Accurate spacing is the key to a good Pronto changeable letter system. Refer to the diagram shown here to select the method of track installation you prefer and determine the total height of your sign. The use of duel track automatically spaces the rows and reduces the number of bars required. If row spacing needs to be greater use a combination of top and bottom tracks.

If the surface you are attaching Pronto Track onto will expand and contract at somewhat the same rate as the plastic track, installation can be done using either rivets or adhesive. Using a chalk line and level, mark the location of your first bar of track.

For a rivet installation: Drill holes through the track AND the background (maximum 8" center to center). To fasten track to 1/8" - 3/16" thick background, drill 0.219 (7/32") diameter holes. Insert the pronto rivet, then push the pin to its closed position. (Drill speed should be a minimum 1800 RPM using a #11 drill bit with a 30 degree angle and 0 degree rake).

For an adhesive installation: Using a syringe or bottle applicator with a thin needle tip, apply a steady line of adhesive, such as WELD-ON #3 or #4, to the back face of the bar of track, Tape in place until adhesive has set up completely. (WELD-ON adhesive available at TAP PLASTICS online or in stores).

If the surface you are attaching pronto track onto WILL NOT expand or contract (ie: wood or metal) AT THE SAME RATE as the plastic/polycarbonate track, use the following procedure:

1. Drill or route oblong or oversized holes in the track every 8" on center.
2. Using a sheet metal or wood screw, put the screw in the center of the hole.
3. Do not tighten the screw. Leave it 1/4 to 1/2 a turn loose.
4. When all the screws are in the track you should be able to wiggle the track a slight amount. Now the track is able to expand or contract with temperature change without cracking or warping the plastic track.

REFERING TO THE DIAGRAM ABOVE: it shows the 2 different methods of installing 2 lines of letters. The example on the left(above) used both a Pronto top track and a pronto bottom track. The example on the right(above) uses a single bar of DUEL track. (Visible space is not drawn to scale).

The table above will help you determine the total visible opening for your sign, based on the number of lines of text used. For example, using a 4" letter with a visible space of 4-1/4", the total height of a sign with 3 rows of letters will be 18-1/4". These measurements are based on using the pronto duel track between rows.

MINI ACRYLIC DUEL TRACK:
For 3" & 4" letters where additional lines of copy must fit in the space, you could alternatively use the MINI ACRYLIC DUEL TRACK which has a profile of only 13/16" high as opposed to the standard duel track profile of 1-5/8".