Brings up a good question
Best way to make a mold on a Shopbot?
And with what?
Brings up a good question
Best way to make a mold on a Shopbot?
And with what?
I did a presentation on mould making and casting at the 2013 Vectric User Group. It was an example scenario of creating multiple hotel wall plaques using casting instead of carving a bunch (carved the one plaque using the ShopBot, made a mould, then did the castings).
I first carved the plaque in 15 lb green foam (I think it was Duna brand?...not sure). Then made a container (called a flask) to make a silicon mould (a negative of the plaque), then made castings with plaster, Durham's Rock Hard Putty, and a quick setting plastic from Smooth-On (the silicon and spray release was from Smooth-On also).
The plaster casting was too fragile for my liking...the Durham casting had tons of air bubbles (which could be fine for a brick!)...the plastic casting was my favorite - strong, fast to set and easy to apply finish.
I just saved the PPT presentation to a PDF to get the file size down for the forum to accept the upload. Not much in the word descriptions on the slides, I'm afraid...I covered most of the details "live" during my presentation. But, I thought it might give you an idea how easy this is to do.
I wonder if it's more cost effective and time saving to cast things instead of remachine - loses the quality of being made from wood but neat to make it in other forms
The best way is to cut a sand blast mask and sand blast it.
Don Clifton
i wonder if glass etching cream would be strong enough vs sand blasting - less clean up
In this case using concrete etc, the easist way would be to make a clamp together melamine box. Machine your text in reverse and screw it/stick it down to the bottom. Pour in concrete, remove sides to demold. This eliminates the draft issue. There are plenty of mold box examples using melamine on the web. The only thing that you need the CNC for is engraving the text (prismatic letters etc) on your interchangeable plate if there are different names etc. When done put it on the shelf for the next time.
There ya go...Easiest solution if you have access to a blaster setup.
I still would not recommend machining bricks on your good CNC machine...
-B
High Definition 3D Laser Scanning Services - Advanced ShopBot CNC Training and Consultation - Vectric Custom Video Training IBILD.com
I'm with Brady! Funny, I had to fight off the urge to just go out, make a mold with my surname and cast a brick today!