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Pantau
09-26-2008, 06:07 AM
Hello everyone,

I'm about to start painting with Golden Open Acrylics. Now I have a question. I allways paint on masonite. On the website from Golden they describe the following ground as the optimal system for preparing wood supports for use with OPEN Acrylics, Gel, and Medium:

<LI class=normtext>Apply 2 coats of an alkyd-based primer, such as KILZ®, or a white pigmented shellac primer like B.I.N.® Let fully dry. <LI class=normtext>Apply one coat of GAC 100. Let dry. <LI class=normtext>Apply 2 or more coats of GOLDEN Gesso, or 1 coat Gesso followed by 1 or more coats of GOLDEN Sandable Hard Gesso.
I must say that I'm surprised by this description, because I've allways learned that it is not wise to work with waterbased paint on top of oilbased paint. For as far as I know an alkyd-based primer contains oil (or am I wrong here?). I remember reading somewhere that alkyd itself can not dry. So, to make alkyd dry it is modified with oil. This means that when you use the ground as described by Golden, you will be putting a waterbased gesso (is GAC 100 also waterbased?) on top of a ground that contains oil.

What do you think? Am I wrong about things here? I don't know the alkyd-based primer from the brand KILZ. Maybe this a special primer? If so, does anyone know a similar primer that is for sale in The Netherlands?

Sincerely,

Charles

Einion
09-26-2008, 07:13 AM
I must say that I'm surprised by this description, because I've allways learned that it is not wise to work with waterbased paint on top of oilbased paint.
There are a lot of things like this that aren't as simple as we've heard.

Once cured oil paints aren't strictly oil any longer - during 'drying' the oils form polymers, effectively turning into a type of plastic.

For as far as I know an alkyd-based primer contains oil (or am I wrong here?).
Alkyd paints are generally oil-modified alkyd resins, but not all I think.

I remember reading somewhere that alkyd itself can not dry.
Don't think that can be right but it's not really relevant as anything we buy does dry and was formulated so that it would, however that's achieved :)

What do you think? Am I wrong about things here? I don't know the alkyd-based primer from the brand KILZ. Maybe this a special primer? If so, does anyone know a similar primer that is for sale in The Netherlands?
Nope, sorry.

Personally I'm not 100% that the method they're suggesting is the best route here, you might like to try a couple of thinned coats of polyurethane varnish followed by priming as normal.

Einion

JamieWG
09-26-2008, 08:01 PM
Hello everyone,

I'm about to start painting with Golden Open Acrylics. Now I have a question. I allways paint on masonite. On the website from Golden they describe the following ground as the optimal system for preparing wood supports for use with OPEN Acrylics, Gel, and Medium:

<LI class=normtext>Apply 2 coats of an alkyd-based primer, such as KILZ®, or a white pigmented shellac primer like B.I.N.® Let fully dry. <LI class=normtext>Apply one coat of GAC 100. Let dry. <LI class=normtext>Apply 2 or more coats of GOLDEN Gesso, or 1 coat Gesso followed by 1 or more coats of GOLDEN Sandable Hard Gesso.
I must say that I'm surprised by this description, because I've allways learned that it is not wise to work with waterbased paint on top of oilbased paint. For as far as I know an alkyd-based primer contains oil (or am I wrong here?). I remember reading somewhere that alkyd itself can not dry. So, to make alkyd dry it is modified with oil. This means that when you use the ground as described by Golden, you will be putting a waterbased gesso (is GAC 100 also waterbased?) on top of a ground that contains oil.

What do you think? Am I wrong about things here? I don't know the alkyd-based primer from the brand KILZ. Maybe this a special primer? If so, does anyone know a similar primer that is for sale in The Netherlands?

Sincerely,

Charles

Hmmm....I don't see that on the site. I see two coats of GAC100, then gesso. That's what I've always done. Did you look here?
http://goldenpaints.com/technicaldata/prepsupp.php

Jamie

Mark Golden
09-26-2008, 08:06 PM
The advice on the Golden Website has been developed over a great deal of work and research, developing a resource for best practices. Since the first studies of Support Induced Discoloration in 1990, (a severe yellowing of cotton, linen, wood and masonite supports) we have tried to develop better priming systems to block the water miscible components in these substrates from coming through to the painting. In most cases an artist may not perceive this yellowing unless working fairly thickly with acrylic paints, and mostly with fairly transparent mediums or glazes. The OPEN Acrylic stays wet on the substrate much longer then traditional acrylics therefore allowing more of the discoloring materials to be pulled to the surface. With linen or cotton, you can wash the canvas and dramatically reduce the yellowing. With wood or masonite, you don't have the same choice. For best results, therefore, we recommend a sealing system. You will see the difference in just the color of the gesso with the sealed and unsealed versions.

It would be wonderful if we had a waterborne acrylic that could seal on all surfaces, but we don't. The GAC 100 will work will on most surfaces, but to really stop the tannins and other materials coming through unprepared masonite or wood, the best is a pigmented shellac. The pigmented sealer tends to offer significant tooth for adequate adhesion of the GAC 100 and subsequent layers of paint. Additionally, modern acrylics were developed to have fairly good adhesion to pigmented alkyds as well. Hope this is helpful. Mark

awerth
09-27-2008, 04:57 PM
If you're open to having someone else prep the surface for you, I've been very happy with Ampersand's line of "board" products, especially their Gessobord. Of course, this might cost more than doing it yourself, but it's a lot easier ;-) Tech info on their sealing process is available at:

http://www.ampersandart.com/tips/archivalinfo.html

They recommend GAC-100 to seal the support if you start with their "Hardbord" product, but if you go with one of the other sealed & coated products (e.g., "Gessobord") you wouldn't need to do that (although GAC-100 does reduce the absorption of water into the gessobord, which I've found kind of helpful when painting with Golden Opens).

JamieWG
09-27-2008, 06:31 PM
Mark, thank you so much for your input. I'm going to test the supports I've prepared with the 2-3 coats of GAC100 followed by several primer coats, and see if any discoloration migrates up through some OPEN medium sitting on the surface. I'd really like to avoid the shellac if I can. I'm about to prepare a batch of large panels, so if I absolutely have to do that extra step, I'd rather find out about it now than later!

Andrew, I love the Ampersand Gessoboard too, but it becomes very expensive once you move up to the larger sizes.

Jamie

George Servais
09-27-2008, 10:43 PM
If at all possible please, for the sake of your health and safety stay as far away from the oil and alcohol based commercial primers like KILZ or BIN. I used them as a commercial stain sealer years ago. That is there primary use. The name KILZ is appropriate for the product. The list of warnings is lengthy and these primers can and do cause blood disorders, nerve problems, lung problems and the list goes on. The primary attraction of acrylics is to not have deal with the smells and toxicity issues associated with other mediums. Please use a good quality gesso like Grumbacher acrylic gesso. I have used it with great success when painting on Masonite. Simply seal it with an acrylic sealer first if you have any bleed-through issues.
I used KILZ during the winter and the ventilation was not as good as it should have been. I woke up a day later in the hospital restrained and sick. It took 3 months to fully recover.
Both KILZ and BIN have extremely strong odors which linger for a long time.
I favor pre primed Gessoed hardboard. Available on line. The extra expense is worth it. Dick Blik has them. I know you are in NZ but a good on line search may get you what you need. Golden should know better.

Pantau
09-29-2008, 07:46 AM
Thank you all very much for your responces. They are all very usefull.

The Ampersand board products sound interesting. Especially the description about masonite is usefull. As far as I knew/know 'Hardboard' is the untempered version and 'Masonite' the tempered version.

This is the informationpage I read about an underground for Golden Open:
http://goldenpaints.com/technicaldata/open.php

I'm still not convinced that it is wise to use an alkyd-based primer as an underground for acrylic gesso and paint. A pigmented schellac might work oke, although schellac has it's own negative characteristics that one should be aware of.

So, for now I think I'll prepare my masonitepanels like this: 1. I'll apply 2 or 3 layers of GAC 100 (I ordered it, waiting for it to arive). 2. than 3 layers of Golden Gesso. 3. 1 layer of Golden fluid matte medium.

Ordering pre-primed panels might be a possibility,although I never use standard dimensions. So I'll have to do some searching where I can order non-standard-dimension-panels that are pre-primed they way I want it and how long it takes for them to be deliverd.

Cheers,

Charles

JamieWG
09-29-2008, 09:37 AM
Charles, Mark and George,

According to my tests, Mark is right as usual. Tests on my panels show serious support induced disoloration---not only with OPEN medium, but with other acrylic traditional mediums as well (though not as pronounced). Linseed oil and Liquin show no signs of color change, so it appears that the sealing and priming I did is safe for oils. This is a bummer. I'm going to have to change my preparation methods for acrylics. Maybe it's still warm enough outside for me to apply the B-I-N coats outdoors. I checked their website and it appears that my local Home Depot carries it. If that's not going to work out, I guess I'll be covering my panels with linen and canvas.

I'm going to retest my own panels on the chance that this one board escaped a sealer coat. I'm also going to test the Ampersand Gessoboard that I use so often.

I'll post results with images. It's not hard to see what happened; the color change is dramatic.

Jamie
P.S. Charles, thank you for posting the link.

JamieWG
09-29-2008, 10:01 AM
I'm adding the image of my first test panel. I'm still going to retest my own surface and some others, and will post all of them to a separate "SID" thread.

The applications of mediums on this panel are a lot thicker than what I use when I paint, but you'll notice that even the thin application of OPEN medium shows staining. In tests to come, I'll apply the materials in a manner more in keeping with what I do when I paint.

http://www.wetcanvas.com/Community/images/29-Sep-2008/13766-Test_1_800_2xGAC100_3_coats_acrylic_gesso.jpg

Jamie

Pantau
09-29-2008, 10:17 AM
Jamie, thank you very much for sharing the information from your tests! :thumbsup:

Some interesting results. I didn't expect that the SID-issues would be that visible.

I'll try some tests as well with some different materials. As soon as I have results I'll post them. Hope that the GAC 100 I ordered will arrive soon.

Charles.

tobiano
09-29-2008, 10:37 AM
Jamie, how long did it take for the yellowing to show? I prepare my own panels and will need to check if mine will do the same. I do use 3 coats of minwax polycylic, then 4 coats of acrylic gesso. So far I haven’t noticed any yellowing of the color, but this is all fairly recent, don’t know about long term. Thanks for posting your test results.

JamieWG
09-29-2008, 11:09 AM
Jamie, how long did it take for the yellowing to show? I prepare my own panels and will need to check if mine will do the same. I do use 3 coats of minwax polycylic, then 4 coats of acrylic gesso. So far I haven’t noticed any yellowing of the color, but this is all fairly recent, don’t know about long term. Thanks for posting your test results.

Tobiano, it didn't take long. I checked the panel after a couple of hours and the color had already started. Certainly if you do it and leave it overnight, you'll be able to tell if there have been changes or not.

Jamie

Pantau
09-29-2008, 04:32 PM
In the meantime I received the following response from Golden Technical Support to my questions:

"Alkyd is actually a type of synthetic resin that, while it seems similar to the oils used in traditional oil paints, is actually quite different in chemistry. The confusion often happens because they are both thinned with solvent and many paints described as 'oil-based' for use on houses are actually alkyd-based instead. As for using our products on top, alkyd-based primers are almost always formulated to receive a water-based paint as they are used extensively to prime raw wood prior to application of a water-based house paint. Because of this, you can safely use our products on any alkyd primer that can receive a latex paint.

I do not know which brands are sold in the Netherlands, so it would be difficult for me to recommend anything specific. I would think that any good commercial paint store that sells products for paining houses would have something comparable. And keep in mind that you can also use a pigmented shellac primer, which are also common for use on woodwork when one wants to seal the surface for subsequent coatings."

Nilesh
10-01-2008, 03:19 PM
Hello everyone,

I'm about to start painting with Golden Open Acrylics. Now I have a question. I allways paint on masonite. On the website from Golden they describe the following ground as the optimal system for preparing wood supports for use with OPEN Acrylics, Gel, and Medium:

<LI class=normtext>Apply 2 coats of an alkyd-based primer, such as KILZ®, or a white pigmented shellac primer like B.I.N.® Let fully dry. <LI class=normtext>Apply one coat of GAC 100. Let dry. <LI class=normtext>Apply 2 or more coats of GOLDEN Gesso, or 1 coat Gesso followed by 1 or more coats of GOLDEN Sandable Hard Gesso.
I must say that I'm surprised by this description, because I've allways learned that it is not wise to work with waterbased paint on top of oilbased paint. For as far as I know an alkyd-based primer contains oil (or am I wrong here?). I remember reading somewhere that alkyd itself can not dry. So, to make alkyd dry it is modified with oil. This means that when you use the ground as described by Golden, you will be putting a waterbased gesso (is GAC 100 also waterbased?) on top of a ground that contains oil.

What do you think? Am I wrong about things here? I don't know the alkyd-based primer from the brand KILZ. Maybe this a special primer? If so, does anyone know a similar primer that is for sale in The Netherlands?

Sincerely,

Charles
All the layers and sanding, and the drying and other prep work can take up valuable time that could be spent painting.

There are simpler approaches, in case they might be of interest.

You could paint on Dura-Lar, for example, backed with Masonite or hardboard. This would also eliminate worries about the usual joined-at-the-hip nature of painting directly on hardboard. If something happened to the hardboard backing (warpage, cupping, and other forms of damage sometimes occur), the Dura-Lar could simply be detached or dismounted, and re-supported by a replacement backing.

The Dura-Lar would probably form an excellent barrier against migration of tannins and other materials.

Mark Gottsegen speaks highly of using linen, cotton, or polyester (which has advantages over the others) stretched over a rigid panel backing, rather than stretched over the usual stretcher bars.

This would also allow for replacement of the backing, if it were ever necessary.

***
Plexiglas and similar (acrylic) products bypass many of these problems.

Acrylics are not only excellent for use in painting -- as binders and mediums, gessoes and varnishes, etc. -- they can also serve as excellent supports, with real advantages over the masonites or hardboards.

id-art
10-01-2008, 04:13 PM
This thread has raised doubts about established practices of long standing. I've been using gessoed hardboard for thirty years or more. I have never noticed any discoloration. As a practical matter is this really an issue? If it is one possible solution may be the vinyl coated hardboard which I sometimes use. Doesn't that seal the surface big time?

JamieWG
10-01-2008, 05:46 PM
All the layers and sanding, and the drying and other prep work can take up valuable time that could be spent painting.

While that may be true, for those of us who do a few hundred paintings a year, it is well worth it to take a couple of days a year to make panels. It only takes me an hour a day for several days to make 60-70 panels, and saves me a ton of money over the course of a year. I do several batches a year. But aside from that, I can't even find panels that I like as much as my own. And how do I know whether or not they are sealing their boards? I'm not really a fan of cotton canvas, though I do use it, and linen is very expensive for paintaholics like me. I need to ration that! So, part of the reason why I make my own is the price, but part is that I like it the best of any surface I've tried.

Bob:
This thread has raised doubts about established practices of long standing. I've been using gessoed hardboard for thirty years or more. I have never noticed any discoloration. As a practical matter is this really an issue? If it is one possible solution may be the vinyl coated hardboard which I sometimes use. Doesn't that seal the surface big time?
Golden has had this information out there for a long time. Hardboard is not a great painting support it seems. The fact that so many of us use it has enabled us to assume that it is a great support, but the evidence points to the contrary. I guess it is up to each artist to do their homework and use what they are comfortable with.

Bob, I like that vinyl coated hardboard too, but I use the vinyl on the back. It saves me the trouble of having to double or triple-seal the backs of the panels, and gives a nice look to the back. Can you actually paint on that stuff?

As for whether or not the discoloration is an issue, well, perhaps not. For myself, I need to do some tests and compare colors on the panel and on something else---like maybe rag paper. Also, don't forget that the thickness of the mediums on my test panel is way thicker than anything I do when I actually paint. The thicker the medium layer, the longer it takes to dry, and the more discoloration it pulls from the panel. I need to also test the amount of discoloration that occurs with medium of a more appropriate thickness, and then decide if the discoloration is in fact enough to stop me from preparing my panels this way. It will take a few more test panels before I reach a decision for my own work.

I should also mention that I've tested not only the Golden mediums on the hardboard panels, but did another panel of others as well, including all of the Interactive mediums and other brands, and they all show similar signs of SID when applied thickly like this.

Jamie

id-art
10-01-2008, 05:57 PM
"...vinyl coated hardboard ...Can you actually paint on that stuff?"

I've painted directly on the vinyl with oils. Very slick, easy to wipe off, some interesting effects. Sand it well and coat with acrylic gesso works fine.

Nilesh
10-01-2008, 07:50 PM
What do you think? Am I wrong about things here? I don't know the alkyd-based primer from the brand KILZ. Maybe this a special primer? If so, does anyone know a similar primer that is for sale in The Netherlands?

Sincerely,

Charles
Why not explore some alternatives? There are many different ways of approaching these things.

***
KILZ is similar to some other products; some of these are (according to local paint shops that are familiar with them, and have worked with them for years, and carry both KILZ and the others) at least as good.

And there are other ways of going about it, too -- ways that bypass this whole messy, time-consuming, multi-staged process.