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

Re: Wood panel preparation (Keith?)

The letter designation is not that much important to me since the wood
will be covered with considerable amnt. of ground - knots and such will
not show. What is actually important is the resin and glue they use to
bring the veneers together. The stock I ordered uses E1 grade
phenol-formaldehyde resin/glue, and this one keeps its properties even at
100C boiling water.

Yes I also was considering to seal the edges with polyurethane or epoxy.
Thanks for mentioning.

I didn't opt for MDF right because of weight. The stock I ordered is
675kg/m3, which means each 13x17" panel will weight about 2 pounds. How
that compares to MDF?


25 Şubat 2009, Çarşamba, 12:40 am tarihinde, Keith Gerling yazmış:
> I admit I'm a little confused about what is and what is not "marine
> grade plywood". Do you know if your plywood has a letter designation?
>  I'm trying MDO, which here:
> http://www.glen-l.com/wood-plywood/marine-plywood.html could be
> considered marine grade.  It is smooth on both sides and the outside
> veneer us very smooth, grainless, and artificial - like pressed wood
> (MDF) but smoother.  Marine grade or not, the edges do swell up in the
> water, so I size to keep the soaks as short as possible.  If I omit
> the size, the soaks can take longer than an hour.  I prefer the finish
> of MDF, which I can buy for $18 for a sheet of 4x8 feet at 1/2 inch.
> The surface is perfect for gum, and the edges can be sealed cheaply
> with 2 part marine epoxy.  But the stuff is heavy!  Very heavy to
> ship.  Prints on the MDF are much more "gumlike" and the ones on MDO
> are too slick and C-print looking.
> Oh - and of the pictures that I shared earlier, none of them are on
> MDO.  Later this week I'll have some completed, but I doubt if the
> difference will be discernable on-line.
> On Tue, Feb 24, 2009 at 3:50 PM, Loris Medici <mail@loris.medici.name>
> wrote:
>> Hi Keith,
>> Yes, I'm a little bit meticulous because I have little time devoted to
>> printing, therefore I don't have the luxury of trial and error, without
>> risking motivation loss that is... ;)
>> That sizing seems pretty weak. (My usual for paper is 3%) Will calculate
>> by measuring the weight of half tablespoon gelatin -> that should be
>> pretty close since we have the same stuff. What if I don't size? (I'm
>> pretty sure you have tried this.) Will that work also?
>> I was afraid of long soaks therefore I ordered marine grade plywood
>> (which
>> is very resistant to water - no warping, no veneer coming apart...),
>> it's
>> not expensive (considering the material) -> I ordered 25 13x17" sheets,
>> it
>> will cost me only USD 48, including cutting the huge raw sheet to size.
>> (Makes less than USD 2 per sheet, and that's cheaper than fine quality
>> watercolor paper!)
>> At your printing size smoothing actually takes something (tactility?)
>> from
>> the prints but I prefer to work on smaller scale which makes a smoother
>> surface a necessity.
>> See the aluminum sheet I just finished to gesso here:
>> http://tinyurl.com/dl5wnu
>> It was shot under oblique incandescent light, exaggerating the texture.
>> (The field of view is something like 4x6" - just to give you an idea of
>> the magnification. 4 layers of acrylic gesso with calcium carbonate,
>> applied with a foam brush.) Ground formulation as following: 40g gesso +
>> 80g CaCO3 + 80ml water.
>> I like the texture, will sand half only of the sheet and see how each
>> side
>> behave... The surface is very nice, feels very absorbent and soft to the
>> touch -> very similar to an eggshell. (That's fine I presume...)
>> Scotch pad idea is great -> will try that first. Yes, I'm concerned
>> about
>> the dust -> I don't think Elif will appreciate it! :)
>> Thanks again,
>> Loris.
>> 24 Şubat 2009, Salı, 5:40 pm tarihinde, Keith Gerling yazmış:
>>> 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.