dip up to a third of the bristle and tap on the rim; a 4″ is meant to carry a big load, but paint driven into the heel still kills the brush. Two hands, always when charged: a fully loaded 4″ of natural bristle is heavy and fatiguing — steady the ferrule and let the brush's width do the work rather than fighting it one-handed. Spread with the grain, then back-brush to level and key the coat. Keep the wet edge moving so a broad surface doesn't lap. Clean thoroughly with the coating's solvent — a wide brush holds a lot of paint deep in the fill, so rinse and work the heel until it runs clear, then reshape and wrap. Even a utility brush repays this: the heel is where brushes die.
Asked before buying
BUYER QUESTIONS, ANSWERED BEFORE YOU ORDER
What's a 4″ brush actually for?
Getting a big oil or stain coat onto a broad surface — siding, fences, decks, large metal — quickly, with a back-brush pass to level and key it. It is not a precision or line tool.
Can I use it for latex siding paint?
No — natural bristle floods and flares in water. Use the polyester MARS 80005.
This or a roller for a wall?
For broad flat area a roller is faster and less tiring; the 4″ brush is for board-by-board work, back-brushing, and surfaces a roller can't key paint into.
This or a dedicated stain brush for a deck?
For big stain jobs the mixed-bristle 80202 holds more and is built for flood-and-wipe; the 80055 stains fine but is the general oil flat.
What's not published?
Bristle length, thickness, ferrule, and fiber species — not in Richard's data, not claimed here.
