Rice/Wheat Paste Making Protocol

Create a Post
Rob Markoff

Rob Markoff

PFG, Picture Framing God
Joined
Mar 8, 1999
Posts
5,183
Loc
San Diego, CA USA
For those who are mixing Rice/Wheat paste on a regular basis, what is your protocol?

I was reading a few conservation supply catalogs and both mention that the cooled, cooked starch should be put through a fine strainer and then cut by 50% to make a workable paste. I have never used a strainer as part of my paste making regimen and wonder what others are doing?

What is your cooking setup? I have a hotplate and a use a single egg poacher/double boiler because I only mix up a small batch at a time, usually one level teaspoon of rice starch to 6 teaspoons of water- but my poacher is aluminum and after years of use is pretty grody. I found a new steel one online with a teflon coated bowl, but before I bought it, I thought I would see if there are other techniques that may be better.

The problem I have found with larger double boilers is that they have such a large surface area and I need to increase the amount of paste I am making so it isn't "lost" in the cooking process.

Please don't reply that you use Hayaku and don't need to mix paste. The water activation of Hayaku is not as controllable as mixing your own paste and you are limited to the size and type of paper that the glue is impregnated on. I have had "bad" rolls of Hayaku, and lately, all of my rolls are "yellowish" in color. It works fine for "general" hinging, but is unreliable for floating and especially on heavier, more valuable pieces of art I want a heavier bodied paper. I want to know exactly what I am hinging with and control the size and type of hinging media I use.
 
I use roughly the same proportions as you do - mix one teaspoon of powder and five/six teaspoons of water in a very small jar. Nuke the jar for around 8 seconds, stir, nuke again for a couple of seconds, stir, repeat until translucent. Let it rest and cool down.

I generally don't water it down from there and use it straight from the jar. Watered down it takes longer for the pasted hinges to dry off enough to apply them to the paper.
I keep the jar with a plastic lid on, in the fridge and it remains useable for several weeks. Water will come to the top after a while, so I soak some of it up with a rolled up piece of paper towel so it's not sloppy.
 
I have always used the microwave to cook the paste. My normal batch is 1/2 of yours - 1 tablespoon of purified water.

I "nuke" the mixture for 10-15 seconds at a time. In a clear glass jar you can actually see the paste change from opaque to transparent. I use a craft stick to stir between nukings. I nuke until I see it boil ( just one bubble is needed to be seen).

I prefer the thick paste for use to avoid excess moisture in contact with the art. If I want a thinner paste I use a wet brush and mix in more water that way. The mixing of the paste and brush is done on a scrap of glass. This mixing on a glass plate also identifies any lumps and works them out.

My bottle of preference is an old baby 4oz. formula bottle with a black rubber stopper.


BTY, I have an assortment of white and cream colored papers in 3 or so weights for hinging material. From 5gm to 32gm
 
I mix mine at the 1:5 ratio in a shot glass, stirring every 10 sec until translucent. A piece of glass on top of the cooked paste lets it hang around in the basement, where it is a little cooler than room temperature, for 3-5 days.
 
So no one strains their paste? We have a microwave, but never have tried this technique. Can you overcook the paste in a microwave? Does cooking it in a microwave change the properties in any way?
 
After I cook my paste I make a 50/50 mix of wheat paste and ethulose. You can also use methyl cellulose but the ethulose is more anti- microbial. After I mix it I strain it to get out the lumps. You should use a horsehair strainer but they are painfully expensive. I stretch a double layer of cheesecloth on a canvas stretcher and it works o.k. I am going to try and mash it through a silkscreen this week. I'll let you know the results. My neighborhood conservator cooks paste in a self- stirring pot that you plug in. It heats and stirs. It's made by Tefal but I haven't been able to find one of those. She makes a lot of paste though. But anyway, I keep my paste around for a week or more in a glass jar in the fridge. Oh yeah....The ethulose is just like wheat paste but you don't have to cook it. Just mix up a teaspoon or so in a cup of water and let it sit until it gets thick.
 
Rob Markoff said:
So no one strains their paste? We have a microwave, but never have tried this technique. Can you overcook the paste in a microwave? Does cooking it in a microwave change the properties in any way?
Click to expand...
I found that cooking it paste the critical point in a microwave turns it into a stiff gel. I don't what the chemical properties are, but it appears to be useless and I throw it out if this happens.

Gently does it! Little by little, with some stirring between nukes, to make it homogeneous! Stop when it becomes translucent!
 
Every two weeks I soak one tablespoon of wheat starch in four tablespoons of de-ionised water for at least 20 minutes (and sometimes over an hour, depending on how my day goes. I then stir it thoroughly, and cook it in a stainless steel pan directly over high heat, stirring onstanly, fast and faster as it cooks. It akes maybe four minutes. I make *very* stiff paste.

The cooked paste is emptied from the pan into a small jar with a bit of water at the bottom. The jar is then filled to the brim with water, the cap put on, and it's put in the fridge.

For some reason, it's far easier to strain paste when it's completely cool. We do force it through a sheer fabric (polyester organza works well) stretched over a beaker, using a tongue depressor. We only strain small bits at a time. Water can be added while straining to thin it, and it can be strained several times to get the desired consistency. Some here prefer to thin it out in a small bowl with a brush.

We keep paste for two weeks in the fridge, strained paste for maybe three days. Other places keep theirs on the counter top, covered in water, for a week (and theoretically changing the water daily). Strained paste might keep for two days unrefrigerated.

I balked at making paste I was fairly certain would be thrown out. My boss quoted one of her old bosses, “Paste is cheap. Art is expensive.”
 
From
Bas van Velzen, Senior tutor, book and paper conservation, University of Amsterdam, in a thread elsewhere:

In general it is not advisable to use rice starch since it yellows
easily and becomes brittle. In Japan it is used for rigid joints
such as in shoji. Also, wheat starch contains more amylose, which is
the part of starch that will become sticky on cooking. Wheat starch
is therefore the conservator's weapon of choice.
By soaking the starch granules in water for some time (1 part to
four parts water, up to 12 hours--overnight) water is allowed to
penetrate between the starch layers in the granules. This will
result in a softer, more easy workable paste once cooked. The
traditional cook and stir method allows for shear forces in the
paste once the granules start to burst open after the temperature
reached +/- 85 deg C. Prolonged cooking and stirring (shear forces)
is necessary in order to break all the starch layers and thus
maximise the gelatinization of the amylose and amylopectin.
The longer cooking will degrade some of the paste. This is not
considered to be a problem and causes the breakdown of the larger
starch conglomerates. In this way a larger spread from small to
larger conglomerates in the paste will occur. Working the paste
after cooling and setting will result in a smaller internal surface
of the paste because small particles will fill all the spaces
between the larger conglomerates. In this way the paste will have a
higher contact ratio with the paper thus making more hydrogen bonds
possible between paper and paste per area. This will ideally result
in a better bond and is responsible for the high dilutions
attainable with well cooked and prepared wheat starch paste.
Conclusion: microwave paste is handy and easy to make but normally
will make lower quality, harder and under-cooked paste. The easiest
way of making paste in my opinion is using a Saucier and covering
the pan to achieve a higher cooking temperature. The constant
stirring in the Saucier will help in breaking up the starch
conglomerates without breaking your back.
 
I use 1 tsp. rice starch with about 5 tsp. water and cook it in the microwave.
However, that last post is compelling, and I'm curious to hear conversation about it.
 
Strain it through used pantyhose material. Wife now down to just knee-highs, so it makes
it easier.

Make a decent batch and stuff a couple of teaspoon fulls in little envelopes of Marvalseal....
and seal them up and through them in the reffer like Hugh has been preaching for years.
 
I use a glass measuring cup with a 1:5 ratio, set micro for 2 minutes; interrupt every 10 seconds to stir, strain, put into miniature zip lock bags from the dollar store.

Throw out when the mould appears ;)
 
I've always wanted a good excuse to buy a saucier, though in this application an electric bain marie would work nicely.

I'll second Baer's reference to Hugh's Marvalseal pouches. You can cook up a couple months supply and always have it fresh. It's self indicating too. When the pouches start to balloon, it's time to pitch them.
 
Baer Charlton said:
Strain it through used pantyhose material. Wife now down to just knee-highs, so it makes
it easier.

Make a decent batch and stuff a couple of teaspoon fulls in little envelopes of Marvalseal....
and seal them up and through them in the reffer like Hugh has been preaching for years.
Click to expand...

....uum Baer....what is a reffer:confused:
 
Create a Post
Back
Top