Joint Compound Problems

So as you all know I have been using a quick set Joint Compound to fill the hirst arts molds I bought. While my initial results were positive, it took the detail well and seemed to setup nicely, the more I work with it the more problems I am running in to.

The first problem is finding the right mix. I don't think there is one really. If I go with a dryer mix (more powder) the bricks turn very brittle after drying. If I go with a wetter mix the bricks don't seem to dry properly or are simply taking a REALLY long time to dry. If the dry time is just extra long I have no confidence that the bricks won't turn brittle. I had hope that any brittleness would be easily compensated for by a good layer of paint for protection. However the bricks are so brittle that they will sometimes break when I am glueing them together or glue just won't hold.

The next problem is the set time. I mentioned yesterday that I let a set of bricks dry overnight in the mold and by doing so I was able to pop out the face brick with the thin ledge without a problem. Last night I tried letting the bricks dry for over an hour before popping them out. They were still too wet to prevent the face brick from breaking. I can't wait over an hour set time for each mold or I will never be able to complete a project.

Since I am running into so many problems with the joint compound I plan to change my method and go for a new casting material. Right now I am considering the dental plaster. This seems to be the recomended material for the best casts according to the hirst site. I am going to look around at some hobby stores to see if I can buy it locally. If not I will just have to buy it online.

A couple other thoughts I have had is that I think I am going to move this production out to my shop. It is rather cold out there right now but I need the extra space for the production of the blocks plus I can be a little more messy out there without too much of a problem. The second thing is I want to try and get some heat lamps setup to allow for a faster dry time of the blocks. Maybe set them up in my paint booth. Finally I am going to build a vibration table. I have found some designs online that have given me some thoughts on how I want to build it. I might try and get to that this weekend. So stay tuned for a how to...