Whether you’re “painting” paint, stain, or varnish onto your work piece, using a paint roller not only makes your job significantly easier, it also gives a more even coat when compared to a brush. However, there are some things you should know and keep in mind when using a paint roller to ensure the best results. It’s not exactly as easy as simply rolling the stuff on – although it’s close.
(For this article I will use “paint” to mean any and all fluid substances you might roll or brush onto a work piece, whether it’s paint, stain, varnish, or any other coating.)
Depending on the viscosity of the paint, the “pattern” the paint roller leaves behind will vary. But there’s one thing pretty much all paints have in common, and that’s that they will most certainly leave a trail of bubbles, ridges, hairlines, or something in between. In any case, you would want to avoid this as much as possible as depending on the severity, it can completely ruin the final finish.
There are other reasons that may cause bubbling during the rolling process, such as mixing or shaking the paint too vigorously immediately prior to application. Running the paint roller across the work piece too fast can also cause bubbling where it otherwise could be avoided. It’s important to stay patient and work methodically as rushing your project will only backfire.
Paints with low viscosity – or thinner in fluid texture – will tend to bubble as you roll, whereas paints with higher viscosity will tend to leave a mixture of both bubbles and ridges of paint due to the excess buildup on the paint roller caused by the high viscosity. Thinner paints not only can be “wrung” out from the roller better, but they tend to flatten themselves out naturally once applied to the work piece.
Thicker paints however, often won’t be able to flatten themselves out before drying, and therefore can prove to be more of a problem. Having said this, regardless of the viscosity, many paints will give the best results when applying a very simple but effective technique. This is called “tipping”, and it’s when you pass a fine haired paint brush over the work piece immediately after application of paint by roller.
Normally this is done by a second person, but it can be done by the person rolling as well, if the object being painted isn’t too big. What this does is it smooths out any bubbles, ridges, or other defects that the roller may have created. While this is another step and you may question its importance, I assure you that it will be worth the extra time and effort.
It is a well-known fact that rolling and tipping produces the best gloss and is the perfect solution for people who don’t paint for a living but just do a little here and there. Professionals will have spray guns and other fancy tools, but most people won’t have these. So for those of you who have struggled with bubble-ridden paint jobs, look no further! Try out this technique, hone it, and put it in your arsenal.
Other Things to Keep in Mind
- Direct sunlight. You should avoid painting in direct sunlight. Sunlight will cause the paint to dry faster than usual, either leaving bubbles where it otherwise would “self-level” or leaving you with insufficient time to tip.
- Humidity. You may not have a whole lot of choice in this as some parts of the world simply have extremely high humidity levels constantly – like here in Japan – but if you do have a choice, it’s best not to paint when the relative humidity is higher than 65 or 70 percent. This isn’t because the paint won’t dry enough, but because the high humidity may cause the paint to dry “cloudy”, leaving the said characteristic instead of the desired glossy finish.
- Wind. This may seem like common sense, but little bits of debris carried by the wind can cause irreparable damage to your little (or big) paint job. Also, as with sunlight, it can cause a premature drying of the paint.
Aside from weather concerns, keep in mind that there are paints that are designed to “self-level” to a certain degree and are also made to naturally dissipate bubbles. But these paints are usually designed for large applications such as ceilings and exterior walls, where it would be unfeasible to tip after rolling and where small defects wouldn’t be noticeable or problematic. Most varnishes and stains require tipping for best results.
So as you can see, there are good days for painting and there are bad days. Check your weather forecast and plan accordingly. Just like you wouldn’t hang your laundry out the night before if the weather forecast showed rain, it’s wise to check all the above weather conditions when toying with the prospects of your next paint job.
*(Although related to painting marine applications, the following website contains some helpful additional information regarding rolling and tipping – Topside Painting.)