Mixing resins with aggregates
The aggregate is stored into batches and the bags are opened. Mix bags of aggregates from each pallet to ensure a consistent mix.
- Tip half of the aggregates (2 bags/50kg) into the mixer and then add the resin.
- Mix for approximately 30 seconds then add the remaining aggregates (2 bags/50kg).
- After the resin is thoroughly mixed through, add the kiln dried sand.
- Mix for 5 minutes until the sand is dispersed evenly though the mix.
- If you’re using a blend of stone (25% 1-3mm and 75% 2-5mm), the smaller stone must be included in the first 50kg of stone in the mixer.
Remember: Ensure each batch is mixed for exactly the same period of time, as small changes in mixing time can alter the colour of the finished material. It is advisable to use a stopwatch to ensure times are accurate.
- Incorrect mixing of the resin will cause the material to fail. The operative must monitor the efficiency of resin mixing by checking the empty tubs. After around 30 minutes, scrape out the skin of the congealed resin from the first few tubs with a sharp tool. There should be no residue between the skin of the resin and the base or sides of the tub. Repeat this check hourly.
- Do not use aggregates that appear damp in the bags.
- Insufficient mixing time may result in uncoated material.
- Keep all aggregates in the shade. Heating them up will increase the curing time of the resin.
- If it looks like it’s going to be a hot day, start early!
Resin quantities to aggregate vary, however a general rule is 7-15% resin by weight depending on the stone size, depth of layer and strength required. A blend of stone sizes 2-5mm and 1-3mm will give a terrific increase in strength or allow a lower resin ratio. This creates a compact finish while many prefer the 2-5mm alone as it creates a preferred gravel like appearance.
However, a thoroughly blended mix, that has the majority of the cavities in the mix filled, will produce a longer lasting surface and it is a more cost-effective way than increasing the resin content to get the same effect.
To achieve a non-slip surface, two things can be done. The first is to introduce a small bag of C52 sand into the mix which will give a gritty finish to the resin or secondly, broadcast some C52 sand onto the actual surface before the resin sets completely.
Mistakes can be expensive to rectify, so please take care to discard any suspect batches.