I'm rebuilding a 1940's solid spruce arch-top; I'll definitely shellac the interior after hearing this. I always wondered why archtops have adjustable bridges when flat-top guitars, violins, etc don't. Now I know.
Not a luthier, but have used shellac a lot on furniture builds, even on the inside of plywood drawers (just a light coat for sealing). So my first guess was that shellac would be a common answer.
A seal coat should not build ,you should only be putting on 1 ml at most single coat . It's a seal coat not for build or sanding . It protects against humidity and it locks the wood down and prevents elevational checking and shatter . 40 years finishing experience . Just started taking guitar lessons ( rhythm? what's that ? lol ) Chemical coatings technology's , color , and infinity yes I understand them better than Stevie Ray Vaughan played. P. S. Thinner does not make more lacquer . If you have to polish you did it wrong . Never ever prep sand with anything more than 150 grit 320 will polish the wood . Polished wood delaminates , shatters, crazes and spider webs . The rule of doing equal coats per side mainly applies to catalyzed lacquers . They shrink and will bend a door or a table . Standard nitrocellulose lacquer the only need to put a seal coat as it doesn't shrink as intensely or as hard as catalyzed lacquers. The reason nitro cell turns White when it gets moisture is because it's made from cotton. Retarder not reducer two different things.
I just found this video and was wondering if there is a way to seal a completely assembled guitar. I have recently been diagnosed with severe wood dust allergies and I have noticed this while playing my guitar. I am assuming that the vibration and projection through the sound hole is probably putting wood dust in the area while I am playing. I would hate to give up playing the guitars I have just for this reason. I know this is an older video, but hopefully you see it and may have some suggestions. Thanks.
Hi Leo, I don't know of a way to seal the inside after the guitar is made, but guitars are notorious for getting filled up with lots of dust over time. I use compressed air to blow out the inside of the guitar. An air compressor is the best way to do that if you have one. Be careful with a can of compressed air, though, because it might cause the wood to get cold really fast, which could cause cracking of the wood or finish. A small vacuum hose that you could fit inside might be helpful too. You are right, though, an acoustic guitar does pump air in and out of the sound hole while you play, so if there is dust inside, it will most likely get some in the air. If you can clean out that dust from the inside, it will help with the dust issue, but the guitar might sound better, too, without all that extra stuff damping the vibration inside.
Sorry for all the questions. Fantastic topic! Does Martin seal the inside of their guitars? If so, do you know what they use? What about the early Gibson arch tops? Original D'Angelico? Do you know if Robert Benedetto seals the inside of his guitars? If so with what?
I always sealed the inside of my guitars with a thinned coat of shellac. The shellac will slightly raise the grain, so I wipe sand lightly with worn-out #220 or #320 sandpaper.
I'm not a professional luthier, but I have heard a lot of luthiers say that you should never seal the inside of your instrument. While you will have to combat humidity more, the instrument will actually be repairable. If you seal the inside and a brace cracks, you now have to sand through the finish while elbow-deep in the instrument, then fix the crack, then refinish. At that point I would be willing to bet many luthiers and guitar technicians would just turn the instrument away claiming it would cost more to repair than it would to buy new.
@@JorgeTheilacker If you finish the inside of the instrument, underneath any braces will not have any finish and any loose braces could be glued down. But if the center seam in the top separates or a crack developed somewhere else, then you would be in for a rough time because you'd have to scrape off any finish to get a good glue joint for the patch
I'm rebuilding a 1940's solid spruce arch-top; I'll definitely shellac the interior after hearing this. I always wondered why archtops have adjustable bridges when flat-top guitars, violins, etc don't. Now I know.
Not a luthier, but have used shellac a lot on furniture builds, even on the inside of plywood drawers (just a light coat for sealing). So my first guess was that shellac would be a common answer.
Love Toms content! The most knowledgeable luthier I know if he has helped me so much !!!
A seal coat should not build ,you should only be putting on 1 ml at most single coat . It's a seal coat not for build or sanding . It protects against humidity and it locks the wood down and prevents elevational checking and shatter .
40 years finishing experience .
Just started taking guitar lessons ( rhythm? what's that ? lol )
Chemical coatings technology's , color , and infinity yes I understand them better than Stevie Ray Vaughan played.
P. S. Thinner does not make more lacquer . If you have to polish you did it wrong . Never ever prep sand with anything more than 150 grit 320 will polish the wood . Polished wood delaminates , shatters, crazes and spider webs .
The rule of doing equal coats per side mainly applies to catalyzed lacquers . They shrink and will bend a door or a table . Standard nitrocellulose lacquer the only need to put a seal coat as it doesn't shrink as intensely or as hard as catalyzed lacquers. The reason nitro cell turns White when it gets moisture is because it's made from cotton.
Retarder not reducer two different things.
I applied a sealant inside my Martin D28 and it enhances the sound.
This was a very helpful video!
Glad it was helpful!
I just found this video and was wondering if there is a way to seal a completely assembled guitar.
I have recently been diagnosed with severe wood dust allergies and I have noticed this while playing my guitar. I am assuming that the vibration and projection through the sound hole is probably putting wood dust in the area while I am playing.
I would hate to give up playing the guitars I have just for this reason.
I know this is an older video, but hopefully you see it and may have some suggestions.
Thanks.
Hi Leo, I don't know of a way to seal the inside after the guitar is made, but guitars are notorious for getting filled up with lots of dust over time. I use compressed air to blow out the inside of the guitar. An air compressor is the best way to do that if you have one. Be careful with a can of compressed air, though, because it might cause the wood to get cold really fast, which could cause cracking of the wood or finish. A small vacuum hose that you could fit inside might be helpful too. You are right, though, an acoustic guitar does pump air in and out of the sound hole while you play, so if there is dust inside, it will most likely get some in the air. If you can clean out that dust from the inside, it will help with the dust issue, but the guitar might sound better, too, without all that extra stuff damping the vibration inside.
I live in Columbia, can I visit your shop in St. Louis?
Sorry for all the questions. Fantastic topic! Does Martin seal the inside of their guitars? If so, do you know what they use? What about the early Gibson arch tops? Original D'Angelico? Do you know if Robert Benedetto seals the inside of his guitars? If so with what?
I always sealed the inside of my guitars with a thinned coat of shellac. The shellac will slightly raise the grain, so I wipe sand lightly with worn-out #220 or #320 sandpaper.
@@gtrjazz Thanks for taking the time to answer.
Could you use laquer instead of shellac?
can you tell us what lb.cut of schallic do you use
thank you
I am a guitar maker from Indonesia, I have been in this job for 12 years. I really want to work in America for this field of mine.
I'm not a professional luthier, but I have heard a lot of luthiers say that you should never seal the inside of your instrument. While you will have to combat humidity more, the instrument will actually be repairable. If you seal the inside and a brace cracks, you now have to sand through the finish while elbow-deep in the instrument, then fix the crack, then refinish. At that point I would be willing to bet many luthiers and guitar technicians would just turn the instrument away claiming it would cost more to repair than it would to buy new.
I believe that If you have a crack inside or a loose brace, the surface that you will glue would not have finish over, don't It?
@@JorgeTheilacker If you finish the inside of the instrument, underneath any braces will not have any finish and any loose braces could be glued down. But if the center seam in the top separates or a crack developed somewhere else, then you would be in for a rough time because you'd have to scrape off any finish to get a good glue joint for the patch
2:05
Thanks papa 😂
Yes but not the same way you seal the outside
Since You are a hell of a talker, Your not able to learn me anything about guitarbuilding. Sealing or not is a question of common sens, nothing more.