Tag: grc

the art of mould making final stage

The mould is now lined / trowelled with glassfibre cement [GRC] 12-15mm thick to create a smooth, glassy finish, then cleaned of any loose threads, and left to set for 24 hours. Once set, the crane is used to pull the finished product from the mould and detailed.

We now have 3 parts of the tree ring clamped together, the seams will be bolted and potentially filled with a gasket [dependent on end environment].

See our facebook page for the full gallery of images.

the art of mould making part 2

The wooden frame is now coated in fibreglass and sanded to create the plug which in turn makes the finished mould, this process will take approximately 3-4 days. This is a third of the overall tree ring so it’s no small task.

the art of mould making part 3

Now that the plug is complete we begin to cover the plug in a fibreglass shell [the red ends in the first image are the beginnings of the mould]. Once the new fibreglass top/shell is completed a frame is built around the mould so it can be inverted, then the plug can be removed from the mould using the crane.

During this process the plug will usually end up slightly damaged, but now if we ever have to make another plug we can do so by working back from the mould.

Stay tuned for the final stage and where will join together the 3 pieces which will make the complete tree ring.

Manufacturing with GRC (Part 2) Making the plug

Making moulds is fundamental to our operation as a manufacturer of GRC products.  And over the years we’ve got pretty good at it.  In this blog we feature the first step in making a new fibreglass mould for a new seat shape in our POD range of street furniture.  That first step is the plug. 

Dave (who wishes to remain anonymous) is one of our three mould-makers, and he started on making the plug a week or so ago.  The plug is the exact shape of the end product, and it is from the plug that he will make the fibreglass mould.  We typically build the plug from timber materials or from CNC-cut high density foam. 

Once the basic shape of the plug is made, the next step is to apply high-build coatings that are then hand-sanded and polished to a high gloss finish.  This is the long and laborious step.  The fibreglass mould surface will reflect the surface of the plug so it’s important the mould-maker (i.e. Dave) gets this step right. 

Dave has photo-documented each step in the process starting with the timber materials, making the plug which in turn makes the mould for the newest member of our POD street furniture range, Bulb.  Next week he will move on to step two – taking the fibreglass mould off of the plug.  

the art of mould making

Today at Quatro we are making a mould for a 4m dia tree ring with bench seat and thought we’d like to share some photos of the process involved in making something that in theory seems so simple.

The timber frames used to make the mould are one of the most time consuming processes in the overall construction of the product, using tecninques heralding back to old barrel making or clinker boat building. The mould is painstaking built in timber first, screwed & glued, [the stage that you see here] then the thousands of screws used to build something of this size are taken out and the holes bogged & filled. Overall this first stage of the mould making process will take approximately a week. This old fashioned technique is favoured by us for various reasons but another way of producing a mould like this would be cutting a CNC 3D mould in foam. A dying art? Stay tuned for the next stage!

Manufacturing with GRC (Part 3) Laying up the firbreglass mould

In the previous blog, we followed Dave in building the plug from which the fibreglass mould is made.  Now that he has built the plug and polished the surface to a high gloss finish, he’s ready for the next stage – laying up the fibreglass to form the mould on the plug.   


To begin he spray-applied a gelcoat layer on to the plug surface.  As soon as this has cured/hardened sufficiently, he begins applying layers of fibreglass chopped strand matt and wetting it out with polyester resin.  This hardens and forms a fibreglass shell – the negative shape of the plug.

The mould for this project is a two-part mould.  Dave lays up the main body of the mould, and then turns the plug over and then lays up the second part which forms the lid section.


Once both mould parts are completed, the plug is separated from the mould.  Here we see Dave sitting on the plug next to the mould.  Nice work, Dave!

Manufacturing with GRC (Part 1) Design & Development

At Quatro Design we design and develop a wide range of our own products. Sometimes an idea or design concept can inspire us to develop an entire product range based on the original concept.


A good example of this is our SOUL range based on the timeless design of the terracotta flowerpot.  Our new Delta seat planters were inspired by the design of a coffee table seen at Harrods in London. 


We are a solutions-based manufacturer, and in addition to developing our own products, we also work collaboratively with architects and designers to design and deliver products that meet their specific design requirements.


Moulds are at the heart of what we do. Mould fabrication can be expensive and we are always mindful of this. We are always looking for creative ways to keep our mould costs as low as possible. Where possible we strive to ensuring a mound has multiple uses.  Oftentimes we’re able to adapt and reuse moulds on other jobs. This helps to keeps to reduce mould costs and consequently the cost of products.  


Our design team understands GRC. We design to ensure that a product is buildable and will deliver the best possible outcome for our clients. At Quatro Design we love challenges and we’re always inspired by new designs that push the boundaries of GRC manufacture for landscape and streetscape-related products.  In recent times we’re seeing an increase in inquiries for custom balustrade planters and green wall façade planters.

asbestos planters replaced

When the York Apartments in Sydney’s CBD were built several decades ago, asbestos was widely used in the construction industry.  And so the planter boxes that line the walls of the carpark levels in the building were made out of asbestos panel. 

But after years of service the planters were falling apart from rootball pressure.  The solution was to replace all one hundred and sixty-four planters with glassfibre reinforced planters made by Quatro Design. 

We’ve included here some images showing the new planters in position and planted out.


mermaid sculpture in GRC

Who says concrete isn’t sexy?  This mermaid sculpture cast in glassfibre reinforced concrete (GRC) proves that it can be. 

Gold Coast sculptor Midge Johansen approached us  to see if we could cast a sculpture in concrete using the silicone mould she had made from her original clay model. We were up to the challenge, and In all we made four mermaids from the mould.  The one pictured here was painted using speciality paints to achieve an aged-bronze appearance. 

The sculpture is 1 metre long x .7 metre wide x .7 metre high.  We cast it using a combination of GRC manufacture techniques.  Firstly, highly liquid premix GRC was poured into the up-side-down mould to fill the difficult-to-access voids that form the mermaid’s head and upper body, and the octopus arms. Then the lower part of the sculpture was formed with spray GRC.  This means that much of the sculpture is hollow making it lighter and easier to handle.   .  

world of concrete expo in las vegas

‘What happens in Vegas stays in Vegas’ isn’t necessarily true. Last week I returned to Australia after visiting in late January the enormous World of Concrete Expo held annually in Las Vegas.

It took me almost two days to see most of what’s on display — which is just about anything and everything to do with concrete.  Three massive halls of the Las Vegas Convention Centre are filled with stands and exhibits by concrete equipment manufacturers and concrete product suppliers. Plus there’s a large outdoor display area.

The glassfibre reinforced concrete industry was represented by NEG, a Japanese manufacturer of alkali-resistant fibreglass used in GRC products.  Also on the stand was Ian White of Power-Sprays which supplies equipment for the GRC industry. Later on during my trip I visited the Power-Sprays factory in the U.K.

Of particular interest to me were the displays of decorative coatings available for concrete. All sorts of special-effects can be achieved on concrete surfaces using dyes, stains, epoxy coatings, metallic additives, etc. We’ll be looking at how we can incorporate some of these effects into our products.

Overall it was a very informative and worthwhile show to attend.  And then there’s all the other attractions in Vegas. Highlights included going to the top of the half-size Eiffel Tower, and then watching from there the Bellagio water-fountain show set to music. Truly spectacular!