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Jun 14, 2021 - 6:47:16 PM

gugger

USA

349 posts since 6/15/2004

I had a resonator that I experimented with True oil over Lacquer on the back of it. It seemed like it was not drying like it did on the couple of necks that I used it on with good results. I did some online reading after the fact and know have a better understanding that that is not advised and is meant to be used on bare wood like the necks that I finished using it. Is there a recommended solvent to clean the true-oil off of it? I am dealing with the back of a standard banjo resonator. Any advise would be appreciated. Also , with a new true-oil finish on a neck, do they recommend, wet sanding or buffing or some other final treatment? Thanks ,Mike

Jun 14, 2021 - 9:23:52 PM

2314 posts since 2/7/2008

Naphtha should remove the uncured Tru-Oil without damaging the lacquer assuming the lacquer is fully cured. In some states where naphtha is banned, a product called "painters solvent" is being sold as a naphtha substitute. It contains acetone and definitely will damage the lacquer, but naphtha will not.

Jun 15, 2021 - 12:01:56 AM

rcc56

USA

3622 posts since 2/20/2016

. . . and some people got upset with me when I once suggested that Tru-oil can be analogous to duct tape . . .

Lacquer over lacquer is good. It's one of the greatest attributes of lacquer-- it bonds with itself really well.
If you can't find a solvent to remove Tru-oil that is lacquer safe, try 600 sandpaper. You can use mineral spirits as a lubricant. You may have to go down to 400, but don't overdo it or you will go through. Then re-coat with lacquer.

For those who don't like using lacquer because of the toxicity, there's always French polished shellac.  Easy to apply once you get the hang of it.  It's good stuff.  It was used on many thousands of instruments by Vega, Stewart, Martin, and yes, Gibson.  If you want to toughen it up, you can add 5% - 10% sandarac, but you will need to wait a little longer between applications and extend the final drying period.  No significant toxicity unless you decide to consume some of the grain alcohol.

Edited by - rcc56 on 06/15/2021 00:12:34

Jun 15, 2021 - 2:47:26 AM

100 posts since 12/4/2007

You can get spray cans of lacquer at Home Depot.

Jun 15, 2021 - 5:39:24 AM

13698 posts since 6/29/2005

One of the primary differences between oil finishes and lacquers is that oil finishes penetrate into the wood and lacquers are surface coats.  Lacquers, either nitro or the waterborne kinds require a sealer to make them bond to the wood—after that successive coats bond to each other—the first coat is critical, and lacquer will craze if not bonded to the wood.

You might have to use something a little more drastic than naphtha to get the tru-oil out of the wood so that lacquer sealer or dewaxed shellac will adhere.

Also, most resonators have a crazy thin veneer on them, so be careful.

Jun 15, 2021 - 7:46:50 AM
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111 posts since 4/14/2021

Automotive wax and grease remover perhaps. Mild enough to not upset the existing coating, but will remove wax and grease residue. Used as a prep prior to repainting. Do your own research before using it.

Buy it at well equipped auto parts stores.

Jun 15, 2021 - 9:00:58 AM

7967 posts since 1/7/2005

Lacquer dries and hardens by evaporation. Oil-based finishes, like oil varnish or TruOil cure by polymerization--which is a chemical action between the oil and oxygen in the air. Painting oil based finishes on top of lacquer interferes with the curing of the varnish and can cause drying problems.
You could add a coat of de-waxed shellac over the lacquer and varnish over the shellac. But varnish over lacquer is a problem. As you found out. Best to choose between lacquer, shellac or oil finish and keep it simple. All three finishes have their strong and weak points.
You can probably remove the uncured TruOil with mineral spirits and 0000 steel wool. Or use a liquid refinisher and steel wool to get back down to bare wood.

DD

Jun 15, 2021 - 9:31:39 AM

5649 posts since 12/20/2005

Careful application of heat will make oil deep out of wood.
I've done this with antique firearms, using a stove.
By holding it at a distance, oil will deep out. You wipe it off as you go.
You have to be very careful especially on corners.
I've never done it with Tru oil. This may not work for this application.
Just an idea.

Jun 15, 2021 - 3:02:55 PM

ragalb

Canada

87 posts since 1/27/2021

quote:
Originally posted by Ken LeVan

One of the primary differences between oil finishes and lacquers is that oil finishes penetrate into the wood and lacquers are surface coats.  Lacquers, either nitro or the waterborne kinds require a sealer to make them bond to the wood—after that successive coats bond to each other—the first coat is critical, and lacquer will craze if not bonded to the wood.

You might have to use something a little more drastic than naphtha to get the tru-oil out of the wood so that lacquer sealer or dewaxed shellac will adhere.

Also, most resonators have a crazy thin veneer on them, so be careful.


There's so much I don't know. I applied just coats of lacquer to my banjo necks i didn't know I needed a sealer. What happens without the sealer? 

Jun 15, 2021 - 3:16:15 PM
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rcc56

USA

3622 posts since 2/20/2016

If it's a closed pore wood like maple, it may work out just fine. If it's an open pored wood like mahogany, the lacquer will sink into the pores as it cures, and you will have to keep sanding and adding more lacquer.

The use of a sealer is considered to be desirable, though. It raises the grain for the last time. Then you sand it smooth, and if you're good, you should be able to get a mirror flat finish with much less sanding. Sealer may also improve adhesion, but I'm not sure about that.

In the old days, the common sealer for nitro lacquer finishes was simply thinned nitro. A lot of folks still do it that way.

Jun 15, 2021 - 5:52:02 PM

gugger

USA

349 posts since 6/15/2004

since the lacquer was well cured for several years or more on the resonator, I tried using some low odor mineral spirits that I had on hand ,wiping it it with a soft cloth. It worked very well and now it is back to where I started. I think that I got lucky on it. I will use lacquer on it now. Can anyone tell me of any final treatments to use on a neck finished with true-oil after the last coat has cured? Polish, Wax ? Any advise along with the advice already posted is appreciated. Thanks ,Mike.

Jun 15, 2021 - 6:26:58 PM

2314 posts since 2/7/2008

quote:
Originally posted by gugger

since the lacquer was well cured for several years or more on the resonator, I tried using some low odor mineral spirits that I had on hand ,wiping it it with a soft cloth. It worked very well and now it is back to where I started. I think that I got lucky on it. I will use lacquer on it now. Can anyone tell me of any final treatments to use on a neck finished with true-oil after the last coat has cured? Polish, Wax ? Any advise along with the advice already posted is appreciated. Thanks ,Mike.


I like to use 0000 steel wool along with paste wax as a lubricant of sorts. I find it difficult to get an even sheen with dry steel wool, but the wax seems to even things out. The result is a slightly de-glossed finish with a slick, smooth feel. 

Jun 16, 2021 - 11:15:33 AM
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rmcdow

USA

938 posts since 11/8/2014

quote:
Originally posted by Ken LeVan

One of the primary differences between oil finishes and lacquers is that oil finishes penetrate into the wood and lacquers are surface coats.  Lacquers, either nitro or the waterborne kinds require a sealer to make them bond to the wood—after that successive coats bond to each other—the first coat is critical, and lacquer will craze if not bonded to the wood.

I have talked with the tech support at PPG (who makes Deft lacquer) about their lacquer line, and how to best use it, as I use their lacquer on many wood projects.  They said that in terms of penetration into the wood, the only difference between their sanding sealer lacquer and their straight lacquer is that the sanding sealer is thinner, sands easier (softer), but is not suitable for a final finish because it is softer.  The lacquer is going to lock into the wood just as well as the sanding sealer will, but the sanding sealer is going to penetrate deeper because it is thinner, and sanding away the raised grain is going to take less coats of the sanding sealer than the lacquer.  They assured me that the lacquer will not craze over time, as long as the wood is prepared as it would need to be for sanding sealer also.  

I apply their lacquer directly to fresh cut (green) sanding wood to seal it and cause it to dry slower, giving less surface checking.  I have not found that the lacquer is any less adhered to the wood (which was green and moisture content above 20%, usually above 30%) than it is to kiln dried wood.  I'm sure this is not really the case over the long term, as I don't think that the solvent based lacquer is going to penetrate moist wood as well as dry wood.  After the wood project is dry, I sand all the surface down and reapply the lacquer, at that time applying more coats than the single coat I originally applied.  Many of my projects have bark inclusions or bark that is left on the piece, and the original application of lacquer does hold those pieces together well.  

A  point I should bring up.  I typically put between 10 and 30 coats of lacquer or oil varnish on a piece of wood (I've been experimenting with Crystalac, only two to three coats needed for good results, but it is not a lacquer or an oil varnish).  The technician said that if I use sanding sealer first, I won't need to use that many coats to get the results I want to get, as the sanding sealer seals the wood and sets up a barrier that keeps the lacquer from soaking into the wood.  It typically takes me anywhere from three to ten coats of lacquer to build up enough of a finish so that the lacquer is no longer soaking into the wood and leaving "dry" spots.  Alternatively, but a bit more risky, I flood the surface with lacquer, and brush it down over a few minutes to fill the "dry" spots.  I don't need the three to 10 coats using this method.  Using sanding sealer, one to three coats will do the same job, typically. 

Edited by - rmcdow on 06/16/2021 11:30:43

Jun 17, 2021 - 6:06:32 AM

13698 posts since 6/29/2005

Rives,

Years back, I had a case of a crazed nitro finish on a banjo neck that occurred after a couple of months in the winter near Buffalo NY, which I had to completely re-do. I was using Behlen "musical instrument lacquer" and their matching vinyl sealer.

I called Behlen and spoke to their chemist who told me a few things, one of which is that while lacquer will melt into itself coat after coat, the first coat must be mechanically bonded to the wood, and the bare wood should not be sanded beyond 320 at the most, 220 is better—if you sand it (particularly closed grain wood) to 800 or 1000, you should  scratch sand it 220 before applying the sealer, otherwise, all the many coats of lacquer will be forming a skin that's not well bonded to the substrate and can craze if the temperature or humidity fluctuates.  I did that, and had no problems thereafter.  We've all seen old guitars and resonators with crazed lacquer.

His advice became my first rung on the ladder of freedom from nitro.

Nowadays I use CrystaLac almost exclusively, often using dewaxed shellac as an initial sealer and on mahogany, sapele and walnut will follow the shellac with their grain sealer rubbed on with a bondo squeegee.  After that, I use their sanding sealer which can be brushed (which I do on necks), but normally spray it because that's easier and you get more finish on it. I use Osmo hard wax finish for the playing parts of necks.

Here's a very open grained sapele guitar back finished with dewaxed shellac/grain filler/sanding sealer/topcoat, then rubbed.

 

I have never had problems with Crystalac and can spray it with no ventilation.  It's quite a bit more durable than nitro.

Edited by - Ken LeVan on 06/17/2021 06:07:38

Jun 17, 2021 - 1:26:19 PM

rmcdow

USA

938 posts since 11/8/2014

quote:
Originally posted by Ken LeVan

Rives,

Years back, I had a case of a crazed nitro finish on a banjo neck that occurred after a couple of months in the winter near Buffalo NY, which I had to completely re-do. I was using Behlen "musical instrument lacquer" and their matching vinyl sealer.

I called Behlen and spoke to their chemist who told me a few things, one of which is that while lacquer will melt into itself coat after coat, the first coat must be mechanically bonded to the wood, and the bare wood should not be sanded beyond 320 at the most, 220 is better—if you sand it (particularly closed grain wood) to 800 or 1000, you should  scratch sand it 220 before applying the sealer, otherwise, all the many coats of lacquer will be forming a skin that's not well bonded to the substrate and can craze if the temperature or humidity fluctuates.  I did that, and had no problems thereafter.  We've all seen old guitars and resonators with crazed lacquer.

His advice became my first rung on the ladder of freedom from nitro.

Nowadays I use CrystaLac almost exclusively, often using dewaxed shellac as an initial sealer and on mahogany, sapele and walnut will follow the shellac with their grain sealer rubbed on with a bondo squeegee.  After that, I use their sanding sealer which can be brushed (which I do on necks), but normally spray it because that's easier and you get more finish on it. I use Osmo hard wax finish for the playing parts of necks.

I have never had problems with Crystalac and can spray it with no ventilation.  It's quite a bit more durable than nitro.


Ken,

I am also using Crystalac for many of my projects, with a lot of success, and am still experimenting to see what the best use is for it.  I recently purchased their grain filler and sanding sealer, and have currently used the sanding sealer first on an 18th century six plank blanket chest, out of pine.  I had a bit of mixed results from that.  The chest had been stripped of the original two layers of paint, likely milk paint, before I got it.  After applying the sanding sealer and a coat of the Crystalac, there were a few spots that did not seal well, as something in the original wood in those spots bled through.  I suspect oil.  I sanded and used Crystalac again, and it worked fine with a great finish that will be my final coat.  I am impressed with the Crystalac, after finishing a large office desk out of cherry, the cabinets sprayed with Crystalac with no sanding sealer, and the top brushed on with Crystalac, also with no sanding sealer.  The top flowed completely smooth with no brush strokes; I applied two coats, and have to say it is one of the best finishes I have done yet.  Hard as a rock, doesn't scuff, resists moisture, and is completely clear to see the cherry grain in its natural color.  

I dug up my email from PPG.  Here is their response

  You don't necessarily have to use the sanding sealer. Depends on how porous the wood is. The sanding sealer will close the pours of the wood so it won't suck up the lacquer and you may not have to do as many coats of the Lacquer.

 

 

This has been my experience with the Deft lacquer.  As I said earlier, my techniques might not apply to most people's way of finishing, as I apply as many coats, over as long a period of time as necessary, to get the results I am looking for, and sometimes over green wood.  I have a 4' walnut buscuit cut from ground level down into the root 4" that took me two years to get a finish I was happy with.  It was green when I started, and took that long to dry out completely, which contributed to the time frame.  Also, I used my own formula, mixed from resins, oils, and gums, and let it bake in a storage unit in the summer for two months at the end of the process.  

 

I enjoy working with various finishes, and have to say that the Crystalac has a lot of what I would look for in a finish that is durable and easy to apply.  If I am looking for a finish out of natural ingredients, and have the time, I use the oil and spirit finishes from Hammerl GMBH out of Germany, as they are the closest I have found to the Cremona finishes as used on the Stradivari instruments, which in my opinion is still a gold standard.  They stand up under moisture and temperature, over time, and with wear down into the wood like no other finish I have come across. 

 

Edited by - rmcdow on 06/17/2021 13:27:52

Jun 17, 2021 - 1:58:43 PM

13698 posts since 6/29/2005

quote:
Originally posted by rmcdow
quote:
Originally posted by Ken LeVan

Rives,

Years back, I had a case of a crazed nitro finish on a banjo neck that occurred after a couple of months in the winter near Buffalo NY, which I had to completely re-do. I was using Behlen "musical instrument lacquer" and their matching vinyl sealer.

I called Behlen and spoke to their chemist who told me a few things, one of which is that while lacquer will melt into itself coat after coat, the first coat must be mechanically bonded to the wood, and the bare wood should not be sanded beyond 320 at the most, 220 is better—if you sand it (particularly closed grain wood) to 800 or 1000, you should  scratch sand it 220 before applying the sealer, otherwise, all the many coats of lacquer will be forming a skin that's not well bonded to the substrate and can craze if the temperature or humidity fluctuates.  I did that, and had no problems thereafter.  We've all seen old guitars and resonators with crazed lacquer.

His advice became my first rung on the ladder of freedom from nitro.

Nowadays I use CrystaLac almost exclusively, often using dewaxed shellac as an initial sealer and on mahogany, sapele and walnut will follow the shellac with their grain sealer rubbed on with a bondo squeegee.  After that, I use their sanding sealer which can be brushed (which I do on necks), but normally spray it because that's easier and you get more finish on it. I use Osmo hard wax finish for the playing parts of necks.

I have never had problems with Crystalac and can spray it with no ventilation.  It's quite a bit more durable than nitro.


Ken,

I am also using Crystalac for many of my projects, with a lot of success, and am still experimenting to see what the best use is for it.  I recently purchased their grain filler and sanding sealer, and have currently used the sanding sealer first on an 18th century six plank blanket chest, out of pine.  I had a bit of mixed results from that.  The chest had been stripped of the original two layers of paint, likely milk paint, before I got it.  After applying the sanding sealer and a coat of the Crystalac, there were a few spots that did not seal well, as something in the original wood in those spots bled through.  I suspect oil.  I sanded and used Crystalac again, and it worked fine with a great finish that will be my final coat.  I am impressed with the Crystalac, after finishing a large office desk out of cherry, the cabinets sprayed with Crystalac with no sanding sealer, and the top brushed on with Crystalac, also with no sanding sealer.  The top flowed completely smooth with no brush strokes; I applied two coats, and have to say it is one of the best finishes I have done yet.  Hard as a rock, doesn't scuff, resists moisture, and is completely clear to see the cherry grain in its natural color.  

I dug up my email from PPG.  Here is their response

  You don't necessarily have to use the sanding sealer. Depends on how porous the wood is. The sanding sealer will close the pours of the wood so it won't suck up the lacquer and you may not have to do as many coats of the Lacquer.

 

 

This has been my experience with the Deft lacquer.  As I said earlier, my techniques might not apply to most people's way of finishing, as I apply as many coats, over as long a period of time as necessary, to get the results I am looking for, and sometimes over green wood.  I have a 4' walnut buscuit cut from ground level down into the root 4" that took me two years to get a finish I was happy with.  It was green when I started, and took that long to dry out completely, which contributed to the time frame.  Also, I used my own formula, mixed from resins, oils, and gums, and let it bake in a storage unit in the summer for two months at the end of the process.  

 

I enjoy working with various finishes, and have to say that the Crystalac has a lot of what I would look for in a finish that is durable and easy to apply.  If I am looking for a finish out of natural ingredients, and have the time, I use the oil and spirit finishes from Hammerl GMBH out of Germany, as they are the closest I have found to the Cremona finishes as used on the Stradivari instruments, which in my opinion is still a gold standard.  They stand up under moisture and temperature, over time, and with wear down into the wood like no other finish I have come across. 

 


Have you tried Osmo?—another German finish with natural ingredients.  An oil/wax finish much different than CrystaLac but works for different things.

Jun 18, 2021 - 3:58:42 AM

rmcdow

USA

938 posts since 11/8/2014


Have you tried Osmo?—another German finish with natural ingredients.  An oil/wax finish much different than CrystaLac but works for different things.

That is the first I have heard of it, and after reading about it, it looks interesting.  The ability to repair a coat within 30 minutes of application sounds like a real plus.  I like slow drying finishes, as it is possible to do repairs in the finish that would normally need to be sanded and finished again after drying.  I'll try it out.

Edited by - rmcdow on 06/18/2021 04:00:14

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