Hey,
I have a couple questions about sealing cradled wood panels (I know alot of questions have already been answered in regards to sealing on this forum but I will try to not ask the same ones that have been answered) I work in larger sized cradled wood panels 36 x 36 inch (91 x 91cm) and 48 x 48 inch (122 x 122 cm) being my most frequent size. I use gac 100 to seal. The problem is working in this size is that I burn through the product very fast even with the 128 oz container. I plan to continue to use Gac 100 for the top of the panel to avoid SID as much as possbile but im wondering if there is another alterternative for the bottom to cut down on costs? since the goal for sealing underneath is to prevent the wood from rotting or warping do to humidy correct? so do you need to use GAC 100 for the bottom? there is alot of wood sealing products out there at big stores like home depot so im just curius is there other alternatives to gac 100?
is Gac 100 really that special? they dont have the ingedients on the label and sometimes I wonder if this is to hide that there product really isint much diffrent then the lest costly products avaible at hardwar stores. I dont want to cheap out tho, and am commited to creating paintings that will last a long time espeshailly now that I am sellling pieces quite frequently – I want to make sure im not cutting corners but the costs for using golden on large scale works is intense.
On that note im also wondering about isolation coat before varnashing, same problem – golden only has the isolation coat product avaible in a really small container, I’ve read that the soft gel could work as a isolation coat but not sure the correct process for diluting it. do you know of any larger quantity products availble for isolation coats before varnashing?
I wanted to link some of the other selant products I have found online at harware stores for wood but it kept freezing when I copy pasted the link in.
Thanks in advance if you take the time to answer!
Carson
Hello Carson,
You raise a few good things to discuss. My answer won’t be sufficient in itself, I’ll also look forward to reading what others say.
First is yes, it’s best to give a good quality sizing and gesso, first to prevent wood tanins and colourful molecules from migrating into your paint, and too much of your paint to sip into the wood, chemically rotting it.
Protection against warping and (mould)-rotting is best assured from earlier proper drying and treatment (in low/high pressure chambers). Your sizing and gesso won’t prevent much warping and rotting that would come from the back side of the wood exposed to too much humidity. This is also true for textiles.
One issue with hardware stores products is they are more wild than artist products. You might find good materials but are also more likely to be disappointed in ten years when things go wrong. They don’t need to have the quality artist brands put into it and are less likely to be able to support you and conservators when troubles arise.
Sealing with them, you have arguably more risks to get bad migrations into the paint and delamination over time. Hard to say unfortunately, it’s a gamble.
Gac100 is surely a good product with fair competition I’m confident. You might want to try other big brands see if you get more bang for your buck. Do avoid mixing two brands however, since it’s hard for one company to support when you use products of two (or more) different companies.
They don’t list the raw materials on the label because US/EU laws don’t enforce the requirement (yet) to write down the INCI ingredient, like in food or cosmetics products. That might come some day…
And you’re likely to still be disappointed. Because INCI wise, the spectrum of ‘Acrylate Copolymer / carbomer’ is infinite. So it’s not to hide that it’s bad, it’s just that it won’t tell you much anyway about the quality. Their INCI list would be something like: ‘Water, Carbomer, Carbomer, Carbomer, glycerine, sodium hydroxide, benzoisothiazolinone’
I’d trust and stick with one of either Daler-Rowney, Golden, Lefranc et bourgeois, Liquitex, Royal Talens, Winsor & Newton, for the choice of long-term reliable polymers in their acrylic primers. Not DIY stores. But I don’t know which is most cost effective among them.
The isolation coat is an arguably good trend, to my understanding:
Plus side is, it’s far safer to replace the top (final) varnish since you won’t damage the pictural layer.
Con side is, it’s far harder to repair the pictural layer if something goes wrong in it (or goes in from behind because the primer was poor quality).
You don’t need to dilute it, it’s just a first varnish that doesn’t dissolve in the same solvent as the top one (and keeps enough flexibility of course). I think Golden and Liquitex offer the two kinds. I don’t know for the other brands.
I wish you a nice day,
Lussh
Hi Carson,
Im copying and pasting from another post, sorry for the redundancy if you already read that one!
It depends what you would like to use this glossy medium for, to reduce absorbency or to block SID?
If you would like to block Support Induced Discoloration (SID) from your acrylic painting, then we recommend either GAC 100 or Gloss Medium. 1-2 coats of each directly onto the wood surface. These are the only 2 mediums we make at GOLDEN that can perform in this way. There may be other brands products that also block SID, but we have not teted for that. Acrylic dispersion ground (acrylic gesso) can be applied over these layers.
SID is mostly an issue when working over dark MDF or some other wood products that have higher concentration of water soluble colorants in the fibers, and when thicker or slower drying acrylics are used over top allowing for longer dwell time of the wet product on surface. SID is only a concern with waterborne painting media such as acrylics, as it requires the water to activate the colorants and then the evaporation of the water to draw the colorants from the wood into the paint layers. SID does not affect oil paints. Here is a video about SID: https://www.goldenpaints.com/videos/support-induced-discoloration–sid—what-is-it–and-how-to-minimize-it
If you are not concerned with SID, and only want to reduce absorbency of the panel to paint in acrylics , then most glossy mediums will do from any brand. You can apply the glossy medium to the surface of the wood, then acrylic dispersion ground (acrylic Gesso) over that. If your surface is still too absorbent, then you can apply more glossy medium before the acrylic colors if you like.
If by the bottom you are referring to the back of the panel, then there are many inexpensive options at the paint supply stores that can be used in this way. Shellac, polyurethanes or polyacrylics should all help preserve the wood panel from behind.
Once your acrylic painting is finished, the isolation coat is helpful if you are applying a removable varnish. It helps the varnish go on easier, but is also there to protect the painted layers from color lift from the solvent used to remove the varnish. It makes a big difference. But, GOLDEN Isoaltion Coat is not the only product that can be used for this purpose. Any glossy medium that is thin enough to not leave unwanted brush strokes, has excellent clarity and is not too soft should perform this role. You can test yor potential products on plexiglas to make sure they are clear enough. For example, GAC 100 is not a good option for this purpose because it is slightly hazy in thicker applications or if it gets built up, and its a little too soft.
Thanks
Greg
