Rubber Lining Preparation

27 October 2010- The entire process of rubber lining preparation involves the following five steps:

• Base surface preparation
• Rubber sheets preparation
• Rubber sheets application on the metal surface
• Vulcanization process
• Testing & Inspection process

Let us now discuss these processes one-by-one.

Surface Preparation

This is very important process for rubber lining. It is to be noted the first thing that is required to prepare the metal surface is that it should be free from paint, oil, rust, dust etc. This is done using sand blasting or shot blasting. When the surface is cleaned, bonding agent or adhesive sealants are applied to surface. In the adhesion process, two or three coats are needed to be applied, as adhesion is an important process for rubber lining.

Rubber Sheets Preparation

The synthetic rubber compound that is produced is as per the chemical and other conditions of the process. The sheets of rubber are made on calendar machine. The thickness varies. For more thickness, 2 or more layers are applied. Usually for pipe fittings, extruded rubber tubes are inserted in the pipes.

Application of Rubber Sheets

The rubber sheets that are produced are applied on to the adhesive coated, half dried surface. This is done using slight pressure of hand or a metallic roll. Sometimes various lining tools are also used. While doing so, care must be taken not to trap air between the metal surface and rubber sheet. All joints are leveled and joined with help of knurling tools.

Vulcanization

In most cases, the vulcanization is done using an auto clave. In the process of vulcanization, rubber changes from plastic to elastic. The pressure and temperature depend upon the rubber compound and thickness of rubber lining. For equipments which are of large size, where rubber lining is done on site, vulcanization is done by open steam and also hot water curing. A specified temperature is maintained cure the rubber.

Testing and Inspection

The rubber lining products are sent for testing. This testing is done before and after vulcanization so that they are free from faults. Any fault can cause failure of the equipment. In complete daylight, visual inspection is done to check mechanical damages blisters and poor joints. Also a spark test with a high voltage is carried out. This is done to check mechanical damages, blisters, holes, poor joints etc. For rubber lining, hardness test is an essential requirement. Knocking test is another test which is undertaken so as to test poor bonding.