permeable alternative to acrylic primer?

[perplexed]

I am working on the restoration of a circa 1860's house. Most of the original 3-coat lime plaster in the house has been replaced with new plaster matching the composition of the original, horsehair and all. Period wallpaper (wood pulp paper stock, not vinyl) is scheduled to be installed in a couple of the newly plastered rooms. The problem is that the lime plaster takes FOREVER to fully cure, and the acrylic primer the painter wants to use on these walls (I think it's Roman's R-35) cannot be applied on new plaster unless the moisture content is less than 15%. All other work on the house has been complete for a couple of months including the HVAC system which has been running the whole time in hope that the plaster would cure more quickly. The lime plaster when last measured (with an electronic moisture meter) was reading about 30%. But, the surface is dry to the touch, and has been for some time.

Is there some 'old world' alternative to a modern primer/size that would permit the wallpaper to be hung but also allow whatever residual moisture in the plaster to pass through and not cause any problems down the road?

[Chris Murphy]

It's not just that the moisture needs to be released from the plaster, it's that moisture is also alkaline and can harm anything that it hits. As far as I know, there is nothing to do but wait, with fans going maybe. The old time frame was 90 days; new gypsum-based plasters generally need at least 30.
I wrote a couple of articles for our newsletter, The Installer, about dealing with the alkalinity of plaster walls, last summer. If it was me, I'd get a pH pencil from Microessentials Lab, and test the walls with that along with a moisture meter. Moisture meters are just one tool for checking if the walls have cured. You could also duct-tape plastic over a section of wall and see if there is enough moisture left that it condenses.
An alkaline surface can 'burn' the paper. It can also keep an acrylic from bonding (and turn an oil or alkyd to soap). An old-time cure for that was to wash the walls with a 50/50 solution of white vinegar & water, spraying it on until the surface would accept no more of the solution (it turns glassy, and starts to run off). But, the plaster must be cured first.

[Bill Archibald]

Paul,

Not to disagree with what you say about the new plaster matching the composition of the old, but be aware that modern plaster is now gypsum based. Yes there are still some restoration experts who will hydrate quick lime for many weeks, even months, as they did in the old days, mix it with sand and horse hair, and replicate faithfully the original system. If that is the case, ninety days or more is not unreasonable for a full cure - especially with summer humidity.

In the old days with the humidity and the use of green wood for the lath, one year before painting was not uncommon. A lot of that had to do with the saponification of oil paints applied to high pH walls. Acrylics do handle higher pH, but it's not something for which I want to test the limits.

Now, the most commonly used plaster today is bought premixed and comes from USG (United States GYPSUM). And there's nothing to stop a restorer from mixing in horse hair or other fibers as a binder into that modern gypsum plaster.

The most common premixed base coat plaster is USG's Structo-Lite, which has no lime in it.

There are two advantages to gypsum, it dries much quicker than lime nor does it have lime's high alkalinity.

Structo-Lite is also commonly used for the second, or scratch, coat.

Here's a link to USG's MSDS for Structo-Lite
http://www.usg.com/USG_Marketing_Content/usg.com/web_files/Documents/MSDS/StrcL_Plaster-MSDS_53-100-076.pdf

Most modern premixed FINISH coat (veneer) plasters have about 15 to 25 % (by weight) hydrated lime mixed in it along with gypsum and silica. Although drying faster than the authentic lime putty, the samll percentage of lime does cause pH concerns.

If it is the authentic 100% lime putty, you will need to remediate the high pH after the plaster has dried. Not only is vinegar and water a solution, but muriatic acid, ammonia, sulphuric acid, and many other acidic washes are suitable choices. I gotta admit that the last time I encountered a high pH wall, white vinegar just did not lower the pH well enough. I ended up soaking the walls with straight clear ammonia. But there were other factors involved that made that job unique.

As said, gypsum does cure faster than lime. But there are two many variables to say XX days are enough. 30 days should be a good minimum. BUT do reliable testing.


There is much info on the 'net about plasters, Wikipedia is a good place to start:

http://en.wikipedia.org/wiki/Plaster

http://en.wikipedia.org/wiki/Lime_plaster

There are also some other great sites dedicated to explaining all about plasters - both lime and gypsum.

I think I got sucked into a plaster education vortex on the internet a year ago last March in a desire to clarify so many misconceptions I had been fed. It's not a bad idea for everyone in this profession to be thoroughly educated, especially if you are tackling a restoration project where the claim of authentic materials are being bantered about.

If I were you, I would ask what products were used. With that knowledge and proper tests, you will be in the best position to make the right call.

Sorry to go off for so long, but plaster has always been a curiosity for me so I chased down a lot of facts. I always wanted the skills to apply a perfect three coat system.

[Bill Archibald]

Just a quick follow up to more directly answer your question.

If this is in fact a faithful use of 100% lime plaster, then time is needed for drying and curing. Authentic materials need authentic patience.

[perplexed]

Thank you Bill and Chris very much for your quick replies.

Based on your comments (particularly Bill's), I want to clarify a few things about the specific composition of the plaster - The contractor actually had to use a gypsum basecoat (Red Top Brand, from USG mixed w/ sand) because the lime/sand basecoat originally specified would not work on metal lath, which unfortunately was used to replace much of the original rotten wood lath. The brown coat however, was a 1 part lime putty to 2.25 parts sand mixed with 1 lb. of horsehair per 100 lb. of dry lime. The lime putty was made from Type S hydrated lime (no quicklime was slaked) that was made into a stiff mix and left for 48 hrs. before mixing w/ sand. The finish coat was mostly lime putty with around 1 part sand to 3 parts lime putty. So, the plaster is obviously not purely authentic with the gyp. basecoat and dry hydrate, but is certainly more authentic (at least on the surface) than drywall or even modern gypsum plaster. With impending deadlines and such, the project was run on a tight schedule and unfortunately, shortcuts had to be taken at the expense of historic authenticity...

Since lime putty was used for the finish coat though, I will test the pH as well as the moisture content of the plaster. Btw, I was wrong about the primer the painter wants to use. It is a Sherwin Williams PrepRite Masonry Primer B28W300, not Roman's R-35. The product data for this primer does not specifically describe it as a 'wallpaper primer', but SW tech support says it is compatible with wheat paste adhesive and will allow the paper to be easily removed later. Have you all had any experience with this particular primer? Also, what would be an acceptable pH level for the plaster to be primed or sized? And finally, I've heard that aluminum sulfate, or 'alum' solution is safer than vinegar or ammonia for neutralizing pH in new plaster. Is this true?

Again, thank you both very much for your insight. This has been a tremendous help!

[Chris Murphy]

Since lime putty was used for the finish coat though, I will test the pH as well as the moisture content of the plaster.
The reason I suggest testing the pH test is that it is one determinant if the wall is acceptable, another being an adhesion test. Since plastering has become a lost art, I've learned not to trust whatever concoction modern-day installers use, even on drywall. This project sounds intense enough to cover all your bases.


I was wrong about the primer the painter wants to use. It is a Sherwin Williams PrepRite Masonry Primer B28W300, not Roman's R-35. The product data for this primer does not specifically describe it as a 'wallpaper primer', but SW tech support says it is compatible with wheat paste adhesive and will allow the paper to be easily removed later. Have you all had any experience with this particular primer?
Yes, and found it wanting on a new 3-coat system. It failed adhesion tests.


Also, what would be an acceptable pH level for the plaster to be primed or sized?
7 is neutral, but most walls need to get to 8-9. If someone tells you to trust in a higher number, tell 'em to put their[I] name on it. Zinnser's Gardz can handle high pH, and I know because I've used it (they suggest 2 coats), but the solution is cheap- vinegar- so I use that.


nd finally, I've heard that aluminum sulfate, or 'alum' solution is safer than vinegar or ammonia for neutralizing pH in new plaster. Is this true?
No, as there is no danger with vinegar, unless the smell of salad dressing sets somebody off. I have heard of using alum, but am unfamiliar with the details; same with zinc sulphate. I do know that using the vinegar solution and putting enough on [I]that the wall accepts no more works, and that is from my and old timers' experience. There used to be glue sizes with an ingredient (escapes me at the moment) that would show 'hot' spots as red; these were then neutralized. If you could find some of that stuff, then you'd be closer to the original type of surface. Other acids- muriatic, ammonia- present unacceptable risks in an interior (to lungs and to adjacent surfaces), and aren't needed. The pH pencil will tell you when the walls are OK.

[perplexed]

Thanks again, Chris!

Assuming the plaster will be washed with a vinegar & water solution and we won't be depending on any alkali resistant properties of primers, would you recommend an acrylic prep coat or 'primer/size' for increased adhesion (like Zinsser Z-54) vs. a 'primer/sealer' like Zinsser Gardz? I still want to allow some permeation, so I'm a little gun shy about using anything labeled as a 'sealer'... I certainly don't want to trap any moisture...

Also, would you recommend using wheat paste adhesive with an acrylic primer/size like Zinsser Z-54? I need the wallpaper to adhere but it also needs to be strippable without damaging the plaster behind...

I don't mean to sound like goldilocks... Please let me know if this isn't possible.

Respectfully,

Paul Waddell

[Bill Archibald]

Paul,

Using your e-address, I see that you are from a well established architectural firm in Mississippi. If I had done my research before my initial reply, it would have been more appropriate for your obvious knowledge and research.

I agree with you about sealing with Gardz, but as I always say, ask any three paperhangers one question, and expect four different answers. I know this is true in your field also. (I studied under some fairly respectable architects in the early 70's). Many installers use Gardz as a base on to which to install many different wallcoverings, including high end pulp papers, with no ill effects. Personally, I am not fond of installing directly onto Gardz.

No I have never used any wall prep from Sh Wms. I use a product from Canada called Swing Wallpaper Prep Coat. It is acrylic and many of us have great results using it.
http://www.swingpaints.com/3107.htm

I am not sure of its availability in the Oxford area. It is tough getting it here in Massachusetts.

AND, as I am sure you have discovered in your research, the age old method of preparing REAL LIME PLASTER walls was to apply a true glue size. I understand that the paper will be hung with wheat paste ? May I suggest that the very best wheat paste can be obtained from our friend Bob Kelly at http://paper-hangings.com/ ?

In my early days I encountered many lime plaster walls, not drywall nor plaster walls skim coated with either joint compound or Durabond (or an ungodly mix of the both). All that was needed was a glue size for prep. I KNOW some are still there after 35 odd years. Lime plaster is absolutely the best surface on which to install paper.

Either prep method (Swing Prep Coat or glue size) will allow for the permeability as you wish.

Will the walls be lined prior to the installation of the pulp paper ??

BTW, the size Chris mention that had a pH indicator was called Adhesium from Muralo. Here is the MSDS for it. I can not guarantee it still has a pH indicator in it:
http://pages.slc.edu/~aschultz/chemical_hygiene/MSDS/all%20msds/PASTE%20ACTIVATOR%20MURALO.PDF

I did notice these three ingredients: HYDROCHLORIC ACID, HYDROGEN CHLORIDE, MURIATIC ACID

I tracked some down up here (in Rhode Island) about six years ago, but realized there were other ways of testing the pH and driving 60 miles would not be worth it.

[HangingInThere]

Paul,

You may want to make a call to Roman Adhesives and ask for Ray Carden in their tech-support. Ray knows the strengths and limitations of their products on the full spectrum of surfaces and I would submit that his knowledge will prove indispensable. ;)

[Chris Murphy]

From that MSDS:

Name: HYDROCHLORIC ACID, HYDROGEN CHLORIDE, MURIATIC ACID
Other REC Limits: 7 PPM

7 parts per million is a heck of lot different than washing walls with it. If "vinegar" isn't industrial-sounding enough, call it "acetic acid."

There were many brands of glue size, and when they were capable of showing hot spots, the package would indicate that. I haven't seen any for well over 20 years, and Muralo doesn't show it on their website.

Here there is an Atlanta-based company known as UPS, and they deliver pH pencils.

No acrylic, or latex, is impermeable. Water, as moisture, will pass through them. On any sound and dry wall, an acrylic wallcovering primer will work. I've never been a fan of the 'tack preps' like R-35 or Z-54, I'd rather use a tinted primer. That being said, I do like using a paper liner called blankstock when hanging plain paper, also available at paper-hangings.com. It'll make the finish paper last a lot longer; Bob's got good info on his site. His wheat paste is the best out there.

Stripping paper off plaster isn't the same ordeal as getting it off sheetrock, but priming is a good idea. If you'd like to explore a bit more on paste systems: http://scenichanger.com/WallcoveringAdhesives.htm

[perplexed]

Thank you Bill, Chris, and HangingInThere!

Bill and Chris, you both mentioned applying a paper liner which I had not considered... It looks like a great idea. I hope we have enough left in our budget for it. Seems like it would take considerably more time and effort, though. I will definitely have our paperhanger contact Bob Kelly though, if only to purchase wheat paste... If we use the blankstock lining paper, I'm assuming it is safe to use wheat paste as an adhesive for everything - lining paper and all our wallpapers. The wallcoverings are all uncoated and unpasted european pulp papers printed with water based inks (from Charles Rupert). There is one cream & gilt pattern (Bradbury & Bradbury) that has a gold metallic ink, though... As long as no alum is added to the wheat paste, there should be no problems, right?

My iinitial thought for wall prep was actually to size the plaster wall with a watered down wheat paste solution, rather than a modern primer. But, I was told by a conservator I work with that if an acrylic primer is used instead of glue size, the paper would be easier to remove later... I don't know if the difference is significant enough to really matter, though. Would the lining paper work either way? Is there any advantage to using a tinted primer in conjuction with the lining paper?

I think I can see the light at the end of the tunnel now... I really, really appreciate everyone's input on all this. This forum has been an invaluable resource to me. Thank you all!

[Bill Archibald]

Paul,

Here is a brief dissertation on liner:
http://billarchibald.com/liner.html

I think some of the reasons for blankstock expressed there can also be achieved by hanging on lime plaster, but not all.

When I install a liner it usually costs about 50% of the install of the finish paper - and I include the cost of the liner. That would be when installing a "run of the mill" pre-trimmed "Brit-pulp". For a more difficult finish paper, that percentage drops.

You may see "acid free" blankstock on paper-hangings.com (http://paper-hangings.com) . In Bob's own words, there is no great advantage of acid free over "regular" blankstock unless installing an ULTRA high end archival wallcovering that is expected to last for decades.

I would be remiss if I did not mention another great friend of the NGPP that supplies blankstock liner, Cavalier Wall Liner (Ed & Greta Hovnanian) - www.wallliner.com

I will not be tempted to delve into the different pastes that our Guild members find work best for them, it seems we each have our own favorites. But the common convention is that liner should be hung with the same paste as the finish paper (don't worry, this is not a hard and fast rule - many deviate with great success).

Wheat is not only suitable, but is also one of the most authentic pastes.

Yes, in general, a modern acrylic prep coat will make removal easier. But on a real LIME plaster wall, that has been made very smooth, the difference will not be that great. Chris stated he is not a fan of the "tack preps" like R-35 and Z-54. I can not speak to his reasons, but my experience is that these types of prep coats, although great to install on, have a nasty habit at stripping time to exhibit the dreaded "Peeling Sunburn Skin Syndrome" (PSSS). The name describes how these types of prep coats sometime react when paper is stripped off them. Remediating this PSSS will negate any other benefit of these "tack preps" .

In my experience, Swing Wallpaper Prep Coat has never exhibited the PSSS. A few of us love to seal with Gardz and then apply Swing Prep Coat. On this surface, any paper installs and strips beautifully. But I understand your feeling about sealing the plaster with Gardz.

Liner will provide beneficial qualities to any install.

IMO, there is rarely any advantage to tinting walls or liner. If the seams are gapped enough to see the wall, the issue lies not with the paper or the wall. Sometimes one can see a very thin white line at the seams. This most likely is not the wall, but the wallpaper's substrate. The white edge of the paper is showing. This can be prevented on pre-trimmed papers by tinting the roll ends before installation with Gouache (http://en.wikipedia.org/wiki/Gouache) mixed to the best color needed. On untrimmed papers, if this occurs, touch-ups may be necessary, again with Gouache. Please be warned that this is not something for the inexperienced to accomplish easily.

It is our pleasure to share what we know.

-Bill

[Bill Archibald]

Paul,

After doing a search and going to the Charles Rupert website,
http://www.charlesrupertdesigns.com/index.php
I have a question.

Is the wheat paste being used because this project is to be as authentic as possible or have people been influenced by Charles Rupert Designs Wallpaper Hanging Instructions, http://www.charlesrupertdesigns.com/index.php/info/hanging ?

[Chris Murphy]

f we use the blankstock lining paper, I'm assuming it is safe to use wheat paste as an adhesive for everything - lining paper and all our wallpapers. The wallcoverings are all uncoated and unpasted european pulp papers printed with water based inks (from Charles Rupert). There is one cream & gilt pattern (Bradbury & Bradbury) that has a gold metallic ink, though... As long as no alum is added to the wheat paste, there should be no problems, right?


You have some alum hanging around that you just have to use, or what?? Just kidding, but you shouldn't need it.

The Bradbury may need a premix, and may do fine without a liner. In general, most papers will do better with one, but it is not always needed.

The liner should be hung with a paste at least as strong as that used for the finish paper. The same paste is usually used throughout just because it's easier. Wheat will make a better size than most premixes.

You gotta read the links sent to you, and pass them along to your hanger. Everything is just theory until you're in front of the wall with the goods in hand.

[HangingInThere]

IMO, there is rarely any advantage to tinting walls or liner. If the seams are gapped enough to see the wall, the issue lies not with the paper or the wall. Sometimes one can see a very thin white line at the seams. This most likely is not the wall, but the wallpaper's substrate. The white edge of the paper is showing. This can be prevented on pre-trimmed papers by tinting the roll ends before installation with Gouache (http://en.wikipedia.org/wiki/Gouache) mixed to the best color needed. On untrimmed papers, if this occurs, touch-ups may be necessary, again with Gouache. Please be warned that this is not something for the inexperienced to accomplish easily.I'll second Bill's motion regarding tinting primers...He's spot on! An added concern I have for those who do venture to add colorant, is that the pigmented primers are initially white. Adding colorant is most often an attempt to deal with the darker background papers. A burgundy wallcovering I recently was called upon to "fix," was due to an installer applying what looked like a flourescent pink primer. Going any darker with more colorant would surely have degraded the integrity of the primer. This particular scenario had other issues also, but winding up with a flouresent pink under burgundy, flourescent green under hunter green, and flourescent blue under navy, were a huge mistake...costing the installer the job!

Pre-trimmed papers inevitably fall victim to blades that windup also smashing as they attempt to cut resulting in a slightly beveled edge that exposes the paper stock. The back edges of, say a burgundy field wallpaper, may be butted perfectly, but the result can still be an every so slight white line on the surface produced by the bevel, as Bill aptly pointed out.

Some of the manufacturers have adjusted to this inherent weakness by printing on paper stock that approximates the surface inks (e.g., black paper stock printed a black field).

If any installation is shrinking back enough to actually view the wall behind...there's a more serious problem...

[perplexed]

Bill,

We chose to use wheat paste mainly because of it's historic authenticity. We had a conservator, Andrew Ladygo of Architectural Conservation Services in Manchester by the Sea, MA (whom you may be familiar with) come to Oxford to take samples of the plaster and paint, and perform lab analysis to identify plaster's composition and what the original finishes and colors were. Half of the rooms in the house were originally painted with soft or glue bound distemper, which was faithfully replicated. The remaining rooms had only remnants of wallpaper paste on the base plaster (under many subsequent layers of more modern paint). There was none of the original wallpaper to be found, so all we could do was look for 'period' looking wallpaper from around the time the house was built.

Now, I did check to see what sort of adhesive Charles Rupert's Designs recommended for their paper after it was selected. And, they do strongly recommend the use of wheat paste... So, I wouldn't say that I was influenced by Charles Ruperts Designs because we knew wheat paste would be used before Charles Ruperts wallpaper was selected. But, I thought it was a good thing that they recommend the adhesive we wanted to use in the first place... Have you or someone you know had problems with Charles Rupert's wallpaper? Just curious.

And Chris,

I just threw the alum reference in there because I'm sitting on a 50 gal. drum of the stuff. Just kidding.:lol: I read about it in your adhesives article. Fascinating stuff... I'll have to go back and read it again to fully digest it all , though... I've been running 100 mph all day...

I just noticed after you mentioned premix for the Bradbury paper that they actually recommend a clay strippable adhesive for hanging Vinyl Wall Covering. This is paper, not vinyl. But, if you read on, they recommend GH-34 and Bob Kelly's wheat paste for ochre, olive, or sienna fill. Why is this? Could watered down wheat paste still be used for size everywhere if clay-based premix achesive is used only for the Bradbury paper?

I wonder why Bradbury and Charles Rupert's adhesive recommendations are so different. The papers don't look that different.

[Chris Murphy]

wonder why Bradbury and Charles Rupert's adhesive recommendations are so different. The papers don't look that different.

They are printed on different substrates, using different inks. Bradbury has at least 2 substrates that I've seen, but I don't handle their stuff that often. So, different papers need different treatments, which includes primers, pastes, liners, etc. Read Wallcovering Adhesives, and you'll start to put some of the concepts together.
You're not using any true vinyls, only maybe vinyl-coated, so wheat size should be OK. It might mildew under a non-breathable vinyl, but that's not what you're using. Clay has the least amount of moisture of any paste, so it dries quicker, helps eliminate curling edges, and is tacky enough for the heaviest materials. Wheat is lighter, and its moisture helps true papers relax and conform to the wall.

[Bill Archibald]

First, I have not hung any paper from Chas Rupert Designs, but have hung many Wm Morris designs manufactured by Sanderson. Nothing but praises from me about them. And I can't remember ever using blankstock under them. I generally use a premix with wheat mixed in.

I was just wondering about the decision for wheat. I can understand the adherence to authenticity. My paste choice is usually based on the paper, the walls, and what is rolling around in the back of my van :devil:

Interesting you mention GH-34. This has been a go to paste of mine since 1980. (GH-34 is a wheat base premix) I have oft mixed it with powdered wheat. Well I've mixed the powdered wheat up and then mixed it with GH-34. Roman Decorating Products, in their infinite wisdom, has decided not to make GH-34 readily available anymore. I am told one can "special order" it. :bash:

And no, I do not recall ever hearing of Andrew Ladygo. I looked up his bio and am surprised I can't remember hearing his name. I am, obviously, very familiar with the Society for the Preservation of New England Antiquities where he started his career (according to what I read)

Speaking of authentic mid 1800's wallcoverings (and earlier), I was wondering if you were familiar with Adelphi Paper Hangings (http://www.adelphipaperhangings.com/). I am sure it's too late for this project to change choices, but if you are not familiar, it could be a good resource for the future.

This project sounds really neat. Not only from the wallcoverings point of view, but considering the plaster and the "glue bound distemper". In the mid 70's, I was "encouraged" by a client to research graining and make my own glaze from scratch. Doing all this as it was done before manufactured products is fascinating (and rewarding) stuff.

And I suppose you are applying to the ceilings the bane to my past life as a painter - calcimine. :cuss:

:roflmao:

-Bill

[perplexed]

I read in the wallpaper preparation article on this webpage (and on Bradbury's installation instrucitions) that on new 3 coat plaster, you should prepare the surface with size mixed with whatever adhesive you plan to install the wallpaper with. If wheat paste is both the final adhesive and used to size the walls, how much should the adhesive be thinned to make size. Also, if wheat will be used in the size but the final adhesive is clay (with the Bradbury paper, for instance), Is there a commonly accepted formula for mixing size from different materials?

Bill, we actually used 'washable distemper' from Aglaia natural paints on the ceilings (see below), which is very similar in appearance and composition to calcimine, but more durable than most calcimine you find on ceiling of old buildings.

http://www.naturalpaintsonline.com/PDFs/WASHABLE%20DISTEMPER%20(0570).PDF

I am not familiar with Adelphi, but I wish I had known about them in the design phase of this project. I must admit that our interior designer actually selected the Charles Rupert and Bradbury papers. At the time, my hands were full with the rest of the house (and other projects), so she helped me out... I have a handful of historic restoration projects under my belt, but my experience with wallpaper up until now has been limited to replicating and replacing existing original wallpaper on existing old plaster. This is my first time dealing with the application of new wallpaper on fresh lime plaster walls, so it has definitely been a learning experience for me...

Paul

[Chris Murphy]

you should prepare the surface with size mixed with whatever adhesive you plan to install the wallpaper with
I'm not going to review what you cited,but I think you have confused some terms (or the sites did, not uncommon). Since glue size is unobtainable unless you want to start cooking hides down now (I'd donate some old shoes), the size you need is just diluted paste, generally 50% added water. It is very runny and is meant to lower the porosity of the surface, adds tack, and increases the working time of the paper. Size and primer aren't the same, but are unfortunately used interchangeably by some who should know better! So the size is just the paste, diluted; but previous advice still applies (i.e., that wheat makes a great size, but clay does too; clear, not quite as good).

[Bill Archibald]

http://www.naturalpaintsonline.com/P...R%20(0570).PDF

Sounds VERY similar to calcimine. But seriously, these types of products (include whitewash here) are great for achieving a flat level coating over (lime) plaster. AND they actually help "heal" cracks. Another benefit to lime, one can mend small cracks with a lime based wash. To freshen calcimine, a wet sponge was run over it. Is the same true with the Aglaia Washable Distemper. Cured lime does not degrade when wetted and dried, whereas gypsum plaster should not be exposed to water or severe moisture conditions.

These thin lime coatings are great products until someone decides to paint over them :cuss: :cuss:

In the late 70's we ran into a formal dining room that had calcimine on every surface (except floor) No one was happy when the only solution was to wash completely off before painting ! Yes, every surface, including the window muntins.




To help clarify "size" vs "primer/ prep coat" this may help:
http://billarchibald.com/size.html
even briefer than the piece about liner.

Although "glue" (rendered animal products) size was oft used on walls, you will be using "paste" size - as Chris pointed out.

Some folks will size the blankstock liner, some will not. There is a great ongoing debate about this. I am of the school that will not (95% of the time) size the liner as I feel it negates the main purpose of the liner - to quickly absorb excess moisture from the paste.

-Bill

[Bill Archibald]

Is the same true with the Aglaia Washable Distemper. I woke up this morning and this question was one of the first things that enterred my mind. Yes, I understand what "washable" means. Please forgive the brain fade and forget I uttered this. :o

-Bill

[perplexed]

Bill,

Think nothing at all about the 'brain fade'. I had one of my own. I must admit that I was incorrect earlier when I said glue bound distemper was used on some of the walls. The original distemper paint was in fact glue bound, but as Chris pointed out, glue made from animal hide is hard to get. The Aglaia washable distemper (which is casien bound) was used on the walls as well as the ceilings. On the walls though, lime compatible natural pigments, also available from Aglaia were added to match the colors (provided by Andrew Ladygo's lab analysis) of the original (glue bound) distemper wall paint. The washable distemper without added pigment is a chalky white. All the washable distemper (walls and ceilings) was applied before the lime plaster had fully cured, and is holding up extremely well...

Thanks for the link to your "size" vs. "primer/prep coat" article. I guess mine is one of the few instances where "size" is actually appropriate... And, I'm obviously no expert on this stuff, but based on all I've heard and read, can see the logic in not sizing the blankstock liner paper.

And Chris, Thank you for the clarification. FYI - The exact quote and link are below:

"On new plaster (after the proper curing time) use size mixed with the adhesive you plan to install the final wallcovering with to prepare the surface."

http://www.ngpp.org/consumers_diy_preparation.php

Thanks again, gentlemen!

-Paul