Friday, August 12, 2011

Testing the gummed paper tape

Brown paper with a thin coating of gum arabic.
The fabric on my small screen needs changing. It's an old-fashioned wooden frame which enables me to change the fabric myself. I found out yesterday that this type of frame is no longer being made,*** (wooden frames are available, see below)  the aluminum ones are preferred because they don't warp. The disadvantage of aluminum frames is that you have to send them to a shop to stretch new fabric.

Luckily screens don't need new fabric often. The small screen has held up well for about three years, through countless washings, often with chemicals such as bleach. Now it has a haze of ghost images and the gummed tape is breaking up. The tape on that occasion came from a roll which was new at the time but which has since become stuck together because of humidity. So that idea about making my own gummed tape in small amounts as needed now comes into play.

For this job the tape has to stick well to the wood and the screen fabric, I want it to last for a couple of years. The idea is to seal the join between the fabric and the wood so that ink can be cleaned out of the screen thoroughly after use.

The brown paper that I have is rather thin but I tried it anyway. The first try didn't go too well. I applied a single coat of gum arabic with an ordinary soft bristle brush, about a No. 8. Afterwards I realised the gum was thick in places. Went ahead today and cut it into two-inch strips, moistened them with a wad of damp kitchen paper, and stuck them onto the inside of the frame and about 3/4" onto the fabric. The tape stuck in some places and came away in others, which isn't good enough, so I pulled it all off.

I  used the same tape to stick a piece of watercolour paper to plywood and that was fine, it stayed firm.

I made a second set of tape, applying a second thin coat when the first was dry instead of just one coat. I then cut the paper into strips as before, moistened it and applied it to the screen. This appears to have stuck properly. When the tape is fully dry tomorrow I will varnish the whole frame and it should be good for another couple of years.

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*** EDIT, added March 11, 2012: Wooden frames for screen-printing are in fact still being made, see http://mary-adam.blogspot.com/2012/03/pakchoi-screenprint.html

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