Underglazes can go on leather up to bone dry?f

[Rebekah Ross]

I see no-one has started a thread in this section yet, so I'll make my very first post as a novice.  I'm most interested in sgraffito technique.  I bought some Amaco velvet underglazes, and my plan is to paint that on, do sgraffito, then bisque fire, then add a clear glaze.  I just painted some sample tiles with the underglaze while they were still leather hard, and so far so good.  Is there any reason to have to wait until the tile is bone dry before painting on the underglaze? Like if it will crack and fall off?  Obviously, the sgraffito is much easier on leather hard vs bone dry tiles, particularly for larger areas of scraping off.  

[Michele Hartung]

I sometimes work with bone dry ware and slips using scraffito when I want a crisp, tight line on the work.  I have been putting bluegrass musical instruments onto work and find that I can "draw" the strings in better on bone dry ware.

[pauline purdum]

Rebekah, my experience is that underglazes go on much better "before" bone dry stage.  The bone dry item sucks the moisture from the underglaze too quickly and you end up lifting too much clay onto the brush as you work.  I use underglazes through silkscreens and don't have any luck using them on bone dry ware.  Really underglazes seem to work better for me on "set up" clay and leatherhard.  You can clean up lines and scrafitto onto the item at bone dry stage rather nicely then.  

[Rebekah Ross]

Thanks very much.  I'll paint on the underglaze after the clay is set up, and then wait for all to get drier before I do my sgraffito.

[Patricia]

I find it's better to do it good leather hard. Too wet and it co-mingles with the damp clay and too dry is does not create a nice bond and flakes a bit as it dries.