Rolling is the most accessible way to apply a liquid coating. It needs little equipment and suits occasional jobs, one-off art prints and short runs. The trade-off is that the finish depends on your technique, so it pays to set up properly and practise on offcuts first.
What you need
- A clean, flat table larger than the print, in a well-ventilated area away from ignition sources.
- A good-quality foam or fine-pile roller compatible with solvent coatings, and a clean tray.
- Masking tape or a sacrificial border sheet so you can roll beyond the edges of the print.
- Appropriate gloves and any other PPE listed on the coating’s safety data sheet.
- A dust-free place to leave the print while it dries.
Step by step
- Check the print is fully dry and has had time to outgas. Coating too soon is one of the most common causes of problems.
- Test the coating on an offcut printed with the same ink and media, and let it dry fully before judging the result.
- Lay the print flat and secure it so it cannot move. Remove dust with a soft brush or lint-free cloth.
- Stir or mix the coating as directed on the technical data sheet. Avoid shaking vigorously, which can introduce bubbles.
- Load the roller evenly in the tray, rolling off the excess so it is wet but not dripping.
- Start off the print on the border sheet and roll across in one direction, overlapping each pass slightly. Keep a steady, light pressure.
- Keep a wet edge. Work methodically so each pass blends into the previous one before it starts to set.
- Finish with light passes in a single direction to level the surface and reduce roller marks.
- Leave the print flat in a clean, ventilated space to dry, and do not handle it until it is dry to the touch and the coating has cured as described in the data sheet.
- If a second coat is recommended for the application, apply it only once the first is dry, working at right angles to the first coat if the data sheet allows.
Getting a better finish
Thin, even coats generally look better than one heavy coat. Heavy application tends to show as runs, puddling or a cloudy patch, and it can take much longer to dry. If you see bubbles, slow down and reduce the load on the roller. If you see streaks, the coating may be setting before you blend it in, so work faster or in smaller sections.
Clean the roller and tray promptly using the method on the data sheet, or treat rollers as disposable if cleaning is impractical. Dispose of used materials and rags responsibly, as solvent-soaked waste can be a fire risk.
When rolling stops making sense
If you find yourself rolling several prints a day, or struggling to keep large pieces consistent, a coating machine will usually save time and material. Our guide to investing in a coating machine explains the signs, and the coatings themselves are listed on our coatings page.
For advice on rollers, technique or a particular media, call us on 01252 624 411 or drop us a line via the contact form.