How to Check for Hull Cracks With a Dye Pen

The dye pen process, or technically called dye penetrant inspection, serves as a means to find cracks in a range of materials. It can pinpoint minute and small cracks that might be invisible to the naked eye. Boat hulls undergo a lot of torque and stress, especially in the transom area, where small feathering or spider cracks can propagate and begin to radiate outward. Cracks that grow without the proper detection and repair can enlarge, causing delamination, water intrusion and structural failure. A boat owner can obtain a dye penetrant testing kit and find potentially dangerous cracks before they spread.

Instructions

1

Determine the area you wish to test and prepare a bucket with a solution of warm water and dish washing soap. Thoroughly clean the area with soap, water and a brush, removing all wax, dirt, algae and oil from the surface of the hull section. Completely dry it with a clean towel. Use a piece of towel and some pure alcohol or electrical contact spray to clean the area again, decontaminating it of microscopic particles.

2

Open the dye penetrant inspection kit and read the directions so that you understand the steps and process. Note that the dye will come in an aerosol sprayer with a chalk developer. Pay attention to the application method as it might differ from kit to kit. Uncap the dye and spray it over the area you wish to treat. Let the dye sit for at least fifteen minutes, or according to the specific directions of your kit. The colored dye will penetrate into the minute cracks in the surface.

3

Wipe the dye penetrate off with a soft, clean towel. Simply swipe back and forth over the surface. If the kit has supplied a cloth fiber, use it instead of the towel. Prepare the chalk developer and apply it according to directions over the test surface, using the kit applicator. The developer will draw the dye up through the small capillary cracks in the hull surface and enhance the size of the cracked area.

4

Construct a small tent to block off as much light as possible from the surface area. Lean two boards at an angle against the top rail of the boat, resting the other ends on the ground, and place a blanket over them. Place under the tent a vapor mercury black light that has at least 100 watts of power. You can use a magnifying glass to aid in your inspection, if you wish. Look for small radial, feathered or spider cracks that have the same color as the penetrant dye. They will show up quite clearly under the black light.