Optimum Mesh Size

For many homes, a difficult debris to handle is pine needles. Our study and research indicate that a pine needle cross section is rectangular and will typically be about 25 x 35/1000 of an inch.

Typically they are in clusters of three needles - 3 to 7 inches long, cannot pass through our stainless steel micromesh and can't get stuck in gutters because our stainless steel mesh hole size is smaller than a pine needle cross section.

Even falling straight down, sharp end first, they do not penetrate the mesh but fall harmlessly on the mesh to be washed or blown over the side.

Also, with all other types of products on the market, shingle grit is a problem. As roofing shingles age, they lose grit and it washes into the gutters. The specific gravity of the grit is very heavy and most of it never washes out. We have replaced competitive products with significant grit accumulation of an inch or more.

In addition, it's like wet sand in the bottom of your gutters, restricts water flow, holds moisture, and delays the drying process thus promoting decay of debris and attracting bugs and insects. In a random sample of shingle grit, measured with a digital caliper, we found only the smallest pieces (1 in 12) small enough to go through our Blackhawk holes.

In another experiment, we poured some finely ground table pepper on Blackhawk mesh, shook it several minutes, and only about 1/2 was small enough to go through the holes.

Scientically and practically speaking, our 1600 holes per square inch results in an optimum hole size of about 19/1000s inch square and solves some other problems we have seen with other micro-mesh products having larger or smaller holes.

One such problem with smaller holes is that some roofing shingles, being petroleum based, on a very hot day will leach a sticky, syrupy product that will actually clog the tiny holes and dry when the temperature cools.

Fortunately, we have only seen this a few times, but never with Blackhawk. The smaller the holes, the more likely this is to happen.

Read the Blackhawk Installation Instructions