Making USA-Iron Kettlebells
Even after making thousands of kettlebells, to us, there are still few things more satisfying than seeing the formation of freshly cast kettlebells from molten metal at the foundry. It is our privilege to make kettlebells for our customers, we love turning up to work each day and we’d like to share with you some of the main processes which go into making each of USA-Iron’s kettlebells. A big thank you goes to all the men and women and along the way that make it possible.
Below we walk you through the main steps turning iron in the scrap heap into quality kettlebell in your hands.
Designing a Kettlebell
You want your kettlebell to feel right in your hands, even in the most gruelling workouts. You should be able to perform the exercises you want and transition between them seamlessly. The right kettlebell design will enable this and not prevent you from doing so.
Before anything is made a lot of hours, research and testing goes into designing a great kettlebell. Kettlebells come in a number of different shapes and sizes. As kettlebell enthusiasts we know what works and what doesn’t. Putting all of this into reality and making kettlebells we truly love is the fun part for us.
Kettlebells have been used hundreds of years with their unique off centered mass of a solid metal “bell” attached to a handle. Sadly, you will find big variations in the quality of kettlebell design. There have been many designs along the way and many compromises by different manufacturers to reduce their costs or hide inadequacies of their designs. The best (and traditional) kettlebells are solid single piece castings which are not covered or coated in plastic, they will have a handle of the right diameter for your hands, a good sized handle to get 1 or 2 hands onto and a flat base, but not too big that it gets in your way. The length of the horns (the stems of the handle which come out of the bell) of the kettlebell are particularly important – not only does this give you space for your hands but as this changes the relative position of the center of mass from the user, and determines the location of the points of contact during use (e.g. in rack position) therefore determining the ease and level of comfort for the user. Check out our reviews to see what our customers are saying about USA-Iron Kettlebells.
The kettlebell should not be a limitation on the exercises you want to perform. You have to work with your kettlebell so a well-designed kettlebell will work in conjunction with natural movements of your body and facilitate anything you challenge it with.
Every angle of our kettlebells has been carefully considered, the width of each handle and the position of the center of mass. Everything from the shape of the bell and size of the flat section on the front of the bell and recessed logo which won’t catch on your shirt. The surface roughness of the casting should be such that it can be used with minimal or no chalk, providing the balance between grip and feel during use. Don’t settle for anything less.
Cast Iron Kettlebells
USA-Iron Kettlebells are made from 100% recycled cast iron. Iron as a dense material provides the weight in a compact kettlebell. As our kettlebells are single piece castings there are no welds which can lead to weaker areas in the iron.
Making the Casting Pattern
All our kettlebells are made by sand casting in which imprints of 2 halves of the kettlebell are imprinted into “green sand “. Green sand is a fine particle clay bonded sand which can support high weights of the kettlebell and provide the ideal surface texture.
After careful designing, the 2 halves of the pattern know as the cope (upper) and drag (lower) (simply called the “tooling” in the foundry) are precision machined. The surface of the pattern is finished to a low surface roughness and scanned for dimensions.
From a solid block of steel comes the pattern
Metal is poured into the sprue which goes into the runner which slows down and smooths out the flow of molten iron to provide more uniform flow rates to the various parts of the mold cavity. The gate is where the molten metal enters the cavity and designed to feed the casting at a rate consistent with the rate of solidification. The molten metal flows into the cavity and starts to fill it. The molten metal needs to move just fast enough to fill the cavity before it solidified but not too fast where it can become turbulent and disrupt the sand (leading to defect).
The riser which is outside of the main body of the cast part, acts as a reservoir to pull in more metal to the cavity when it cools and contracts so that the kettlebell ends up the right shape, size and weight. This is particularly important for larger casting. There is a lot of variation in the weight of kettlebells on the market with some kettlebells being +/- 3lb! With the correct foresight, experience and continuous development and improvement this can be addressed – do you’re using the weight you expected!
If any of these above points are not fully considered and optimised this will lead to a bad kettlebell which is the wrong weight and with big surface defects.
Each USA-Iron Kettlebell has its very own sand mold which is only used only once so making every kettlebell unique. The sand from the mold is what gives sand cast iron it’s unique texture – the perfect texture for a kettlebell, which is not rough and is not too smooth which becomes slippery during your workout.
The kettlebell is allowed to cooled before being broke out of the sand and vibrated and tossed to remove any remaining sand. The sand is collected and reused for future patterns.
Grinding and MachiningThe kettlebell has now taken shape, it is broken from it’s feed and send on for grinding. We grind down each kettlebell by hand with a fine white stone, which remove the sharp edges but does not cause excessive removal which can lead to flat sections. This removes the casting seams and any high points. The base is also ground or machined flat.
Each kettlebell is individually checked for signs of shrinkage, damage or defects and remaining seams. If it does not pass quality control, it is either sent back for further grinding or it is re-melted into a new kettlebell.
Coatings are applied to cast iron surface of the kettlebell for 2 reasons, i) to provide corrosion protection and ii) to change the texture and grip of the kettlebell in your hand. Often the former is only considered. In many gyms you’ll see beaten up rusty kettlebells which have their own charm, but they should start out with an excellent touch coating. Typical coatings including painting (brush, spray or e-coating) or powder coating. Painting by spray or brush often leads to poor adhesion to the surface. E-coat provides a more uniform coating except however gets slippery when wet (not what you need at the end of a long workout) and can suffer from degradation in UV-degradation meaning the coating can deteriorate after using outside for prolonged periods. The benefits to the manufacturer of e-coating are that it is a cheaper technique and faster for processing large volume of samples as you are not needing to heat and cool your kettlebell however the compromise is the quality of the feeling in ones hands.
Powder coating is an art in of itself. When done correctly and using the right materials, powder coating provides the perfect balance between feeling and grip. In powder coating the surface of the kettlebell is cleaned and prepared for coating. The dry powdered coating is applied in a clean environment, before curing in an oven to 400°F. The kettlebells are cooled at a controlled rate and the coating hardens and performs a protective coating. We use an US-Developed and manufactured ultradurable powder coating under conditions which are optimised for each size of kettlebell to provide optimal adhesion to the metal.
Packaging and delivery
Each kettlebell is checked one final time before loading into custom made extra stiff boxes. Each box is designed specifically for each kettlebell and is reinforced with an additional carboard liner so that your items get to you safely. Each kettlebell is sent out to you in its own box with individual tracking information which is send to you so you can check when your parcel will arrive. 95% of orders are shipped within 24 hours – if you do not see updated within 48 hours – feel free to contact us. We ship UPS 3 day service for free. Unfortunately none of the carriers are guaranteeing their delivery times (from summer 2020) so some items are taking longer. If your items is stuck in transit with no updates for 2 weeks or more, please let us know, we will start the process with UPS and if they can not locate it, we will ship a replacement. Please note UPS requires us to wait 2 weeks before we can start a claim.
Bulk orders to gyms and our partners are packed up onto pallets and individually wrapped with foam.
If you love your kettlebell from us, please share your experience on the reviews. If you have any issues with your order, please send us an email to firstname.lastname@example.org. When you provide feedback and suggestions to us – it is going right to the source.
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