Lehman Equipment produces two similar yet different product lines of equipment for Slip Casting: Lehman's Slip-O-Matic series of Casting Equipment (available in two different pump designs) for the production or professional ceramic studio while the less expensive Studio Star series of Casting Equipment is for the hobbyist or the casual slip caster.
Both the Slip-O-Matic and the Studio Star lines of Lehman Slip Casting Equipment are made from pumps assembled and fiberglass cast in Kentland Indiana. Yep, American Made because when given a choice Dogwood Ceramic Supply always picks products made in America rather than something from everybody's favorite fourth world country.... and Lehman's Casting Equipment (or pouring equipment if you must insist) has been Made in America since 1965.
Lehman introduced the original Model "M" slip pumping tank to the world in 1965. The Model M, with the Slip-O-Matic pump, would become the foundation model for the entire Lehman Slip-O-Matic professional slip casting product line.
The drive assembly (or bearing assembly) of the Slip-O-Matic Centrifugal pump has no bearings or moving seals exposed to the abrasive liquid which improves the durability of the unit versus lesser pumping systems. This unique pump drive assembly is used in several different types of pumping systems in the Lehman Slip-O-Matic product line, including the original pump in the Model M which was a centrifugal design with a housing and impeller mounted to the end of the driver assembly. For the original Model M, as well as many of the current pump designs, a four-leg tower was used to suspend the drive housing and pump head into a large container holding the casting slip.
Because there is no bearing or seal exposed to the slip, the pump can be run either in or out of the liquid with no wear or damage to the system. Being able to run the pump with or without liquid is important for the active studio who may need to drain the storage tank from time to time, such as when switching between types of slip or shutting down the casting department for summer vacation. In addition, since the sealed drive assembly for the pump is suspended in the slip, the rotating drive shaft creates a constant mixing action in the slip tank for improved handling of the slip.
Based upon the sealed drive assembly, there are two different pump designs within the Slip-O-Matic Slip Casting Equipment product lines... the Standard Centrifugal and the Reversible.
Lehman Slip-O-Matic Standard Centrifugal Pump Designs
|Lehman T-100 Casting Table||$1,915.00||$1,530.00|
|Lehman T-60 Casting Table||$1,710.00||$1,370.00|
| The BEST pump for slip casting.
Period. There are no bearings or seals exposed to the slip. Full two-year
warranty on the pump system.
The Slip-O-Matic Centrifugal Pump (otherwise known as the BP24 pump) is shown to the right with the motor attached directly to the drive shaft and the exhaust hose mounted to the pump head for demonstration purposes.
The BP24 is used exclusively in the Lehman T60, T100.
In actual usage the BP24 would be suspended into the slip holding tank (mounted into place onto the side of the 50 gallon slip tank using the mounting plate shown in the photo) and the motor would apply the force to the drive shaft through a simple pulley system.
How good is the BP24 pump? The BP24 in the Lehman T-100 used by Dogwood Ceramic Supply lasted nearly 15 years until it failed... and the part that failed was the impeller in the pump head, not the drive shaft/bearing assembly. Some of our active customers have been able to go 20 years between pump replacements. Yea, the pump is that good.
The Lehman Slip-O-Matic BP24 Centrifugal Pump is found exclusively in the Lehman T-100 and Lehman T-60 professional casting tables.
Lehman Slip-O-Matic Reversible Centrifugal Pump Designs
|Lehman RM30 Casting Tank||$1,730.00||$1,385.00|
|Lehman RD30 Casting Table||$1,760.00||$1,410.00|
|Lehman RD630 Casting Table||$1,835.00||$1,470.00|
|Lehman RD630m Casting Table||$1,935.00||$1,550.00|
The purpose of a reversible casting pump is to pump slip into the mold AND drain the slip from the mold using the casting equipment rather than trying to turn and dump a very large mold. A true back saving device for those who must cast large molds on a regular basis. The standard Lehman Slip-O-Matic drive assembly is combined with a simple reversible pump head...
.... using a rotor that is inserted into a stator... also known as a worm or screw gear turning in a stationary rubber channel.... the aluminum housing and insert are to mount the pump head to the bottom of the slip tank and hold the rubber channel firmly in place.
We would be remiss if we didn't mention the fact that reversible pump heads always have issues with either efficiency or durability and the Lehman reversible pump head is no exception. Remember, slip is abrasive, basically nothing more than liquefied clay particles including a lot of fine silica (sand). Over time the slip particles will wear down just about any surface, even the stainless steel parts in the T-100 will wear over time. That said, the stainless steel parts in the T-100 might last a few years or even a few decades while the rubber channel (stator) in Lehman's reversible pump will not be so lucky. Depending upon the type of slip used in the casting process (stoneware versus earthenware versus porcelain) the rubber stator may last only a few 1000 gallons of slip casting. Use the reversing feature for every mold and that casting volume will be cut in half simply because the pump has been driven in two directions thus handling twice the total volume of slip. Even the stainless steel worm gear (rotor) will wear over time and need to be replaced... specifically because the rotor must fit tightly into the rubber channel to provide the greatest degree of pumping efficiency and the slip will polish (and shrink) the stainless steel rotor quite nicely. It is an extremely beautiful, mirror like surface if enough slip is cast against the surface of the stainless steel rotor.
Sounds like we don't like the reversible pump. Not hardly. It is a fantastic product for those who truly need the ability to pump slip into and drain large molds. The reversing feature has save many casters from back injuries or hernias from trying to dump large molds filled with dozens upon dozens of gallons of heavy slip. Just consider the replacement cost of the rubber stator and stainless steel rotor when making a purchasing decision of any of the Reversible Pumps versus the more durable Standard Pumps.
The Lehman Slip-O-Matic Reversible Pump is found exclusively on the Lehman RD 30, the RD 630 and matching RD 630M as well as the classic RM 30. The RD 30 and RD 630 are the two most popular units of the series.
The entire Lehman Studio Star line of casting machines (or ceramic pouring equipment and tables for those of you so inclined) use a centrifugal pump where the drive shaft of the pump is supported by a bearing at the point where the drive shaft enters the pump head. Some of these pumps are externally mounted while others are suspended in the slip. Regardless of the mounting location, a packing and seal system is required to operate the pump head and to protect the drive shaft bearings from the abrasive slip. In industry terms this design of pump is known as an outboard bearing design, in Lehman's vernacular the pump is the called the Studio Star pump and is available as an external pump (EX) or submersible pump (SP).
Lehman Studio Star Casting Equipment
|Lehman CT6-L Drain Table||$665.00||$600.00|
|Lehman PP30 Mobile Caster||$835.00||$750.00|
|Lehman CT425 Mobile Casting Machine||$1,225.00||$1,080.00|
|(not shown)||Lehman CT630 Casting Machine||$1,430.00||$1,210.00|
|(not shown)||Lehman CT630M Mobile Casting Machine||$1,530.00||$1,300.00|
|(not shown)||Lehman CT850 Casting Machine||$1,785.00||$1,500.00|
The outboard (or external) bearing design is every economical to build and yields a lower cost casting pump and table. Over the years Lehman has made significant improvements in the design of the outboard bearing pumps. But in spite of these improvements, all slips, even porcelain slips, will eventually destroy the packing and/or seal protecting the bearings because of the microscopically small abrasive particles in the slip. Bottom line, the outboard bearing pump design is fine for the casual slip caster, but most moderate volume slip casters should strongly consider units with the much more reliable and durable Slip-O-Matic pump used in the professional casting tables such as the Lehman T60 or T100.
|One very important note regarding outboard bearing pumps... because of the pump design, when the packing and/or seal finally breaks, the pump will leak slip. It the pump is an external pump (such as the EX-4 pump system shown to the right) the size of the leak will be equal to the volume of slip previously in the tank.|
Despite the durability issues with the outboard bearing pump designs, the Studio Star casting tables remain popular in the hobby markets where selling price of the product is the only concern (and as a side note, the outboard bearing pump design is exclusively used by Lehman's few remaining competitors... especially the casting equipment imported from that 4th world country) and for situations where breaking down and storing the equipment is more important than the durability of the equipment.
The Lehman Studio Star SP4 Submersible Pump is used with the Power Potter 30 portable casting system, the Lehman EX4 External Pump is used on the CT425M and all larger CT variants.
Lehman manufactures a wide selection of supporting equipment, such as slip mixing and reclaimers up to 600 gallon in size. Many of these large holding tanks and pumps are custom designed and built for overhead or underground delivery of slip to the casting department.
With a large and complicated product line, the list of Replacement Parts is equally large and complicated. Dogwood Ceramic Supply lists the most common parts, many of which we have in stock for immediate delivery. Of course the full selection of parts are available with advance order.
Why use the phrase Slip Casting Equipment versus Pouring Equipment?
Casting is the manufacturing process in which complex forms are produced in large quantities through the use of hollow molds into which a liquid material is poured, allowed to solidify and then released. Obviously many industries cast materials and since ceramic slip (liquefied clay) is used in the process for our industry, the proper term to describe the entire process is "Slip Casting" or "Ceramic Slip Casting" when referring to the process of casting earthenware (ceramic) slip. That said, the slip is "poured" into the molds and the term "ceramic pouring equipment" or "ceramic pouring table" is used by many in our industry. However, the terms "pouring equipment" or "pouring table" do not properly describe the equipment items as some of the product items are indeed a table (such as a drain table) and others are much more complex with the drain table plus pump system attached to a storage tank. Adding the descriptive adjective "ceramics" to the "pouring table", as in "ceramic pouring table" does little to clarify the identification issue because it does not assist with the basic description of the equipment itself. Complicating this entire issue of Slip Casting versus Ceramic Slip Casting is the fact that while low fire earthenware slips (ceramic slips) are most often used with the Lehman Casting Equipment sold by Dogwood Ceramic Supply other slips, such as terra cotta, porcelain or stoneware slips, may also be used. Bottom line, everything is confusing and not exactly technically correct, thus we, following in the traditions of Lehman since 1965, use the generic "Slip Casting Equipment" phrase to describe the Lehman Manufacturing equipment we sell rather than the more specific terms "Ceramic Slip Casting Equipment" OR "Ceramic Pouring Equipment" as the generic phrase has a broader meaning and more accurately describes the products and variety of customers purchasing the equipment.
website last updated: October 2015
Dogwood Ceramic Supply
12590 Dedeaux Road
Gulfport Mississippi, 39503
Telephone (228) 831-4848 Fax (228) 831-3111
Showroom Business Hours:
Monday, Tuesday, Friday and Saturday 10AM to 5PM
Thursday 1PM to 6PM