When making a flat sign panel there are a range of sheet materials that you can use. If you want the most cost effective solution that does the job that you want, it’s important to choose the right material. Of course, most signs are made of two components – the sheet material (often called the substrate) and the vinyl graphics that are applied to it, but this blog is just going to look at the sheet material for now.

Foam PVC

Foam PVC goes under many names – foamboard, Foamex (actually a trade name) or just PVC. It’s usually white (although is available in colours) and is available in a range of thicknesses, with 3mm, 5mm and 10mm being the most commonly used in the signage trade.

Foam PVC Sheets

Foam PVC is a hard, rigid, plastic board that is ideal for long term indoor and short term outdoor applications. It’s a cost effective solution and works great indoors for all kinds of signage, display and point-of-sale applications. It can be used for outdoor signs, but as I say, it’s really only suitable for short term signage. It’s rated at 2 years life outside as the weather will eventually get to it, and if it’s used for large panel signs it ripples and buckles with changes in temperature.

Best Used For – Interior sign and display

Avoid – Large exterior panels


Acrylic is a transparent thermoplastic that is also known as Perspex and Plexiglass. It’s available in many thicknesses and in a range of solid or semi-transparent colours, as well as fully clear. It’s available in two varieties – cast and extruded. Cast is made by mixing the chemicals used to make the sheet and then pouring them into a mould and leaving them to set. Extruded is made like pasta – by making a “dough” and then forcing it through rollers to get the finished sheet thickness or shape.

Acrylic Sheets

Cast acrylic has better chemical and scratch resistance but is more expensive than extruded. It is also available in a wider range of colours and thicknesses.

Extruded acrylic has finer dimensional tolerances and is easier to flame polish (a method of making edges smooth where panels have been sawn to size), as well as being available in a wider range of shapes (such as square and round rods).

Because acrylic is available in transparent (lets light through) colours and fully clear variants, it is often used in conjunction with backlighting of some kind – usually LEDs or fluorescent tubes. This includes sign panels in lightboxes, both internally and externally. Plain coloured acrylic is not used as much these days as it is much more expensive that Aluminium Composite (more on that later), so clients tend to go for the cheaper material and flood it with coloured vinyl. The end result is very similar, and superior in some ways.

Acrylic is very prone to expansion and contraction with temperature changes. A 3 metre sheet can grow and shrink by up to 50mm in extreme temperatures, and this means it is not suitable for rigid fixing. Any fixings much have some breathing room, and indeed, large panels in lightboxes are ideally “hung” inside the box from the top edge, leaving the other three edges room to move.

Best Used For – White or coloured semi-transparent panels in backlit signs

Avoid – Rigid fixings on exterior panels and large sign panels where budget is limited


Correx is a brand name for fluted polypropylene board, also known as Polyflute, Coroplast, FlutePlast, IntePro, Proplex, Twinplast, Corriflute or Corflute.

It’s an extruded sheet material that is lightweight and tough but can easily be cut with a sharp knife. It’s made of polypropylene and has a construction much like corrugated cardboard. Corex is an inexpensive material most commonly used for temporary signs both indoors and out, and is ideal for fixing using cable ties as it is relatively soft and does not crack in the corners.

Correx Sheet

Correx signs can often be seen fixed to mesh fencing, railings, lampposts and telegraph poles, usually in sizes ranging from A4 to A2. Correx is available in several different thicknesses, with 3, 4 and 5mm being the most common. The main downside is that the flutes are often slightly visible on the finished printed panel, which makes Correx unsuitable for display purposes where ultimate appearance quality is important.

Best Used For – Tough, reusable temporary signage

Avoid – Large signs or high quality prints

Aluminium Composite

Aluminium composite panel also goes by many names, with Dibond, Dilite, ACM and BCP being popular terms. ACM is a “sandwich” board, with two thin sheets of aluminium bonded around a thicker low density core, usually polypropylene, giving a thickness of 3mm. ACM panel is very string, rigid and smooth, but is lightweight given its strength. ACM is ideal for exterior signage as it resists weathering and stays flat without expansion or contraction when fixed flat to walls and other surfaces.

Dibond Sheet

ACM is available in different qualities, with better quality sheets having thicker sheets of aluminium in the construction. Lower quality panel (often called hoarding panel) has the lowest amount of aluminium, but is still very strong and stiff when compared to foam PVC  Correx.

ACM is regularly used in the sign trade for all manner of interior or exterior signage where durability and strength are required. Due to its strength it is also used for panel and post type signs, where the sign panels have channel riveted or glued to the reverse side, to allow for pole fixing using special clips. ACM can also be scored and folded to make “3D” sign trays, and can also be machine routed to special shapes, including lettering. ACM comes in white as standard, but is also available in a range of painted colours, and also metallic finishes such as brushed metal and polished mirror effect.

Best Used For – Long lasting outdoor signs, especially in large sizes

Avoid – Signs where budget is very limited


So as you can see, there are several signmaking materials that can be used to make all kinds of signs. In a pinch, any panel can be used for practically any sign, but as you’ll now understand, it’s much better to choose the right panel to best suit the budget and job in hand. If you need advice on the best material for your requirements, just ask – Ad Bell are always here to help.