I don't get it- you want to expose the remaining emulsion as long as possible afterwards, and it should be exposed enough to be water resistant before you put the water on it. I have been in a tight spot before experimenting with a new emulsion brand and exposure times, and underexposed it (i.e. the blacked-out area washed out in like 20 seconds), so I quickly turned off the water (in fear of washing out the exposed part too), then dried it off and put it back under the halogen lamp to expose the remaining emulsion, just to make sure it was water resistant.
On making you're own frames, just take four pieces of a softwood with approx 1"x1" cross section, obv saw them to size to make a frame, set them down on a flat surface in the frame shape, and staple every joint with carpenters staples and a staple gun. For a lot of my frames, that's it. Knock the staples in with a hammer. You can use a drill, long screws, and/or wood adhesive but most of the time it's unnecessary. Then cut a piece of polyester mesh just a couple of inches larger on each side than your new frame, lay it over the frame, then use your staple gun to fix it to the frame. I do this by putting one staple right in the middle of your longest side of the frame (stapling down the mesh), then pulling it super taut (careful not to tear yr mesh though) on the directly opposite side, and putting a staple there. Continue this method, moving first half an inch to the right of your original staple, then doing the opposite side (holding taut), then half an inch left of the first staple, then the opposite, etc, until the entirety of both sides are lined with staples. Then rotate frame 90 degrees and repeat the process o the shorter edge of your frame, starting in the middle.
When it's done, degrease your screen with bleach solution.
It's probably a good idea to sand/smoothen the internal edges and surfaces of your frame before applying mesh to make sure it doesn't snag.
As for knowing the mesh size, either buy it from a proper silk screen suppliers where they'll state it, and recommend the best for a particular application (finer meshes, i.e. higher mesh count ~70T + are best for printing on paper/ less absorbant surfaces, larger meshes, e,g. 43T best for fabric), where it'll be quite expensive, or just chance it with whatever suitable looking polyester material they have at your local market stall for much much cheaper. For DIY (non commercial) uses I doubt it's worth the difference, or you'd notice a hell of a lot of difference between mesh counts as there are other factors like squegee technique that dominate probably.
If you have any more questions feel free to ask. I'll upload a photo of my DIY super silk screening table later, under which I have screwed my halogen lamp.
Last edited by stateJon (08-02-2010 20:32:53)