When using a UV flatbed printer, properly preparing the surface you are printing on is crucial for getting good adhesion and print durability. One important step is applying primer before printing. But is it really necessary to wait for the primer to dry completely before printing? We performed a test to find out.

The Experiment

Our experiment involved a metal plate, divided into four sections. Each section was treated differently as follows:

• Primer Applied and Dried: The first section had primer applied and allowed to dry completely.
• No Primer: The second section was left as is with no primer applied.
• Wet Primer: The third section had a fresh coat of primer, which was left wet before printing.
• Roughened Surface: The fourth section was roughened using sandpaper to explore the impact of surface texture.

We then used a UV flatbed printer to print identical images on all 4 sections.

The Test

The true test of any print is not just the quality of the image, but also the adhesion of the print to the surface. To evaluate this, we scratched each print to see if they still held on to the metal plate.

The Results

Our findings were quite revealing:

• The print on the section with the dry primer held up the best, demonstrating superior adhesion.
• The section without any primer performed the worst, with the print failing to adhere properly.
• The wet primer section did not fare much better, suggesting that primer effectiveness is significantly reduced if not allowed to dry.
• The roughened section showed better adhesion than the wet primer one, but not as good as the dried primer section.

The Conclusion

So in summary, our test clearly demonstrated that it is necessary to wait for primer to fully dry before printing for optimal print adhesion and durability. The dried primer creates a tacky surface that the UV ink strongly bonds to. Wet primer does not achieve the same effect.

Taking those few extra minutes to ensure your primer has dried will reward you with prints that stick tightly and hold up to wear and abrasion. Rushing into printing right after applying primer will likely result in poor print adhesion and durability. So for best results with your UV flatbed printer, patience is a virtue - wait for that primer to dry!