There are some folks who actually make waxed rocks.
However, I am referring to wax used for lost wax casting.
There are many kinds or formulas of wax. There is one group of waxes that has be engineered especially for making master models for use in casting of metals. Casting wax.
In that group there is a wide range of characteristics for color, hardness, formability, strength, machinability, hand carving, injection molding. flexibility, melt point… The list is quite long.
The one thing they all must have is the ability to melt and burn out very cleanly in the burn-out process. While not damaging the internal mold surface.
The lost wax casting process is ancient technology. Know and used for over six thousand years of human history. Certainly not starting with the wax formulas in use today. But there has been a great amount of time to create casting wax with superior characteristics.
Materials other than wax can be used to create the casting models. I have experimented with 3D printing resins with some success.
Anything that will burnout and literally vaporize from the heat of the kiln can be used. I know insects and plant material have been used. It must not leave an ash residue or damage the mold. Clearing actions can be taken in some processes if the mold and sprue is large enough to allow blowing out the debris.
Wax is used in a large scale industrial casting process where a ceramic shell is formed over a (usually hollow) wax master. My process is for much smaller detail casting using a plaster-like investment mold-process used by dentist and jewelry makers.
I think wax really excels (rocks) as casting master material because of several reasons.
First because it burns out so cleanly and investment (the mold material) has been specifically designed to handle the wax.
Second is many forms of the wax are extremely easy to machine and carve with tools. I love both CNC machine carving and hand tool carving. What is shaped in wax is exactly what is produced in the metal casting.
Wax can be sanded and polished for an excellent surface finish before casting. The casting is only as good as the finish on the model
Wax can also be liquid injection molded into rubber molds for making many exact duplicates. More on that in a future post.
The most important feature of wax carving is that it can be additive as well as subtractive. Wax melting points can be engineered. Wax can be built-up as well as carved away. Cool melt wax can be applied to the surface of higher melt wax with a heated tool to add detail or make repairs.
The various creative methods available with totally workable material such as wax makes it the near-perfect material for casting. I love working and creating with casting wax.
All the carving and forming work is lost in the casting process. But as mentioned, there are ways to duplicate a design using rubber molds and wax injection. The wax is always lost, but the design CAN be duplicated if desired.
Sand casting, flexible rubber molds and other processes for casting have their place. They generally preserve the master model. Meaning it is not destroyed in the process. A lot of advantage in not loosing the model.
The prime advantage to lost wax investment casting is the extremely fine detail like filagree that can be captured and presented in the produced casting. Perfect for making jewelry, (teeth), and other super fine detailed parts.
It should be obvious, I love working with casting wax.
It is only one step in a creative process of casting metal. It is the step where, starting with a block of wax, all the shape or form changes from design to tangible model of the intended casting.
Dozens of videos exist on the process. So no details necessary here. Search “lost wax casting”. More info than I can post here.
A Blinding Conclusion
I believe I have invested in the proper level of LASER engraver for my needs and expectations. Both in price and performance. I am pleased with the performance of a 5 watt power level. The trade off is slower speed but I have plenty of time for that.
The LASER is a two and one half dimensional material remover. It is not capable of three dimensional material removal without (I imagine) very sophisticated power level modulation or a fully proportional Z axis movement.
If such control were implemented the results would be a fully charred and burned surface. The LASER is a burning tool.
The depth achievable of a three dimensional burn would also be very limited as the cutting tool is a tapered highly focused pin point of light. Z axis height modulation would be a must.
Material like wood and bamboo have grain fiber that burns away at different rates. The bottom of a wide area that is flat engraved is seldom smooth. The choice of material is critical for clean cutting.
Such burn variation can be (and is) a feature of LASER engraving.
The low powered LASER engraver is a wonderful addition to my hobby-class work. It does highly detailed 2.5D engraving in combustable materials. Smoke, soot, ash, odor are major by-products of a LASER. Not similar to the fine and course swarf (chips) produced from using sharp edge tool rotary machining operations in wood and metal. There are some fumes from cutting oils which vaporize in metal machining. Wood and metal swarf mostly falls to the floor. Smoke doesn’t.
My three dimensional CNC machines and Vectric Aspire software are not being replacedby the LASER.
Three dimensional (wax) machining for jewelry is best done on a 3 to 5 axis machine tool. I tested cutting wax with the 5 watt LASER. It made me laugh. It sucked in the 5 watts of light and begged for more.
A commercial LASER 40 watts and higher is certainly a different story but the same limitations. The LASER does its particular 2.5D thing and is not a replacement for any true 3D machining process.
I am so happy I long ago convinced myself that, although the process is very interesting, I have absolutely have no practical use or need for a high power and very high cost LASER tool.
When low powered RTR (ready to run) diode LASER machines became available for under $200, I felt it was a good time to go play with a new toy. They are not a child’s toy, but the cost puts them in range of the price and safety conscious hobbyist. The difference between men and boys thing…
Doing a little thinking through writing. I have ordered a LASER engraving machine. Everyone should know what LASER engraving is. Unless you been under a rock under the sea for the last 25 years or so. I should not need to explain the concept in too much detail.
It is a CNC controlled machine that uses a LASER (light) beam to literally burn away the surface of material upon which it has been focused. Following a computer-numerically-controlled (CNC) two-dimensional path, it engraves or cuts through the material. There are limitations on what materials are suitable.
This is NOT a kid’s toy. It is NOT a toy at all. Little Jonny does not need a LASER powerful enough to burn. Even a very low power LASER pointer does not belong in a toy category. A LASER engraver/cutter is literally playing with fire. It is a serious TOOL
That said, I have a LASER machine on the way and intend to play with it in a serious and responsible way. That is a privilege earned from surviving to this phase of my life. I have become responsible for my actions and know how to properly use the powerful tools in my workshop.
The “What Next” is discovering how I will apply this tool with future projects.
An engraver makes lines and marks on the surface of material. It’s a tool for decoration. What I will be doing is adding detail to otherwise plane looking surfaces. It’s a graphic tool rather than a construction tool.
The LASER machine will also CUT THROUGH thin material. That process is a part of construction. Cutting shapes away as with cutting with a knife or shears. Super powerful LASER and Plasma cutters do most of the metal cutting in industrial workshops.
My tool will do the same cutting in thin (several millimeter) combustible organic materials such as wood, cork, some plastics.
I have no definite applications in mind. The plain fact is I bought the machine because the price made it attractive. The plan is to see what I can do at the five-watt (output) power level. With a $200 entry fee I decided I didn’t need a fully qualified plan-of-use.
If I find serious use/application for a more powerful machine, this first investment gets me playing and learning the software and the skills. It is an educational investment.
New tool is about to be added to my KautzCraft workshop. I have ordered a small 4.5-watt (output) LASER engraver. Work area is only 160mm x 150mm. So, it is quite small. So is the purchase cost. Less than $200.
The low cost was the fatal attraction. I have considered LASER engravers for years. However, the cost (many $K) did not justify the return on investment. There are just not enough items in my workshop needing LASER engraving for the previous high investment required.
The machine I ordered is not for everyone. It has no interlocking safety features to keep the careless operator safe. Knowing the risks are important. Running the engraver is not group event. Single user in a closed access area is my plan.
Here is a picture of what I have ordered. Yeah, it’s Chinese but most every high-tec CNC tool is these days. Includes all my 3D printers.
At this point I am most interested in decorative engraving rather than using the LASER to cut through material. This little LASER will do cuts for sure. Just not as thick or as fast as a LASER with higher power (and higher cost).
If I discover a real need (or demand) to do heavy cutting, a higher power LASER can then be added. What I learn on this small LASER using the software system common to any size machine will be time well spent.
More information to follow this announcement once the smoke starts rising. Yep. LASERS make a LOT of smoke from burning the target material. A fact barely mentioned by most machine vendors.
This machine never left China. The order was cancled. I now have a LASER engraver with more area and a bit more power. Articles to follow and check into KautzCraft Laser for more info.
I have always use an air/propane turbo torch to melt silver, brass, bronze for my investment castings. The torch works fine for small amounts in the 20–30-gram range. I have melted as high as 70 grams, but the process gets much more difficult.
The open puddle of liquid metal loses heat rapidly. I must follow the melt (in a crucible) from my heating area to the mold flask with the torch constantly “playing” on the melt puddle. It’s a two-hand operation with the torch in my left hand and the crucible (clamped in holding-tongs) in my right hand.
The pour is single handed into the top of the mold flask. A growing issue is my (PN) Peripheral Neuropathy sometimes gives me a bit of hand quiver if I do not consciously try to relax my right arm.
I like to do larger pours with larger projects. A few days ago I cast a 60 gram melt of silver for a small bell. Before that I did a large ~200g melt of brass for a solid brass gnome figure. Both jobs pushed my personal comfort limits for torch melting and pouring.
Casting 1700-2000 degree metal is nothing that one should feel difficult or uncomfortable performing.
I must be completely in control of the casting operation. The transfer process from the melt to the pour stage with heavier and larger volumes has begun to exceed my comfort zone.
I considered the melting furnace since day one. However, the volume of the metal for my jewelry work has typically been small. Nothing that a torch could not handle comfortably. Time and old age alter my comfort zones. Now is the time to stop considering and act. Ha!
RioGrande, my jewelry tool and materials supplier, offers several Italian made models of melting furnaces. However, the 1kg (gold melt) capacity furnace with a purchase cost of over $650 has always been a deterrent. The larger sizes are up to $950. A cost not justified for my needs.
Amazon has a huge selection of similar Chinese made melting furnaces. Some under $300. I choose a 1kg capacity furnace (shown) with a little higher wattage than others. I leave my selection reasons there as I am not making recommendations on brands and models. Reasonable cost was the major decision factor.
A closed chamber electric melting furnace with digital temperature control provides a far improved melt environment. Metal is not overheated and far fewer contaminates are introduced to the melt. The crucible is graphite which adsorbs oxygen.
Pour timing is less critical as the metal remains liquid a bit longer between the melt and the actual pour. I can use two hands (if needed) between the melt furnace and the mold flask pour point.
I believe small single item castings will continue to be more practical using the torch melt system. It is quicker than heating a 1kg (about 500g for silver) capacity electric furnace for a 25-gram casting. A load that small is almost lost within the crucible.
I will understand the process method balance once I have a chance to use my new melt furnace. One thing I know for certain. I will be far more comfortable with larger loads with the furnace. Perhaps small loads will be no problem at all… just longer to melt than the torch.