Fibreglass Fibre Reinforced Plastics FRP Fibreglass Safety and

Fibreglass

Fibre Reinforced Plastics…. . . FRP. . Fibreglass

Safety and Composites • Respiratory protection • Skin Protection • Eye protection • Hearing protection • Consideration of others Strand magnified at 1000 x

Tools and Materials • • Grinders Sanders Cut-off saws Die-grinders Air chisel Blow gun Heat gun Pneumatic/manual • Masking materials • Repair materials • Glass cloth • Clamps/fasteners • Cleaners • Safety equipment • Clean up materials adhesive applicator guns

Surface Preparation • The first step in any successful repair is the appraisal of the surface • Wash the panel with warm soapy water to remove water soluble contamination then rinse clean • Once dry, clean all panels with the appropriate wax and grease remover so as to float all (solvent soluble) contaminants to the surface

Tools, Equipment and Abrasives

Cleaning • Acetone • Brushes • Containers • Safety!

Sanding & Grinding

Grinding Disc Grits • 50 grit • 40 grit • 36 grit • 24 grit

Differences in Sandpapers Aluminum Oxide Silicon Carbide Garnet Aluminum Zirconia

Grinders / Sanders

Single Action vs. Dual Action

Sandpapers And Their Application • 36 -50 grit is used for damaged material removal, as well as primary shaping and beveling prior to repair procedure • 80 -120 grit is used for shaping of the repair bevel, primary featheredging • 150 -180 grit is used for back sanding, final smoothing and featheredging prior to primer surfacer application

Fibreglass is a Plastic?

Fibreglass • Fibreglass is made up of three basic ingredients: – fibreglas mat – resin (polyester or epoxy) – catalyst

• Reinforcing fabric must be of loose construction to allow repair adhesive to penetrate and ‘wet’ the fabric

Types of Fibreglass Mat • CHOPPED STRAND MAT (CSM). - The most common fibreglass reinforcement, is made up of randomly arranged glass fibre strands, pressed and held together with a binding agent. - Available mainly, in three different weights, one and half, and two ounces per square foot. Metric equivalents are 300 g, 450 g, and 600 g per square metre, or GSM. - CSM lends itself ideally to most laminating jobs including, boatbuilding, car body, roofing, ponds, etc.

• Chopped strand • Continuos strand

Woven Cloth • Glass fibre filaments, spun into a yarn then woven to make cloth, provides great strength with minimal thickness, is usually used as an alternate layer between CSM, giving added strength without substantially increasing laminate thickness.

• Uni-directional E-glass • Bi-directional E-glass • Woven Roving

New Technology • Kevlar • Carbon Fiber

• Production Application Methods • Chopped strand roll for use with chopper gun

• Gel coat is used as a finish coat • To add colour to the product • Is UV protectant • Can be multi colour • Applicator Gun

• Epoxy Resins

Resins • Polyester resin is usually available as a twocomponent system, with resin in one container and the hardener often known as the catalyst in the other. • Some systems use a catalyst and a promoter to activate the resin. It is important to note that these two products should not be mixed together prior to mixing with the resin. Fire or explosion may occur • It is important to note that FRP resins cannot be used on SMC repairs!

Resins continued. . . • Resin and catalyst (hardener, activator) are mixed by quantity (ounce or milliliter) • Rule of thumb: 1 oz. resin requires 10 drops of catalyst to cure correctly • Incorrectly measured resin will have adverse effects on the repair

Not following recommended curing guidelines can lead to product failure Assuming one manufacturers procedures will work for others can be a costly mistake Never cure any repair Above 225° F. Curing Fibreglass is ideally done At 140° F for 30 -45 minutes

One Sided FRP Repair

Two Part Repair Materials

Damage Identification • One of the most critical steps in assessing damage to FRP is to note where the damage ends. Great care must be taken to note all cracks and fractures are removed

One sided repair materials - Cleaner - soap and water - wax and grease remover - Repair material - cosmetic - panel patching adhesive - Abrasives - 36 to 50 grit grinding disc for beveling - 80 -100 grit for featheredging damage - 120 -220 grit for shaping and smoothing

Preparation -When beveling the damaged area, make sure all of the scratch or gouge is removed and the bevel is 2 -3” away from the centre of repair area and all paint material is removed from the immediate area

Follow manufacturers guidelines as to drying and recoating times Always finish imperfections (pinholes etc) off with same material or if acceptable use a high density cosmetic filler

Two Sided FRP Repairs

Types of two sided damage - damage that penetrates the panel and breaks the reinforcing fibres -large crack -fracture -hole - damage results in pieces missing -broken or missing pieces -hole

Two sided repair materials Cleaning - use recommended cleaners Adhesive - panel patching adhesive Filler -cosmetic -structural Reinforcing fabric Appropriate abrasives

Cleaning Fibre reinforced parts Soap and water -removes water soluble contaminants -use a wash mitt or sponge -rinse thoroughly with water Wax and Grease remover -may be needed on heavily contaminated parts -use of scrub brush may be used -should not be applied to the damaged area

Plastic cleaner -Liquid or aerosol -can be called a “mild” wax and grease remover -may contain alcohol -do not apply to the damaged area or broken fibres Using cleaners -do not use a solvent soaked rag -apply solvent to the surface of the panel so as to float contaminants to the surface -pour or spray on -always use clean cloths to wipe solvents -always wipe in one direction to prevent recurring contamination

Repair procedure -clean area as to manufacturers recommendations -on the exterior side of the panel, create a bevel with appropriate grinding disc, making a gradual taper 1 1/2” wide, leaving no sharp edges -remove all loose material -prepare the back of the panel by removing any loose material -sand the area to receive the reinforcement patch -wipe, then blow the panel clean

Reinforcing the panel back -the back of the panel is reinforced to provide strength to the panel and the repair -a backing patch can be used -built up from layers of reinforcement material and adhesive (pyramid patch) -made as thick as the panel to be repaired -backing panel can be used -cut from scrap SMC or FRP having a similar contour to the damaged panel

Front reinforcement -proper reinforcement of the front of the panel will allow repair to remain hidden through temperature change -try to copy the amount of reinforcement in the original panel -reinforcing strips should be cut according to the position they assume in the cavity, from the smallest to the largest

1. Cut several pieces of of reinforcing fabric large enough to overlap the damaged area by 2” 2. Use as many pieces as deemed necessary to duplicate thickness of panel to be repaired 3. Lay out a piece of wax paper or aluminum body tape larger than the reinforcement patch will be 4. Mix repair adhesive

5. Sketch out the rough dimensions of the patch on the wax paper or body tape 6. Apply adhesive to the wax paper or body tape to a uniform thickness is achieved with a plastic spreader 7. Begin laying out reinforcing fabric, applying more adhesive between each layer to achieve saturation, stopping between layers to use wax paper and a saturation roller to remove any air pockets (do not leave wax paper between coats) 8. Alternate this procedure until appropriate layers of cloth and repair material have been achieved to match thickness of panel being repaired 9. Apply patch panel, and allow to cure in place, heat may assist in cure time

A backing panel can be made of scrap SMC with a contour matching the panel being repaired

Making a backing panel 1. Cut a piece of SMC which overlaps the damage about 2 -3” all around 2. Grind or sand off paint or primers from the front of the backing panel and wipe or blow off 3. Clean and sand the backside of the panel that will receive the patch approx. . 3” all around 4. Apply a 1/2” bead of adhesive all around the edge of the backing panel 5. Press the backing panel into place until the adhesive has 100% contact all around 6. Smooth out excess material

Completing the repair using a bridging strip - A bridging strip is usually needed when sectioning a panel - Adds reinforcement to the repair - Helps minimize shrinking caused by changes in temperature

Making a patch panel -patch repair can be made if a similarly shape panel is available -uses a square or rectangle hole -requires bonding strips

To make a patch repair: 1. clean the damaged part 2. cut out the damaged area keeping the cuts as straight as possible 3. cut bonding strips about 2” wide and fit them around the hole 4. remove all paint from bonding strips 5. clean and scuff backside of panel where the bonding strips will be applied 6. apply a 1/2” bead of adhesive to the bonding strips 7. secure the bonding strips in place with screws or clamps until adhesive cures 8. cut and fit patch panel, leaving at least 1/2” gap all around 9. clean and scuff sand the back of patch panel 10. apply adhesive to the bonding strips and secure panel into place

11. remove the screws 12. use a grinder to make a 2 -3” bevel on either side of the gap between the damaged panel and the patch 13. blow or wipe clean 14. cut enough reinforcing material to fit into the taper 15. apply adhesive to the taper, then lay reinforcing cloth, more adhesive, more cloth, until height is achieved. Finish with saturation roller and wax paper