despite using fresh plaster, clean utensils and water my plaster "goes off " before I can get it on the wall

Hi, you need to keep the mixed plaster in a cool environment as possible. The plaster maybe not wet enough when mixed or you have mixed too much. If you have plaster sat in a mixing tub too long it goes off much quicker. The best thing is to pay a professional to do the work, there is an art to plastering :) Hope this helps Julian

First as you say make sure all water tools and buckets are clean. Always add water to mixing bucket first - then the plaster (NEVER put plaster in first) It should take approx 11 - 11.5 litres of water for a full bag of plaster - Bearing this in mind please note an amature would only get about half a bag on to be able to control. Having said the above it is always best to guage the water to plaster by the feel and consistency. When you mix the plaster make sure you do not "overmix" it - the longer it takes to mix - the quicker the plaster sets. Once it is mixed get it onto a wet brushed spot board - the longer you leave it in the bucket the quicker the setting time. One last thing that is very important - check the date on the side of the bag of plaster - they have use by dates - if the date is up throw it away and get some more. Please also note that the plaster needs to be stored away from moisture and of the ground. Hope this helps Regards Cy Garrett CGarrett Ltd

If all tools are clean, fresh cool water is used and the plaster is well in date then the culprit could be your over mixing the plaster. Stop mixing as soon as Lump free. Andrew