Metal retort stands and clamps are used in many science laboratories to hold equipment and labware in place for a variety of experiment and apparatus set-ups. It's important to choose the best retort stand, rods, and clamps for your needs, and to ensure that they will work together as needed.
Some important features to consider are size, material, chemical resistance, and durability. Use this guide to help identify the best retort stands and accessories for your laboratory’s needs.
Metal retort stands (or bases) come in a variety of sizes, shapes, materials, and features. As far as size goes, you want to be sure the base can easily fit in the space you have, while providing enough leverage and stability for your specific set up.
While retort stands may often be referred to generically as metal bases, it's important to know a bit more about the specific metal used as well as the experimental conditions that the base will need to withstand.
Steel – Steel is known for its long-term strength and durability. Steel bases are heavy and therefore very stable. They're great for high impact, heavy load, and high stress/strain scenarios but not the best choice for use at low temperatures.
Steel is not very resistant to most chemicals, so it's important to ensure that a steel base is finished with a chemical resistant coating. The environmental impact of steel is relatively low; steel is recyclable and produces low emissions during production.
Pressed Steel – Pressed steel offers the same benefits and characteristics as above, but is much thinner and therefore light weight, which is great for maneuverability but they provide less stability with heavy loads.
Cast Iron – Cast iron bases provide greater physical and mechanical durability compared to steel varieties, including during use in extreme temperatures. Cast iron bases also have better chemical corrosion resistance, but it may still be necessary to look for a chemical resistant top coat depending on expected use.
While the most common shape for retort bases is rectangular with a hole drilled in the middle of a short side to accommodate a rod, there are a few other options including triangular, A-shaped, H-shaped, and T-shaped.
Some retort bases may also offer holes that are present in the center of the base. The best option for you is one that accommodates your space and set up best. Mapping out your space is recommended.
There are some unique retort base features that may provide additional strength, stability and convenience.
For example, some bases feature rubber bottoms to resist movement or slippage. Leveling screws are a great feature when additional precision and stability are required. If you will be storing multiple bases, their ability to stack or nest may be important considerations as well.
Like retort bases, the metal rods that are used in conjunction with them come in a variety of materials:
Aluminum – Aluminum is a light weight and naturally corrosion resistant metal. Aluminum is non-magnetic and good for use at cold temperatures. It's important to consider the strong heat and electric conducting characteristics of aluminum. Recycling aluminum is relatively easy.
Steel - Steel is known for its long term strength and durability. A steel rod is best suited for high impact, stress or stain conditions, It is not well suited for use at cold temperatures. The environmental impact of steel is relatively low; steel is recyclable and produces low emissions during production.
Stainless Steel – Stainless steel rods are extremely durable, even at low temperatures. They're also corrosion resistant and non-magnetic. Relative to other metal rods, stainless steel is a weak conductor of electricity.
Metals rods also come in a variety of lengths, diameters, and thread sizes. For your convenience ALL Eisco retort stands and metal rods feature a 10 x 1.5mm thread size and therefore are all compatible and can be used interchangeably as your lab’s needs change.
Appropriate rod lengths and diameters will depend on your specific use. Again, we recommend mapping out your expected laboratory set up before purchasing any lab equipment.
There are generally two main types of clamps; those used to hold rods/bars together and others meant to hold laboratory apparatus like burettes, test tubes, and flasks.
Regardless of what type of clamps you need, it's important to consider the strength of the material the clamp is made from as well as corrosion and rust resistance depending on your intended use.
Clamps for Rods/Bars
Clamps that hold rods and bars together are called boss heads. When choosing a boss head, you will want to take into consideration what size rods/bars can be accepted.
Boss heads are adjustable and the adjusting screws are typically made of metal or plastic. Plastic thumb screws are fine if your set up will not need to be adjusted frequently, but if you will be regularly moving and adjusting your boss heads you will appreciate the longevity and strength of metal thumb screws.
There are a few different types of boss heads and the most important difference is what configuration they can hold your laboratory equipment in.
Orthogonal - Most boss heads will hold 2 rods perpendicular, or 90° to one another. A vast majority of boss heads are orthogonal and are either square shaped or linear
Universal swivel – These boss heads adjust to allow any angle between 2 attachment points. The dual swivels allows for 360° adjustments
Clamps for Burettes, Test Tubes, and other Apparatus
The other main category of clamps is used to hold common laboratory apparatus, typically while attached to a rod or bar via a boss head.
It's important to note if a clamp includes an integrated boss head, or if you are required to use a boss head in addition to the clamp. Be aware of what diameter you need the boss head to accommodate as well as what diameter will be required for the other end that will hold the lab apparatus.
Burette clamp – Burette clamps may be single sided or dual sided. The clamp typically holds the burette in place via spring loaded jaw action
Vinyl coated clamps – Vinyl coated clamps offer an extremely secure, slip free grip of your lab apparatus.
Cork lined clamps – Cork lined clamps do offer a tight enough grip, but the main reason to choose a cork lined clamp is if high temperatures and/or open flame will be a part of your experiment.