How can I get a consistent spray pattern and avoid sags with my spray coating?
I am having trouble getting a consistent spray pattern with my spray on coating. I also seem to be getting drips and sags. Can you make some recommendations to assist me?
Your question actually involves 3 different problems. Spray pattern, drips, and sags all have somewhat different causes and solutions.
How to get consistent spray pattern with spray on coatings
If your final mix is always the same consistency, and the products were mixed the same with the same proportions of liquids, powders, and lacquer thinner, they should always spray the same unless the gun or air supply is varied. Same coating, trigger pull, tip size, air pressure, and distance will provide a consistent spray pattern. We recommend individuals without experience spraying from a texture hopper practice first. You can spray any readily available material which can be thickened or thinned with water. We suggest a food item such as pancake mix. This is slightly sticky, can be thickened as needed, and can simply be disposed of as any food item.
Remember… the powders are something you can vary depending on the conditions. Less powder will mean less lacquer thinner required, but you may require more bedliner since you are not using all the powder sent.
Avoiding drips when spraying on a bed liner or other coating
Drips are caused when the coating is applied too thick in a single coat. This is more prominent the thinner your coating is, and one reason we recommend using our Poly Powder, along with a texture hopper to spray most of our coatings. By thickening the bedliner, koi pond coating, or other product, you can usually spray a single coat at about twice the thickness without drips. If drips start, stop spraying and wait until thumbprint tacky (usually about 2 hours at 75° F) before spraying additional coats.
Thickening the coating usually means that an HVLP spray gun won’t work. You generally need at least a 3.0 mm spray tip to spray coatings thicker than our products without Poly Powder. A standard texture hopper usually includes a 4.0 mm, 6.0 mm, and 8.0 mm spray tip, and can apply our coatings even with more than 50% Poly Powder added.
For color applications where the dark grey Poly Powder additive isn’t suitable, we have other additives to thicken our coatings. We can custom quote kits with our grey Poly Powder, or our Max Coat silica additive. These additives provide a thicker coating without as much effect on the color.
Why coatings sometimes sag with spray on coatings
Sagging (not dripping) occurs when additional heavy coats of bedliner are applied too soon. If the previous coat(s) are still too soft to support the extra weight, the coatings can sag. We always recommend that the surface be thumbprint tacky or more fully cured before spraying additional vertical coats. This is when lightly touching the surface leaves a thumbprint, but doesn’t come off on your finger.
In cooler temperatures, our protective coatings will be thicker (just like oil) and will require more lacquer thinner to spray. This can be a problem, since the lacquer thinner will also take more time to evaporate. This may contribute to sags on verticals. A lot of lacquer thinner can also be a problem with adhesion since it reduces the “stickiness” of the sprayed product.
If using more lacquer thinner, it might be best to plan on a 3 coat application to the verticals. It’s not necessary for the coats to cure completely between coats, so lighter coats which don’t run take less time than fixing runs.
Most of our coatings will also take additional coats after the bedliner is fully cured. In some cases, you may observe a slightly oily finish once the cure is complete. If this happens, simply wipe or rinse the surface with a mild detergent or water alone to remove most of the oily residue. This helps ensure there is no bond breaking element involved. For coatings which are cured more than 24 hours and are glossy, we also recommend light scuffing before additional coats are sprayed.
The only way to ensure your bedliner won’t run, and always have the spray pattern consistent is to apply the products such as our cartridge based products which cure in seconds. There is no time to run, and the product is always the same consistency if it is stored at the same temperature. The cartridge based products are more of a dealer application however since they require equipment not usually found in a do it yourself environment. You may want to view the Rhino/Line-X Alternative Polyurea Coatings Instructions to see if you have the equipment needed to use these coatings.
For additional questions, please get in touch with us at 855-545-4900