Acid brushes for tubular gluing are cheap and perfect for the job. Available at your hardware store.
Ram-pro 48 Flexible Horsehair Bristle Tin/Metal Tubular Ferrule Handle Acid/Flux Brushes for Home/School/Shop/Garage
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1/4 Diameter Horse Hair and Tin Handle Acid Brush 900431 - Gordon Brush
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Buy Brushes - 12 Count 3/8 Inch Horsehair Flux Brushes, Disposable Glue Brushes for Woodworking, Epoxy Brushes for Resin, Great for Crafting, Soldering, in The Home, and School, or Shop Online at desertcartBahamas
Tubular Tire Gluing (Sew Up)
Horsehair Bristle Acid Shop Brushes 1/2 36 Piece 2 Packages