GRP Silicone Bag Infusion Process

GRP Silicone Bag Infusion is one of a range of GRP manufacturing methods used at AllScope Projects.

The silicone bag infusion process offers great precision, high quality, minimal waste, less set-up equipment and can be used several hundred times. Not only that, it provides a quick production turnaround and is easy to store.

This process has developed from the traditional ‘vacuum infusion process’ that used a disposable plastic film for each vacuum process.  

In comparison, the traditional ‘vacuum infusion process’ typically creates a large amount of waste in materials and time. As each production cycle requires a new set of materials to be cut, shaped and sealed manually, the hand laying set-up time becomes time and labour intensive. More tooling and materials are needed and the nature of the set up creates a higher risk of inconsistent resin flows, leading to failures and repetition of the set-up process. 

The ‘silicone bag infusion process’ removes all of this waste and increases production volume with less production time. As a single part membrane, it is quicker to lay and prepare for resin. It also provides a more airtight and consistent resin flow, vastly improving quality and minimal repetition due to low failure rate. The silicone bag is also reusable time and time again.

The GRP Silicone Bag Infusion Process

1. A master mold, that contains the surround flanges, is cleaned and coated with a release agent. The flange area is checked to ensure it is flat and smooth.

2. Where required, a layer of paper membrane can be placed on the inside of the flange, as close to the cavity as possible. This allows air to move from the cavity to the vacuum channel.

3. Layers of glass fibre are laid inside the cavity to the required strength, weight and structure required.

4. The resin inlet and vacuum outlet are then installed.

5. The silicone bag is placed over the mold and is securely positioned into the cavity.

6. Air is removed from any space between the mold and the silicone bag, tightly compressing the bag and glass fibres and pressure is tested to ensure there are no leaks.

7. We then catalyse the resin and introduce it via the resin inlet line.

8. Once the resin has fully infused, it is left to cure. This process is completed in a temperature controlled environment to ensure the resin does not cure before the infusion is completed.

9. The silicone bag is then removed via an easy peel one piece process, as the part extracted from the mold. 

Benefits of GRP Silicone Bag Infusion Process

The benefits are clear to see for designers, manufacturers and customers.

Ability to produce more complex shape parts:

Due to the flexibility and close contact composition of the silicone membrane, it can custom form tight around more curves and recesses of a more complex part mold design. In line with significant time savings and reduced waste, the preparation time is much quicker and as a single unit silicone bag, means there is no waste through multiple plastic cutting lay-up. 

Significant Cost Savings: 

Although there is an initial investment in the creation of the silicone bag, it is far more economical in the long term. The silicone membrane material can withstand hundreds of resin infusion cycles and as one unit, removes the need for multiple individual plastic layers. 

Significant Time Savings:
The materials are light weight, easy to manoeuvre and production time is reduced due to faster lay-up preparation time. This naturally enables a higher volume production in a shorter time period. 

Consistent Quality and Strength:
The silicone membrane forms a tight seal that enables a more uniformed resin flow and precise fibre consolidation, resulting in a stronger and more durable part. 

Lower Environmental Impact: 

The single unit silicone bag reduces the need for multiple plastic cut parts and the controlled resin flow means less excess resin and material is wasted. The durability of the silicone bag means it can be used hundreds of times before a replacement is needed. 

Silicone Bag Process Parts:

At AllScope Projects we can use the GRP silicone bag infusion process for a range of parts and sectors including: 

• Rail and transport: Ceiling panels, access panels and bulkheads.
• Washroom and sanitary: Baths, shower trays and cubicle panels.
• Marine: Hulls, decks, seating and hatches. 
• Industrial: Protective covers and housing units.
• General: Signage, cladding and ducting parts.

AllScope Projects are UK manufacturers and members of Made in Britain and CompsitesUK .

To find out more about the GRP silicone bag infusion process and how it could improve your product quality and production process, get in touch on 01282 446330 or click to use our contact form here.