Official Luthiers Forum!

Hi Eveyone,

May I say this forum is great. I have learnt many good things from you all here. Thank you for taking time out to help a newby builder.

I would like to join the top and back for my weiss, however, humidity levels here in the dry tropics can be high. At the moment it is around 50% which is ideal but that will change quickly with the onset of the wet season in the next few weeks.

If I go ahead now, how long will the glue take to cure?

By doing the job now, may it cause problems like splitting etc down the track? I can control the environment if necessary with the aircon.

Once joined would it be ok to cut out the shape and store the wood for a few months till after the wet season between some ply lightly weighted? Storing will be in the home but the humidity environment won't be controlled.

Thank you all for your attention.

Cheers

Alan

 

 

Alan:

Welcome. We're glad you're here. That's a lot of questions, but I'll give it a shot. Others will be along shortly to correct me      :

First, if you intend to pursue building guitars at even a moderate level, especially in your climate, you're going to need "some" degree of humidity control. Now you do NOT have to control the temp/humidity in a large area. It can be a small closet, or something you built specifically for wood and guitars in progress...but the ideal temp/humidity falls somewhere in the 72 degree, 45% humidity range, give or take, at least it does for my area - and that of many builders. Personally, I worry more about humidity than I do about temperature swings. You may need a humidifier (if you're home is air conditioned, or a de-humidifier (for the wet season) or some combination of both. For example, I have to use both to keep my humidity somewhere in the 45-46% range. But once your humidity is controlled, you can take the work out, to your workspace area, do your work, and put it back in the controlled environment - and it should be just fine. And woods that you intend to build with (tops, backs/sides, bridges, neck wood, bracing, headplates, etc.) in the fairly near future (a few weeks)? Well, they're going to need to be properly humidified before you work with them. So eventually, you're going to have to deal with the humidity issue. One other thing: if the "average" humidity for the area in which your guitars are going to live is very high, then you're probably going to need to build your guitars at, or near, that average humdity. Like I said, others will be here momentarily to help me answer this question for you...but trust me when I say that extreme variations in humidity will not bode well for your guitars. No matter what humidity you build at, you're going to want to build at a level that will minimize the humidity swings to which your guitars will be exposed to. This usually means keeping the guitar in a case, and keeping the case properly humidified with either a humidifier, or a dessicant. Make sense?

Glue curing time will vary depending on the glue being used. Let us know what kind you're using, and someone will have an answer for you. But a good guess for joining a back, with a typical glue (titebond, hide) is a day or so AT THE MOST. Especially in 50% humidity. For example, where I live, if it's warm, and the humidity is good...I can use titebond and feel comfortable taking a top out of the clamps in 4-5 hours. I usually leave it overnight, but I've done it in a much shorter time frame. Just use your best judgement, and remember that leaving it clamped for a day only wastes a day. It won't hurt the joint.

As for the newly joined back cracking, again that's going to depend on the temperature/humidity combination. For example, a guitar built at 70% humidity, then exposed constantly to a 30% humidity level, may likely crack. Similarly, one built at 30%, but kept at a constant, moist 70% may crack also. The trick is to avoid the extremes...and that can only be done with a bit of proper planning.

I hope this hasn't been too confusing. Best of luck.

Bill

_________________
Eagles may soar, but weasels don't get sucked into jet engines.

Alan-
If you just want to join the plates without adding braces at this stage, nothing bad should happen to them as the humidity rises. You may see some interesting changes in shape, though.
When the humidity drops back to 50%, your plates will return to the same shape, and you can get back to work with bracing, etc.
I do second the advice to try to get some sort of humidity control in place- if not for your entire shop, at least for the area where you store your current projects.

cheers

John

Joining the top halves won't be a problem. You can join and store them. Humidity can be a big issue when you brace the top/back, and when you're closing the box. When you get to that point, all needs to be acclimated to a reasonable humidity for several days (weeks).   On the other hand, if the guitar will live in the same environment in which it is built, I have read that humidity shouldn't be a problem.    I'm getting ready to build a climate controlled room in my shop, but for the first 5 guitars I did what Bill said above. I work when the humidity is right and keep all the parts I'm working on in the house until needed. It's a pain, but it works. If I wasn't married, I'd build in the house like Hesh.

Ron

_________________
OLD MAN formerly (and formally) known as:

Ron Wisdom

Somewhere in the middle of Arkansas......

G'day Alan, I'm in Cairns and have been building in the garage for the last year. I've found that it doesn't matter a lick if all I'm doing is joining the top or back plates without braces. I used Titebond Original on the joints and left them clamped up over night with no problems at all.

If you brace up then your in for an adventure if the humidity hasn't been controlled. Nothing has cracked on me, but it just has warped in truly unbelievable ways.

Once the top and back plates are braced I leave them uncarved until I'm ready to glue the top and back to the sides. Then I try and get everything together in the space of a weekend.

On my first guitar I was too keen to get to carving, and once a lot of the brace wood was removed the plates ended up looking like potato chips after a weekend of high humidity. That was last December. I had to wait for the weather to change and the plates moved back into their correct shape, then glued up to the sides as fast as I could.

Now I've been placing all my wood in a large cardboard box that I've
covered with heavy plastic and then put about a kilo of silica gel in
some old socks into the box. It absorbs the excess moisture and
the RH has been staying at around 45-50%. I only bring it out to work on it, then back
in the box it goes.

I'm going to look for a dehumidifier for a small bedroom that I will use to store wood and do the glue ups for this coming wet season. Hopefully it will give some more control.

For what it's worth. The D-style that I built at the hight of the wet without any humidity control went through the dry season without any adverse effects.

_________________
Allen R. McFarlen
Barron River Guitars & Ukuleles
Facebook
Cairns, Australia

when folks talk about it being okay to build ina high rh area if the guitar will live in a high rh area, they are correct, but the facts seem to be seldom accurately evaluated.

the out side rh is obviously a factor, but most guitars do not live outside. most live indoors where the rh is largely controlled by hvac systems to a greater or lesser extent.

thus if you live in the tropic wet zones, most home these days have ac which will lower the rh of the interior spaces markedly. many also use dehumidifiers to further reduce the rh in order to prevent mold formation, etc.

then it must be acknowledges that the guitars whole life may not be spent in a single geographic area. it may be sold, the owner may move, etc.

also many tropical areas have two seasons, hot/wet, and hot/dry. the rh wil vary widely.

experience has shown that building at a middling rh gives the best chance for long term playability and surviva

but if you absolutely know that your guitar will never encounter differing rh levels then building at a higher rh may not pose problems.

it should also be noted that hide glue may hay problems in high rh environments, e.g., it can suffer from mold formation.

Thanks eveyone for your advice.

Sorry, I should have informed I am going to use the original Titebond.

Also I intend to wait till after the wet season is over before attempting bracing the top and back.

The cardboard box to store the wood in with the silica gel to maintain humidity levels is a cracker of an idea. Thanks Allen!!!

Cheers

Alan