sealing the inside

[spookelele]

Is there a reason you can't seal the inside of a uke?
Other than reach?

I was just wondering.. if you sealed the inside of a uke.. if it would prevent issues of drying out/splitting/warping.

 

[BR Ukuleles]

I seal the inside of all my instruments with a couple coates of shellac during construction. Several other builders here do as well.

I doesn't prevent damage caused by too dry or wet conditions, but it does buffer the effects of very rapid changes.

 

[DownUpDave]

I seal the inside of all my instruments with a couple coates of shellac during construction. Several other builders here do as well.

I doesn't prevent damage caused by too dry or wet conditions, but it does buffer the effects of very rapid changes.

Hey Allen, I have a LfdM and Luis does the same as you do for those same reasons as well. I one negative is you lose the great smell from the wood when you sniff the sound hole. I have a mahogany baritone that is over 40 years old and it still gives off a nice aroma.

 

[sequoia]

It's funny, but I like the look of raw wood when I look into an instrument. Most of the really nice guitars and ukes I look into have raw wood. I have no idea whether this is an acoustic choice or whether it has to do with the cost of finish and/or labor. However, I can think of many good reasons why the inside of an instrument should be finished out. Sealing wood, moisture, controlling expansion, etc. etc. I just don't like the look personally. On the other hand, I could see where a more reflective surface on the inside of the instrument would be a plus. Perhaps a real luthier could chime in.

 

[Sven]

... Perhaps a real luthier could chime in.

Allen just did, didn't he.

 

[chuck in ny]

at one point in my career i sprayed lacquers to beat the band. coatings are a lot of fun and satisfaction. i got it out of my system in time and now it's 'less is more.'

 

[Michael N.]

It doesn't do a great deal Sequoia, other than what Allen has already stated. It slows down the exchange of moisture but at the expense of the instrument being a touch more difficult to repair should you ever need to glue cracks.

 

[greenscoe]

Glue and paper was used on the inside of lutes (bowl back mandolins). Maybe Michael N. is able to say whether this was intended to reinforce the stave glued joints or to stabilise the staves to prevent the joints opening due to constant changes in moisture content?

 

[Beau Hannam Ukuleles]

I seal the inside of all my instruments with a couple coates of shellac during construction. Several other builders here do as well.

I doesn't prevent damage caused by too dry or wet conditions, but it does buffer the effects of very rapid changes.

Ditto-
I do it just before gluing the top on

 

[gozierdt]

A lot of the luthiers on the "Official Luthiers Forum" who do professional repairs say that
finishing the inside of a wood instrument of any kind makes future repairs much harder.
They almost all recommend using hide glue for the same reason that it's much more
repairable than epoxies or PVA glues. So I gave up finishing the inside of my guitars
(and I'll do the same for the ukes I'm about to build), but I'm still holding back on
switching to hide glue. It would actually be easier on ukes because of the smaller
dimensions/gluing areas. Maybe I will give it a try...

 

[BlackBearUkes]

As a builder and repairman for many years, I don't finish the inside of any of my string instruments for the reason listed already. I use hot hide glue only on vintage instruments that call for it and on the violin family. The nature of the violin calls for access to the inside many time during the instruments life and hide glue makes sense. Ukes and guitars don't have the long life span of a violin and using hide glue to make repairs easier for the luthier does not make any sense to me. I don't want the uke or guitar to be easy to come apart. To many times older guitars and ukes that come into my shop that have put together with hide glue had problems because the glue failed on its own, destroying the instrument along the way. Some of this is due to neglect, temperature changes, etc., but not always. Sometimes the glue just fails. The newer glues aren't so fragile and fussy. A guitar is damn lucky to be around after 100 years of playing, everything wears out. Violins are different, they are around for many 100's of years so taking them apart for repair makes them better. I like all glues and each has its place in todays world.

A lot of the luthiers on the "Official Luthiers Forum" who do professional repairs say that
finishing the inside of a wood instrument of any kind makes future repairs much harder.
They almost all recommend using hide glue for the same reason that it's much more
repairable than epoxies or PVA glues. So I gave up finishing the inside of my guitars
(and I'll do the same for the ukes I'm about to build), but I'm still holding back on
switching to hide glue. It would actually be easier on ukes because of the smaller
dimensions/gluing areas. Maybe I will give it a try...

 

[Beau Hannam Ukuleles]

Saying that sealing the inside is bad for future repair is like saying wearing a car seat belt is bad because if you get in a crash its harder to get out....

Sealing the insides is a preventative.
Yes- future repairs are "harder" as you have to scrape/sand the shellac off for the new glue/cleat to stick but that is a small price to pay for the benefits.

 

[BlackBearUkes]

Small price to pay for what benefits? Wood still cracks and moves ( due to damage or climate), shellac or no shellac. Plus, if you have ever tried to repair and sand a top crack on the top plate in the bottom portion of a guitar with a cleat or two on the inside, sealing the plate on the inside makes the job much more difficult and costly to the customer. But not to worry, I always explain why the added cost.

As long as I'm on the subject of repair work, try explaining to the customer why the new poly finish on there uke or guitar can't be repaired successfully like a lacquer or oil finish. They love that one.

Saying that sealing the inside is bad for future repair is like saying wearing a car seat belt is bad because if you get in a crash its harder to get out....

Sealing the insides is a preventative.
Yes- future repairs are "harder" as you have to scrape/sand the shellac off for the new glue/cleat to stick but that is a small price to pay for the benefits.

 

[Beau Hannam Ukuleles]

The benefits already mentioned- it slows down the rate of expansion and contraction- or- wetness and dryness.

Frankly, I don't care if it's harder to repair.

My job as a builder is to make it as stable as possible in every way when I deliver it, and sealing the inside is one more step in that direction.

I won't lesson the quality of my build just because some clumsy numb nut is going to drop my instrument one day in the distant future. Better it crack due to customer negligence then crack because I didn't do everything I possibly could to prevent a crack....

Make sense now??

ps- i'm not saying that non inside sealed instruments are destined to crack, or luthiers who don't seal are negligent etcetcetce- I didn't seal the inside of any instrument for 10 years and never had a problem. But now im selling internationally (to dry and wet climates), I feel it is safer to seal.

Last week I was talking to a world renowned cello maker (his cellos are $60,000 each!) and I asked him if the old masters (ie Stradivarius) sealed the insides of their instruments (violins and cellos) and he surprises me by saying no. But...the world was a smaller place then (1600's) and musicians didn't travel as far and wide as today.

 

[BlackBearUkes]

The reasons for not sealing the inside of the violin family of instruments has nothing to do with location or how many people are on the earth. It has everything to do with repair. Wood will contract and expand no matter how many coats of sealer or finish you apply inside or out. Why make it harder than it has to be. Because you think the instrument will be better off with a sealer coat doesn't make it so.

One more story and I'll let this go. A classical guitar of European origin (well made instrument of professional quality) came into my shop fro a top crack repair. This was years ago. When I looked inside the guitar, there was a huge amount of dust and grime. All of it was stuck to the inside finish the luthier had applied. It was a freaking mess and I declined to work on it. For all the good intentions this luthier had at the time, it was a mess. I hope this never happens to any of you guys.

The benefits already mentioned- it slows down the rate of expansion and contraction- or- wetness and dryness.

Frankly, I don't care if it's harder to repair.

My job as a builder is to make it as stable as possible in every way when I deliver it, and sealing the inside is one more step in that direction.

I won't lesson the quality of my build just because some clumsy numb nut is going to drop my instrument one day in the distant future. Better it crack due to customer negligence then crack because I didn't do everything I possibly could to prevent a crack....

Make sense now??

ps- i'm not saying that non inside sealed instruments are destined to crack, or luthiers who don't seal are negligent etcetcetce- I didn't seal the inside of any instrument for 10 years and never had a problem. But now im selling internationally (to dry and wet climates), I feel it is safer to seal.

Last week I was talking to a world renowned cello maker (his cellos are $60,000 each!) and I asked him if the old masters (ie Stradivarius) sealed the insides of their instruments (violins and cellos) and he surprises me by saying no. But...the world was a smaller place then (1600's) and musicians didn't travel as far and wide as today.

 

[Beau Hannam Ukuleles]

The reasons for not sealing the inside of the violin family of instruments has nothing to do with location or how many people are on the earth. It has everything to do with repair. Wood will contract and expand no matter how many coats of sealer or finish you apply inside or out. Why make it harder than it has to be. Because you think the instrument will be better off with a sealer coat doesn't make it so.

One more story and I'll let this go. A classical guitar of European origin (well made instrument of professional quality) came into my shop fro a top crack repair. This was years ago. When I looked inside the guitar, there was a huge amount of dust and grime. All of it was stuck to the inside finish the luthier had applied. It was a freaking mess and I declined to work on it. For all the good intentions this luthier had at the time, it was a mess. I hope this never happens to any of you guys.

Removing shellac for cleats on a crack repair is an extremely simple procedure of sanding, or scraping, or wiping with alcohol- On a guitar, it adds perhaps 2-5mins to the job.

You said that "Wood will contract and expand no matter how many coats of sealer or finish you apply inside or out. Why make it harder than it has to be. Because you think the instrument will be better off with a sealer coat doesn't make it so. "

Sealing inside slows this process down, minimizing problems cause by....wait for it......rapid shrinking or expansion which make cracks.

I think the instrument will be better off only because the instrument will actually be better off.

Like I said, i dont care if its very slightly harder to repair- if i do everything well, there is nothing to repair.