Expando FAQs

Got questions? Read these Expando FAQs to find answers to some of our customers’ more common questions.

What size holes do I need to drill?

Drill holes 28-40mm in diameter.

How deep do I drill?

Drill to 80-90% of the depth of the materials – do not go through. Hole depth must be a minimum of four times the diameter of the hole.

How far apart should I drill the holes?
See diagram below

The spacing, length (or depth) angle and diameter of the drill holes will be determined by the properties of the material to be removed and may require adjustment when areas of different hardness are encountered in the same rock body.

The following are examples of hole patterns for different situations and are to be used as a guide only.

It is recommended that a test pattern be trialled to ascertain the quality of the material to be demolished.

Removal of a toe rock

Removal of a toe rock

Bench Cut
Note: High faces may need to be cut in several layers.


Bench cut


Table 1 : Bench and Toe Cut
(Remove toe before starting bench cut).

Diameter (d) 28mm – 40mm
Spacing (s) 300 – 500 mm
Height (h) 100% (+ 5% if flatter base required)
Angle (<) Parallel to free face


Shallow Trenching


Shallow trenching


Deep Trenching


Deep trenching

In thin materials holes should be angled between 45 and 60 degrees for greater breaking effect.


thin materials holes

How much EXPANDO will I use?

32mm Drill x 1 meter deep hole = 1.3kg Expando
34mm Drill x 1 meter deep hole = 1.5kg Expando
38mm Drill x 1meter deep hole = 1.8 kg Expando

Before drilling consider the maximum broken rock or concrete size you can safely manoeuvre.

The following are some estimated weights per M2 of each material.

Sandstone 1M2 = 2.2 to 2.7 Tonne
Granite = 3 Tonne
Limestone 1M2 = 2.4 Tonne
Concrete = 2.4 Tonne

How should I design my hole patterns?

Consider the maximum broken rock or concrete you can safely manipulate. Then plan out your hole pattern.

Available Types of Expando

Chemical reaction of Expando depends on the temperature of the breaking object.

SCA I 20°C – 35°C

SCA II 10°C – 25°C

SCA III 0°C – 15°C

The reaction time of Expando to crack stone varies from 24 hours to 72 hours, depending on the cracking object, material, hole design and temperature. Generally speaking, within the temperature scope of each type, the higher the temperature of the object and the closer together the holes, the quicker the object will crack (otherwise, the opposite will occur).

Technical Information

Tips on how to use Expando

Safety Instructions

Additional technical support

For more technical advice or support, contact our support hotline directly on 0402 759 895 or email info@expando.com.au