Building Conditions

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Lostininverness
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Building Conditions

Post by Lostininverness » Sun Sep 20, 2020 9:06 am

Hi All,

First post with some questions to hopefully help get me out of my procrastination mode and into action!

As some background, I've built a few electric guitars in the back 1/2 of our Christchurch double garage which is two bays long rather than the norm of 2 bays wide. Its your "traditional" thin metal shed which I recently built a wall along the 1/2 way point, and have lined the walls with insulation and 12mm ply. I've plans to insert clear acrylic sheeting in the window openings (double glazed???), do something with the external door (maybe remove the metal outside and fill with foam) and put some thick poly sheeting in the ceiling once I've tidied up the roofing a little and stuck in some extra clear roofing sheets. Although a knee injury might have stuffed up my plans to do anything roofing related in this summer.

I store all bits of random timber I've collected in the shed and have all previous guitar building work in there. We get a fair amount of seasonal weather variation with temps between -3 to 32 degrees, and it looks like the RH is generally between 70-90%.

I've put off building anything acoustic so far due to climate control (and it seems a bit daunting). It would be a lot of cost to try and keep things at RH% that I've seen mentioned. So what I would like to know is, what would be the effect if I built a guitar in the shed keeping an eye on the climate conditions (I'm looking to get a meter of some sort installed in the shed) at points that are the more critical (is that when only the braces are being glued - or are there more???)? And would it be a disaster once I've completed building (big words I know) and its inside in more stable conditions?

If I can get advice on what you guys have done to make your workshops suitable, I'd really appreciate that. I like workshop photos and tours on-line, they are really informative - as I said, I've done plenty of procrastination.

Oh, and the posts in the Gallery section are amazing, there is so much talent on this forum.

Thanks in advance for any advice.

Cheers
Grant

blackalex1952
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Re: Building Conditions

Post by blackalex1952 » Sun Sep 20, 2020 12:39 pm

I have an underbench RH control system ie a cupboard with a dehumidifier in it. When the humidity has been high in the workshop, I have made the go bar deck into a sealed space using plastic and a plastic "door" with a bathroom heat lamp inside and use that for my cross brace gluing keeping the humidity the same as the conditions in the dehumidifier. The heat lamp also gives me more open time when using hot hide glue...just think outside the box! I keep the guitars that I'm building at the time in the underbench dehumidifier most of the time, even for building the back and sides and the neck. I don't think that plastic sheets as double glazing will achieve much because double glazed glass relies on a partial vacuum between the two sheets of glass. I have some double glazed glass panels in the shed, rejects from a glazier, but I use them for vacuum laminating and as flat surfaces. Cheers! Ross
"Everything I say on the topic is based solely upon inexperience and assumption!"

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kiwigeo
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Re: Building Conditions

Post by kiwigeo » Sun Sep 20, 2020 3:38 pm

I was born and raised in Christchurch....the place is cold and damp because it's built on a swamp. I solved my
humidity problems by moving to Adelaide :mrgreen:
Martin

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Mark McLean
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Re: Building Conditions

Post by Mark McLean » Sun Sep 20, 2020 9:47 pm

There are two critical stages of your build where high RH can really ruin your job. These are: (1) the bracing of the soundboard and back, and (2) the point at which you close the box by gluing the top and back to the rims. If your wood is swollen by high water content as you perform these steps - and then it dries out later - you will get distortions of the plates, or shrinkage and cracks. Most of the rest of the build can be done without too much concern for RH. Also, if the guitar lives all of its life in conditions of high humidity the same as when it was built, you might not get any problem. So, you can try to manage by just waiting for the right day to do the critical steps (but you actually need a few days in a row so that the timber has acclimatized to "dry" before you glue up). Or you condition the humidity in the whole workshop ( an affordable second-hand dehumidifier might do the job for that size workshop. Or you do like Ross and develop some sort of drying storage conditions and take the wood out only for short periods to glue up, then put it back in the dry space. The "Brisbane Humidity" thread going at the moment has some good tips.

Lostininverness
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Re: Building Conditions

Post by Lostininverness » Mon Sep 21, 2020 6:18 pm

blackalex1952 wrote:
Sun Sep 20, 2020 12:39 pm
I have an underbench RH control system ie a cupboard with a dehumidifier in it. When the humidity has been high in the workshop, I have made the go bar deck into a sealed space using plastic and a plastic "door" with a bathroom heat lamp inside and use that for my cross brace gluing keeping the humidity the same as the conditions in the dehumidifier. The heat lamp also gives me more open time when using hot hide glue...just think outside the box! I keep the guitars that I'm building at the time in the underbench dehumidifier most of the time, even for building the back and sides and the neck. I don't think that plastic sheets as double glazing will achieve much because double glazed glass relies on a partial vacuum between the two sheets of glass. I have some double glazed glass panels in the shed, rejects from a glazier, but I use them for vacuum laminating and as flat surfaces. Cheers! Ross
Hi Ross, thanks for the advice! That's a great idea. So do you have the heat lamp on 24hrs around the time you are doing the braces gluing, and how do you remove moisture etc from the "box"? Do you monitor the humidity in the box and what do you do to maintain it at a constant level? So do you have a set up like Alan posted in the "Brisbane Humidity" thread?
Cheers Grant

Lostininverness
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Re: Building Conditions

Post by Lostininverness » Mon Sep 21, 2020 6:22 pm

kiwigeo wrote:
Sun Sep 20, 2020 3:38 pm
I was born and raised in Christchurch....the place is cold and damp because it's built on a swamp. I solved my
humidity problems by moving to Adelaide :mrgreen:
Gotta love the swamp! I'm a stormwater/drainage asset engineer for the Council, and the funny thing is there is now a push to reinstate the wetlands/swamps that the cities forefathers worked so hard to drain!

I'm assuming though that Christchurch can't be that bad to build in? With some controls?

Lostininverness
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Re: Building Conditions

Post by Lostininverness » Mon Sep 21, 2020 6:29 pm

Mark McLean wrote:
Sun Sep 20, 2020 9:47 pm
There are two critical stages of your build where high RH can really ruin your job. These are: (1) the bracing of the soundboard and back, and (2) the point at which you close the box by gluing the top and back to the rims. If your wood is swollen by high water content as you perform these steps - and then it dries out later - you will get distortions of the plates, or shrinkage and cracks. Most of the rest of the build can be done without too much concern for RH. Also, if the guitar lives all of its life in conditions of high humidity the same as when it was built, you might not get any problem. So, you can try to manage by just waiting for the right day to do the critical steps (but you actually need a few days in a row so that the timber has acclimatized to "dry" before you glue up). Or you condition the humidity in the whole workshop ( an affordable second-hand dehumidifier might do the job for that size workshop. Or you do like Ross and develop some sort of drying storage conditions and take the wood out only for short periods to glue up, then put it back in the dry space. The "Brisbane Humidity" thread going at the moment has some good tips.
Hmmm, I think "waiting" for a clear window might be a struggle to time? I only build when I have time around other life commitments, and that sounds like it might not be the most sensible way!

So how "climate-tight" does my workshop need to be? Whats the norm for how insulated etc. a workshop needs to be? At the moment there are massive gaps between the walls and roofing iron. They will be taken care of once I insulate the roof. But can using a box that I control the humidity in, will that mean I can delay sorting out the workshop and start building?

And yes, I've been checking out the Brisbane thread for ideas too.

Cheers Grant

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Mark McLean
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Re: Building Conditions

Post by Mark McLean » Mon Sep 21, 2020 8:26 pm

Yes, waiting for the right day to do the next step in your build is very frustrating. If your building is part-time and fit-it-in-when-you-can (as mine is) then it tends to be rainy days that you have spare moments - but that is exactly the time that you can’t do the critical steps. It sounds like you do need a work round for the RH issues. If your workshop is decidedly al fresco then just putting a dehumidifier in there will not fix the problem. But a “dry box” is definitely a solution that has worked for many people in the past. Try searching the archive here for information, or do the same at some other luthier sites like the OLF or MIMF - you will find a number of discussions of methods.

blackalex1952
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Re: Building Conditions

Post by blackalex1952 » Mon Sep 21, 2020 11:38 pm

So do you have the heat lamp on 24hrs around the time you are doing the braces gluing, and how do you remove moisture etc from the "box"? Do you monitor the humidity in the box and what do you do to maintain it at a constant level?
No need to keep the heat lamp on for 24 hours, they are quite hot and penetrate the timber due to radient heat...I use heat lamp method for softening glue when doing a job like removing a fingeroard...Because the go bar deck is wrapped in plastic on three sides with a flap on the fourth side, like a door,when necessary for cross grain gluing and gluing the top to the sides I monitor with a humidity guage, turning the lamp off if it gets too low. Hide glue sets pretty quickly, and once the RH is right in the go bar deck, it remains pretty stable for an hour or so, I can always turn the heat lamp on manually while waiting for the glue to hold, abou an hour, whilst doing something else. The assembled glue up is then returned to the underbench RH controlled cabinet. The "box" if you are referring to the dehumidified underbench box runs out through a pipe connected to the dehumidifier, which I previously explained...if you are referring to the plastic wrapped go bar deck as the "box" read my explanation about relative humidity and temperature in the thread 'Brisbane Humidity".- Ross
"Everything I say on the topic is based solely upon inexperience and assumption!"

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