UVPoxy provides a crystal clear top coat finish to your projects, but what happens if you get bubbles and how can you avoid them?
Unlike deep casting epoxies like FlowCast® which have a lower viscosity, and take hours to solidify, allowing more bubble release during the reaction, UVPoxy is a viscous and faster curing epoxy. UVPoxy's fast cure time allows you to machine and finish your project faster. With this fast cure, extra attention is needed during the working time (approximately 20 minutes) to avoid bubbles. This article will take you through step-by-step how to apply UVPoxy to reduce bubbles, you can also find detailed instructions on the use of UVPoxy by consulting the UVPoxy Application Sheet.
Common reasons for bubbles in UVPoxy include:
- Over mixing.
- Forgetting to apply a seal coat to the wood and other porous material prior to applying UVPoxy. Skipping this step means that when UVPoxy is applied, it will attempt to fill grooves in your wood, which then brings bubbles out of the wood during application.
- Air releases from under what is being casted is let out.
- Air can get trapped at interface between the existing surface and the new UVPoxy layer.
How to avoid bubbles when applying UVPoxy top coat:
- Clean the surface to be coated with rubbing/isopropyl alcohol to remove any contaminants and dust that may cause bonding issues or bubbles.
- Pre-seal by applying 2 thin seal coats of UVPoxy with a foam brush to fill in any gaps that could release air bubbles. Apply these coats within 4-5 hours of each other while the epoxy is still tacky to touch. This gives the next coat a surface to adhere to.
- Immediately after applying each pre-seal coat, use a torch during the working time to pop any air bubbles that may come up.
- If your first coat has completely cured, you will need to rough up the surface before applying your next coat. Use 220 or 320 sandpaper to scuff up the entire surface to be coated, then wipe it clean with rubbing/isopropyl alcohol. Ensure the alcohol is completely dry before applying your second coat of epoxy.
- You can then apply your final UVPoxy pre-seal coat (up to 1/8” thick) using the V-notch spreader’s ¼” notched edge to spread the UVPoxy coat across the entire surface at a 1/8” thickness.
- Don’t over-mix. It is common to over-mix when using a powered mixer, such as a drill. We recommend slowly mixing the epoxy coating product by hand to avoid excess air entrapment in the batch. With smaller batches, it is more likely that air bubbles will be introduced.
*Note: When you start to mix UVPoxy it will start to look cloudy and then become clear once mixed enough to pour.
- Apply the final UVPoxy layer in two quick steps:
- Ensure your project is level, and with your one container of mixed epoxy, pour a portion of it to add a thin layer to the surface. Manipulate and spread the UVPoxy over the entire region you wish to coat with a foam brush or the flat edge of the v-notch spreader. This will break the surface tension and release any air trapped between the surface and the UVPoxy coat.
- Immediately after applying the thin coat, pour on the rest of the UVPoxy and spread to a maximum thickness of 1/8". Do not allow the thin coat to gel before applying the rest of the UVPoxy coat.
- Watch it throughout the entire workable time as bubbles will continue to release as it settles (approximately 20 minutes). During the working time, use a torch every 3-5 minutes as needed to pop any bubbles in the coating. When using the torch keep the flame 4-5 inches away from the epoxy coating and use a smooth sweeping motion to avoid overheating. WARNING: DO NOT heat the epoxy coat once it starts to gel (i.e. after about 20 minutes). Heating during and after gelling can cause surface waviness, discoloration, cracking/crazing and un-even curing.