The main thing with plaques is to create a good draft (angle) around the letters using some sort of filler that will be easy to sand and smooth that way the letters impression in the sand mould will come out in good quality without breaking the sand. Its important to get the sand mould correct the first time because plaques are all about good finishing, any casting defects are hard to fix and will be visible to the observer eye and definatly to a metal caster.
Using my new greensand I made the mould for the no. 38. The casting turned out well I just had a bit of grinding of aluminum flash around the plaque. I got carried away with the parting powder so that ruined a bit the flat surface around the number...... but that will be painted anyway ;-).
The second house number 25 was custom made from a-z, the base I made from MDF and also the letters. I used 8mm MDF to make the numbers so the numbers where chunky and needed a good draft around them. The last thing and VERY IMPORTANT, I used clear varnish for both plaques that prevents the sand from sticking to the pattern.
I almost thought the number 25 would have casting defects because I didn't have enough molten metal too fill the feeder on one side. To my surprise it was perfect. After cutting of the the sprue and riser and a bit of flash grinding I only had to give the numbers a good polish on the buffing wheel.
Last thing I drilled holes to mount it on the wall.
I used black gloss external metal paint for both of the number plaques and I polished the no. 25.
Both of them will be mounted on the wall of our houses for many years to come.
