TypicalGirl Posted August 12, 2011 Report Share Posted August 12, 2011 Next question... I'm working on a series of mugs with sprigged designs on them. One of my mentors wants me to reproduce them in multiples. I'm not sure how to go about creating a sprig mold of the design (once the mugs are fired) and thought someone might have some ideas for me. Thanks! Link to comment Share on other sites More sharing options...
Lucille Oka Posted August 12, 2011 Report Share Posted August 12, 2011 It can be done but the final size of the sprigging will be smaller. There is a negative-positive-negative-positive process to reach clay reproduction. But why not start again and re-sculpt the sprigging and make a plaster mold. You can even make it with the curve. It takes some work and you must be mindful of undercuts but it is simpler. Link to comment Share on other sites More sharing options...
TypicalGirl Posted August 12, 2011 Author Report Share Posted August 12, 2011 Thank you Lucille- you bring up a point I hadn't considered. Shrinkage never occurred to me (duh). You're right...it might be simpler to re-do them specifically for molds. Link to comment Share on other sites More sharing options...
BeckyH Posted August 13, 2011 Report Share Posted August 13, 2011 Yep, to make multiples, a mold is a good way to go. If you want to keep the current size, create an original larger than the finished size you want, then make a plaster mold. You could either cast the whole mug or just cast the design so you end up with a curved section with the design on it. Then you would make a slab and press it into the mold, remove it when it's leather hard and attach it to the mug. Trim the flash from between the parts of the design and you're done. Slip casting stuff with lots of relief can be tricky, as it will tend to crack whilst drying. The mug you show is nifty! Link to comment Share on other sites More sharing options...
Dinah Posted August 16, 2011 Report Share Posted August 16, 2011 Use room temperature vulcanizing product such as Optosil (Bayer Dental) which I bought from my dentist in the UK back in the late 80s which, btw, is still workable because it's a two step product which needs kneading to blend catalyst before applying it to the surface of your bisqued pot. I've used it on tied knots for decorative work, for instance, dried grasses too; and when I was doing ceramic restoration work it was invaluable in duplicating a particular bit of raised work or a decorative lug which had been damaged. There are current products which will do the same. Plaster sprigging is useful, yes, and affordable and doable by most potters, but pretty crude compared to this type of product and its new generation cousins. It will make reproducing the sprig super easy and with a bit of cornflour dusting extremely simple to create multiples. Because of its flexible mould body, extricating clay sprig is easy-peasey. Cured molds are long-lasting. I've got a cache of them for various decorative touches. Details are exacting as you would expect from a dental grade mould product. Another method which is cheaper would be to use layers of latex brushed on raised relief, let each one dry thoroughly, after about 4 or 5 mix latex with sawdust and pat it over the original area let dry thoroughly then remove and let it cure a couple of days. Probably wouldn't hurt to initially brush on a bit of mold release soap before the initial brushing of latex. I cite this last method, because when I was doing restoration work a plaster mould would have been impossible - and unprofessional -- to effect on a valuable ceramic item. Link to comment Share on other sites More sharing options...
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