Official Luthiers Forum!

There are some great threads if you search the archives. You will learn that nearly all of them suck especially the digitals and many of them can be 15% off which can crack a guitar top.

We've tested them all over the years and offer calibration services to our clients so long as Hesh here doesn't have to go to the post office and you can bring it to us with maybe lunch too...

Some summarized things that we have learned. YMMV and I don't care.

1). Digitals suck and if it can't be calibrated don't buy it.

2). Digitals rely on an electro chemical reaction meaning that if by chance you find a digital that is acceptable for now check it in three, five, etc. years it can be 20% off and there is nothing that you can do about it.

3). There is an issue of "range." By range I mean that a hygrometer may be accurate in a specific range of say 15%. So for 45% it may be plus or minus say 4% which is usable. But for 55% it may be plus or minus 10% which is getting not usable.

Methods of calibration using chemicals provide the stated results at the RH of calibration, say 75% but when you consider the issue of range the thing may be 15% off in the range that we care about which is basically 40 - 50%.

The jury is still out on this one since we never verified this but some chemicals may damage the chemicals in the digital hygrometer rendering it either inaccurate or providing the manufacturer with a scapegoat when you learn that the thing that you just purchased for $40 is a POS.

The makers of the Caliber hygrometers used to say their warranty is null and void if you do the chemical testing. Of course this is said in the small print on the instructions in the box not on the outside of the package.

4). Some mechanical hygrometers can be way off too and need calibration so a mechanical hygrometer is not in and of itself an answer.

So.... WTH does a Loothier do?

This:

1). Purchase a mechanical hygrometer that can be calibrated such as the Abbeon which is on my wall in my lounge and I'm looking at it right now. I've had this one from Elderly Instruments for 15 years now and it's been great the entire time. It gets checked annually and I've only had to increment it no more than several percent to calibrate it and some years not at all.

PS: Nothing is more important to a proper guitar building shop (repair too) than accurate RH readings and keeping the shop in the proper range. Ignore this and your creations will surely fall apart or crack all to heck in time and no I am not calling you Shirley.

2). Purchase the stuff to do a "wet bulb" test and learn how to do one. There are many different ways to do a wet bulb test, some of the threads in the archives here have my take on how to proceed with the testing and calibration. I'd find it for you but I'm old and hung over.... today. I'll be old tomorrow too but I digress.

3). Perform a wet bulb test (can you hum a few bars...) with the mechanical hygrometer very close in proximity to the test. Simply breathing on stuff can skew things so being dead already provides better test results. Where is a White Walker when you need one. Winter is coming....

4). Note difference, calibrate the hygrometer, repeat and check yourself (for accuracy on the test not looking inside your depends). Once your hygrometer is within a few percent of the results of the wet bulb test you are good for a year. Repeat in a year. I would repeat in 6 months the first time with a known unknown new hygrometer attribution Rummy.

It's really very simple and easy but you can never trust a digital or a fart. Learning to do wet bulb tests is easy, fun and it's science too which sadly can be spelled sc*ence these days by some but who cares most of them can't tread water well anyway.

Good luck!

As far as practical advice goes, search on ebay for 'Cole Parmer Hygrometer' - there is one currently available...the instrument is made by Lufft (the maker of the Abbeon gauges) and is identical (less the logo and face colors) to the $200 gauges offered as new or the $100-plus used gauges. At $45 delivered, it will run about 1/4 to 1/2 the cost of a similar Abbeon-badged Lufft unit. Again - identical instrument for way less because you now have 'Super Shopper' knowledge...no, no - thank me later.

Ever the clever gentleman when it comes to recognizing a bargain, Mr. Morelli has several of the Cole Parmer-badged units...lovely gear. The photo is of one of his hygrometers and the bargain-priced Abbeon-badged Lufft we rebuilt (thus, gaining the wisdom to never, ever do it again).



https://www.ebay.com/itm/Cole-Parmer-In ... Sw~KpcbNES

Resist the temptation to purchase one of those stunningly vintage, deliciously corroded Abbeon gauges removed from a steam ship boiler room by a ship -breaker losing employees to careless accidents at a rate of a half-dozen a week on some subcontinent mud flat. Any gauge showing that sort of corrosion has likely led a very hard life indeed, so search for something bright and shiny and quite naive as far as the ways of better traveled hygrometers are concerned. If you've already run out and made the purchase of a piece of maritime history, consider immediate resale, as disassembly and refitting is a fiddly job that will likely have you searching for suitable profanity and heading out to the nail salon for repairs immediately afterwards. Breaking a couple nails in pursuit of saving $50 or so is a false economy, if nail salon prices and your time are properly considered in the value proposition.

Ah, it wasn't me.

There is another one there for $49.

1). Digitals suck and if it can't be calibrated don't buy it.

Mr. Castonguay:

I should have PM'd you with this information; however, I have a strict rule regarding reciprocity when it comes to all that Canadian 'niceness' nonsense...in my view, the sooner you people learn that no good deed goes unpunished, the better.

But seriously, I suspect another similar gauge will be offered for sale shortly, and it seems the market will remain largely ignorant of the Cole Parmer-branded instruments as a viable alternative to the Abbeon hygrometers outside this grand group of luthiers...or at least until someone reposts the thread on other enthusiast fora.

W