Mojorule Posted February 13, 2012 Share Posted February 13, 2012 So I bought an electronic 'weather station' today from a well-known budget German supermarket which has stores throughout Europe and offers different 'seasonal' items every week. Since I bought my SJ, I've been using my father-in-law's decorative, but apparently operational barometer/hygrometer to keep an eye on humidity, and have been on the look-out for a reasonable replacement, so that I might return his unit. Southern Hungary is not overrun with such items, even in a town which lies on the Danube and houses a college that trains water management engineers. So it's taken nearly a year to locate something. Rather shockingly, there is a 10% difference between the humidity readings of the two instruments. That would be the difference between perfect 45% (analogue decorative job) and slightly worrying 35% (new digital thing). Which should I believe? It's not as though either is a lab quality scientific instrument. In short, to break out the soundhole humidifier, or not? (Woody lives in its case, and standard humidity before huge snow fall and big heating bills has been 60% - according to the analogue machine. No cracks as yet and the guitar sounded fantastic last night. I have put a water tray on the radiator in the room where the guitar lives, and keep filling it up, but that just maintains the analogue reading at 45% - without it that starts to drop towards 35%.) What say you good people? Link to comment Share on other sites More sharing options...
j45nick Posted February 13, 2012 Share Posted February 13, 2012 You need what is called a "traceable reference" hygrometer, which will have been tested and calibrated to a specific standard. Off-the-shelf hygrometers are notoriously inaccurate and unreliable, as you have discovered. Link to comment Share on other sites More sharing options...
jedzep Posted February 13, 2012 Share Posted February 13, 2012 Wassup Mojo? I just started running my mouth in the vintage group regarding my feeling on guitar hydrating. Check it out and lend your 2 cents. Link to comment Share on other sites More sharing options...
Jeremy Morton Posted February 13, 2012 Share Posted February 13, 2012 Jed Zep, Do you have a link to that vintage group. I am curious as to what they say. JM Link to comment Share on other sites More sharing options...
jedzep Posted February 13, 2012 Share Posted February 13, 2012 Jed Zep, Do you have a link to that vintage group. I am curious as to what they say. JM I was hoping you'd chime in on this. I think about it waaay too much. Â http://forum.gibson.com/index.php?/topic/81986-humidifierswasted-time-and-money/ Link to comment Share on other sites More sharing options...
nodehopper Posted February 14, 2012 Share Posted February 14, 2012 I have three...one is a digital Hygo-Thermometer. One is the dial kind you buy at a cigar shop and then the third is a weather station. All were giving me different readings and in my case it was also a difference of maybe 10%. My solution was to set them all to match the middle value of the three, which was the Digital Hygo-thermometer which I felt was the one that was most likely the accurate one. Â All in all as long as you keep your guitars between 35% to maybe 55% you will be fine, the important thing is to keep the RH fairly stable ...Summer to Winter and in between. Going from 50% in May to 18% in June(Like can happen where I am in California) is what does damage. Obviously if you have an arsenal of vintage Pre-War guitars then maybe you should worry about it more than I do. My Music Room varies from about 40% to 50% give or take.... Link to comment Share on other sites More sharing options...
rar Posted February 14, 2012 Share Posted February 14, 2012 Rather shockingly, there is a 10% difference between the humidity readings of the two instruments. That would be the difference between perfect 45% (analogue decorative job) and slightly worrying 35% (new digital thing). Which should I believe? It's not as though either is a lab quality scientific instrument. You can use the moistened salt test to see how accurate each is when the relative humidity is 75%, which should give you a pretty good idea which is more reliable. Just Google something like "hygrometer calibrate salt" to see how it works. Â -- Bob R Link to comment Share on other sites More sharing options...
gearbasher Posted February 14, 2012 Share Posted February 14, 2012 I bought a "weather station" that came with three hydrometers. All of them read differently +/-5%. I bought 10, cheap, chinese made, digital hydrometers on eBay. All read exactly the same. Go figure. Link to comment Share on other sites More sharing options...
EuroAussie Posted February 14, 2012 Share Posted February 14, 2012 I have two in my music room. A planet waves which sits on the keyboard next to the top of the guitars (closest to guitars) and the other part of the room humidifier that sits on the floor, a couple meters away. They always give different readings (usually within 5-8%) with the planet waves one (higher) is always higher than the one on the floor from the room humidifier. Â When they are placed in same spot, directly next to each other they have same reading, so at least to know one is not faulty. Â I figure that the moisture is rising so it will be higher reading the 'higher' you go in the room. So I generally follow the one on the keyboards at headstock level of the guitars, as its also the one closest to teh guitars, as per picture. Â Link to comment Share on other sites More sharing options...
j45nick Posted February 14, 2012 Share Posted February 14, 2012 This is the one I use. It cost about $65 from an online weather instrument company. I just have it about halfway up the wall in my music room/office, which is quite small: about 3.4m by 3.4m (11' square). Its calibration is traceable to the National Bureau of Standards (or some other standard). Â Link to comment Share on other sites More sharing options...
jedzep Posted February 14, 2012 Share Posted February 14, 2012 This is the one I use. It cost about $65 from an online weather instrument company. I just have it about halfway up the wall in my music room/office, which is quite small: about 3.4m by 3.4m (11' square). Its calibration is traceable to the National Bureau of Standards (or some other standard). Â Holy crap! My Weather Channel weathermate is reading 19% rh right now. I think I'm dehydrating right in my chair. Link to comment Share on other sites More sharing options...
drathbun Posted February 14, 2012 Share Posted February 14, 2012 As long as you're keeping the average RH percentage within reasonable limits (40-50 is my range), you needn't worry about the discrepancies. As has been said above, it is rapid swings in range of RH/temperature or extended periods of dry/damp, hot/cold that do damage. Rapid warming from cold to room temperature for example will cause damage. Â With humidity it takes a while for moisture to get in and out of the wood. I used to be anal about making sure the guitars were at 45% RH and would panic if I came down to my music studio and found the humidifier had shut off over night and the room was at 27% RH. Â Now I just check on the water level and RH % every day and fill the tank when needed. The outside temperature here plunged to -15C over the last 24 hours and over night my humidifier ran out of water. I came into the room this morning and the readings were averaging 37% RH. So I filled the tank and a few minutes later the room was averaging 45.67% RH (I have three hygrometers placed around the room). No biggie. Â Â Link to comment Share on other sites More sharing options...
chasAK Posted February 15, 2012 Share Posted February 15, 2012 I put my planet wave next to two different humidifiers andthey all read within a 4% spread. I had an old 68 j160 for better than 30 years. I did nothumidify it and neglected it for much of that time and it ended up with bridgeand belly issues. Â chasAK Link to comment Share on other sites More sharing options...
Mojorule Posted February 17, 2012 Author Share Posted February 17, 2012 Thanks for all the advice. Â Nick, I can't afford a scientific hygro right now, and I would have to buy online, as truly one cannot buy anything in this part of Hungary apart from palinka, carp and kolbasz. OK, I exaggerate, but many things are hard to come by, which might explain why some people seem to find it possible to save some money on a paltry salary here. If I bought online, you can be sure there would be a huge P and P add-on and a mark-up just because it's Hungary. (Despite getting a very good deal on my guitar, the price was higher for Hungary than for certain other nearby countries, just because, well, there is no competition in Hungary.) Sure the guitar is a valuable thing, and I can't afford another, so I need to look after it. But I also take JedZep and Rod's point about not obsessing - I may check the humidity quite often, but I don't think I've been particularly OCD about the thing. I want to play the guitar and not just baby it. Â This thread was really the result of the difference in readings, and the inability to work out what to do. True I was wondering whether I shouldn't be taking things a bit more seriously, given how expensive a Gibson is, and given how much I love mine, but my main quandry was whether to humidify if one of the hygrometers reads 35% (or 34%), while the other reads 45%. People often say that a humidifier is necessary if things fall below 35%, but do people who worry about such things more than Rod and Jed humidify as soon as the reading goes one below 35%, or not? Does anybody humidify once the humidity falls below 45%? And I wouldn't want to over-humidify, which would be the case if I stuck the humidifier in and the 45% reading happened to be correct. (I once read on one thread that over-humidification is a common problem in the eyes of one luthier.) If the humidity is somewhere between my two readings, then would any of you humidify because it is somewhere between 34% and 45%, or would everybody leave it, since 35% is not dry enough to damage the guitar? Â Oh, and just to amuse the sceptics, today's parallel readings were 50% and 36%. So the old barometer shifts 5% and starts heading towards dampville, while the digital jobby shifts 1 or 2% and stays in drytown. Any verdicts as to the likely winner in the accuracy stakes? Â Bob, thanks for the salt test tip. All the links I've looked at work with analogue hygrometers. Is the test good for digital ones too (which probably can't be calibrated, but can be adjusted by mental arithmetic)? Link to comment Share on other sites More sharing options...
Mojorule Posted February 17, 2012 Author Share Posted February 17, 2012 Well this chap uses it on a digital hygrometer. Honestly, cigar smokers, they're more obsessive than guitarists. Despite the beer. And I thought that cigar smoking was meant to be a relaxing pastime! Â http://www.youtube.com/watch?v=d7Ap96SlGZA Â All I need to do now is locate a ziplock bag. May need to order that online too! Link to comment Share on other sites More sharing options...
jedzep Posted February 17, 2012 Share Posted February 17, 2012 Thanks for all the advice. Â Nick, I can't afford a scientific hygro right now, and I would have to buy online, as truly one cannot buy anything in this part of Hungary apart from palinka, carp and kolbasz. OK, I exaggerate, but many things are hard to come by, which might explain why some people seem to find it possible to save some money on a paltry salary here. If I bought online, you can be sure there would be a huge P and P add-on and a mark-up just because it's Hungary. (Despite getting a very good deal on my guitar, the price was higher for Hungary than for certain other nearby countries, just because, well, there is no competition in Hungary.) Sure the guitar is a valuable thing, and I can't afford another, so I need to look after it. But I also take JedZep and Rod's point about not obsessing - I may check the humidity quite often, but I don't think I've been particularly OCD about the thing. I want to play the guitar and not just baby it. Â This thread was really the result of the difference in readings, and the inability to work out what to do. True I was wondering whether I shouldn't be taking things a bit more seriously, given how expensive a Gibson is, and given how much I love mine, but my main quandry was whether to humidify if one of the hygrometers reads 35% (or 34%), while the other reads 45%. People often say that a humidifier is necessary if things fall below 35%, but do people who worry about such things more than Rod and Jed humidify as soon as the reading goes one below 35%, or not? Does anybody humidify once the humidity falls below 45%? And I wouldn't want to over-humidify, which would be the case if I stuck the humidifier in and the 45% reading happened to be correct. (I once read on one thread that over-humidification is a common problem in the eyes of one luthier.) If the humidity is somewhere between my two readings, then would any of you humidify because it is somewhere between 34% and 45%, or would everybody leave it, since 35% is not dry enough to damage the guitar? Â Oh, and just to amuse the sceptics, today's parallel readings were 50% and 36%. So the old barometer shifts 5% and starts heading towards dampville, while the digital jobby shifts 1 or 2% and stays in drytown. Any verdicts as to the likely winner in the accuracy stakes? Â Bob, thanks for the salt test tip. All the links I've looked at work with analogue hygrometers. Is the test good for digital ones too (which probably can't be calibrated, but can be adjusted by mental arithmetic)? Mojo...just for your info, cold winters up here north of the Catskill Mts., a relatively dry place, along with having wood heat, often brings my indoor rh down into the 20-30% range. Still no ill effects on my vintage acoustics over the years. But oh boy, the static electricity can reach out and grab you when you touch your strings. Link to comment Share on other sites More sharing options...
Mojorule Posted February 17, 2012 Author Share Posted February 17, 2012 Mojo...just for your info, cold winters up here north of the Catskill Mts., a relatively dry place, along with having wood heat, often brings my indoor rh down into the 20-30% range. Still no ill effects on my vintage acoustics over the years. But oh boy, the static electricity can reach out and grab you when you touch your strings. Â If only you could amplify that little Gibson when the static starts to flow! Link to comment Share on other sites More sharing options...
Mojorule Posted February 17, 2012 Author Share Posted February 17, 2012 I wonder what humidity Bill Clinton kept his cigars at when in the Oval Office. Link to comment Share on other sites More sharing options...
jedzep Posted February 17, 2012 Share Posted February 17, 2012 I wonder what humidity Bill Clinton kept his cigars at when in the Oval Office. Â I hear an intern was in charge of that department... Link to comment Share on other sites More sharing options...
drathbun Posted February 17, 2012 Share Posted February 17, 2012 I hear an intern was in charge of that department... Â Would that be called a hummeridifier? Link to comment Share on other sites More sharing options...
rar Posted February 17, 2012 Share Posted February 17, 2012 Bob, thanks for the salt test tip. All the links I've looked at work with analogue hygrometers. Is the test good for digital ones too (which probably can't be calibrated, but can be adjusted by mental arithmetic)? As Mojorule already said, it works fine with digitals. And, as for cost, my cheapest (which cost about $10) turned out to be a little more accurate than my most expensive ($40), though both were within a few percent of being correct. Spending a lot of money is not at all necessary to get more than sufficient accuracy. Â -- Bob R Link to comment Share on other sites More sharing options...
Mojorule Posted February 28, 2012 Author Share Posted February 28, 2012 OK, so I did the salt test last week. And the result was so way out I did it again. Same result. Can a digital hygrometer really be 23% out on the low side? Both times it read 52% instead of 75%. (Just for scientific purposes, I should note that I used a sandwich bag with a knot in and/or a sandwich bag tie, as the law of Hungarian supply and demand made ziplock bags a fantasy item last week. It's not that you can't get them, just that you can't get them when you want them. Are sandwich bags porous?) Link to comment Share on other sites More sharing options...
rar Posted February 29, 2012 Share Posted February 29, 2012 Can a digital hygrometer really be 23% out on the low side? Short answer is yes, I believe. Lots are off by 10%, and a fairly small percentage of them are just nowhere close to right. So it may be that there's a problem in the way you're doing the test, but it certainly may be that you have a really inaccurate hygrometer. Â -- Bob R Link to comment Share on other sites More sharing options...
j45nick Posted March 5, 2012 Share Posted March 5, 2012 I realize this thread has been dead for a week or so, but I stumbled across the calibration certificate for my hygrometer, whose calibration is traceable to the National Institute of Standards and Technology (formerly the National Bureau of Standards). Â At the time of testing and certification, the actual relative humidty was 40% at 1015 mB atmospheric pressure. My hygrometer read 42%, which is considered within tolerance. What was an eye-opener was that the acceptable range for a hygrometer of this standard, when the actual RH was 40%, was 38-46%! Â If that range is permitted for a reasonably high-accuracy certified hygrometer, it's no great surprise that we are seeing range vary as much as it is with the various instruments here. Link to comment Share on other sites More sharing options...
Mojorule Posted March 5, 2012 Author Share Posted March 5, 2012 Thanks Bob and Nick. So long as I can trust my wildly inaccurate meter to be wildly inaccurate in a consistent manner whatever the humidity (and not to behave in humidity terms like a spring that has been stretched too far). Link to comment Share on other sites More sharing options...
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