|Project by Lee A. Jesberger||posted 07-11-2007 04:09 AM||3724 views||4 times favorited||21 comments|
When gluing up panels in a vacuum bag, it is important to have a substrate under the parts. This substrate is called a platten. The platten is supporting the parts, much like a bench top. The platten is inserted into the bag along with the project being glued up.
The more important purpose though, is to permit air evacuation from all areas of the bag. In the picture showing one of our plattens, you can see 1/8” saw kerfs, about an 1/8” inch deep. These permit air to be removed from under the flat panels, with no obstructions. It is important to keep these airways, or saw kerfs free of glue build up. Also, cured urea resin glue is hard, brittle, and quite sharp, so keeping the platten free of dried glue is important to prevent it from cutting your bag, or interferering with your projects laying flat .
The tops of projects must also have a platten, but this can be a 1/4” thick piece of M.D.F., and cut about 1/4” larger in both directions, than the panel being glued. It dosen’t need kerfs.
The bags themselves must be kept clean of dried glue for the same reason.
Notice also, that it is a piece of Mellamine, which prevents the glue from sticking to it. It has all corners and edges rounded with a 1/4 round bit, which prevents the sharp corners of the platten from puncturing the bag.
If your bag should get punctured, it is repairable, much like a pool liner.
It is also possible to make your own bags if desired. There are several sites on the net that offer both the supplies and instructions to do this.
We don’t make our own bags, but this is due to a lack of time as much as anything else.