Fibreglass is an excellent repair material. As a composite –...
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Fibreglass (GRP) Flat Roof Repair Kit
£54.00–£270.00Price range: £54.00 through £270.00
Fibreglass is an excellent flat roofing material that has established...
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Fibreglass (GRP) Flat Roofing Kit (600g)
£150.00–£1,239.00Price range: £150.00 through £1,239.00
Fibreglass is an excellent flat roofing material that has established...
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Fibreglass Pond Kits – Resin Library
£88.00–£1,039.00Price range: £88.00 through £1,039.00
Resin Library’s fibreglass pond kits (GRP pond kits) have everything...
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Fibreglass Repair Kit
£24.00–£128.00Price range: £24.00 through £128.00
Fibreglass is an excellent repair material. As a composite –...
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This product has multiple variants. The options may be chosen on the product page
Fibreglass Kits contain materials needed for a range of fibreglassing projects, from pond linings through to flat roofing projects and more general fibreglassing work. Kit sizes cover surface areas ranging from 1 m2 to 100 m2 and laminate thicknesses of 450 g and 600 g CSM. Each kit includes glass fibre chopped strand matting (CSM), Lloyd’s approved polyester resin, MEKP catalyst (hardener), grey resin topcoat. Tools (optional) include rollers, brushes are tailored to individual kits sizes. Glass bandage roll and acetone are sold separately. Primer (recommended for bonding to concrete, plywood and other surfaces) is also sold separately. Each product type contains a more detailed description with recommended instructions and applications and safety considerations. Video instructions are also available for certain applications. Note: the polyester resin and topcoats contained in these kits require MEKP catalyst addition to harden. An absence of catalyst – or an incorrect amount – will mean the laminate will not harden, compromising its integrity.
Fibreglass (GRP) linings, coatings and mouldings offer a superb form of waterproofing, durability and aesthetics. Fibreglass kits listed here can be used on new flat roofs and repairs, pond and water feature linings as well as other surfaces. They can be used to protect substrates like timber, concrete and existing GRP from external stressors like water ingress, abrasion and impact. Universal fibreglass kits are general purpose and recommended for more bespoke projects. Individual materials like polyester resin and glass fibre CSM can be purchased separately.
Fibreglass itself has been used for decades in the construction, marine, aerospace and renewable energy industries. Low cost and easily accessible relative to other resins like epoxy and polyurethane, it demonstrates an excellent strength-to-weight ratio as well as long-term waterproofing and abrasion resistance. It is also resistant to a broad range of chemicals like acids and fuel oils.
Compatible with timber decking, existing GRP, concrete and other adequately prepared surfaces.
Note: a resin primer is strongly recommended for surfaces like concrete, which could be affected by water ingress, or plywood, which could see limited adhesion.
Fibreglassing itself requires a degree of planning, preparation and skill to ensure a quality finish.
The kits supplied here are specific to hand laid fibreglassing.
Step-by-step instructions on how to use each kit. Fibreglassing tutorials for respective applications are also available. Technical support is also available by email or telephone.
Q. What comes in a fibreglass kit?
A. Basic materials and tools include polyester resin, MEKP catalyst/hardener, glass fibre mat, paint brush and/or long pile refill, plastic mixing container and a paddle roller.
Q. How do you fibreglass?
A. Basic fibreglassing involves the use of polyester resin catalysed by MEKP and glass fibre matting. Techniques on how to fibreglass are available in more detail in the Resin Library Knowledge Centre Guides.
Q. Is fibreglass waterproof?
A. Yes, fibreglass demonstrates exceptional water resistance. It is used to build boat hulls and provide waterproofing for buildings, to name a few examples.
Q. Can I leave fibreglass unpainted?
A. Yes, it is possible to avoid topcoat/flow coat paint but ensure that glass fibres in the laminate itself have been adequately covered.
Q. Can I use fibreglass on existing fibreglass?
A. Yes, a fibreglass-fibreglass bond can be created provided adequate preparation has been performed. This is common for fibreglass repairs.
What is fibreglass?
Fibreglass, also known as GRP (short for glass reinforced polyester) is a composite. A composite material combines two or more materials, often with different properties. In the case of fibreglass, polyester resin and glass fibre chopped strand matting are bonded together. Once cured, a single ‘matrix’ is created whereby the embedded fibres increase the mechanical properties of the matrix whilst being held in place by the cured resin.
Why use fibreglass?
Like carbon fibre, fibreglass is lightweight yet incredibly strong, possessing strength-to-weight ratios similar to that of steel.
They can be applied to and moulded into almost any shape or structure and does not rust – features which set it apart from metals, which require heat-based welding and are prone to rust. These properties make fibreglass an excellent protective material for applications like flat roofs, ponds and water features. It also makes it an excellent repair material for damaged boat hulls and other components.
How to use fibreglass kits
Resin Library’s Fibreglass Kits are tailored towards a range of applications, covering basic laminating to yachts and boat hull repairs (marine repair kits), pond and water feature linings, flat roof repairs and more generic repair kits.
Each kit contains the necessary materials and tools needed to create a fibreglass laminate for a range of sizes, typically ranging from 1 m2 to more than 10 m2.
What kit size do I need?
This depends on the size of your project. Since the kits listed here are intended for surface coverage, users should measure the total surface area of their project. Kits sold by Resin Library are listed in square meters (m2), so the easiest way would be to multiply the length of the surface by its width. A 600 g CSM single layer fibreglass flat roof with dimensions of 2 meters wide and 4.5 meters long would equate to a surface area of 9 m2.
A minimum 10% excess surface area is recommended for most applications. Therefore, a kit size of 10 m2 would be recommended.
Conversely, if a yacht hull repair was being made in fibreglass and the damaged region was had a surface area of 0.45 m2 but four layers of laminate were required, then that would equate to a total of 1.8 m2 and as such a kit size of 2 m2 would be appropriate.
This multi-layer design could also be applied to repair cracked fibreglass yacht and boat hulls (sold as part of the marine repair kits).
Each kit comes with sufficient resin and MEKP catalyst/hardener to ensure glass fibre CSM saturation.
Laminating with fibreglass
Polyester resin is reinforced with glass fibre chopped strand matting (CSM). The most common and easily accessible method of lamination is the hand lay-up method. Here, the resin/initiator mixture is saturated with glass fibre strands or laid on a glass cloth. It is then driven into the glass matting using a polyester roller. Complete saturation (also known as wetting) of the fibres is important for quality and a paddle roller is used to encourage consolidation of the laminate. Once cured, a thin layer of topcoat/flowcoat resin is usually applied to give an additional protective and aesthetic layer to the laminate.
There are two main types of fibreglass laminating: (1) hand layup and (2) spray layup. The fibreglass kits sold by Resin Library are designed to assist in hand layup methods of fibreglassing.
Limitations of fibreglass
Some of the components in fibreglass kits (namely the resins and catalyst) are considered hazardous. As such, a safe working environment should be created prior to use. Prospective users should consider risk factors such as manual handling, working at height, chemical awareness (COSHH) and other considerations, some of which are detailed on the HSE website.
Another limitation of fibreglass centres on its lifecycle, which typically exceeds 30+ years. Extensive efforts are being invested into fibreglass recycling. Driven by regulation, leading companies are pioneering efforts to recover the components for further usage. This has led to companies such as Ineos’ recycled polyester resin that presents the same properties as that of new polyester resin.
Working with fibreglass can be quite tricky. At Resin Library, we understand this and have taken the time to provide a range of guides, articles videos to help our customers better understand the techniques and best practices involved.
That said, we understand that things go wrong sometimes (it’s always good to practice first) and have outlined some of the most common issues that may be encountered.
This section provides more general issues that you might encounter in working with fibreglass.
For more specific guidance, its also worth checking out the Troubleshooting sections on each product page.
Problem: My resin is very thick, what can I do to thin it out (reduce viscosity)?
Solution: Adding acetone (a solvent) in a 5 – 10 % (volume to weight ratio) to polyester resin will help thin it out. It is worth testing this diluted resin in advance to ensure it provides a desirable finish.
Problem: the polyester resin becomes thick and clumpy when I use it
Cause:
+ Generally shows the resin to be in state not usable
+ Too much MEKP catalyst has been added – a maximum concentration of 4 % volume (MEKP) per weight (polyester resin) should be used
+ The resin has been used outside of a 15-20 minute working window once MEKP catalyst has been added
+ The resin has been exposed to elevated temperatures
Problem: the resin is too thick and viscous
Cause:
+ Temperature is too low (under 10 oC)
+ Consider adding acetone at no more than 10 % volume acetone (millilitres) per weight resin (kilogram).
+ Check in advance and note that the final quantity of resin (kilogram) per unit surface area (square meters) will be lower. You should ensure it does not drop below 1.1 kg/m2 and 1.5 kg/m2 for 450- and 600-gram glass fibre matting respectively
Problem: the resin is curing too quickly (becoming clumpy) when I add MEKP catalyst.
Cause/Solution:
+ Use a lower concentration of MEKP
+ Prepare less, but more workable amounts of catalysed resin
+ Check the temperature – above 20 oC will lead to faster resin curing rates. Consider applying resin when temperatures are cooler
Problem: the fibreglass laminate is showing pinholes and exposed fibres.
Cause/Solution:
+ You have probably not used enough resin
+ For 450 gram glass fibre use around 1.1 to 1.3 kg/m2 and for 600 gram glass fibre use 1.5 to 1.7 kg/m2.
+ Re-apply a layer of resin provided the laminate has not been exposed to rainwater.
+ Check the guide instructions on how much resin to apply per square meter of matting
Note: this could also be caused by exposure to rainwater pre-curing. If so, the laminate may been to be re-applied; water interferes with curing and adds defects.
Problem: the laminate is not bonding to the plywood
Cause/Solution:
+ Plywood should be subjected to some abrasive treatment with sand paper in advance. It should then be wiped and cleaned prior to applying a resin primer.
+ The resin primer is needed to facilitate the bonding of laminate to the plywood.
+ It may be possible to lift the fibreglass layer up and apply a layer of primer underneath. However, this may prove difficult and for smaller sections may not be worth it.
+ If using OSB3 timber decking instead of plywood, sanding and primer application are not required since the timber is highly adhesive
Problem: the laminate has white patches and blotches
Cause/Solution:
+ This is a sign of insufficient resin coverage and poor laminating technique
+ Check the laminate has not been exposed to rainwater.
+ Unless the surface is wet, consider reapplying more resin.
+ If applying more resin, ensure sufficient coverage and that a polyester roller and paddle roller is used
+ Sometimes air pockets form and cause a bulge. In this instance it is more appropriate to to sand down the bulge back to the original substrate and re-apply the laminate. If doing so, ensure the area is clean (ideally with an acetone wipe) and free from dust, debris, etc.
Problem: air bubbles/voids – could be small and isolated or large and connected
Causes:
+ Air trapped in the resin mix
+ Insufficient resin
+ Poor wetting
+ Incorrect usage of reinforcement
Problem: de-lamination (separation of individual layers in a laminate):
Causes:
+ Reinforcement contamination
+ Unclean surfaces during lay-up
+ Damage from sharp impact
+ Excessive exotherm (heat) during lay-up
Problem: crazing (minute cracks in a resin)
Causes:
+ Excessive stress in the laminate during curing
Problem: warping / shrinkage (changes in size and shape)
Causes:
+ Temperature differences or exposure to heat during curing
+ Excessive temperatures
+ Too much catalyst
Problem: washing (fibre displacement during laminating – particularly during moulding)
Causes:
+ Resin formulation too viscous
+ Defective reinforcement
+ Excessive force used
Problem: too much resin in certain areas
Causes:
+ Poor resin distribution
+ Reinforcement shrinkage
Problem: insufficient resin in certain areas
Causes:
+ Poor resin distribution
+ Insufficient resin (too little per unit area of matting)
+ Too high of a resin viscosity
+ Poor laminating techniques
Problem: surface defects
Causes:
+ Porosity/pinholes
+ Roughness
+ Blistering
+ Wrinkles
+ Protruding fibres
+ Poorly coated fibres
Problem: tackiness or sub-cured
Causes:
+ Insufficient catalyst usage (1 – 4 % MEKP recommended for polyester resin, equates to 1 – 4 mL per kilogram of polyester resin)
