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| Is polyester different than polyeurythane? http://www-.luthiersforum.com/forum/viewtopic.php?f=10101&t=46870 |
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| Author: | meddlingfool [ Sun Dec 20, 2015 2:33 pm ] |
| Post subject: | Is polyester different than polyeurythane? |
Forgive my lack of chemistry knowledge... |
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| Author: | Don Williams [ Sun Dec 20, 2015 3:51 pm ] |
| Post subject: | Re: Is polyester different than polyeurythane? |
Yes. Entirely different beasts. |
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| Author: | meddlingfool [ Sun Dec 20, 2015 4:12 pm ] |
| Post subject: | Re: Is polyester different than polyeurythane? |
Interesting. I thought so, but I really don't know much about finishes. I'm completely done with polyester though. I need to figure out a gloss finish I can do myself. Polyester, even the super thin UV stuff, survives on the overtones and treble that it destroys. |
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| Author: | PeterF [ Sun Dec 20, 2015 4:36 pm ] |
| Post subject: | Re: Is polyester different than polyeurythane? |
Where I work, we occasionally get furniture finished in high gloss polyester and that sometimes ends up close to 1mm thick! I can't imagine putting that on an instrument. |
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| Author: | kencierp [ Sun Dec 20, 2015 6:04 pm ] |
| Post subject: | Re: Is polyester different than polyeurythane? |
I believe Taylor uses UV cured polyester -- its thin as thin can be! Larivee and others have ponied up for the UV equipment too -- I think its only a matter of time before Martin starts using it on its lower level models. Big savings relative to process time and floor space requirements. |
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| Author: | kencierp [ Sun Dec 20, 2015 6:10 pm ] |
| Post subject: | Re: Is polyester different than polyeurythane? |
Not too shabby! http://www.ryanguitars.com/Innovations/ ... -more.html |
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| Author: | meddlingfool [ Sun Dec 20, 2015 6:19 pm ] |
| Post subject: | Re: Is polyester different than polyeurythane? |
Taylor is definitely not a tone I'd aspire too. I've never heard a Ryan. |
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| Author: | kencierp [ Sun Dec 20, 2015 7:25 pm ] |
| Post subject: | Re: Is polyester different than polyeurythane? |
Taylor's like all guitars have their own personalities - I've heard some good ones, great ones and not so much. Just for the heck of it I've played some of the consignment "hand made's" at Elderly - unfortunately those instruments mostly fall into the "not so much" sound and appearance and never leave the store -- so I figure using Martin, Taylor, Larivee (I think now satin finish only) and a few others as bench marks for those starting out in the craft is pretty good advice. Kevin Ryan seems to have done well for himself using advice from Bob Taylor -- he commands a bunch of $$ for his work. http://www.ryanguitars.com/Guitars%20fo ... SN775.html |
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| Author: | Bob Garrish [ Sun Dec 20, 2015 7:52 pm ] |
| Post subject: | Re: Is polyester different than polyeurythane? |
The specific hard finish used is of little consequence tone-wise, the thing that matters is how much of it you put on. Polyester, because it's more flexible and resistant to shrinkage, can be laid down in thick layers for increased protection or to reduce necessary skill in workers applying it. It can also be laid down thinner than lacquer and provide superior protection to the instrument with less finish, because it's more flexible AND harder. The article Kevin wrote is good stuff, and I don't think it would be a stretch to say he's one of the top elite luthiers on the planet. The only reason Martin didn't make the switch years ago is that, as Martin, they are bound by history even more than design. This means they make changes in a very slow and measured way. |
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| Author: | Mike OMelia [ Sun Dec 20, 2015 11:31 pm ] |
| Post subject: | Re: Is polyester different than polyeurythane? |
PeterF wrote: Where I work, we occasionally get furniture finished in high gloss polyester and that sometimes ends up close to 1mm thick! I can't imagine putting that on an instrument. Taylor does. But I'm sure it's not 1mm |
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| Author: | James Ringelspaugh [ Sun Dec 20, 2015 11:47 pm ] |
| Post subject: | Re: Is polyester different than polyeurythane? |
Try and try and try as I might I have never found a better finish for acoustic guitars than shellac. Unfortunately if I tried to use it in a production shop it would probably bankrupt me. |
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| Author: | meddlingfool [ Mon Dec 21, 2015 1:06 am ] |
| Post subject: | Re: Is polyester different than polyeurythane? |
Of course, hand made is no guarantee of actually being good, just as there is also no guarantee that price and sound quality will align with each other. Trevor Gore made mention of the high damping factor of polyester, and I'm inclined to agree. Never again for me. |
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| Author: | kencierp [ Mon Dec 21, 2015 7:26 am ] |
| Post subject: | Re: Is polyester different than polyeurythane? |
Quote: Never again for me. Did you have access to a UV polyester finishing system -- WOW how cool is that! Does Trevor have physical blind test reports indicating this (about .005" thick) polyester damping factor is something humans could really hear? What size sample pool? I'll never have a UV spray system -- but really, its seems a little far out to me that Kevin Ryan and Tom Anderson would be selling $20k guitars that have a detrimental finish. I use nitro and shellac not because they sound better, but because I am able to work with those products and the delivery systems for application. |
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| Author: | Hesh [ Mon Dec 21, 2015 7:48 am ] |
| Post subject: | Re: Is polyester different than polyeurythane? |
kencierp wrote: Did you have access to a UV polyester finishing system -- WOW how cool is that! Does Trevor have physical blind test reports indicating this (about .005" thick) polyester damping factor is something humans could really hear? What size sample pool? I'll never have a UV spray system -- but really, its seems a little far out to me that Kevin Ryan and Tom Anderson would be selling $20k guitars that have a detrimental finish. I use nitro and shellac not because they sound better, but because I am able to work with those products and the delivery systems for application. Seems far out to me too and not in the "oh man, far-out" meaning.... My experience is with cat poly and cat poly that has been professionally sprayed with the specific intent of a film thickness of .003" or less. In my experience cat poly is likely one of the more restrictive finishes but that's where a very thin film thickness goes a very long way in exploiting the attributes of poly, super tough, likely the toughest commonly available finish out there while still being acoustically transparent. I don't doubt that all things being equal cat poly may be more restrictive but all things do not have to always be equal either.... Context when we are discussing these things is important too. More specifically what kind of instrument is key to determining what finish may be a good way to go. A gigging musician has needs that are very different from the player who say plays a classical in their home and is an adult with some knowledge as to the care and feeding of a fine acoustic instrument. For the classical folks where string energy is obviously less than a steel string it's even more important to have a very thin, acoustically transparent finish. For the steel string road warrior who's ax is subject to roadies, the ravages of travel, and perhaps even the music and style that they do (Pete Townshend....) a tougher finish is likely as important as that last few percent of acoustical transparency. Townshend would not do well, or his ax wouldn't with a french polished shellac finish but the classical virtuoso would appreciate french polished shellac. It's important to keep in mind in my view that our instruments change hands and will not alway be in my 45% RH environment or never played by someone who does not yet get belt buckle/guitar considerations. IME cat poly is a very fine finish, very tough too and when done very well by a pro who does this all day long and can do very thin finishes it's an excellent finish for what many steel string guitars will encounter in their lives. Can we hear differences? I've been saying on this forum for a decade that I can at times hear a thick, clicky... restrictive finish as often is found on some inexpensive imports. But when playing a very well made, high-end instrument with a well done cat poly finish although I am sure there is some restrictiveness the instrument having to do well with life in general comes into play too. It's all relative as they say. |
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| Author: | Alex Kleon [ Mon Dec 21, 2015 11:19 am ] |
| Post subject: | Re: Is polyester different than polyeurythane? |
Where does repairability enter in the discussion, with polyester finish? I'm assuming that unless you have the ability to spray polyester, finish repair might be limited to a CA drop fill. Alex |
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| Author: | Hesh [ Mon Dec 21, 2015 11:22 am ] |
| Post subject: | Re: Is polyester different than polyeurythane? |
Alex Kleon wrote: Where does repairability enter in the discussion, with polyester finish? I'm assuming that unless you have the ability to spray polyester, finish repair might be limited to a CA drop fill. Alex Good question for Joe White, Oh Joe????  By the way Rick Turner was one of the first ones on this forum to go with cat poly and the finish was so very tough that he could glue bridges with CA right on the finish. Don't try this with other finishes....... |
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| Author: | meddlingfool [ Mon Dec 21, 2015 11:44 am ] |
| Post subject: | Re: Is polyester different than polyeurythane? |
Is cat poly polyester or polyurethane? Ken, UV cure is achievable for most small shops. If you have to ability to spray solvents safely, you can spray the UV stuff. You no longer need a big fancy flash cooker to cure it. You can get a magic wand to wave over it for the instant cure. Last time I looked into it, you could get systems for less than 5k. I think Pat Hawley here took the plunge on Cardinal... |
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| Author: | jfmckenna [ Mon Dec 21, 2015 12:05 pm ] |
| Post subject: | Re: Is polyester different than polyeurythane? |
The Ryan Guitars article said that repair was easier then Lacquer. That surprised me but I know nothing of this finish. The article also said that it is the most superior finish for acoustic guitars. I've noticed that when a lot of luthiers adopt a finish they do so because it's the most 'superior finish' of all time ever. So it goes. It sure does look pretty especially if you like the show car glaze look. When I sit and intuitively think about a finish for a guitar I'm not so sure a rock hard finish is the most ideal. But I doubt I or anyone would really be able to tell the difference in a blind test. |
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| Author: | DanSavage [ Mon Dec 21, 2015 1:06 pm ] |
| Post subject: | Re: Is polyester different than polyeurythane? |
Hesh wrote: My experience is with cat poly and cat poly that has been professionally sprayed with the specific intent of a film thickness of .003" or less. In my experience cat poly is likely one of the more restrictive finishes but that's where a very thin film thickness goes a very long way in exploiting the attributes of poly, super tough, likely the toughest commonly available finish out there while still being acoustically transparent. I don't doubt that all things being equal cat poly may be more restrictive but all things do not have to always be equal either.... I used Eastwood 2K Aerospray cat urethane on the last rebuild and I liked it and will probably use it on the rebuild I'm working now. (http://www.eastwood.com/eastwood-s-2k-aerospray-high-gloss-clear.html) It went on thin and is a really hard finish. I don't have the facilities to spray catalyzed finish system with my spray gun, so having a 2K finish in a rattle can works well for the small jobs. |
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| Author: | StevenWheeler [ Mon Dec 21, 2015 7:09 pm ] |
| Post subject: | Re: Is polyester different than polyeurythane? |
The finish Joe White uses is Cat Polyester, and he does a mighty fine job of it too. Some of the users on this forum had a problem with one of the uv cure products. Not the finish but the pore fill. It seemed to never fully cure down in the pores where the uv light couldn't reach. I'll look that up and post the thread. |
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| Author: | John Arnold [ Mon Dec 21, 2015 7:27 pm ] |
| Post subject: | Re: Is polyester different than polyeurythane? |
This confusion of polyester and polyurethane has developed because of the use of the term 'poly', which means 'many'. The two finishes are very different. Polyurethane is often formulated to cure by oxidation (like a traditional varnish or enamel), while polyester is usually catalyzed by mixing in a toxic chemical or by exposure to intense UV light. Quote: Where does repairability enter in the discussion, with polyester finish? I'm assuming that unless you have the ability to spray polyester, finish repair might be limited to a CA drop fill. I have done both CA drop fill and overspray with nitro lacquer. Both can give satisfactory results. Collings uses UV cured polyester as a fill coat, and sprays nitro lacquer on top of that. |
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| Author: | Ken Franklin [ Tue Dec 22, 2015 4:08 am ] |
| Post subject: | Re: Is polyester different than polyeurythane? |
You know, the wax in some people's ears is more than .005. |
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| Author: | B. Howard [ Tue Dec 22, 2015 7:10 am ] |
| Post subject: | Re: Is polyester different than polyeurythane? |
Alex Kleon wrote: Where does repairability enter in the discussion, with polyester finish? I'm assuming that unless you have the ability to spray polyester, finish repair might be limited to a CA drop fill. Alex Polyester or polyurethane....or any other poly type closed chemistry type finish, the answers are about the same. The average shop will be limited to CA drop fills on any of this stuff. They are however quite repairable with the proper equipment and materials. Polyester can be repaired with either polyester or the proper type of 2 part urethane. There are 2 part urethanes out there from the autobody trade designed to blend and buff out without any witness marks over non-system substrates. Prep is again the main key to success followed by the knowledge in how to cut and spray a spot repair with increasing amounts of reducer. Personally I have found acid cured polyester to be the absolute best pore filler material available. so much so that I now charge more for a traditional paste filler finish. Most of the major manufacturers agree but decide to use a UV product for expedience. I have however held off on using it for a top clear coat thus far but I am going to give it a test in the new year to see for myself....... |
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| Author: | Tai Fu [ Tue Dec 22, 2015 1:52 pm ] |
| Post subject: | Re: Is polyester different than polyeurythane? |
I used epoxy filler... Liked it so much that I'll be doing that in the future. Nitro has a bad tendency to shrink and no matter how hard to fill it with paste filler it will always sink in. Furthermore paste filler only really works on large pore wood such as oak and ash, and not so well on mahogany or rosewood. I did a rosewood and mahogany build with epoxy pore fill and the finish came out excellent... I use less lacquer for the spray because even the first coat looked so nice. Though I will admit my last commission the customer wanted matte finish because he said he was tired of the plastic coated guitar thing... It made my job much easier. |
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| Author: | Pat Hawley [ Thu Dec 24, 2015 8:49 pm ] |
| Post subject: | Re: Is polyester different than polyeurythane? |
I indeed took the plunge on UV cured polyester but not the Cardinal product as Ed suggested. I bought the package from uvcure.com i.e. including the light, sealer, pore filler and top finish. The light I would gladly recommend to anyone. It's a quality product. The finish I'd recommend only to those such as myself that do not want to deal with the solvents in the more popular products. The uvcure.com stuff has zero VOCs. But here's the catch: with the smelly stuff the approach is to spray on a thin layer and then let it sit for a few minutes to gas off. Then you can spray on another thin layer and let it sit for a few minutes before spraying on a final thin layer. With this approach you can get a workable thickness that hangs well prior to curing with the uv light. That doesn't work with the uvcure.com stuff as there is nothing gassing off and if you just try to spray it on thick it will drip. It does not hang well. However I have learned how to overcome this by spraying on a thin layer and then doing a quick, partial cure with the uv light. I can then spray another layer on that and do another partial cure. The timing is not all that difficult and with this approach I can easily build up as many layers as I like without any drips (I typically do five) before doing a final full cure. The whole process goes quite fast. By the time I'm done my finishes are in the .003" .005" range. I've tried many finishes and my own personal view is that overall, polyester is the best. I will still do a French polish on a classical top for those that feel it makes a difference. I am a little surprised, however, how few general public people even care. At the last show where I displayed I made a little set up where I finished a board with polyester and invited people to try and scratch it with their finger nails. Very few people tried. I also finished a piece of paper so that people could fold it to see how flexible the finish was. I also had a digital vernier caliper there so that people could actually measure the finish to see that it was only .003" thick. Again very few people bothered. It almost made me start to wonder why I was going the extra mile to provide a thin but toughest finish available. Cheers, Pat |
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