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  #1  
Old 17-07-03, 07:45 PM
connie
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Default pin holes in gesso

I am in a fix. I have gessoed three supports sucessfully. Thought this gesso is not that big of a deal. Now months later I am trying to gesso
a new panel. I am on my fourth try and it is looking like the tiny holes
are visable---again. These are so small I can not feel them at all.

I have followed Ralph Mayer, Altoon Sultan and this sites instructions,
trying different things at different times.

I guess I'm beginning to wonder, that if this process is so difficult/fickle
should I buy these gesso panels? I enjoy making them, but is
it always like this? Does it get to the point that you know that you can
gesso a panel successfully?

Of course I would appreciate any help or thoughts.
  #2  
Old 18-07-03, 02:33 AM
JohnH
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Default pin holes

Connie, I too was very perplexed by those dreaded pin holes - seemingly showing up unexpectantly. From my years of making traditional gesso panels I found that one of the keys to reducing pin holes was to buy the right glue. I don't know if the panels you made turned bad because you used a new batch or a different brand of glue?

Trial and error was what it took to find the glue I liked best - then I went back to the supplier and bought enough to last a long long time. Hide glue that has two distinct components when veiwed in granular form seems better than one that looks too uniform or almost crystaline.

Other things to take into account are:

- Do you sand your hardboard? If you do, only use a superfine paper and clean the dustings off completely.

- Don't apply the clear size coat too strong. You should not always rely on water to glue ratios that you may come across - test your own materials the best you can. Not all hide glues have the same strength. This applies to the strength of the glue solution you use for the gesso mix too - too strong will tend to enhance air bubble formation.

- I tend to like a simple mix of just precipitated calcium carbonate, hide glue and water (distilled). Simple can translate into less varriables and therefore less problems.

- let the gesso sit for at least an hour.

- Apply your first layer firmly with finger tips in 3 to 4 inch squares. Overlap just a bit and take care in these overlapes as pin holes like to form there.

- Use a wide 3" short bristle varnish brush to apply the gesso. Go back and forth along the band of wet gesso until it begins to pull. then move to the next band down the panel.

- The last two coats (I generally use 7), coat the whole surface and gentley rub in with your fingers. This won't prevent pin holes but it makes sanding so much faster when the intersects of your brush coats are filled in.

This is just a simple overview, I'm sure all gessoers have their own ways that work best for them. I hope you find your way too.[/u]
  #3  
Old 18-07-03, 11:56 AM
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PhilS PhilS is offline
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John, your idea of rubbing the final coat with fingertips is brilliant. I wonder why I never thought of it!

Connie, for what it's worth, I use Fredrix Dry Gesso mix at a 1 to 1 ratio (actually slightly more powder than water). They recommend a 2 to 1 ratio but I've found that too thick. I prime with rabbitskin glue I bought years ago from Daniel Smith. This method has worked for me for 15 years.

The trick to avoid pin holes is to really brush out your first coat. That is the critical one. Get yourself a good 3-inch brush (the most expensive one at your hardware store). When you apply the first coat, brush hard at first, then very gently go over and over with light strokes. This fills in those nasty little holes. The subsequent coats go much faster. I also agree with John - don't sand your panel too much prior to priming and clean it well.

This has worked for me. I hope it helps.

Phil
  #4  
Old 18-07-03, 02:32 PM
Suzanne
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Default pinholes

There is an easy fix for pinholes. Dip your fingers in some water. Rub the water into the gesso using a circular motion and a stiff hand. Keep rubbing until the water melts the top layer of gesso and then rub some more until you are redistributing the topmost layer of gesso. Rub in a consistent circular motion until the surface feels and sounds almost dry again. Move on to an adjacent area of your panel and repeat. If you are getting through more than the top layer of gesso you are using too much water. A light resanding will be neccessary as the surface will be roughened slightly.
This works even years after a panel is gessoed although I generally do this after every other coat when applying gesso.
  #5  
Old 18-07-03, 11:24 PM
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RobM RobM is offline
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I was under the impression that over stirring and over heating was the cause, but at one point in the gessoing process I kept a close observation of what was going on....I saw that not 'working' the gesso in it's initial stages and leaving it quite thick in it's layering tended to produce the pinholes. I also saw that when applying a layer the brush marks would show up, albeit a few microns in depth. The subsequent brush strokes at 90 degrees (or thereabouts) to the previous also left brush marks but had in places left a minute void due to not 'working' the gesso.
My experience of gessoing, usually a days work on a panel of MDF 8 feet by 4 feet is that initially the gesso remains really fluid but as the day progresses the gesso becomes quite 'thick'. I do add a little water at this stage to make up for that which has evaporated.
I do strain the gesso twice before using which does alliviate most bubbles introduced by stirring. I also ensure that during the straining process the gesso does not have to travel far between the strainer and the receptacle. Allowing gesso to pour from a height is obviously going to introduce air bubbles.
All in all, the gesso should be applied and worked into the previous layer, however there does come a time when the gesso starts to 'drag' and it is just before this stage that the 'working' should cease but ensuring that there are no voids.
Rob
  #6  
Old 19-07-03, 01:28 AM
David McKay David McKay is offline
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Dear Fellow Gessoers:

I have been reading with interest, your comments about pinholes in gesso and gessoing in general. I have a technique that is slightly different from what I have heard about so far, and thought that this might be a good time to share it. Basically, I mix and apply my gesso as described in D.V. Thompson's book, The Practice of Tempera Painting. I typically gesso half a dozen or so panels at a time. I usually do not smooth a panel until I am ready to paint on it. That way if one gets marked, it is cleaned during the sanding process.

I use very rough sandpaper wrapped around a flat wooden block of about three or four inches across. I use very light pressure and with circular strokes sand the gesso until all of the brush marks from applying it are gone. This of course leaves thousands of scratch marks but at least the surface is quite flat, or level. Then I take a sponge dipped in cold water and wrung out and again using circular strokes go over the panel. I frequently rinse and wring the sponge out. The water dissolves a little of the gesso and deposits it in the scratch marks. It reminds me of working with a giant eraser and eliminates the scratch marks and any pin holes in no time.

I have not tried using my bare hands, but will give that I try the next time. I think that would be particularly effective for the first coat.

David
  #7  
Old 20-07-03, 06:24 AM
madim
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My solution for the smoothing of the gesso is to keep a spray bottle of water handy, when I have applied the gesso, and think it is not smooth enough I spray the surface, and spread it with my hand to eliminate some of the textures, but then I also love the texture I get with the too thick gesso, and have been known to do it on purpose

It helps some way

Madeleine
  #8  
Old 24-07-03, 02:56 PM
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Dennis H Dennis H is offline
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I use a treatment for pinholes that I hope will not cause problems down the road.
I mix whiting with casein emulsion to make a smooth paste or putty. Using a small stainless steel blade or a single-edged razor blade I scrape some putty across the gesso surface and force it into the little holes. I then re-sand and re-polish the gesso where I did this work and the panels afterwards seem to appear unmolested and flawless. There's no build-up on the topmost surface, just discrete fills in the pinholes that had occurred. I often do my underpainting in casein, so I know it has great adhesion to the glue-gesso ground. I guess that any future circumstance that would make the fills release from their pinhole pockets would also cause my paint work itself to lift. So I haven't worried too much over the chance of them failing.
Who knows, maybe we should instead encourage and embrace pinholes as a way to help key the paint film to the ground? At the museum where I work, we have a nice Reginald Marsh tempera, whose gesso ground was obviously sprayed on. There is a nice splattered surface, with raised bumps and a smattering of popped bubbles, and pinholes. It's a pretty nice surface, and gives a contrasting texture to Marsh's light and washy technique in the painting.
Dennis
  #9  
Old 24-07-03, 03:54 PM
JohnH
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Dennis, I believe you are right about achieving a character to the grounds that conveys some character though sometimes those accidents of texture and/or pinholes in the ground may show up in the wrong place - especially if one is painting subtle details in a face where the style dictates tight precision.

I tend to be wary of a ground that is not free from pinholes, one that is patched up by sealing the holes with a filer or a rubbing down technique. I've done them all including casein - just makes me uncomfortable :-?

I still believe the solution (is that a pun?) is mostly about the glue. I had worked my rear off trying to make a flawless gesso. I did end up conquering the technique though it took Herculean efforts and all the constellations had to be lined up perfectly. It was only until I used a new supply of glue that for a short minute I thought to myself something must be wrong - but oh yes! What a wrong :-o I realized I could now make a flawless gesso with a great deal more freedom - almost carefree! Even though gessoing is still labour intensive it's a joy now.

Back to the gesso surface... I do like it to be clean, smooth, and flawless, though not perfectly flat. This can be achieved through daubing the last coats of gesso in an irregular pattern with a 2" to 3" sash brush, and then only lightly sanding by hand (no block) using small pieces of sandpaper. Then the surface can be rubbed in with a damp cloth wrapped on one finger. A nice though subtle effect.
  #10  
Old 10-09-03, 06:33 PM
Anonymous
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Default holes in the gesso

Dear people who are using gesso and advicing each other so wisely,

A colleague of mine recently gave me a tip about the gesso and after trying it I am hooked. He suggested adding 2-3 drops of Linseed oil to the gesso. The first panel I tried to 'gesso as usual' and added to the last gesso for the last layer a few drops. The results were magnificent. It is so much smoother and easier to use. Plus no bubbles! The second panel I added linseed oil to the gesso before the first application and thus using the oil in all layers. The gesso was better manageable then normal, but I favour the first try out. The result there was smoother and better to handle. Give it a try. It worked for me!
 

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