Hi everybody
I have a big problem about blackening my cold cast bronze objects
There are a few spotty parts on my cast after laying down the cast in black patina liquid you can see the picture below
http://www.dosyaupload.com/4Qnx
If you can help me about this I would be very happy
Am I doing something wrong ?
That link is either click bait or being misread by my browser. Either way, an older thread that could still use some info.
Keep in mind I do not use Smooth On products, and the following is based on my own experience and others ive seen first hand. I cant speak for the lucky ones that have had success with the prior mentioned methods and materials.
With metal powders the mesh number, in this case 200 and 400, just isnt the best for the task. I may be wrong but I assume the reason 425 mesh metal powders are the most commonly sold by retailers is due to its mesh size alone. The finer the powder (mesh) the more airborne it becomes and the need for expensive respirator systems is needed. My assumption is 425 mesh seems to be less likely to cause "lets sue them" circumstances.
Ive tried numerous times using various metal powders in the 325 to 425 mesh, cold casting, brushing into the mould, mixing into A or B or both.... Ive had no real success with various materials. The only real success I have seen first hand with 425 mesh powders was when the casting material was clear polyester resin tinted black. Basically surfboard resin. Then steel wooled for the metallic sheen to shine through. The issue with casting resins is the inherent soft surface combined with the cure process. To get the sheen you need to scratch the surface. For the material to cure it pushes the metal away...
I use MPK90 in black. Its a high impact and fast curing plastic. But its also expensive. In the end I know what works by trial and error. Why try and save a percentage in materials when you lose that in trial and error with lower cost materials? I also relegated 425 mesh metal powders to castings that would need to have a magnet attached. For metal powders I use industrial grade in the 10,000+ mesh. When you get into what the term "mesh" means, thats an incredibly fine number. So fine in fact when my lungs were pumped a few years ago from a fluid build up there looked to be a T1000 lurking in the fluid. Once that metal gets into your lungs, it only comes out in death or happenstance such as having your lungs pumped. For an idea of what that metal powder handles like, its like running a felt tip marker over paper, yet its powder. The outcome is no need for steel wool and perfect castings every time. I have tried to explain the process to a couple people but they had no success. Again I use a tried and true material, they used another brand. I wont get into casting in color as I cant for the life of me type that out. Ive even done in in front of an experienced mould/cast person and they were dumbfounded.
Some examples of castings:
Strait from the mould knives with the original, cast in color:
Strait from the mould badges and brass knuckles:
Transformers badges, completed but again, no steel wool, just a black wash.