Painting fiberglass stairs is not a difficult project. It can be done by anyone with only basic painting skills, and does require any construction skills at all. Aside from the peculiarities of the fiberglass itself, this project is relatively straightforward. Because of the drying times involved, this project could take a small amount of time each day for as long as a week to finish properly. The final pay-off will be a professional paint job that stands up to both traffic and the elements.
Clean the surface to be painted thoroughly. Mineral spirits or denatured alcohol are the method of choice by many, while others suggest using a solution of trisodium phosphate. It is essential that all grime, grease and dirt are removed from the stairs, or paint will not bond properly. Improperly cleaned surfaces may appear to bond with the fiberglass for a short period of time, but the end result will be peeling and flaking of the paint. Rinse well.
The Importance of Dry Surfaces
If the surface of the stairs is still wet when the paint is applied, the moisture will be sealed under the paint, and that spot will eventually bubble, losing its bond with the fiberglass. Between each step, allow the stairs to dry thoroughly. A shop fan can be used to speed up the process, if necessary, but patience is by far the most beneficial thing to apply to the job.
A Note About Staining Fiberglass
Fiberglass can be stained, but it does not perform well with ordinary wood stains. The composition of fiberglass does not accept this type of stain, and it only accumulates between particles. Instead, use an oil-based stain. This type forms a chemical bond with the fiberglass. Wipe the stain on in a thick, even coat using a shop rag, and then use your brush to remove excess stain. Repeat as necessary to achieve the desired color.
Apply the First Coat
Paint should be applied to fiberglass in several thin coats. Brushing and rolling are options, but a sprayer saves the painter a great deal of tedium and time for this type of project. Try not to overspray, and coat the entire surface of the stairs evenly. Because there are several coats involved, only light coats are required, followed by a period of curing before adding the next coat. Allow the stairs to dry for 24 hours before moving to the next coat.
Apply the Finish Coats
The more traffic the stairs will receive, the more coats of paint are required for an appealing, durable finish. Fiberglass painting already advises the use of a minimum of 4 coats, and higher traffic areas would be well advised to use at least 6 Remember to allow each coat to dry for a whole day before applying the next coat. This may seem like a long delay, but painting over a still-damp area could ruin the whole job in just a few days.