NPL Tasks- Foam Cutting

All drawers and specimen trays will be lined with polyethylene Ethafoam® or equivalent foam padding. This is an archival quality plastic foam. The surface of the foam has no openings, so dust and insects cannot accumulate easily inside the sheets, as with other types of foam. The foam sheets are also easily cleaned, usually with soapy water and a rag, or by immersion in soapy water.

Cutting Ethafoam tray linings is a task everyone has to do, at least once. Normally, it is part of the first-day orientation. If liners run out, templates and scalpels are found in the filing cabinet near the printing station, in a drawer labeled Foam Cutting Templates and Tools. It is important that you cut foam only on approved glass surfaces. One table in the main room is glass-covered, and there is a portable glass surface that can be found beside this table against the wall. Regular window glass should never be used, as it can cause injury if it breaks.

 The following procedures follow Brinkman, Paul 1999. Score! A method for constructing improved polyethylene liners for specimen trays. Collection Forum, 13(2):90-92.

One of the unique features of Brinkman's method is creating foam liners that cover the walls as well as the floor of the drawer or tray. To create the wall covering, the foam liner is expanded in area and scored at the fold between the wall and floor of the liner. This creates a sharp angle and maximizes the use of the space in the tray and drawer. It also eliminates the creation of rounded void spaces beneath the liner, where bugs and dust can accumulate. Scoring involves making a cut approximately 1/2 way through the foam, along the length of the fold.

Cutting foam liners

Select a template (1) for the tray size or drawer for which you wish to create a liner. 

Select a piece of foam (3) that is larger than the template on all sides. 

Position the template on the foam. You may be able to minimize wastage by positioning one or two edges of the template at the edges of the foam.

Use a sharp knife. The best knives for cutting foam are X-acto® knives or surgical scalpels. These can be kept very sharp by honing them on the whetstone. The sharper the knife is, the better it cuts the foam. Avoid slicing off body parts whenever possible.

Cut along the edges of the template.

Scoring drawer liners

For drawer liners, center the floor template on the liner and make a scoring cut around the edges of the template. One technique that works reasonably well for maintaining a constant depth of cut is the following. Place the thumb of the hand holding the knife on the edge of the template. As you draw the knife down the edge of the template, you can hold the point of the knife at a constant depth. It is not an exact procedure. The depth of the scoring cut still will vary greatly. If the cut does not score the foam along the entire length, retry scoring the section that is uncut. If the cut goes all the way through for part of the length of the cut, the liner is still usable. If the scoring cut actually removes one of the walls of the liner, that liner should not be used. Recycle the foam and try again. Do not use tape to patch bad scoring cuts.

Placing the liners in trays and drawers

When placing a liner in its container, orient the scored side of the foam down. This will allow the walls of the liner to form 90 angles with the floor of the liner.

Make use of all of the foam

All pieces of foam that are large enough to cut out the smallest liner (the 2"x3" liner templates) should be saved until they can be cut. Therefore, don't panic if you screw up a drawer liner. That foam will still get used. Any foam pieces smaller than that size can be discarded.

Perfect foam

If possible, don't use foam liners with tears or holes in them. Recut the damaged foam for smaller liners and make a fresh liner for the size you are working on.

When templates get ragged, they need to be replaced. If you have clearance to use power tools, you can follow these steps to make fresh templates.

Creating new templates for cutting foam liners

• Measure the dimensions (side-to-side and front-to-back) of the bottom of the drawer or tray to be lined. Measure the height of the walls of the tray or drawer.
• Use inside dimensions of the containers.
• Select a relatively stiff material for a template (masonite works well; plexiglass might also work). This will be used to lay over the foam sheet and cut the outline of the tray/ drawer liner.
• Draw a rectangle on the masonite, using the dimensions of the tray/ drawer floor (bottom). To each of the four sides of the rectangle, append a rectangle extending out the same distance as the height of the tray/ drawer wall. The drawing should now resemble a tray or drawer with its walls flattened out into the same plane as the floor of the tray/ drawer. 
• Carefully, cut out the template shape along the outlined figure. The easiest tool to cut masonite is a power saw. Either a circular saw or table saw will work. If you are not familiar with power tools, have someone who knows how to operate them cut the template for you. DO NOT operate power tools when you are alone. (see Health and Safety; Power tools)
• Make fine adjustments to the template by cutting some sample foam liners using the new template. If the template is a little too large, trim the sides equally until the correct size is obtained. Try not to cut off too much.

Template for scoring drawer foam liners

For scoring the foam liners of drawers, an additional floor template should be cut out. This template is drawn exactly as the first part of the templates above. It is only the outline of the floor of the drawer, so does not require the walls to be added.