Also called "liquid sandpaper," deglosser is a chemical solvent that removes the surface sheen from painted or varnished surfaces. Because new paint does not adhere effectively to shiny surfaces, the surfaces require sanding or deglossing to dull the finish before new paint can be applied. Traditionally, hand sanding was preferable for stripping away the surface gloss; in many cases, it is still the rule of thumb. Both methods have pros and cons.
You must remove the sheen from all shiny surfaces before painting or before applying a clear finish. A shiny surface forms an impenetrable barrier that does not allow new paint or wood finish to bond effectively. Liquid deglosser is comparable to fine-grit or microgrit sandpaper. If you're repainting an item with small spaces, such as a child's rocking chair, it may be easier to apply liquid deglosser in restricted areas than it is to get sandpaper into those tight spots.
To apply liquid deglosser, saturate a lint-free rag with the solution and rub the surface of the glossy item, gently rubbing and buffing away the shine. You may brush on additional deglosser and leave it on the item. Wait until the item is completely dry before painting. For small details, you can use a cotton-tipped swab.
Hand sanding to remove surface sheen doesn't make a dusty airborne mess that sanding rough wood creates. You'll need fine-grit sandpaper, like 220 or 240, and you'll lightly rub the sandpaper over the surface. Avoid using a coarser grit that can scratch the item.
Wear protective eyewear when using sandpaper or deglosser and wear chemical-proof rubber gloves when applying the liquid solvent. Sandpaper presents no environmental hazards, but use caution when applying liquid deglosser. The solvent vapours can be highly flammable, even explosive, so do not use deglosser near an open flame, like a pilot light. Promptly wash skin with soap and water if it's splashed and do not breathe solvent vapours. Contact your local waste authority about ordinances concerning disposal of leftover deglosser or empty deglosser containers. You may also call the EPA Solvent and Hazardous Waste hot line at 1-800-424-9345 for disposal instructions.
Deglosser does not replace sandpaper for smoothing wood grain. The liquid solvent only cuts the sheen on a high-gloss painted or clear-coat surface.