To wipe on poly (polyurethane), you typically use a lint-free cloth to apply thin, even coats to the surface of your project, following specific techniques for horizontal and vertical areas, with sanding and buffing steps in between and at the end.
Applying polyurethane with a cloth, often referred to as "wiping poly," is a popular method for achieving a smooth, durable finish, especially on furniture or trim. This technique allows for greater control and reduces brush marks compared to traditional brushing methods. The process involves several key steps to ensure a professional-looking result.
Achieving a beautiful, wiped-on polyurethane finish involves careful preparation and application. Here's a breakdown of the process:
1. Choosing Your Applicator
It starts with the cloth. The first step in wiping on poly is selecting the right applicator. A high-quality, lint-free cloth is essential. Materials like old cotton T-shirts, microfibre cloths specifically designed for finishing, or commercially available wiping pads work well. The goal is to find something that applies the finish smoothly without leaving behind lint or fibres.
2. Applying the Polyurethane Coat
Once you have your poly and your cloth, it's time to apply the first coat. Dip a portion of your cloth into the polyurethane (or pour a small amount onto the cloth) and begin wiping it onto the surface in the direction of the wood grain. Ensure even coverage across the entire piece.
- Horizontal Surfaces: Apply heavy coats on horizontal surfaces. For flat, horizontal areas like tabletops or shelves, you can afford to apply a more generous amount of poly. The finish will level out nicely on its own due to gravity.
- Vertical Surfaces: Apply thin coats on vertical surfaces. On upright surfaces like table legs or cabinet sides, applying thinner coats is crucial. Thicker coats on vertical surfaces are prone to sagging, dripping, and running, which can ruin the finish. Wipe the poly on lightly and quickly, working your way across the surface.
Aim for an even, wet film across the surface. Wipe off any excess finish before it starts to dry.
3. Allowing Proper Drying Time
Allow the first coat to dry completely according to the manufacturer's instructions on the polyurethane can. Drying times can vary significantly based on temperature, humidity, and ventilation. Proper drying is vital for the subsequent steps.
4. Preparing for the Next Coat
Sand between coats. Once the previous coat is fully dry, lightly sand the entire surface. Use a fine-grit sandpaper, typically between 220 and 320 grit. The purpose of sanding between coats is twofold:
- To knock down any raised grain or imperfections.
- To create a slight "tooth" for the next coat to adhere to, promoting better inter-coat adhesion.
After sanding, thoroughly remove all dust using a vacuum, a tack cloth, or compressed air before applying the next coat.
5. Applying Subsequent Coats
Repeat step 2 (applying the coat) and step 4 (sanding between coats) for subsequent layers. Wiping poly typically requires multiple thin coats (three or more are common) to build up a durable finish. Applying several thin coats provides better results and durability than one or two thick coats.
6. Achieving a Smooth Finish
Final buffing. After applying the final coat and allowing it to cure fully (check the manufacturer's instructions for curing time, which is often longer than drying time), you can buff the surface. This step is optional but helps achieve a super smooth feel. You can use very fine abrasives like 0000 steel wool or synthetic finishing pads to gently buff the surface, following the grain. This process removes any final minor imperfections and provides a silky smooth touch.
Tips for Best Results
- Always work in a well-ventilated area.
- Wipe on poly in consistent, even strokes.
- Check for drips or runs, especially on vertical surfaces, and wipe them away immediately.
- Allow adequate drying and curing time between steps.
- Clean spills or drips quickly with mineral spirits or the appropriate solvent for your poly.
By following these steps, paying attention to the specifics of horizontal versus vertical application, and incorporating the necessary sanding and buffing stages, you can achieve a professional, hand-rubbed look with wiped-on polyurethane.
