
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Mario, what do you use to finish your guitars now? That's what I'd like to use. I think Taylor uses this finish as does Doolin... |
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| Author: | Mario [ Fri Jul 14, 2006 3:22 am ] |
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That would be polyester. Saying "poly" just confuses everything <bg> We need to specify... Yes, polyester can be brushed, also. Same recipe as for spraying, same time frames(the MEKP cured needs to have each coat applied within 45 minutes in order for all the coats to burn-in to one another). I've used disposable foam brushes(4"). One coat, one brush. Toss the brush.... It is slow to set up, so it does self level pretty nicely, but there is still a lot of sanding left to do before buffing. Good news is that it sands nicer than anything you've ever sanded before. It's tuff to buff.... Since brushing doesn't disperse it into the air, a good respirator and good ventilation is all that's required. And gloves... I brushed my first few guitars, until I got the hang of the mixing and all that jazz, then switched to spraying, but those first brushed guitars looked just as good, and have remained that way(no shrinkage issues!). You still need to sealer(can be brushed or wiped-on, though again, srapying leaves you much less sanding). If you can brush a waterborne, and don't mind the sanding that that requires, you can brush polyester. It is a VERY strong smelling finish, so you won't use this in your home or apartment. But it is cured in 24hrs, and there is no odor or off gassing after about 12hrs. No idea where you'd get it by the gallon. Especially in Canada! If anyone ever finds a source, please let us all know. |
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| Author: | Alain Desforges [ Fri Jul 14, 2006 3:31 am ] |
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Thanks Mario, that's the ticket! Yes, I guess a gallon will be hard to find. I'm trying to contact McFaddens but I can't seem to google it anymore, which is strange, since I remember having been on there before... Thanks again. |
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| Author: | Scott Thompson [ Fri Jul 14, 2006 4:05 am ] |
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[QUOTE=Alain Desforges] Thanks Mario, that's the ticket! Yes, I guess a gallon will be hard to find. I'm trying to contact McFaddens but I can't seem to google it anymore, which is strange, since I remember having been on there before... Thanks again.[/QUOTE] http://www.lawrence-mcfadden.com/ |
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| Author: | Alain Desforges [ Fri Jul 14, 2006 4:41 am ] |
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Thanks for the link Scott! I'll put in my favorites now... |
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| Author: | Rod True [ Fri Jul 14, 2006 2:32 pm ] |
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Mario, there is a builder in Langley, BC who uses cat poyester. John McQuarrie at Northwood guitars. I have talked with him several times, like most guitar builders, he is happy to spill the beans so to say. He gets his stuff from a company called Acrylco Mfg Ltd, they are in Delta, BC. Phone # (604) 524-9441 I'd call John and ask him about it first, just to make sure it's the same stuff, which I'm sure it is, just best to double check right. Oh, and I know you can get it by the gallon as my father-in-law used this stuff on his first guitar. Stinky stuff he said, but so nice to work with, cures very fast, just like you've stated. Not cheap mind you, but nothing good ever is right. |
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| Author: | Rod True [ Sat Jul 15, 2006 2:21 am ] |
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bump |
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| Author: | Mario [ Sat Jul 15, 2006 2:52 am ] |
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Good stuff, Rod! I'll look into it this coming week! Importing the McFadden's is not easy..... Thanks much! |
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| Author: | SniderMike [ Sat Jul 15, 2006 3:13 am ] |
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IC&S which sells Ilva's polyurethane, as Robbie mentioned earlier, also sells Ilva's polyester. They sell the polyurethane in very small quantities, so I'd be willing to bet that they sell the polyester in small quantities too, but can't be sure. Might be worth looking into. Mike |
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| Author: | Mario [ Sat Jul 15, 2006 3:41 am ] |
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Do they have a distributor in Canada? |
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| Author: | SniderMike [ Sat Jul 15, 2006 3:58 am ] |
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Not sure, Mario. I do remember Karen saying something about having to go through Canada when ordering the quart size urethane's though, but she may have been confused. Camger (www.camger.com) also distributes Ilva products. They sell gallon sizes of the urethane, not sure about the polyester though. Hope that helps. Mike |
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| Author: | Mario [ Sat Jul 15, 2006 4:58 am ] |
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Thanks for the elads. Yes, that could help. I'm not ready for some more, yet, but was going to bring in another 5 gallons of McFadden's this fall. It'd be very nice to find a local product that is as good. This gives me time to bring in a quart or gallon, and try them out. If they aren't up to snuff, I'll get my McFadden's fix this fall; if they are up to snuff, woohoo! |
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| Author: | Robbie O'Brien [ Sat Jul 15, 2006 7:56 am ] |
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[QUOTE=Mario] Yes, polyester can be brushed, also. Same recipe as for spraying, same time frames(the MEKP cured needs to have each coat applied within 45 minutes in order for all the coats to burn-in to one another). It is slow to set up, so it does self level pretty nicely, but there is still a lot of sanding left to do before buffing. Good news is that it sands nicer than anything you've ever sanded before. It's tuff to buff.... You still need to sealer(can be brushed or wiped-on, though again, srapying leaves you much less sanding). [/QUOTE] Mario I have a couple of questions about the polyester stuff. I have no experience with it. How exact does the mixing ratio have to be? Also you mentioned it must be recoated in 45 minutes for all levels to blend. It is my experience that catalyzed products are reactive finishes and not evaporative. That is they build in layers. Did you mean that you can recoat in under 45 minutes without sanding between coats? After that I assume you must sand between coats. How many coats can you apply in a day? Also, what kind of sealer do you use under it? |
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| Author: | Mario [ Sat Jul 15, 2006 9:00 am ] |
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How exact does the mixing ratio have to be? Very. It's quite touchy to even small errors. I use small syringes to measure small amounts... Also you mentioned it must be recoated in 45 minutes for all levels to blend. It is my experience that catalyzed products are reactive finishes and not evaporative. That is they build in layers. Did you mean that you can recoat in under 45 minutes without sanding between coats? After that I assume you must sand between coats. At or before 45 minutes, it is still very wet and tacky; it does not even come close to being dry to the touch for hours. With that 45 minute window, you simply add the new coat over the old. If you wait longer than 45, say 60 minutes, may as well walk away until the enxt day, sand, then start again. I use a timer, which I put in my pocket so that I stay on schedule. It's THAT touchy. How many coats can you apply in a day? 3 coats are all that is needed. [ Also, what kind of sealer do you use under it? It's a urethane rosewood sealer that they supply with the polyester. It's a two part system on its own. You MUST use this sealer, as the polyester doesn't stick all that well to most woods we use. But it's water-thin, and wets the wood beautifully, bring out the nicest of the wood. There's a helluva learning curve to all of this, as it's touchy in a lot of aspects. Make one mistake, at any one point, and you're starting completely over. But once you have it figured out, it's incredible. And spray? If it weren't for the odd dust bump, i wouldn't even have to sand and buff my necks. Often, I'll just sand the dust bumps and buff that area. Brushing leaves a lot of sanding to be done, but it's do-able |
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