Pointing Mix

1. Mixing

1.1 Place 2.0 litres of clean water per 12.5 kg bag (or pro rata for smaller quantities) in a mixing tub and gradually add dry EasiPoint powder whilst mixing. Always add powder to water, rather than water to powder to avoid inconsistent mixing and the danger of lumps blocking the gun.

1.2 Mix in a wide shallow pan with a low speed mixer. (Use of high-speed mixers should be avoided this may result in air being entrained within the mortar).

1.3 Mix until the mortar achieves a consistency similar to plaster adding a small quantity (up to 0.5 litre per full bag) of additional water if required. Allow the mortar to stand for approximately 5 minutes during which time the mortar will stiffen. Remix with the addition of a small amount of water if necessary. The quantity of water that may be needed will vary with the colour of the mortar being used (seek advice). This can be checked by filling the tube; the mortar should not run out but should fall out in ‘drops’ when the tube is shaken.

1.4 Mixed mortar may be kept for up to two hours before use, depending on weather conditions. It may be necessary to cover the bucket / hopper with either damp hessian or polythene sheeting. If the mortar stiffens within two hours then it may be re-mixed.

1.5 Use a hand brush and mixing water to wash down the sides of the mixing pan and tubes before adding the next bag of mortar. Care should be taken to avoid any hardened lumps of mortar or debris falling into the mix, as these will block the gun.

2. Use of Gun & Filling Joints

2.1 Adjust the gun to ensure the rubber washer is just in contact with the walls of the tube. Only fingertip pressure on the trigger is required, greater pressure indicates that the washer is too tight and needs adjustment. Fill to within 20mm of the top and shake gently to dispel air pockets. Full tubes may be stored upright in a bucket with 20mm of water in the bottom to prevent the mortar in the nozzle from stiffening.

2.2 Place the tube in the gun so that the chamfer of the nozzle faces upward. Squeeze the trigger pumping a small amount of mortar into the  mortar bucket to ensure there is no blockage.

2.3 Pointing should commence at the top of the wall and proceed in horizontal bands downwards convenient to scaffolding arrangements. The horizontal bands should be completed in areas approximating to the extent of the joint that can be filled with one tube.  The depth of the horizontal band should relate to comfortable working heights and convenient scaffolding arrangements. The horizontal bands should be completed in areas approximating to the extent of  the joint that can be filled with one tube. The depth of the horizontal band should relate to comfortable working heights and convenient scaffolding lifts, approximately 1m or 12-13  courses of brickwork.

2.4 Hold the gun at the handle and close to the nozzle to maximise control. Keep the nozzle just clear of, or lightly resting on the wall. Inject mortar into perpendiculars starting with the lowest course, filling each joint from the bottom to the top.

2.5 The trigger of the gun should be pulled with a long squeeze to achieve a smooth flow of mortar and consistent fill. There should be little pressure build-up in the gun and so, unlike a mastic gun, the mortar stops flowing when the trigger is released.

2.6 After filling perpendiculars, swivel tube so that the chamfered nozzle runs parallel to the bed joints and holding gun a constant angle to the wall fill the bed joints in a smooth action, always pulling towards the operative. Approximately 4 brick lengths of bed joint will be filled at one pass. If the joint is of inconsistent width or depth requiring varying amounts of mortar, then either the speed at which the nozzle is moved along the joint or the speed of pumping (or both) can be varied. The trigger should be squeezed with confidence so that mortar is injected  to the back of the joint and slightly overfilled.  Wastage of mortar due to overfilling is less expensive than time wasted going back to an area of underfill. After some practice with the gun, wastage will be kept to a minimum.

2.7 Attention should be paid to complete and continuous filling of the joints  at corners, so that weak points and cracks are avoided. It is recommended that the joint is filled by running the nozzle around the corner rather than up to and away from the corner at each side. Where joints are less then 10 mm in width, the use of a restrictor nozzle may be required.

3.  Tooling-Off

3.1 The most effective (and easiest) joint profile is the half round or “bucket handle”. Using the ‘bucket handle’  jointing tool to press the mortar into the joint ensures that the joint is filled and sealed against the top and bottom faces. Other joint profiles may be achieved using a pointing trowel or a proprietary pointing tool.

3.2 The mortar must be tooled-off after it has formed a semi-dry surface skin but before it is too stiff to work; this can be seen by the mortar loosing its initial “wet” sheen. The time the mortar takes to dry to this state varies with the absorbency of the brickwork and the weather conditions. If the wall is particularly porous or in very warm weather, the wall should be mist sprayed prior to pointing to reduce initial suction.

3.3 The tooling-off technique with the “bucket handle” tool is to push rather than pull or drag it when making the first pass. This allows the operative to apply more pressure, which carries along a small wave of mortar filling and pressing the mortar more effectively into the joint. Corners, details and reveals should be tooled-off so that mortar is pushed or pressed into all the corners rather than pulled away from them. The jointing tool may be “rocked” around external corners to avoid pushing the mortar out. If the joint width varies then different sized jointing tools will have to be used to maintain a consistent finished appearance. When tooling the excess mortar should ‘crumble’ away. If the mortar folds over onto the brickwork or watermarks can be seen on the surface, leave and attempt again in 20 minutes.

3.4 Brush off with a fibre brush when the mortar has dried sufficiently not to be marked, but before it has cured. Generally brush off at the end of the days work, but do not leave overnight. Brushing off hard enough at the right time will remove mortar smudges from the face of the work. Brushing off too early will smear the mortar onto the face.

3.5 After tooling-off on very dry days it will be necessary to “mist spray” the joint to avoid fast drying which could cause cracks.

Advice offered by Amber Precast Ltd is given in good faith and it is to the best of our knowledge accurate and true, but is offered without guarantee.

If you require more information please contact us on:
tel: 01773 540707 email: info@amberprecast.co.uk

Technical Data Ref: TDS/016 January 2010