Hardboard versus fiberboard for acrylic/oil paintingsApproveRejectUn-ApproveSubscribeUn-Unsubscribe
Question asked 2017-06-05 05:50:42 ...
Most recent comment 2017-06-28 17:32:02
Sizes and Adhesives
I have recently read that the outgassing of formaldehyde from urea-formaldehyde used to manufacture HDF and MDF is a problem when it comes to conservation, since it can influence the acidity of both the work and the environment, leading to possible degradation of the artwork. I also read (Getty's "Facing Challenges of Panel Paintings Conservation", part 3 by Paul van Duin) that urea-formaldehyde itself degrades over time and the author estimates its longevity (when protected from light) to be a couple of decades. In light of this, I was wondering if hardboard (wet process board) wouldn't be a better choice, since it doesn't contain UF?
On the other hand, I used to coat the panels I paint on with a water solution of PVA with a pH of 6-7 (according to manufacturer), and I read that PVA can be a source of acetic acid, but I'm not sure if this is relevant.
Answers and Comments
Good points and questions. There is evidence of the
deterioration of urea-formaldehyde adhesives which release harmful vapors.
First, you can purchase zero formaldehyde MDF. This quality
is used for museum displays where issues of off gassing are paramount.
Hardboards can also be purchased with no formaldehyde component. I find neither MDF nor hardboard perfect due
to other physical properties but that is another issue. I do not believe that
the deterioration of PVA is a major concern but if you want to be extra
careful, use a diluted high quality acrylic dispersion or even an acrylic
solution (eg B-72 in acetone/ethanol) as a size. Others may have additional
thoughts on this matter.
At this point we have an inquiry into a couple of our moderators who are more knowledgable about these products....so hang tight. There will be a detailed response come Monday.
Koo, you are correct as to the relevence to plywood as well. We hope to hear from someone very well versed in these issues rather than postulating ourselves.
The off gassing of UF glues is known to tan and embrittle
animal glues like those sometimes used as a size or incorporated into genuine
gesso or chalk glue grounds.
There is also mention in the literature that it
can also contribute to the degradation of some pigments. This one of the
reasons why materials containing it are avoided in museum
displays. I do not believe that the concern is necessarily about
the structural failure that you are worried about.
is difficult to know if your use of such materials would be a major
problem but they should be avoided if possible. If you continue to use these substrates avoid the use of animal glues and make sure that your panel is well sized/sealed before applying your ground and paint layers
In this scenario, I do believe that the zero-formaldehyde
wet-process hardboard is the better option, especially if it is braced for rigidity.
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