Apr 27, 2007

Testing Brushes

testequip01 Many years ago DuPont developed a method of testing brushes they feel has proven to be a good indicator for benchmarking brush performance. The method was later adopted by several of their own customers for their own internal benchmarking.

The general purpose of the testing is to measure the capability of a brush to pick up paint, to release paint onto a surface, and to visually reflect its effectiveness.

The two basic components of the test are a completed data sheet and the paint stripe test. The key performance indicators on the data sheet are Paint Pick-up, Paint Lay-down, and Stripe Length. DuPont identifies the Stripe Length as the actual measurement on the paint stripe from the beginning of the stripe to the point where the brush begins to skip or miss. The skip point is somewhat subjective but if all brushes are tested equal, the comparative results in theory will be consistent. Keep in mind, brushes are also tested for abrasion resistance and bend recovery.

Procedural testing is fine for the basic tests outlined above but how well do the brushes perform on the job based on these tests? Based on my experience with testing brushes, not very good at all. I have a general conclusion that all brushes lack precision accuracy except for one brush I am aware of. And, while that particular brush might not hold as much paint as the next brush, its main purpose is accuracy and precision feathering. Taking an extra few loads is not really all that bothersome to me.

Understand for a moment my line of thinking on this. I do not use masking tape; the brush must have the capabilities to produce freehand precision cuts. The brush is not positioned on the wall as shown in the example stripe test above. I do however position the flat edge against the wall for feathering-off a previous cut. That method is only used in a dry-brush motion which is the opposite objective what the stripe test provides. For lack of a better example, view the video clip below and note that at the end of the stroke Brian turns the brush flat against the wall for feathering or leveling purposes only. It's a secondary action with a specific purpose.

In all my years of painting I never had a need to take a load of paint and spread it flat against the wall as shown in the stripe test. I believe rollers are designed for that job. The brush is used to make a small narrow cut the majority of the time. On flat work such as bookshelves the paint is applied with a roller and only leveled off with a brush. The brush really doesn’t need to hold any paint in that situation but it does need to feather out brush and roller marks.

I never toured the DuPont testing facility or have any knowledge of other tests brush manufacturers perform. What I do know is all brushes seem to perform much like the other as far as accuracy. If your goal is to tape-off everything before you paint then any brush will perform well, some might hold more paint than the next.

So in conclusion, I suppose the industry testing methods are proving to be just fine for a mainstream painter or Do It Yourself person where tape gives you the edge. Where are the tools for the professionals?

Now don’t think for a minute I can’t produce a nice finish or work with most “professional” brushes on the market, I can. The difference is, how much slower will I have to work to use it and how much skill on my behalf will I need?

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