Weldbond : Working with Plaster & Drywall

Weldbond offers superior bonding strength! 

It's ideal for cementing joints to walls, floors and ceilings, including fillets, tiles, slates and pointings. Weldbond also adds great strength to plaster work over glazed tile and painted surfaces.

Preparation for all plaster work: Clean all surfaces thoroughly. Glossy (painted) surfaces must be sanded. Porous surfaces must first be primed.

To make a sturdy plaster bonder: Use Weldbond straight from container or dilute 1 part Weldbond with 3 parts water. It gives extremely high adhesive strength to all types of plaster— cement, or finishing plaster— as long as surfaces are clean and structurally sound. Plaster keying: Apply the 1-part-Weldbond-3-parts-water mix with a pump type sprayer, roller, sponge, or brush and proceed to plaster while adhesive is still tacky. Porous surfaces must be primed with a solution of 1 part Weldbond, 5 parts water and allowed to dry.

To plaster over painted surfaces and glazed tiles: Thoroughly clean surfaces. Glossy painted surfaces must be sanded. Apply concentrated Weldbond to surface; plaster it while still tacky.

To bond gypsum board: First seal porous surface, 1 part Weldbond with 5 parts water and allow to dry. Bond this material to any surface using concentrated Weldbond. If the surface is uneven, use a plaster slurry to take up the unevenness. To make the slurry, add plaster or cement to Weldbond to form a thick paste.

Gypsum board to foam plastic to concrete: Make a thick paste by adding Portland cement to 1 part Weldbond, 1 part water. Apply to surface in daubs no smaller than 2" in diameter, 16" apart. Place each sheet into position using a wood shim and mallet, levelling as you go. If drying conditions are poor, increase the paste's tackiness by reducing the water content and/or by using ready-mix mortar instead of Portland cement.

Strapping-Furring: Seal any porous surface to be strapped with the sealing mixture. Acts as a vapour barrier. Next, mix 1 part Weldbond with 1 part water. Add sand-mix cement or Portland to obtain a thick, workable mixture. Apply along full length of strapping or by using daubs every 6" to 8". Tap into position and level as you proceed.

Sand and cement: To render over glazed tiles and painted surfaces, sand first. Clean surfaces, apply concentrated Weldbond and allow to dry. Next, apply a further coat of concentrated Weldbond and render up while still tacky. Note: when using this method over painted surfaces, the bond achieved will depend on the paint holding the weight of the rendering.