Is there anything a knife can’t do?

Apr 22, 2025 | Industry Advice

When it comes to a sign-maker’s toolbelt, the knife has an almost endless number of applications. In his last column, Paul Hughes discussed the benefits of the trusted tool in vehicle wrapping, and for this issue, he has once again written about the nifty knife only this time on its use for cutting boards.

Paul Hughes The Sign Makers Workshop scaled e1744126974366 Is there anything a knife can’t do?

Paul Hughes

In the last two issues, I wrote about Knives and their importance to the sign-maker and vehicle wrapper. This time, let’s look at how we can use them to cut signboards.

The sign industry uses many materials, including aluminium composite material (ACM), PVC foam boards and fluted boards, to name a few.

Being able to cut these materials is a must for most businesses. Some purchase materials which are cut to size but for flexibility of workflow, it is desirable to be able to process the materials in-house.

How many boards you need to process in a week will most likely decide how you achieve your cuts; larger volumes are suited to CNC machines, guillotines or circle saws, all of which need a significant investment to acquire.

Medium volumes can be handled by hand-held saws, routers, cutting rails or wall-mounted cutting frames, which come at a reduced cost compared to the larger machines.

So, where does this leave the small-volume companies? The trusted Knife of course.

The perfect tool

ACM, PVC foam boards and fluted boards can all be cut with a quality 18mm bladed knife.

IMG 3501 Is there anything a knife can’t do?

A knife running along a straight edge

A quality safety straight edge is the perfect partner to the knife for this application. A steel rule will suffice but leaves the fingers very vulnerable to being cut if the blade of the knife decides to climb the edge of the rule, which it will inevitably do with prolonged use. This event will have you purchasing a safety ruler immediately, trust me I have the scars to prove it.

When we want to cut any sign-making material we are not trying to cut through in one pass of the knife, much better to do multiple passes working our way through the material.

ACM is very difficult to cut right through so it is best to adopt a slightly different approach.

Cutting ACM should be done on the rear of the board because the blade will cause a burr on the face if used there. The aim at this point is to cut through the first layer of aluminium and score the core of the material, which should take two or three passes.

When it is done move the sheet to the end of the bench placing the cut along the edge, it can then be pushed down to remove it. The snapped edge will be reasonably smooth, hence why it was made the front of the board.

Smoothing out those edges

There are some ways to remove the burr with some using a file and sand paper. A hardwood seam roller pressed firmly along the burred edge pushes the burr back into the material. A plumber deburring tool pulled along the edge will also remove any. I prefer a curved surform, again pulled along the burr which removes it leaving a smooth clean edge.

Generally cutting foamed PVC is much easier and will cut right through with a number of passes with a knife but it can still produce a rough edge, especially in colder conditions when the material is more brittle creating a splintered edge; this can also be removed with the deburring tool or the surform.

Being able to cut boards in-house is a must for all sign-makers, but it’s horses for courses for what equipment you need.

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