Mouldmaking using Gel-Flex PVC Compound

Anyone who has experimented with casting will appreciate that the process of designing and making the mould is the most critical part of the process. ‘One-off’ simple block or slab casts can often be produced using scrap mdf to create the framework before pouring and then breaking the frame for removal of the completed cast. This is usually successful but can be restrictive in terms of detailing and can often mean destroying the mould to remove the cast.

In order to capture more intricate details of an object we can use silicone rubber which is widely used in the art and design industry. The main drawback of using silicone is its cost and only having one-purpose once it has cured.

A great alternative we are encouraging for testing is ‘Gel-Flex’ PVC Compound which can be melted, poured, cast into and then remelted and re-purposed to make several moulds with the same amount of material.

Monty gel flex tests (2) Monty gel flex tests (1)Using Gel-Flex

At present we are unable to provide a method of melting the compound in the workshop but this product can be easily used at home by heating using a conventional hob or microwaved in a suitable dish (As Monty explains below – preferably glass!). Instructions are provided with the product which you should always read and make sure you understand thoroughly before using.

gelflex

Once the product is in a liquid state it is poured in the same way as with conventional silicone mouldmaking into a box mould over the object you are wanting to cast.

The main drawback to using Gel-Flex is that it isn’t as durable when being used to produce high numbers of casts. Eventually the mould can become over-stretched and can rip. The beauty being that the material can then be melted again and poured to create the mould again – eco considerate and cost effective if you need to mould multiple items.

Monty gel flex tests

Case Study: 1:1 Facade study casts by Monty Dobney

“Gel Flex was great to create the intricate detailing required to for a 1:1 model of my paternated bricks. I first laser cut and glued together (the most time consuming step) an mdf master for the mould to then be covered with the Gel Flex.

After reading the instructions I decided to melt it in a microwave oven, on the first attempt I melted the plastic ‘microwaveable’ container which I had decided to use to melt it in. But two containers stacked seemed to do the trick for holding their form! It was also important to keep checking on it as it can very easily ‘over cook’ which turns it brown (as can be seen in the image below) and a strong burning plastic smell!  I successfully used the Gel Flex to cast from both plaster and wax.”

Monty Gel Flex Tests (4) Monty Gel Flex Tests (5)

Gel Flex is available to buy from 4D Modelshop where you can get 10% student discount or at  Fred Aldous in Manchester and can be found by clicking here.

1:1 ‘Green’ Facade detail by Alexandros Pavlides

As part of his ‘Sensory Markets’ project Alex Pavlides has created a 1:1 section of brick wall to display a possible facade detail providing an organic coat to existing brick walls in Manchester. 1.1 Facade Detail (1)The approach to recreating the brick wall was much like that of Polys Christofi’s project last year but focussed on a much smaller area for the detail. Bricks were made using plaster casts from vac-formed moulds before being painted to resemble red brick and then pointed like a full scale wall. 1.1 Facade Detail (6) Details of the intervention were made up using laser cut acrylic bases, abs tubing and threaded rob before being sprayed silver to represent the intended metal finish of the mountings. The detail mounts were then fixed to the ‘wall’ and mesh was added to the ends creating an elevated platform to encourage plant growth in front of the wall. The mesh was then secured using washers and bolts. 1.1 Facade Detail (8) Alex describes his approach to the project:

“I’ve tried [to] introduce an intervention that makes the alleys memorable to the people by making the alleys acting as “landmarks” in the city. The intervention is about applying moss on different surfaces in the alleyways and create architecture from moss. I designed an external skin of the brick walls made of steel wire mesh and the moss will be applied on the mesh at different points of the city. “

1.1 Facade Detail (15)Alex is currently working on getting moss to grow on the mesh to be displayed later in the year and we look forward to seeing the results! We will post an update of how he progresses.

Scott

1:1 Facade Detail Model, Henry Faulkner

[Re_Map] student Henry Faulkner has created this 1:1 detail model demonstrating the variable solar shading facade concept he has designed.

facade section1These two renders show how the facade would appear with shades open (above)and then closed (below)
facade section2Henry describes the project for us:

The overall project has resulted in a mixed use development which aims to provide housing and an educational facility for academic refugees from around the world. The vast majority of refugees entering the UK in recent years have been from the middle east and northern Africa, from countries such as Iran, Afghanistan and Syria. Taking influence from their history and culture, I developed a facade component that adopts an Islamic geometrical pattern, using its rotational symmetry to create a dynamic solar shading device. (Henry Faulkner 2014)

Henry FaulknerHenry cut the gearing for the model using acrylic to create the components which he had developed through test models previously. The refined design was then drawn up in cad and the component profiles laser cut – fabric included. When cutting fabric or any material you are unsure of it’s always a good idea to run some tests on a scrap piece to ensure the finish you wish to achieve.
Henry Faulkner Re_Map (3) Wire was used as a former and support for the fabric ‘fans’ which when stretched out want to fold under their own weight.

Henry Faulkner Re_Map (2)Henry Faulkner Re_Map (5) Henry Faulkner Re_Map (7)

Henry Faulkner (8) Henry Faulkner (9) Henry Faulkner (11)

1:1 Structural Detail Model, Polys Christofi

I have no doubt that many of you will have noticed the unusual 1:1 detail model that was developed here over the last few weeks before our Christmas break. Polys Chritsofi had decided he wanted to produce he structural study at 1:1 on a mock up brick wall facade. This was an advance on his previous cardboard mock-up which was made at 1:2 Scale.

The journey from idea to reality was an interesting one with several learning curves along the way. Rather than using brick slips (thin cut brick faces) to create the brick wall backdrop Polys decided to use vac formed moulds to create plaster bricks to save on weight and cost. It was an unusual approach that turned out very well.

The detail itself was largely CNC’d outside our workshop and brought in for assembly and finishing. To create a smooth joint between cut components the pieces were laminated together and clamped to dry before being coated in sandsealer.

Applying sandsealer, sanding and repeating is often necessary to achieve a smooth finish on pores materials such as MDF. Any flaws in the surface can further be smoothed using a filler. When the finish was smooth after much sanding, the components were primed with spray primer and painted with a roller.

The plaster bricks were painted with spray paints and individual speckle detail added by hand later. The bricks were then fixed to a back board with an imitation lintel as featured on the actual detail. Once fixed to the back board it was clear the piece would be awkward to move and it was decided that the facade should be made into a skate by fixing wheels that would allow the whole model to be wheeled around.

The bricks were evenly spaced and fixed with Grip Fill adhesive.  To finish the look of the facade mortar was mixed and applied to the joints in the same manner as an actual wall would be pointed. Polys had no experience of this but with a little guidance from Jim was able to get the job done.

 

Finally the finished components were assembled and bolted in place on the facade board. This level of realistic detail is rarely necessary to convey a design and could be argued is not in this case but the new skills learnt through the process, and their application in later design ideas, will undoubtedly prove very useful for Polys.