Advertising signs can often be seen to bubble and degrade over time with the result that the sign looks unprofessional. The sign then does not convey the right marketing message and creates a poor impression. This is mostly due to the problem of outgassing or the release of gases from the materials. By understanding the surface of the sign and the type of vinyl film being used you can avoid these problems and have a long lasting sign that is visually appealing.

Outgassing is a common problem when creating advertising signs. A typical scenario could be if you have an acrylic sign that is blistering or bubbling - acrylic suppliers claiming their acrylic doesn't outgas and sign vinyl suppliers say that it isn't their fault, the acrylic outgassed. It is a natural affect of the production process of many surfaces including plastics, paints, vinyl coverings, leather and PVCs to name a few.

An easy explanation is that a form of outgassing can be seen in motor vehicles. A new car can be left in the sun and you will find an oily residue build up on the windows and windscreen. This is a result of the release of gases from the vinyl material in the car being deposited onto glass surfaces.

As with most advertising sign creation, knowing the materials you are going to use and preparing the surfaces correctly will help you avoid any outgassing issues and achieve a quality result.

The surface or substrate you will be using is the first to be analysed. If the surface is old, then there is a good chance that any outgassing has finished. Newer surfaces such as the panels of a new motor vehicle, a sign in a foyer, display systems including portable display stands then your choice of vinyl material becomes most important. You can avoid outgassing issues by choosing a vinyl film that is porous enough to allow the gases to pass through. The following list of products is from most to least porosity:

• Cast Vinyl

• Polymeric Vinyl

• Monomeric Vinyl

For each of these you should not have too many issues, however, quite often in the printing process you need to layer vinyl over each other to get the desired effect. Obviously, this will decrease the ability to release gas from under the vinyl. Care should still be taken therefore when layering.

Polyester and polypropylene films are not porous. The classic example of using these products is a sign with a mirror chrome finish on a black acrylic material. Even if the best quality products are used, it cannot be guaranteed that outgassing will not occur. Another example is where a gold or silver window film is put on a window. Unless the window has been thoroughly cleaned and dried when the window gets hot, the water trapped under the vinyl material will become gas and you will have a bubbling affect.

Whenever a sign is being developed, preparation is the key:

• Firstly know the characteristics of the surface you are using, particularly as it relates to outgassing. Even painted surfaces may cause issues, particularly if using water based paints. You will need to allow them to cure properly, best over 7 days or more before applying any vinyl.

• Secondly choose the most appropriate sign vinyl film for that surface, application and the time you want the sign to last.

Often the cost is a determining factor of the type of film used. Cast film is the most expensive, but is also the most porous and is likely to have a longer life expectancy than other films. Your choice of film can be guided by how long you require the sign to last. However, the reality is that material costs are relatively insignificant in making a sign. The major cost is in the labour to create the sign. For example, if a Calendared vinyl contributes 10% of the total cost of the sign, using Cast vinyl will contribute about 5% more. The benefit is however a longer lasting sign and one that is unlikely to give you any issues with outgassing