U of S | Mailing List Archive | alt-photo-process-l | Re: Wood panel preparation (Keith?)

Re: Wood panel preparation (Keith?)

Well, here is where we may go our separate ways, because we are
meticululous and me?... not so much!

Sizing Strength:  I don't actually know.  I use a half tablespoon of
Jelatin (Toz - no idea of the bloom) to 450 ml water to which I add
about 3 ml Gluteraldahyde.

Coating:  I'm using two surfaces at present.  MDO is a very smooth
plywood used for signs and for boatbuilding, but I'm not sure if it is
actually "marine grade".  MDF is a heavy pressed wood.  MDO is very
smooth so it takes three coats of the affore-mentioned gesso.  MDF
requires only two.  I'm sure a roller would be great.  I prefer a big
rough brush, as I like the brushstrokes.  I do not sand, as this
provides a surface that is too smooth and perfect.  Something tells me
this is the method you will prefer :)  - When I did sand I just used a
rough screen -  the type used for smoothing drywall plaster, or a 3m
scotchpad green thing - sandpaper made a big mess - the pumice powder
got into everything.

2009/2/24 Loris Medici <mail@loris.medici.name>:
> Thanks Keith! As I understand it, I need to increase the whiting amnt. in
> my preliminary formula, since I choose to mix equal *weight* of acrylic
> gesso with whiting (50g gesso + 50g CaCO3), but you say equal *volumes*...
> That was good to know. Thanks for the info about sizing.
> Few more questions:
> - What is your sizing solution strenght?
> - What is your coating method? (Detailed description please; how much
> layers? exact application method and procedure? - crossing fingers: I want
> to be able to coat with a foam roller...)
> - Do you sand the acrylic gesso before sizing? If yes, how? What is your
> exact procedure?
> I feel like leaving the "traditional gesso" plan behind, it's too much
> complicated for my liking -> I may resort to it if everhing else fails,
> but I'm afraid it has its own problems as it looks like a method that
> should be mastered - painfully!
> Thanks again & regards,
> Loris.
> 24 Şubat 2009, Salı, 4:22 pm tarihinde, Keith Gerling yazmış:
>> Hi Loris!
>> The #1 formula you present is very similar to the one I use with great
>> success:  1:1 Liquitex acrylic gesso to water and then to that 1:1
>> dilute gesso to pumice by volume.  That produces a surface that acts
>> very similar to paper, so I size it with gelatin and hardener.  This
>> mix is very good for coating porous surfaces such as wood, plaster
>> (spackle-ed wood) and old gumprints on paper.  For surfaces such as
>> aluminum and glass, bubbles of water tend to form between the surface
>> and the gesso with long soaks.  For these surfaces I do not use
>> acylic, preferring to mix up a concoction of gelatin, pumice and
>> marble powder.  I haven't used this in a while and I haven't reduced
>> it to a recipe, but essentially it is a gelatin mix (the same as used
>> for sizing paper) with 50% pumice and marble.  It produces a surface
>> that is so hard that it is actually very hard to remove even with a
>> belt sander!
>> Hope this helps
>> On Tue, Feb 24, 2009 at 2:30 AM, Loris Medici <mail@loris.medici.name>
>> wrote:
>>> I will try to print gum on wood panels (marine grade plywood). I will
>>> try
>>> two different grounds: 1) Acrylic ground + whiting (I presume that's
>>> what
>>> you do Keith?) 2) Traditional gesso ground...
>>> 1) Keith, what is your acrylic formula? I plan to dilute acrylic gesso
>>> 1:1
>>> with water and then add equal amnt. of calcium carbonate (marble dust)
>>> and
>>> some white pigment into it. For instance: 50g acrylic gesso + 50ml water
>>> +
>>> 50g calcium carbonate + 10g titanium dioxide (titanium white -> purest /
>>> brightest white pigment).
>>> 2) Traditional gesso: 100ml water + 10g hide (or rabbitskin) glue (high
>>> bloom gelatin) + 60g calcium carbonate + 12g titanium white.
>>> I need a good working recipe and application (and finishing) procedure
>>> for
>>> #2. BTW, traditional gesso is a PIA! (Have to keep it hot + it doesn't
>>> set
>>> quickly, so takes awfully long to complete 4 - 6 layers...)
>>> Another questions:
>>> 1. Do you harden the traditional gesso ground?
>>> 2. Do you add a hardened gelatin layer on top of the acrylic (or
>>> traditional gesso) ground?
>>> Thanks in advance,
>>> Loris.