TECH SHEET 22 IRON-IN MESH To: Users of Flex Proof Vinyl Repair Products Subject: Iron-In Fiberglass Mesh (Fine, Medium, and Super Mesh) Flex Proof meshes are specially treated to improve strength and reduce repair time. The proprietary treatments, although invisible to the eye, add strength to the fiberglass yarn. But their main function is to cause a weld with the vinyl. Be careful. There are some suppliers who provide look alike fiberglass tailored to other markets. They are cheap and easy to find. Sadly, some users have had problems with re-dos. Fine Mesh is indicated for very thin or heat sensitive vinyls including the expanded materials. It is preferred for very difficult, cosmetically critical repairs. It is also the only mesh suitable for those unfamiliar with iron repair. Medium Mesh is a somewhat thicker square weave material. If you have had problems with compound sinking over Fine Mesh use Medium. Use a Jacobs' Iron and refer to Tech Sheet 30. Medium Mesh is also very good with the F Compound dash and arm rest repair. See Tech Sheet 44. Super Mesh is a heavy satin weave material with very high strength. It is best for use on very high quality, high weight vinyls with sufficient thickness to completely absorb the mesh. Orientation is important at times as the strength of the weave is higher in the warp direction. The fill strands are flattened and somewhat weaker. Cutting and laying the weave on the bias (strands diagonal to vinyl cuts) is recommended. Users who are doing restaurant chairs report that Iron-In meshes save them 50% of their former repair time simply by eliminating the sub-patch. They report using mesh on everything, even small cigarette burns. We call your attention to two reports where the Fine Mesh failed to hold. The first describes a door panel armrest that held only four months before the Fine reinforcement ruptured. The second is a 16-inch cut in a restaurant cushion stated, "every strand of the Fine was torn apart in two weeks time." Let's analyze the situation. First, it tells us that the iron-in mesh really welds to the upholstery even with a narrow (possibly only _") bite on each side of a cut. It also tells us that fiberglass yarn won't stretch, which means that when the yarns go straight across, and you have a high unit pressure such as a knee, elbow, or hand, then nothing can give at that point. The fiberglass at that point has to take it all. There can be no sharing. If the Fine had been cut on a bias this would have allowed some stretching at the point of contact so that more strands could share the load. Also, two layers of Fine mesh would be stronger than a single layer of Medium. Add a third if needed. The minimum of tooling to make the fullest use of these products is a No. 6 or No. 7 Iron, Non-Stick Mat to iron through, and a contoured Chill Bar. A small amount of B-2 or Topcoat Compound is useful to wet the cut and increase the bite. Again, see Tech Sheet 30 for a complete description of the Iron Repair Method. Be careful if you must use cheap, highly-plasticized repair compounds as some formula components will degrade the reinforcement over time. Re-do's aren't worth a few pennies saved. Finally, remember to trim the reinforcement in such a way that the woven strands cross the vinyl cut at a 45 degree angle rather than straight across. This orientation is critical in applications such as armrests, dash boards, and heavy duty restaurant repairs. Rev. 08/96