All*Star carries a product group called Grid and Pod Gasketing. It is a non-adhesive product in a variety of shapes, sizes and densities. Each router manufacturer is a little different in terms of the size channel they use with their table. In fact, two different routers from the same manufacturer may also be different, based on model number, year it was built, or if there was a custom/retrofit change to the router table or pod. When determining what the right size is, our standard response is to measure both the width and depth of the channel you are gasketing. You want a gasket that will be just about the same width as the channel (a 1/4” wide channel wants a 1/4” gasket). And stick above the surface of the channel by about 1/16” (a 1/4” deep channel wants a 5/16” gasket). Also, channels that are rounded or dove-tailed should utilize a round gasket, while channels that are squared should use a square or rectangular gasket.
The correct density is determined by a handful of variables that exist at individual locations. They include the strength of the vacuum system you are using, the weight of the substrate that you are routing, how much gasketing you are using, even factors like the altitude and humidity at your location. Luckily, if we ever prescribe the incorrect density level there are only two ways we can be wrong: its either too stiff or too firm. You want your gasketing to be dense enough to recover time after time. If it flattens out too quickly, it needs to be firmer. On the other hand, if the gasketing does not compress and seal when the vacuum is engaged, it is acting like a platform and needs to be softer. Most customers use our medium density (CR and CRS series). Those with lower volume vacuum systems (less then 6-7 horse power) may opt for the low density (CE series). And customers working with very heavy weight materials (such as stone, aluminum, thick wood products) may use our firm density items (IR and IE series).
Typically, in-board gasketing is used by customers are making dedicated fixtures for long term, repeat job applications. The advantages of using an in-board gasketing in applications like these are that by recessing the gasketing (usually a 3 parts in to a 1 part above the fixture ratio), the gasketing will have an extended life time. It is only compressing to the level of the fixture, rather than fully compressing each time. The tolerance of the Z-axis will also be much tighter as there is a solid reference point to use. Also, one can program the channels to bring the gasketing to the very edge of the part, maximizing the vacuum area for the part and therefore improving holding power. However it does take some extra time to construct a dedicated spoilboard using in-board gasketing. The on-board gasketing advantages are for individuals who want to quickly set of a fixture, hold their part, and move on to the next job/program/application. The gasketing is applied directly to the surface of the spoilboard (no channels or additional programming needed) just to the inside of the intended tool part of the part. The foam perimeter creates a “suction-cup-like” hold when compressed by the vacuum.
To help reduce vibration, the thinner the on-board gasketing is the better off you are. However, you need enough thickness in the gasketing to counteract any variances your sheet material may have (such as a warp, grain, texture, etc.). A standard rule-of-thumb is that customers working with wood materials will use out 1/16” thick foam, while customers working with plastic substrates will utilize our 1/32” thick gasketing. Those dealing with extremely inconsistent surfaces may go as high as 1/8” thick.
The most common variable used to determine how wide a gasketing product should be is the radius you are attempting to turn with the gasketing. An 1/8” wide gasket is going to have a much easier time making a tight angle than a 1/2” wide gasket would. But a 1/2” wide gasket will have a much wider surface contact area, resulting in a better vacuum seal. The 1/4” width is the most commonly ordered size.