Support for Large, Lightweight, Flat Objects

The system utilizes standard aluminum rolled or extruded channels which are made for window and door screens and are assembled into frames using push-in aluminum or plastic corner devices. A stable and low-stretch fabric is rolled into the channel in lieu of standard insect screening. When supported horizontally, this “screen” structure makes a suitable textile storage platform (Fig. 1).




Figure 1. Example of storage trays in use.

• Channel corners, molded plastic or stamped aluminum
• Flat work table
• Non-woven lining fabric (optional)
• Scissors
• Screen channel
• Screen printing or filter fabric, polyester monofilament construction
• Screen Roller
• Screwdriver, 1/4in flat blade
• Short-hooked linoleum knife or utility knife.
• Spline, solid, tubular or spline, fluted vinyl cord
  
  
  

1. Have the frames cut by the manufacturer or distributor in order to get clean, accurately mitered corners. A powered miter saw with a fine-toothed aluminum-cutting blade and wax lubricant can also be used, or saws that are used for making frames.
2. Clean the sections with a general purpose detergent to remove cutting oil or wax. Rinse well.
3. Assemble the frames with the push-in corners (Fig. 2).
   
   
   Figure 2. Push-in corner.
   
   
4. Make a jig with corner blocks to keep the frame square during rolling.
5. Lay the screen printing fabric over the frame. The fabric should be at least the size of the outside of the frame, although it is rolled into channels on the inside edge of the frame.
6. Begin rolling the spline into the channel at a corner, catching a layer of the fabric in the process. Use a standard or custom screen roller that fits the spline channel of the frame. The fabric must be stretched ahead of the roller, kept in parallel alignment to the channel and the spline must be guided and rolled in at the same time. When rolling the opposite side, the fabric must also be stretched laterally to insure a very taut platform. The technique requires physical strength and practice.
7. Roll in the fabric all around, either continuously if possible, or by doing opposing sides.
8. Turn the corner with the spline or cut it at each corner.
9. Adjust any loose areas by pulling up on the loose fabric edge to pop the spline out and re-roll it. Loose “bubbles” can be felt when running your hand around the fabric just inside the frame line (Fig.3).
   
   
   Figure 3. Plan view of construction of storage tray.
   
   
10. After the tension is adjusted properly and evenly, trim the excess fabric. Cut against the outer wall of the spline channel, just above the spline while stretching and increasing the tension of the loose edge away from the direction of the cut. Keep the blade sharp so that the fabric will cut cleanly and to avoid frayed threads coming out of the channel. Sometimes the channel vendor will agree to roll in your fabric, but they may be concerned about risking the material. Make sure that they roll it tightly so that the frame is slightly “hourglass-shaped”.
    
    
    

Screen channel comes in a variety of sizes from which a selection can be made, based on the size of the platform to be built and the weight of the textiles to be stored on it (Fig.4).

Figure 4. left, Extruded channel section. right, Rolled channel section.

For small platforms of up to about 24in maximum dimension, the 3/8in x 1in window channel size works well. For larger platform sizes the sections produced for screen doors are more appropriate. The 1/2in x 19/l6in section is suitable for up to 7ft. Over this length consider the 1/2in x 2in, 1/2in x 21/2in, or 1in x 2in sections. The last is screw-fastened, whereas all the others use the simpler push-in corners. Some manufacturers also make a 1/2in x 19/l6in rolled section with an extension that makes it much stiffer but does not add significantly to the weight (Fig. 5). This section uses the same push-in corners and fits the same 1/2in nominal slotted racks.

Figure 5. Rolled channel with stabilizing extension.

The screen channels are available in aluminum or steel, plain or painted in a variety of architectural finishes, and sometimes anodized. Anodized aluminum is the most inert and durable, but the enameled aluminum is very serviceable and much less expensive. Never use plain or “mill finish” as surface oxide is always rubbing off and will stain the objects. The aluminum channels may be extruded or rolled; the extruded types are stronger, but more costly. The rolled steel channels are strongest, but are only available in painted finishes and there is a high risk of corrosion and staining. The steel channels should be considered only for very heavy loads, and will require an adequate barrier such as a polyester film interleaving sheet. Cross-braces also are available for large screens.

Spline is available from the channel suppliers in various sizes and shapes (Fig. 6).

Figure 6. left, Smooth spline. right, Fluted spline.

Always order a size to fit very snugly with your combination of channel and fabric as it must resist the pull-out stresses created by weight on the platform. Spline is usually very inexpensive by the full roll and very expensive by the foot, but it is often included with a cut frame by the vendor.

Standard fiber glass insect screen is coated with PVC and should not be used because of plasticizers and residual chlorides. A good general choice is filter fabric with a mesh size of 50-70/in, and thread diameter of 120-160 microns. The coarser fabrics are not as slick as the finer meshes and help prevent sliding of the textiles on their surfaces. Do not use nylon, polyethylene or poly-propylene fabrics as they stretch excessively and “creep” over time, resulting in sagging.

A better roller than those available at hardware stores can be made by lathe-turning a wheel of about 3in diameter which has an edge turned to fit loosely in the spline channel. The wheel can be of acrylic sheet, aluminum or other suitable material. Mount the wheel with a bolt axle in a yoke which is inserted into a wood handle. This tool is used to exert a great deal of force so it should be built strongly.

The screens can be lined to prevent fiber dust from filtering down through the platforms. A non-woven polyester fabric is ideal for this lining and very economical. Pin the lining to the platform with stainless steel pins to prevent it from sliding. When soiled, the lining can be replaced easily, so it makes sense to use this additional layer rather than use an impermeable filler cloth which would be difficult to clean.