Cooking Wheat Starch Paste

[RobynPlater]

Hi Everyone,

I'm after some step by step instructions on how to 'cook' wheat starch paste. I just had my first attempt and I'm pretty sure that it can be classed as a disaster.

I'm using the following:
Japanese Shoufu Paste
Dionised Water
Gas Hob
Saucepan (with about 1 inch of water)
Glass Bowl (sat on top of saucepan - not in contact with water)
Wooden Spoon
Metal strainer

I've followed instructions from Joanna Kosek publication 'Conservation Mounting for prints and drawings' which instructs to mix 1 part Shoufu to 3 parts water and to cook for 1 hour. Let it cool, then pass it through a strainer. My problem is that the mix reached the consistency which I thought was appropriate after about 5 minutes, indicating to me that I had my temp to high, therefore cooked it too fast?? I reduced the temperature, added another part water, but same thing happened. Anyway I persisted up to the hour (more to see what was going to happen than believing that it would miraculously work) eventually adding about 7 parts water. By the end, all I had was a fairly firm ball of paste that I managed to push through the strainer and into a sterilised jar, with the assumption that it is no good for anything.

So, my questions are:
1. How long do you cook your starch paste for?
2. What does the length of time you cook the paste for affect i.e. tack, smoothness, how long the paste will store for, or how long it will stay adhered once it is applied.
3. Is there a recommended ratio for mixing? I've seen anything from 1:3 to 1:5 or is it something you have to adapt, depending on what application you are using it for?
4. Once I get a paste made, when I'm ready to use it do I then need to water it down further?

If it helps, my end application is to float mount card invitations using pass through hinges made from 16gsm Japanese Paper.

Hope you can help.

Thanks
Robyn

[Roboframer]

The pot-within-a-pot (bain marie) method is the traditional way but I don't know of anyone (bar you) that uses it, most use a microwave, including many conservators.

I mix 1:5 or 1:6 and blast on 'high' for 10 seconds, stir; repeat, stir;repeat until the right consistency - it'll cool thicker. I don't use a strainer.

I only use it freshly cooked, well, same day, anything left over gets tossed. I have tried storing it but it always goes runny and re-nuking doesn't fix it, maybe I'm doing something wrong because others say they keep it for up to a week. Not fussed though, it costs nothing (a teaspoon of powder makes plenty, far more than you'd need for the job you mention) and takes seconds to make.

[Roboframer]

Here's an article http://frametek.com/HTML/Articles/Wheat ... Paste.html

Look further under 'Hinging Artwork' for more answers to your questions.

[David McCormack]

I’ve used wheat starch paste only a few times but have never had any problems. I don’t own a microwave so cook mine on a gas home at home and take it to work the next day. I keep the paste in a 35mm plastic film container with a lid (remember those!) and throw it away after about 2 days. I use the paste either neat or mixed with some water in a glass ramekin depending on the job.

I use Linco wheat starch mixed 1 part to 5 parts deionised water (from local car accessory shop) and cook for about 15 to 20 minutes. I’ve never used a strainer as the paste always seems smooth enough and lump free to me.

Hob.jpg

Paste.jpg

[RobynPlater]

Thank you both for your advise.
I've had success with the microwave method . I also think if I'd followed my instincts, as David illustrated and cooked it for less time, I would have got there too.

I used the paste on a test piece (A6 postcard) and the kozo paper has adhered well, but on the front if I hold the mounted postcard up to the light at the right angle I can see where the hinges are. It's a very slight raised indentation/embossing on the surface of the image. How can I prevent this from happening?

I would appreciate some opinions from people with more experience than me. My guess is that I've either applied too much paste or pressed too heavily (but generally I'm very light handed).

Thanks
Robyn

[Roboframer]

Did you look further within my link? Just in case http://frametek.com/HTML/Articles/Wheat ... nging.html

[RobynPlater]

Aahhh! Thank you. Sorry to be such an unnecessary pain. I missed that extra link. That will teach me to not read Forum replies when I should be concentrating on the (current) day job.

Thanks again. I'll try out the method and post how I get on.

Cheers - Robyn