Poly or Laquer..... why?

[Rudeboy]

Simple question, and i'm sure its been covered before. But what do you use for the final clear coat and why?

is one better than the other?
better protection?
better looking?
does it make a difference?

[jrfrond]

Lacquer is the better choice in my book. Poly is nearly indestructible, so it offers the best protection, but you are entombing the wood in plastic, so it will barely age, if at all, simply because it cannot release moisture.

Lacquer is easy to work with, though it is highly flammable and volatile, plus it looks best, is repairable and easier to clean out of your spray gun. Just make sure you use a quality lacquer like McFadden or Sherwin-Williams.

[Skel]

Sorry if this is totally off base but I'm selling a guitar that "should" have a nitrocellulose finish. I keep getting questions about this. Why would this be a good thing? Is there a way to tell for sure if it is?

Thanks

[Geoff St. Germaine]

Originally Posted by jrfrond

Lacquer is the better choice in my book. Poly is nearly indestructible, so it offers the best protection, but you are entombing the wood in plastic, so it will barely age, if at all, simply because it cannot release moisture.

Why do you want the wood to age? Also, why wouldn't the builder have ensured that the wood had a suitable moisture content prior to building the instrument?

Originally Posted by Skel

Sorry if this is totally off base but I'm selling a guitar that "should" have a nitrocellulose finish. I keep getting questions about this. Why would this be a good thing? Is there a way to tell for sure if it is?

Thanks

I've met people who think that a nitro finish sounds better than other finishes. How old is the guitar that you're selling? You could look for checking/crazing and yellowing of the finish which can indicate that it is a nitrocellulose lacquer finish, but it isn't definitive either way.

[Basshole]

Personally, my body chemistry is such that I stick to Nitro, and it gets gummy. I hate it. For that reason, I like Poly better. Some claim that Nitro sounds better. I can't hear it. YMMV.

[Dan Knowlton]

Originally Posted by Basshole

Personally, my body chemistry is such that I stick to Nitro, and it gets gummy. I hate it. For that reason, I like Poly better. Some claim that Nitro sounds better. I can't hear it. YMMV.

Yeah, me too! I keep several coats of a really good wax on the body and neck of the bass to keep that from happening. I'll probably reach the point where I have too much wax on it, but until then - ya gotta do what ya gotta do!

Dan K.

[62bass]

Originally Posted by Dan Knowlton

Yeah, me too! I keep several coats of a really good wax on the body and neck of the bass to keep that from happening. I'll probably reach the point where I have too much wax on it, but until then - ya gotta do what ya gotta do!

Dan K.

Lacquer is easier to repair usually. A new coat will melt and bond well to old layers Poly is tough to repair and often needs to be sanded down to bare wood and refinished.

However, poly is much more moisture resistant and chemical resistant an d stands up to wear better. Nitro lacquer will be damaged easily by alcohol and other chemicals.

In a solid body instrument you won't hear any difference in sound between the finishes. An acoustic guitar or violin-yes.

Personally, I prefer the look of nitro lacquer over poly.

[jrfrond]

Originally Posted by Geoff St. Germaine

Why do you want the wood to age? Also, why wouldn't the builder have ensured that the wood had a suitable moisture content prior to building the instrument?

So are you saying that once you have a suitable moisture content, it's OK to seal the wood in plastic?

Instruments finished in lacquer age well for a reason. Moisture can escape, letting the wood dry out more, creating more air space in the wood cells which equals more resonance.

As far as sticking to lacquer finishes, that is usually only a problem when too much retarder was added when the lacquer was shot, rendering the finish softer than normal. Unfortunately, there is no way to know this.

FYI- Fender "lacquer" finishes du jour are nitro over a poly base.

[Phil Mailloux]

Originally Posted by jrfrond

Instruments finished in lacquer age well for a reason. Moisture can escape, letting the wood dry out more, creating more air space in the wood cells which equals more resonance.

I'd love to see the scientific documents where you found that one. Should be an interesting read... if it can be found.

[tjclem]

I shoot poly because of the trouble involved in shooting Lacquer in the high humidity of central Florida...t

[Webtroll]

I love the look of worn spots where and instrument is played. I admire relicing but don't really want to invest in doing that myself if I can wear one out myself or buy one that's been played hard. Laquer for me please.

[mike phillips]

so what im gettin out of this is laquer will age and wear and poly will stay fresh and new

[62bass]

Originally Posted by mike phillips

so what im gettin out of this is laquer will age and wear and poly will stay fresh and new

Sort of. Lacquer will wear faster than poly. If you're trying to decide on a finish you can apply yourself and you have no experience, then Poly is probably your best choice. There's still lots to learn to apply poly and even simple Minwax Wipe On Poly has certain do's and don'ts to get an acceptable result.

The original post asked about what was better for a FINAL coat and that hasn't been covered.

Bear in mind that not all finishes are compatible with each other. So you can't just go and spray lacquer over a thick poly finish and expect good results. It's usually best to stick within one group of products from the first coat to the last.

[Geoff St. Germaine]

Originally Posted by jrfrond

So are you saying that once you have a suitable moisture content, it's OK to seal the wood in plastic?

Yes, why wouldn't it be?

Originally Posted by jrfrond

Instruments finished in lacquer age well for a reason. Moisture can escape, letting the wood dry out more, creating more air space in the wood cells which equals more resonance.

Why would the wood necessarily dry out more? If the wood can breathe through the finish then it is going to gain/lose moisture depending on the humidity.

[wilser]

There's a lot of inacurate information in this thread.

fyi, as far as sealing the wood goes, lacquer and poly will do exactly the same thing. lacquer will not let more moisture out of the wood than poly.

lacquer will age just as poly will age. poly does not stay 'fresher' than lacquer, it just wears less because it is more solid.

adding more retarder does not render the finish 'softer', it'll just take longer to cure and more solvents will evaporate leaving a THINNER finish that should require more coats than if no retarder was used.

of course, I am not an expert on finishing, but a quick browse through any decent wood finishes book will clear this stuff up. I consulted 'Understanding wood finishes' by bob flexner.

[Phil Mailloux]

Originally Posted by wilser

There's a lot of inacurate information in this thread.

fyi, as far as sealing the wood goes, lacquer and poly will do exactly the same thing. lacquer will not let more moisture out of the wood than poly.

lacquer will age just as poly will age. poly does not stay 'fresher' than lacquer, it just wears less because it is more solid.

adding more retarder does not render the finish 'softer', it'll just take longer to cure and more solvents will evaporate leaving a THINNER finish that should require more coats than if no retarder was used.

of course, I am not an expert on finishing, but a quick browse through any decent wood finishes book will clear this stuff up. I consulted 'Understanding wood finishes' by bob flexner.

+1 on every single point in this post. Including consulting the Flexner book, that's one of the great books in my ever growing builder's bookshelf, soon to be two book shelves at the rate I'm buying them.

[62bass]

Originally Posted by Phil Mailloux

+1 on every single point in this post. Including consulting the Flexner book, that's one of the great books in my ever growing builder's bookshelf, soon to be two book shelves at the rate I'm buying them.

I agree. Flexner's book is a good one. I also like the books by Jeff Jewitt. His "Hand Applied Finishes" is great for some basic finishes that can be done without spray equipment.

There's a lot of inaccurate statements made about finishing all the time, same as there is about amps and speakers. Most of it gets started by someone who doesn't know and then gets repeated and altered each time it's repeated and people start accepting it as truth.

It's best to start with one of the good books mentioned and try a simple finish out for yourself. With practice your skills develop and you can then go on to tougher methods.

[Jazzdogg]

I've seldom heard as much misinformation passed along as gospel as I have when the topic is finishing; it's one of the subjects our students have the greatest difficulty understanding, much less mastering.

Flexner & Jewitt are both excellent resources. Jewitt's website is very informative as well:

www.homesteadfinishing.com

[pilotjones]

Also +1 to Geoff's statements: a piece of wood eventually reaches an equilibrium moisture content (EMC). That is, it loses or gains moisture to or from the atmosphere, until the "forces" (actually partial vapor pressures) causing it to lose moisture to the air equal the "forces" causing it to gain moisture from the air.

At this point, if the atmospheric humidity remained the same, the wood would also remain at a constant moisture content. In reality, of course, atmospheric humidity goes up and down, and so the wood's moisture content tracks this change, up or down, until it reaches a new equilibrium.

The thickness and type of the finish will change the rate at which the wood tracks the atmosphere, but it doesn't change the final value of moisture content.

[Jazzdogg]

Originally Posted by pilotjones

Also +1 to Geoff's statements: a piece of wood eventually reaches an equilibrium moisture content (EMC). That is, it loses or gains moisture to or from the atmosphere, until the "forces" (actually partial vapor pressures) causing it to lose moisture to the air equal the "forces" causing it to gain moisture from the air.

At this point, if the atmospheric humidity remained the same, the wood would also remain at a constant moisture content. In reality, of course, atmospheric humidity goes up and down, and so the wood's moisture content tracks this change, up or down, until it reaches a new equilibrium.

The thickness and type of the finish will change the rate at which the wood tracks the atmosphere, but it doesn't change the final value of moisture content.

+10! Very well said, sir! I'll bet you got an A+ in wood technology, didn't you