Wooden microphone box - finish

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bancho

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I'm going to build myself some wooden boxes for diy microphones I have. I have a question about the wood finish - which is the best and which to avoid. I don't want to destroy the capsule with some finish which could melt (by evaporating) the diaphragm.
Probably the water based lacquer is ok but I'd like to know about the others: wax (which?), oil (which?), shellac, epoxy... anything else?
Does anyone have experience with this?
 

soliloqueen

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The issue here is hydrocarbon solvents, like toluene and benzene. Unfortunately, as you suspect, these are what is used in most wood finishes. A water-based laqueur might be a good idea, and allow it to completely dry. In general, As long as whatever you're using emits all of its solvent at once at the beginning, you should be fine. I don't have a ton of experience in formulations, thugh.
 
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soliloqueen

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Ok, great!
What about oils / wax?
oils polymerize and probably are safe, but this can take up to 30 days depending on ambient humidity. really, you're looking for something that's stable and doesn't give off long-term fumes or droplets. the composition doesn't matter as much. the worst case scenario would be an aromatic hydrocarbon that continuously emits into the box. second worst would be anything else that continuously emits into the box, then an aromatic hydrocarbon that evaporates quickly, then anything else that evaporates quickly. it would be fine to use a "dangerous" chemical if it's gone quickly enough, and it might even be better than a safer chemical that sticks around longer.
 
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The diy woodworker community, which I get down with, has become pretty obsessed with Rubio Monocoat.

It’s a penetrative hardening wax. Offers near poly protection. Looks extremely natural but you can also make it look like glass if you follow off label methods.

No gas, VOCs, or dust. It soaks into the wood in one coat and then you just wipe off all excess. It’s also food safe. Is handleable in 1 day and fully cured in a week. If you’re any good at sanding this stuff will make your mic box look better than any thing you could buy.

If you’re really concerned email them and ask but it’s gonna possess all the qualities of any other finish normally used for this application.
 

k brown

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Folks - there's no such thing as water-based or acrylic lacquer; lacquer is, by definition a solvent-based finish.

FWIW, my favorite wood finish is gloss water-based urethane, that's then de-glossed with steel wool. Then apply paste wax, and buff. The steel-wooling and buffed paste wax top coat removes the 'plasticy' appearance, and this combo is much toupher than wax alone.
 

Matt Nolan

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Folks - there's no such thing as water-based or acrylic lacquer; lacquer is, by definition a solvent-based finish.

The first part may be right, but I'm not sure the second part is. Traditional Japanese Urushi lacquers pre-date the use of solvents and self-polymerise.
 

k brown

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The first part may be right, but I'm not sure the second part is. Traditional Japanese Urushi lacquers pre-date the use of solvents and self-polymerise.
I foolishly assumed the discussion was about modern, readily available finishes . . .

Since the 19th century the word has pretty universally referred to solvent-based coatings.
 

KIDVOX

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The issue here is hydrocarbon solvents, like toluene and benzene. Unfortunately, as you suspect, these are what is used in most wood finishes. A water-based laqeur might be a good idea, and allow it to completely dry. In general, As long as whatever you're using emits all of its solvent at once at the beginning, you should be fine. I don't have a ton of experience in formulations, thugh.
i us french polish when i build replicas of pre 1900 instruments. the solvent is just plain alcohol. the finish is a satin gloss. no skill is required and its fully cured in less than 24 hours. if im building a clssical guitar i use birchwood casey true oil. again very little skill required and fully cured in less than a day ( or 48 hours ) a medium sheen and hard wearing. just options to considerIMG_20230926_224621.jpg
a lute with a shellac finish.
IMG_20230926_224716.jpg

a little guitar with the gun stock finish.

just options
 

KIDVOX

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the thing about these finishes is that the cout of lacquer i very thin, revealing the textur of the wood used. i was talking to a (rip) violin making buddy about the use of sprayed varnishes nd car paints etc on electric instruments when he commented that " you might as well glue a plastic bag on to the wood. ade me giggle but its horses ad courses
 

Tubetec

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Ive used french polish on a few mic boxes , its very satisfying to wipe on a layer everyday for a week and watch the finish build ,
it smells nice , slightly fruity and boozey

I re-finished my Les Paul Junior in french polish , I love the way it takes a patina ,
not that I use it much ,

Ive been onto my luthier buddy for years to try french polish , and get away from the toxic crap
humidity and temp make a basic spray room here implausible half the year , unless you go to full climate control .

If you happen to be drinker as well as guitarist and play in venues with chicken wire across the stage maybe a shellac based finish isnt the best option :D
 

Matt Nolan

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I foolishly assumed the discussion was about modern, readily available finishes . . .

Since the 19th century the word has pretty universally referred to solvent-based coatings.
Playfully, assume makes an ass out of u and me. One should be careful when making definitive statements.
 

soliloqueen

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maybe a solvent lacquer would still be best even though it's corrosive to the diaphragm because it's gone so much faster than the other options. volatility is your friend in some ways.
 

KIDVOX

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I re-finished my Les Paul Junior in french polish , I love the way it takes a patina ,
not that I use it much
i know what you mean by the patina of french polish. could you please post a pic here. just curious as ive never seen a lp in french polish.
these are the LP's that i built a while ago. both in 2K finish
IMG_20230929_225154.jpg
 

mappee

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Although this thread is about wood finish on the mic box, we would all benefit more
if we find and alternative to the interior foam which crumbles and gases. idk
 

KIDVOX

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Although this thread is about wood finish on the mic box, we would all benefit more
if we find and alternative to the interior foam which crumbles and gases. idk
i was thinking about this. how about the paper used in hepa filters ( car air filters for example ) they are designed to be solvent and water resistant, also have a long service life ie many thousands of liters of air passing through them while retaining the structual itegrity i guess in a mic this material would last for years. could be worth a try
 

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