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I am still in my first year in my new workshop and still working out the best humidity controls, my question is how dry do you think is too dry, I've been bottoming out at 38% on cold dry days, is this too dry ?

38% is not too bad. I like my shop in the 40-45 range, but if it hit 38 here or there I wouldn't sweat it.

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John Mayes
http://www.mayesluthier.com

It's fine Russell, we are lucky in that we don't get the enormous swings in RH that is common in the US. Even on snowy days like this I never have a reading below about 35%, and we rarely go above 50%. If it get's down too low, just put a bowl of water with a tea towel end in it as a wick, that'll get it up plenty. In very damp weather a ?99 dehumidifier from B&Q will be quite sufficient. Expensive climate control systems are wasted money in our climate.

Colin

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I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

but also if it is COLD then you gotta be careful about glue chalking. I never glue stuff up unless it is at least 65f.

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John Mayes
http://www.mayesluthier.com

It has been my experiance that the biger issue is how big (rapid) the swing is I live in an area that the avg RH is 38-45 so that is what I maintain my shop to.

The only failures I have had as been with major drops in in the winter. I glued up braces at 40% one day and a dry cold front came through the next night. The drop was in the 15%-20% range in a 24 hr period that is drastic, and yes braces poped off. I was really supprised the top joint did not split.

Moral of the story is I worry more about major swings in the RH tha I do about staying at 54% constent.

What happens if glue chalks? If you see it chalking is it too late to bring the piece into a warmer environment for curing?

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Gwaltney Guitars

Thanks Guys

I do have a small dehumidifier which I run when needed, but I don't have anything to put humidity into the air and was trying to avoid that.

The temp is maintained as I have radiators in the shop with thermostats fitted, just wasn't sure how dry was too dry.

Many Thanks

On a related note,
I assembled the body of my latest Mandolele lately at about 40% and did an epoxy fill last week. All was ok until I left it to cure in the house for a few days when it dropped to below 20% rh. The back was concaving. The assembly seemed to hold up ok though and when I rehydrated it inside a box with a damp rag, it came back to the original arch. Whew!
Does this seem normal?

Wade

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Wade
Nashua, NH
http://www.wadefx.com

Colin...I had to smile at your post...While most of the posts here are decidedly American in tone, I think that most Americans would not know what a tea towel is even if they saw one. I really enjoy the diversity of this forum have Brits in you, Russell and Dave (sorry if I missed any), some Aussies, a Kiwi or two, Arnt in cold but beautiful Norway and Gg and Mattia also from Europe.

My wife (who is Irish) and I enjoy our tea from a "brown betty" and have a stock of tea towels . On the east coast of the US the humidity is much closer to the UK and Europe than the western part of the US so for me too much rather than too little humidity is usually the problem.

That's it Shawn, can't beat an old brown tea pot for good tea! And, none of those tea bags, proper loose leaf tea for the authentic English cuppa! Can't beat it.

Colin

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I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

I've had my eye on the hygrometer the past few days 'cause I think I might get some time to build these holidays (3 weeks off!). The day before yesterday it was 75%, yesterday in the morning 22% and in the afternoon 76%. The temp's been in the nineties the whole time too.

So much for that idea.

if the glue chalks then it is too late. You better take whatever it was you were gluing apart and reglue as the bond will be severly weakened.... at least that is what I found out... LMI's glue seems to be pretty picky about this.

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John Mayes
http://www.mayesluthier.com

My control limits in my wood room are 38% - 42% RH.

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tim...
http://www.mcknightguitars.com