A foam insert will keep your important items safe from jiggling about in your case and protect them in transit. You can have a foam cut-out designed and constructed professionally for anything that needs to be stable in your case when transporting it from A to B. Typical items that are set into foam inserts to keep them stable include:
- Tools: wrenches, screwdrivers, spanners, cutters, etc.
- Guns and ammunition
- Scientific instruments and materials
- Sporting goods
Polyethylene (or closed-cell) foam is a rigid material that holds goods securely in transit. This is the most commonly-used foam for packaging purposes, and it is capable of keeping heavier items, such as your drill or firearm, held tightly in place.
Polyurethane foam is a softer foam, and consequently it is more difficult to cut for the hobbyist. This type of foam works well for cushioning more delicate materials from the shock of impact or vibration.
Polypropylene foam is resistant to a wide range of environmental stimuli, including many chemicals and the application of heat; it typically has a melting point of over 150 degrees Celsius.
Several different foam sheets, and a plastic backing sheet, may be laid down in the case to provide optimum stability or workability.
Cutting with hand tools
If you do not need very exacting tolerances for your foam inserts, and have a steady hand, you can make a DIY foam cut-out with a sharp utility knife or a hot-wire foam cutter. This may take some practice to get right though; be sure to have a few 'sacrificial' scraps of foam available to test out the procedure beforehand.
A laser is commonly used to cut out the pattern required for the items to fit snugly into the foam case inserts. Laser cutting and engraving is, like 3D printing, a process that was formerly the province of industry but now is becoming increasingly available to the hobbyist. It is possible for the dedicated amateur to rig up their own laser foam-cutting operation at home, if they do their research. Software such as AutoCAD is used to delineate precisely the places where the laser should 'cut'. This is a complicated and involved process and not for everyone.
It may be possible to cut thinner layers of foam consistently with an easy-to-use home device such as the Cricut, and layer them on top of each other. A type of foam known as Kaizen foam (a type of polyethylene foam) comes in 1/8-inch-thick layers, which can be peeled apart and re-adhered to each other to create a foam cutout of arbitrary thickness. If you need a very specific thickness of foam that goes beyond the granularity of 1/8 of an inch, you will need to consult an industry professional to discuss your requirements.