Information you need to know
Powder-coated aluminium lettering is not a good idea. If you have been thinking along the lines of using built-up aluminium lettering with a powder-coated paint finish then we need to explain why this isn’t a good idea.
These letters are a typical application for powder-coated aluminium built up lettering. These are in fact stainless steel face illuminated letters powder coated Gold.
Why aluminium built-up lettering and powder coating do not mix
If you have read the aluminium built-up lettering page you will know that the only way of joining aluminium built-up lettering is by the use of a structural adhesive.
This adhesive, in our opinion and experience, means that powder-coated aluminium built-up lettering is not a practical option.
How powder coating works
A metal part, in this case, an aluminium built-up letter, has an earth clamp connected to it and then runs through a coating booth. An electrical charge attracts powdered paint onto the metal part. Once covered in powder the metal part then passes through an oven where it is baked. During the baking process the powdered paint fuses to the metal. That’s a rough guide to how powder coating works.
The temperature range of structural adhesive
Structural adhesives used to bond aluminium built-up lettering together have a theoretical maximum operating temperature of around 120 degrees C. Some manufacturers will sell you an HT (high temperature) version which has a maximum range of around 180 degrees C. This, they claim means that structural adhesives are fine for powder-coated aluminium built-up lettering. It is our experience that this is not the case.
The operating temperature of powder coating ovens
From our research talking to a number of powder coating companies, we have discovered that the average oven temperatures used in powder coating processes are around 200 degrees C. As you might have already guessed herein lies the problem with powder-coated aluminium built-up lettering the oven temperature exceeds the adhesive temperature.
Some powder coating companies could get close to the 180 degree maximum of structural adhesives but even then they could not rule out temperature changes within the oven. Low-temperature powders were suggested as a solution; these fuse at around 140 degrees C. The problem with low temp powders is cost and availability. Powder coat is sold in a minimum of one 25kg box. Even if you don’t need 25kgs of powder you end up paying for it.
You can’t have powder coated built up lettering then?
Yes, you can. All we need to do is switch from powder-coated aluminium built up lettering to stainless steel built-up lettering. Our joining techniques for stainless steel do not involve any structural adhesives.
For powder coated built up lettering we switch to a high-temperature welding system which delivers joints capable of withstanding almost 300 degrees C far in excess of powder coating oven temperatures.
Why we recommend stainless steel instead of aluminium powder coated built up lettering?
We recommend you use stainless steel instead of aluminium for the simple reason we know stainless steelworks. We’ve researched powder coating and structural adhesives and we know for a fact that the two are not good bedfellows.
Take advantage of our experience and chose a proven alternative once painted there is no discernable difference between built-up letters built from aluminium or stainless steel.
Wet spray painted built-up lettering
If you want powder coated built up lettering we have a proven solution in place. If you need a special paint finish that powder coating cannot deliver we also offer a full paint shop service via our approved sub-contractors. Whatever paint finish you need we have you covered.
Powder-coated aluminium built-up lettering switch to stainless for a better, more reliable result.