How to remove finish blushing?

[HotBluePlates]

So I bought an 70's Alvarez dreadnought a while back, because the guitar was cheap due to its rough condition. I actually think it is quite a good-sounding guitar for the price I paid (under $300).

One of the goals of the purchase was to do some "practice repair work" on an instrument that wasn't a big cash investment. This guitar will likely be the topic of quite a few posts or continuations of this thread.

Anyway, it appears to me to have been subjected to a lot of heat at some time. On the back, there is a portion of binding at the waist which has shrunk and popped loose from its channel. The back at the upper and lower bouts have significant finish blushing (a whitish haze), with a portion at the waist without any blushing. It appears to me that either intense sunlight (or some other heat source) was applied to the back, with something laying across the waist area that blocked the heat.

Anyway, the guitar's sides and back are rosewood. The references I found online for repairing guitars with blushing almost universally referred to spraying lacquer in high-humidty environments. They recommended the use of a blush eraser to release trapped humidity.

The question is this: I think the blushing is due to moisture being driven out of the rosewood due to heat applied, and that it is not trapped near the surface (as assumed in the typical cure for blushing). I'd like to know if a blush eraser will actually penetrate deep enough into the lacquer to work in this case, or if the back needs the finish completely removed and resprayed. I'd like to know what steps to take to protect/repair the binding.

I had figured that the binding would need to be taped off to keep from being melted by any sprayed lacquer/blush eraser. I had figured I would get the finish fixed on the back, then heat the binding to soften, and reglue/tape it in place to fix.

I'll post some pictures later today of this guitar.

Oh... there are other finish issues on this guitar. Mainly dings, chips and the like. I know I could strip all the old finish off and resrpay, but as I said, I'd like to get some practice with steaming out dings and making small finish repairs, even if it takes much more time to get the guitar back to 100%. I'm not fixing it for a customer, so I have nothing but time.

Thanks!

[G._Hoffman]

The problem you are going to have is that those old Alverez's were not finished with nitrocellulose lacquer, but with a catalyzed polyurethane (or some such) that is impossible to work with.  There are no chemicals that will soften it, and short of stripping it there really isn't anything you can do.  You can't blend in new lacquer to fill in the chips and dings, you can't overspray without having witness lines - basically, they are very tough and are harder to damage, but when they do get damaged you're screwed.

Sorry to be the bearer of bad news. 

Pretty much the only thing you can do is to fill them with super glue, and sand/polish them level.  There will be witness lines, and there will be color differences, so really the only time we advise it is if you have a chip in the neck where it bothers you when playing.  You can sometimes minimize the witness lines by sort of "feathering" the edges of a crack or a ding, but it will still show. 

As for steaming dings and dents, I'd avoid it all together.  It doesn't work all that well, and it can damage a guitar.  I know a lot of furniture repair guys like it, and it may work well for them, but for guitars it just isn't a useful technique. 

The binding at the waist is pretty typical on older guitars.  It isn't necessarily a heat thing - cellulose binding just shrinks.  You can some times make it stretch back in with a bit of heat (try a hair dryer on med-high).  Glue it back in place with Duco plastic cement.  If that doesn't cut it, you will have to find some binding that matches and patch it in.  Good luck with that. 

Gabriel

[HotBluePlates]

Thanks for the head's up on the finish type. I wasn't sure if this was poly, because it feels a lot thinner than any poly finish I've ever encountered.

If a complete strip and refin is in order, it wouldn't completely break my heart. I'll be doing the work myself, and I figured no better than a 50/50 shot of avoiding a complete refinish.

Here are the promised photos. I'll post some more shortly that show the other issues. Then you'll see why I figured it might be a more valuable learning tool to do a long series of small fixes.

[HotBluePlates]

So here are some more of the pics.

First up is an overview shot. Doesn't look too bad here, which proves why eBay could be dangerous.

Next is the nut, which has pieces along the fingerboard edge chipped out. My guess is that they were caused by binding on the wound strings, maybe in slots cut too small. I'm not certain, but it sure seems to be made of bone; it doesn't feel as light as the average plastic nut. Obviously, I've got a new bone nut blank ready to replace this one.

The picture is over-bright. You may have to view your monitor off-angle to really see the chips.

[HotBluePlates]

Next up is the homemade "bearclaw" that the previous owner added to the top at the bass-side waist. It seems like this is more carelessness than over-excited strumming... the treble side has much more even (but extensive) wear due to strumming.

There is additional dinging that's fairly deep on the lower bout.

[HotBluePlates]

Last, but not least... the headstock. There is some finish tear-out at nearly every tuner bushing. Some chips took out significant portions of the headstock veneer. I had already resigned myself to the fact that the only way to fix this mess was to take the finish off. Some kind of repair will have to be done to replace the missing wood, then refinish. And since the other sides of the headstock are as bad/worse than the face, I just assumed this would be the candidate for a complete re-do.

I'm open to any suggestions you may have, because a lot of the woodworking will be a first-time effort for me.

[G._Hoffman]

Thanks for the head's up on the finish type. I wasn't sure if this was poly, because it feels a lot thinner than any poly finish I've ever encountered.

If a complete strip and refin is in order, it wouldn't completely break my heart. I'll be doing the work myself, and I figured no better than a 50/50 shot of avoiding a complete refinish.

Here are the promised photos. I'll post some more shortly that show the other issues. Then you'll see why I figured it might be a more valuable learning tool to do a long series of small fixes.

That kind of blushing, there is no question it is some kind of poly, or some other finish that isn't lacquer.  Lacquer looks a lot different. 

As for a refinish, you are running yourself into a very problematic issue.  That finish almost certainly won't respond to chemical strippers, so you will have to sand it off.  Not something I would ever want to do, particularly since you must be very careful not to sand into the wood underneath. 

If someone were to bring that to us, we would advise not worrying about the appearance.  If it is something you are doing for your own education, you'll need to decide if it is worth it or not.  If you DO decide to refinish it, get a copy of Dan Erlewine's book on finishing from Stew-Mac - I've been doing this for 20+ years, and I still learned a thing or two when I read it.  (It didn't make my finishes better, but it did make them easier!)  I'd also avoid nitro, unless you have a professional spray booth in which to do it.  Explosions are things to avoid, when you can.  Use a waterborne finish, such as those sold by both Stew-Mac and LMI.  Better for your health, easier and faster to work with, and they look just fine.  I'd be using them myself, but I need to be able to repair nitro and don't want to run two sets of chemicals through my spray booth.


Gabriel

[HotBluePlates]

Thank you for the advice!

I don't mind sanding the old finish off, even if it will take nearly forever to do a good job of it. Like I said, I have plenty of time to do it.

Is nitro a bad idea to use on the guitar? I have sprayed a nitor finish on a guitar before. I used ReRanch products, so it was pretty easy even if it was out of a can. I do know about the fact that nitro will be outgassing for a considerable amount of time, and it can be unhealthy to breathe. I can use a different type of finish, so maybe an experiment with something new is worthwhile.

The chips on the headstock face look like someone tried to remove the tuner bushings in order to replace the tuners... and the finish (and sometimes wood) came with them. The bushings are not seated firmly against the face. But if that's the case, why would they not stop after the first one that went badly?

Anyway, I imagine it will take a long time to get this guitar back to 100%.

[tubenit]

Hey HotBluePlates,

Great to see you posting.  Gabriel knows ALOT more than I do about guitars and finishes.

Having said that, I painted houses and refinished furniture professionally for 17yrs and YES I have stripped polyurethane. In fact, I did two different dining room tables recently (in 2010) both of which had poly finish NOT lacquer. I do know the difference. And yes there was blushing similar to your guitar.

It is an absolute bear to get urethane off effectively.

However, there are some heavy duty strippers that will work with polyurethane that Lowe's sells. The method I use is to brush the remover on ONE direction only. Do NOT brush back into your first brush stroke because it lessens it's effectiveness. I use thick industrial razor blades and with my hand pull the razor blade vertically to the horizontal finish. This will eventually scrape and strip the finish down to a level that you can effectively sand off the rest. If you do this properly, there will be little to no finish left to sand off. You would be amazed at how effectively I can get a finish off to leave very little sanding left.

Given the thin nature of a sound board and that it is a soft wood (such as spruce), I would be VERY VERY nervous to sand the entire finish off. I think it would be too easy to sand to far into the wood. Especially if you have belly bow like on some Alvarez guitars. You could easily sand thru way too much soundboard.   I would much rather strip most of it off and then sand it with an orbital sander (or block sand)  and use 320 grit paper.

Just my two cents worth. Gabriel may be giving you better advice, but I am saying this is how I would do it based on lots of refinishing experience with furniture.

Best regards, Tubenit

[G._Hoffman]

Hey HotBluePlates,

Great to see you posting.  Gabriel knows ALOT more than I do about guitars and finishes.

Having said that, I painted houses and refinished furniture professionally for 17yrs and YES I have stripped polyurethane. In fact, I did two different dining room tables recently (in 2010) both of which had poly finish NOT lacquer. I do know the difference. And yes there was blushing similar to your guitar.

It is an absolute bear to get urethane off effectively.

At a guess, this is a different kind of Poly than you are used to.  Most of the 70's and 80's Asian guitars used finishes that were never legal here in the USA.  The use a chemical catalyst, and are a gigantic pain in the arse* to work with.  That said, if you have a stripper you think might work, you can always give it a try.  The worst that is likely to happen is nothing, after all.  That is what we've always found with the strippers we usually use with nitro (mostly Zip Strip and Citrus Strip).  You can sometimes have some luck with heat, but controlling that process is a nightmare.  No matter what process you use, follow the age old advice, and test in an "inconspicuous" spot first.


Gabriel



*Could someone please explain to me how Firefox's spellchecker doesn't have arse, but DOES have - and tried to correct with -  arsed?  The former is the root word of the latter, and while I could understand not having slang words in the dictionary.....WTF?

[tubenit]

Good advice to test an inconspicuous area.  Gabriel, you're probably right & I admit you have far more knowledge and expertise than I do with these guitars.

Best regards, Tubenit (Jeff)

[Willabe]

    Hi All,
     
        HBP, I bought my younger brother an Alvarez 20/30 years ago (lower end model, but was a step up from what he had at the time ) and from your pics the head stock and back look all most the same.  It now has the same type of finish haze on the back. Dont know when it happend but it never left our parents house were my brother lived and were from Chicago (weather) . My brother is blind and played guitar before I did but he has many health problems now, so any way he gave it to my wifes kids. But same haze on the back.

        Sounds like you`ve got a good learning project on your hands if you to go that way.   


       Brad           

[HotBluePlates]

Thanks for the advice Tubenit! I have used a stripper before on the "legal, american poly" finishes, so I know what you're describing. It may be worth trying out, because I have a nightstand that needs refinishing, and I'm sure modern furniture has some kind of poly finish on it. If it doesn't work on the Alvarez, it will probably still work on the nightstand.

That said, this is a really thin finish compared to other poly finishes I've seen. Add to that, that this is a Martin copy with wood herringbone (mostly exposed due to wear-through on the top), and I'm sure that I'm going to attack this the very slow way: sand everything by hand (with a block, of course). I guess I should say the top's finish seems really thin; the back and peghead face have fairly thick finishes.

Anyway, it seems I might have weeks or months of sanding in my future! Oh well, it will be a learning experience.

[tubenit]

Klingspor has some very good sanding discs if you want to try an orbital? I have bought 400 - 1200 grit from them and they worked really well.

Best regards, Tubenit

[HotBluePlates]

The catch is I don't own an orbital sander!  

And the follow-on concern is the speed given by the power sander becomes a liability once the finish is almost gone. I am starting to think the approach I might try is to use a razor-blade as a scraper to remove a lot of the finish by hand. That way I can move very slowly with it once I'm almost through the finish.

Maybe now isn't a good time to bring it up... but the guitar could also use a neck reset.    

The existing saddle is so short the strings have almost zero break angle over it. I know that having the plane of the neck (when adjusted dead-straight) is best pointing to the top edge of the bridge, so that the saddle came have some decent height, allowing better break-angle over the saddle. So now I'm debating with myself about trying to pull the 14th fret and inject steam to pull the neck off. The thought is that sooner or later, it will have to be done, if I want the guitar to play and sound its best.

Bear in mind folks: this guitar is a learning vehicle and not my only instrument. I have a very nice Taylor from '95 that is my main acoustic guitar. Surprisingly, this Alvarez sounds in a similar league, which is why I was willing to buy it in spite of all the cosmetic issues. So on one hand, I'd like to get it to perform as good as it can. On the other hand, it was so cheap that I'm not afraid to really screw up on it. I'm also in no hurry to complete it as a project, so I've got plenty of time to try to do the job properly.

I say all this because what Gabe said is right for the most part. If a paying customer wanted to do all this, it would make sense to tell them, "keep it as-is, and buy a better guitar with the money a neck reset and refinish would cost you." The only cost to me will really be the time, tools and material to do the job myself.

So any advice on the sticky situation of a neck reset? "Don't do it" is probably valid advice... but pretend that I'm the kid that's gonna jump off the roof no matter how many times you tell me it would be better if I didn't!  

[G._Hoffman]

So any advice on the sticky situation of a neck reset? "Don't do it" is probably valid advice... but pretend that I'm the kid that's gonna jump off the roof no matter how many times you tell me it would be better if I didn't!  

I can't imagine trying to do finish work without a random orbit sander.  I'm in love with our air powered ones, but electric ones work pretty well too.  It is well worth the investment.


As for the neck reset, the first question is what kind of top is it?  I'm not familiar enough with the particular model, but if it is a plywood top the answer is don't do it.  Neck resets on plywood top guitars seldom work out well.  Actually, never.  The steam you need to remove the neck also delaminates the top.  Bad, bad, bad, bad, bad.  Unfixably bad. 

If it has a solid top - and preferably top, back, and sides - then it makes sense to do the neck reset when you are doing the refinish, because you can do a MUCH better job of refinishing it that way.  I'd also want to remove the bridge.  That being said, I'm not sure what kind of glue they used to put that neck in.  The Asian builders had a bad habit of using epoxy on things, which is all but impossible to remove. 

Beyond that, I do believe that Frank Ford has a thing about neck resets on Frets.com, so go and have a look.  Go VERY slow, and be careful at each step of the way.  Its not actually that hard, but you need to do each step right, and there are a lot of steps.  Make sure you let the guitar sit for a while before you try to refit the neck- the wood needs time to dry out again.  I'd even wait a while before I tried doing any of the finish work - at least a couple weeks.  And just in case you hadn't figured it out, a neck reset is a very big job. 


Gabriel

[HotBluePlates]

I think the model (it's not in front of me at the moment) is 5056.

I think I've seen someone write online that the top is plywood. That said, the thing that made me hold the guitar more than 3 seconds when I got it was the very responsive sound it made when played. Deep lows, good mids, nice overtones. I know from the Fender acoustic I had when I first started playing that plywood tops don't sound like that.

I looked at the edge of the soundhole, and it doesn't look laminated the way the Fender does. It is a little hard to tell, because there is some color variation. The back is solid rosewood, no doubt (thanks to the lifted binding). The sides are almost certainly the same.

A neck glued in with epoxy would be disheartening. The only way to do a thorough setup then would be to shave the bridge down, which is not an approach I would take.

[Voxbox]

Just my 2 pennyworth -

I know that Jimmy Moon of Moon Guitars in Scotland uses the razor-blade technique to remove finishes, he did so on a friends Yamaha SG1300. It laborious but it works.

In addition, the finish that George Lowden uses on his acoustics can be repaired invisibly without refinishing the whole guitar, at least by Lowden, but I just dont know what he uses. So it can be done....

[G._Hoffman]

I looked at the edge of the soundhole, and it doesn't look laminated the way the Fender does. It is a little hard to tell, because there is some color variation. The back is solid rosewood, no doubt (thanks to the lifted binding). The sides are almost certainly the same.

Look for grain lines.  If the grain lines continue through, its solid.  But if the back and sides are solid, I would be shocked if the top was not.  


Gabriel

[G._Hoffman]

In addition, the finish that George Lowden uses on his acoustics can be repaired invisibly without refinishing the whole guitar, at least by Lowden, but I just dont know what he uses. So it can be done....

Nitrocellulose Lacquer, and yes it can.  But that is not what we are dealing with here.


Gabriel

[HotBluePlates]

After some reading and research, I'm thinking it may be a fool's errand to try to reset the neck. I don't know for sure, but I suspect the neck is glued in with epoxy. My guess is based on seeing that the fretboard inlays are glued in over-size cutouts with epoxy. If it's a significant possibility, I don't really want to spin my wheels rigging up a steam generator, just to find out the neck won't come off at all.

In a related note, there was a Taylor road show here last night. I took my old Taylor to get a real A/B comparison against some of the models available. It was nice to see how my guitar's voice had grown up over the last 15 years. But I also got comfirmation of my suspicion that my Taylor needed a slight neck reset. Between the bolt-on neck and the warranty, it's a free repair (to me). For one of the costliest common repairs normally undertaken on a guitar, that just rocks!

[G._Hoffman]

My guess is based on seeing that the fretboard inlays are glued in over-size cutouts with epoxy.

While it is still a reasonable possibility that they used epoxy on that guitar, the inlays don't mean much in that regard.  That was the way most people did it back then, and most of the really good inlay artists still use epoxy for fingerboard inlays.  Their holes are a lot tighter, and they use super glue for inlay that are going to be finished over, but for things that will be exposed and on a fairly abused surface (such as the fingerboard, where you've got strings and finger nails and all the rest) epoxy and ebony dust (or charcoal dust, which works much better than ebony dust because its black) is quite common.


Gabriel

[HotBluePlates]

I see what you're saying. It's just hard to know up front whether the neck was glued with epoxy, given that Alvarez guitars aren't as documented as Fender, Martin and Gibson. I would just hate to waste the time and money getting the stuff to steam off a neck joint, just to find out it was glued with epoxy.

[Voxbox]

Hi G.Hoffman,

I asked Lowden what they used and got this reply -


"With difficulty small cosmetic repairs can be carried out usually nearly invisible..... The finish is two pack polyurethane and this means to blend old and new finish requires careful preparation, but generally can be done quite well by someone with specific experience of two pack finishes."


Now we know! And I can confirm from experience that their small repairs are superb and are nearly invisible, unless you get in there with a magnifying glass  

[G._Hoffman]

Hi G.Hoffman,

I asked Lowden what they used and got this reply -


"With difficulty small cosmetic repairs can be carried out usually nearly invisible..... The finish is two pack polyurethane and this means to blend old and new finish requires careful preparation, but generally can be done quite well by someone with specific experience of two pack finishes."


Now we know! And I can confirm from experience that their small repairs are superb and are nearly invisible, unless you get in there with a magnifying glass  

Yeah, I'm familiar with the techniques required.  One of our employees went out to Taylor to take their class on finish repair.  It actually helps with Nitro repairs as well, keeping finish cracks from resurfacing.  Its pretty tough to discribe, but basically you have to kind of make a gently sloping trough on either side of the crack or dent, and kind of feather in the new finish.  I still don't find touched up polys to look as good as touched up nitro, though the color match can be easier.


Gabriel

[Fresh_Start]

HBP - I know that Gabriel can't imagine working without the power sander, but he's a pro.  With one guitar and relatively unlimited time, I'd stay away from any kind of power sander.  It's just too easy to burn through and/or remove too much material, especially around the edges.  I say this from painful personal experience doing a nitro lacquer finish - 3 times eventually - on a Tele body.  Also, are the top and back both dead-flat?  If not, even a big sanding block with too coarse a grade of sandpaper can get you in trouble quickly.

Neat project by the way!

Cheers,

Chip

[G._Hoffman]

HBP - I know that Gabriel can't imagine working without the power sander, but he's a pro.  With one guitar and relatively unlimited time, I'd stay away from any kind of power sander.  It's just too easy to burn through and/or remove too much material, especially around the edges.  I say this from painful personal experience doing a nitro lacquer finish - 3 times eventually - on a Tele body.  Also, are the top and back both dead-flat?  If not, even a big sanding block with too coarse a grade of sandpaper can get you in trouble quickly.

Neat project by the way!

Cheers,

Chip

My dad developed bursitis in his shoulder from doing too much hand sanding, so I'm pretty committed to a good random orbit sander.  That being said, my experience is that sanding through a finish has more to do with a lack of proper preparation prior to finishing (sorry about the alliteration) and poor technique with the spray gun and the sander than anything else.  If you get your pre-finish work right¹, and spray a nice, wet², level coat of lacquer, you won't have to sand enough to have a problem.  The other trick with a random orbit sander is not to try to use it to perfection.  With prep sanding, I would say I get it 90% of the way there with the dyna-braid (our air powered sanders), and between coats I probably get it about 75% of the way there.  I get the last part by hand sanding with small sanding blocks (about 1"X2", hardwood for dry sanding, and a dense foam/rubber block for wet sanding).  I also usually do all the sanding with 220 by hand, but my prior sanding with 150 is good enough that it only takes me 10-15 minutes for an electric guitar body, as I'm mostly just knocking down the fuzz from raising the grain (wiping down the guitar with a damp cloth) between 150 and 220. 

I could go on and on about this stuff, but I won't.  I'll only reiterate my suggestion to NOT try spraying nitro at home.  If you make a mistake, it can make a really pretty fireball, but I'm guessing you won't appreciate the beauty from the inside!


Gabriel



¹Prior to finishing, careful sanding at every grit you use, always with the grain, raising the grain between your 150 and 220 grit passes, sanding to 220 (and no further, as you can inhibit the finishes adhesion to the wood), and making sure that it is as perfect as possible after each grit will get you as far as anything.  And I'm serious, you neither need nor want to sand bare wood past 220 if it is going to be finished.  I don't care what the internet "experts" say, every finish manufacturer on the planet will tell you I'm right.

²This, aside from inadequate surface prep, is the single biggest mistake amateurs make when spraying lacquer.  Any website that tells you to spray dry coats of finish is giving you bad advice.  You MUST spray wet coats if you want the finish to be right.  I go one step further, and spray two wet coats (admittedly, barely wet, but wet) consecutively.  One coat horizontal, and the second vertical immediately following the first.  You need good technique with your spray gun, but it makes a world of difference in the finish quality.  And somehow, every website I've ever seen talking about finish work tells people to spray dry coats.  The chemicals just don't work that way, folks.