Frames in zero degree temperatures

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Bill Henry-

Bill Henry-

Brussel Sprout Connoisseur
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Aug 17, 2002
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Boondock Bowerbank, ME
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Retired from the grind
The outside temperature is hovering around 0° F.

A customer just picked up a completed piece: an unglazed oil painting surrounded by a wood frame joined with V-nails and Titebond II glue. While I was wrapping it, she mentioned that she had errands to do and that the frame would be sitting in an unheated car for a few hours and questioned if or how the frame/oil would react to the cold.

I suggested that it would be safer if she return home so as not to subject the frame to the cold, but couldn’t tell her specifically what might happen if she didn’t.

1) Presumably, the oils do not contain any moisture, but would the medium become more viscous i.e. turn more into a wax-like consistency and tend to become brittle and flake in cold temperatures?

2) Would the glue bond weaken in very dry, zero degree weather?
 
I don't know specifically about the oil paint, although it would likely become more brittle. I'd be more worried about dimensional changes in the canvas. As the temperature drops, the moisture content in the canvas fibers would rise. This could cause stretching or shrinking, depending on if it's linen or cotton and the type of weave. And that could cause problems with the paint/ground/canvas bonds.

I've been thinking about this too, as the paper pieces I finish working on are delivered. I've been packing them on foamboard with Mylar overlay, but when the temp changes from indoors to outdoors is extreme I'm considering a top layer of foam board wrapped in bubble wrap for insulation.

Most pieces can withstand even fairly drastic changes in temperature and humidity, as long as the change occurs slowly. When museums ship art and artifacts they generally stipulate that the package be left intact for at least 24 hrs before unwrapping, so that everything has a chance to slowly acclimatize.

The more insulating the packing, the easier it is on the piece.

Rebecca
 
Bill, If you had just joined the frame within the hour, I might wonder.

But your glue is dry, the bond is set. If the frame is at 70 degrees, sits in the car which probabley has a heater so it didn't start a 0, with few hours and the frame in 1" thick the heat exchange would be 10 degrees per hour per 1" of wood..... therefore the frame temp would drop 20degrees per hour. So 30 degrees at the end of 2 hours.....3.5 hours to hit "0" if it was just sitting outside without a windchill factor.

My guess is that the frame and oil were about 50 degrees by the time the customer got them home.
Think of all those frames and oils that sat in Russian summer dachaus all winter long . . . and are still in fine shape. (except for the bullet holes :D )
 
In very low temperatures, freezing of inherent moisture in hygroscopic (porous) materials could be a problem. In very high temperatures, melting of some materials could be a problem. Chemical changes do occur at certain temperature extremes, depending on the nature of the materials. But most of the materials commonly found in a picture frame are relatively tolerant.

Generally, the rate of temperature change is more important than the beginning or ending temperatures. Quick expansion and/or contraction is quite destructive to anything hygroscopic.

That's why attic storage is so damaging -- the temperature could fluctuate 100 degrees or more in an average day. And it's also why items stored in the middle of a big box or chest suffer less damage than items exposed to open air; the insulation protects them by slowing the rate of change.

If the frame is transported in an insulating package, which would slow down the process of cooling & eventual re-warming of the assembly, then it would probably be OK.
 
Amy, Live to Learn has been my breath since I was about 5.

Sources for the previous:

Glue: Woodworking in an unheated garage in temps that reach -5. Letters to glue manufactures get you a mountain of info, more technical then FACTS could handle.

Rate of tempature loss: designing and building super insulated homes / and watching CSI.

Understanding the nature of wood that we use: been an informed and educated woodworker since age 5, when I was taken on a tour of a drying kiln.

Knowing that people have and use heaters in their cars, especially women: That theory I just pulled out of my but. :D

I only know two other framers in my 38 years who have/had a moister meter for wood in their shop. This will tell you what the moister content is of the wood in the moulding.
Sounds like something that is useless...but, the moisture content, according to the Western Wood Council, for moulding grade wood in a finished form should be between 4% and 6%. If it is about 8% it has a very real chance of warping.
Depending on the grain alaignmet that can and usually is in the case of picture moulding; radially. Send it back.

If the moisture is over 12%, it was never kiln dried. Send it back and take the sample off the wall. This is a common practice in southeast asia. Labor is cheap but kilns take time and energy which is not cheap.

If the MC is UNDER 4%, it has been stored in a dessication environment (Arizona, in a tin wearhouse where temps can reach 160+ degrees.
When it makes it to your customers beach house, they bring it back with the finish falling off in strips. I've even seen gesso explode. Hmmmm; send it back? :D

Contact your Farm Extention Office, they have amazing info on the wood we use. If you thought to tell me that 'you're in a city, not farm country'. . . think again. I think that New York City's office is in the Bronks.

Not all education is at the conventions. Look at your net income....spend 10% annually on your education. There was a thread recently that people listed the magazines that helped their education . . . Martha, AD, Sunset,Fine Woodworking,Popular Science....
 
Moisture Content - everything you want to know is in "Storage of Lumber" Agriculture Handbook No. 531, USDA Forest Service. Unfortunately, it is out of print. I was able to have a gentleman in Alaska send me a PDF version of it which I would be happy to share with anyone who cares to download a 5.3MB file.

But in summation, here is my interpretation of the facts therein presented (compared to Baer I must admit that my interpretation is through only 23 years experience).

All wood will reach an Equilibrium Moisture Content if left in a particular environment for a long enough time. The ECM is mostly dependant on the Relative Humidity, and a little bit on Temperature. For instance, left at 70°F and 70% RH, wood will reach an EMC of about 12.5% MC (regardless of whether it was kiln dried in the first place or not). At the other extreme, if placed in an environment of 10% RH (a typical un-humidified house in heated climes), the EMC will be about 2% MC.

The MC of lumber by itself has no bearing on whether it is warped or will warp. Warpage is a function of the difference between radial and tangential shrinkage coefficents, and a change in MC (usually a matter of starting MC compared to EMC). Lumber that has reached an EMC can be machined and will stay stable as long as the EMC is maintained, whether it is 2% MC or 20% MC.

The furniture industry generally finds an acceptable moisture content to be between 6-8%, although some people require 5-7% and others 7-9%. These ranges put the MC pretty much in the middle of the naturally occurring extremes. However, in some cases, either the minimum or maximum expected EMC may be more important than the average and a different starting MC may be required.

Our expected range on lumber we are receiving is 6-8%. However, we will not reject lumber unless it is less than 5% or more than 9%. In addition to proper starting MC, it is necessary to maintain the proper RH to eliminate warping.
 
When art crates are shipped on airplanes, the cooling of the cargo section of the plane, to just above freezing, if factored into the insulation built into the crate, to insure that the temperature change is kept gradual. The low temperature is likely to threaten to the oil, since it is thin and will chill more rapidly and it should not be stressed by vibration. A backing board, screwed into the stretcher bars should help damp out vibration.

Hugh
to damp out such vibration.
 
As a Picture Framer living near San Diego, California, I have trouble understanding this thread :confused:
I do worry about folks leaving things in the back of their car on a hot summer afternoon, and usually caution them about not having the direct sun hitting the pictures, but 0 degrees? Is that a condition that people are out in?
kaffeetrinker_2.gif
 
Originally posted by FramerRandy:
...but 0 degrees? Is that a condition that people are out in?
Click to expand...
When it gets that warm you start seeing people in shorts and t-shirts....
 
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