Official Luthiers Forum!

+1!

As an amateur builder I really wouldn't worry so much. The humidity question is really important in the US where they have huge humidity swings and central heating which works. For UK conditions, building without humidity control is fine provided (a) you don't close up the body in high humidity, and (b) the instrument isn't kept next to a radiator, or equivalent.

I build ukuleles which are notorious for cracking in the US. Only one of mine cracked, and that one was forced to live in an attic for a year. I also own a 1920s Kumalae, sold to me from Scotland, which has no cracks - not sure if there's an uncracked example in the whole of the US.

I have a simple device made from two six inch by 1/4 strips of veneer, glued together with the grain at 90 degrees. It curls left if it's humid, right if it's dry. Straight is around 55%, and I'll close the box anywhere there or drier.

If selling your builds you'd want to be fussier, to avoid repairs and keep your reputation. But as an amateur, just tell the recipient how to look after it!

Pat,
Thanks for the suggestions, I'm happy acclimatising a room for a week and gluing indoors. That's not too bad.

Rodger,
Confirms what Pat is saying! I'll make sure to glue up in the same conditions.

Chris,
Cheers, Some great information! I'll breath a little easier having read that. I'll do what I can and implore anyone who has one (only me, my dad, and, soon, my brother! lol) to look after it carefully.


I was really starting to panic about humidity issues but even if I just have to run a dehumidifier in one room for a week or so before gluing up, it's not too bad.


Best to all,
Nick

I noticed today that the humidity got down to 45% in my shop today, with the door to outside wide open

So on very hot days similar to today you might get lucky

Just a shame we don't get many of these days

Even fewer in Wales than London, I'm sure
And it would be more useful if we had a few (at least) in a row!

I did track RH in my garage and I did all major gluing at under 60% - best I could manage in what is essentially an outdoor environment - that guitar is going to live in a hard case with a humidifier if RH goes down... In the future, I'm definitely going to dehumidify the wood and a room to 50%ish (I figure slightly higher than US makes sense) for a week before gluing. I think that's probably safest....

Though, I do wonder, and maybe someone could suggest an answer: I know it isn't recommended but I'm building a guitar for a boat; do I want to build that in higher humidity seeing as it will see mostly moist air?

You should build it ON a boat just to be safe. But, the added benefits are really only noticeable when using moon spruce.

_________________
Pat

As Rodger said in a previous post, and just to clarify my last post...probably a day or two to acclimate the back/sides/top. If you get minor cupping don't worry about it because these pieces of wood are so thin and floppy the braces will take care of it (might be more of an issue on heavier rosewoods though, just flex it and decide). The brace wood can be the issue because it's so much thicker. I would think a week of acclimating would be ok but I would go 2 weeks+ to be safe. It would be a real bummer if you get all your brace stock dimensioned then they go banana on you before glue up and you have to start over.

I just used a cheap cigar box hygrometer for my first 6 builds and I kept my shop at about 40-45% according to that hygrometer. Just recently I got a very nice German made hygrometer from a fine weather instrument shop (accurate to <3% RH) and it showed my shop is actually at 50-55% on average. So I have built my first 6 at 50-55% RH and didn't know and they all seem to be holding up fine. But it is quite humid in the South of USA so this may be close to ideal building RH for me. Anyways, just something to think about.