Aqua Stik Epoxy Repair
Browsing Youtube, I found an interesting video on a repair Epoxy material by the name of Aqua Stick. I am not sure how it is available, but I am sure that you can search it on the internet.
It looks to be very user friendly, and has some very interesting potential applications in the arena of adhesive application and repair for underwater environments. No metering/measurement of the two parts is required, as they only require a kneading action to mix the two doughy components to uniform color.
Carbon Fiber Repair Panel
I found a great video demonstrating the repair of a carbon fiber composite panel. The is is a carbon fiber reinforce epoxy structure that needs a localized repair to the core material. This repair uses a vacuum bagging process to help maintain a high-quality laminate.
The video is sped up to quickly demonstrate the overall process required. This process requires a high level of attention to details, as they are very important. Training and experience are necessary for good results.
Chemical adhesion between all of these layers will create a bond that is durable and suitable for restoring strength back to the structure.
Chrome Plated Fiberglass
Fiberglass Composite materials can be coated to show many different finished effects. I ran across a neat Youtube video demonstrating a spray on chrome process with a fiberglass grill shell.
It is pretty cool to see the change in appearance as the coating is applied. I am amazed at how wet the part is sprayed. Definitely not a traditional spray application method. The coating is just dripping off of the part. My guess is that the spraying with an air nozzle is working to help remove any runs and wrinkles in the surface finish.
This coating process will act like a painted surface more than a part that has been subjected to a hardened plating process. Surface adhesion will be very important to test the durability of the finished look.
Repairing the Inner Fender
One of my recent projects involved the repair of a 1993 International Medium-Duty truck hood made from SMC. There were several areas needing attention, and one of them was the driver’s side inner fender. This piece had formerly been attached with button-head pop rivets. This design is common to composites, and allows for easy replacement of the separate fiberglass pieces. The pop rivets had come loose over time, allowed to move around, and cause severe damage to the extent that the riveting flange was broken off. My only solution was to bond the two pieces together.
Material Fatigue in the corner
The loose panel flexed so much and for so long that it fatigued the material and failed in the corner of the inner fender next to the attachment to the rest of the hood. To repair this, I removed the area with the rivets, ground down the surfaces of both pieces on both sides, and reattached them with fiberglass and epoxy resin.
Prepared glass and resin
I wanted to place epoxy and fiberglass on both sides of the repair area to ensure a good, solid bond that would hold very well.
Epoxy Resin and Fiberglass applied
After the area was prepared, I applied epoxy resin to the surface to ensure good adhesion. I had a low spot that was a gap, so I mixed some microfiber and epoxy to make a paste and fill this gap. A stronger bond is produced when the fiberglass is not spanning an open gap between the two pieces. I placed two layers of 3oz Chopped Strand Mat over the paste and worked the air out to make a nice consistent repair. I then ground down the surface to make a nice-looking, consistent repair.
Back end of the inner fender
The rear of the inner fender had similar problems. A hole had emerged in the black SMC piece. I ground down both surfaces and placed some fiberglass across the area to bond it together.
Grinding Tools
During my recent International Delivery truck hood project, I did some grinding on the composite SMC truck hood prior to performing extensive repairs. It is important during any composite repair exercise to have good surface preparation. There are many ways to accomplish this depending upon the work area, tools available, and the work to be performed.
The following is how I did it.
Composite Grinding Tools
Beginning with personal safety, I used a dust mask to prevent inhaling the dust into my lungs. I used OSHA Z87 approved safety glasses to protect my eyes. A pair of earplugs protected my ears. Abrasion/dust resistant gloves for my hands, and a light jacket to keep the dust from my skin.
For removing the layers of SMC to feather edge the surfaces, I used several abrasive tools. A five-inch pneumatic grinder with 80 grit sandpaper worked well on the large areas to quickly remove large amounts of material. A right-angle die grinder with Roloc 3″ or 1.5″ sanding disks worked well for the concave areas and other difficult access areas. A straight die grinder with a fluted burr worked to get into the detail areas of the front grill and other cracks that needed material removed.
All of the tools I used were air powered, so I had a good air supply that would keep up with me. The large amount of dust that is produced from this sort of work presents explosion hazards when using electric tools. Large dust piles can also spontaneously combust, so care must be taken during dust storage and disposal.
A air blow gun was also used in this process to clean the dust from the part and from my clothes. It is important to keep personal safety equipment such as safety glasses and earplugs in place when using the blowgun. A small vacuum can also be substituted with care taken to prevent dust ignition/explosion.
After all of the material is removed from the SMC hood, all of the dust is blown off to leave a part with a bonding surface that is clean, dust-free and ready to be repaired with epoxy and fiberglass.
IH Hood Repair– Passenger Corner
One of the repairs on my International Hood was for the passenger corner. This portion of the hood was damaged before I got it, and was COMPLETELY MISSING!
Time, effort, epoxy, and fiberglass, allowed me to successfully completed the repair. This SMC hood will be repaired as good as new!
Damaged area to be repaired
The hood was placed upside to allow for work access. The repair area had several cracks and breakage areas. The repair began with surface preparation.
Surface Preparation on the repair area
I used a grinding disc to remove material on the front and back side of the repair to scarf the repair into the large area. Good surface preparation gives us a clean area that can hold a bond and create a transition area. I also drilled some holes in the end of the cracks to stop their propagation.
The back side was prepared too
The back side was prepared for repair by grinding the surface to allow for good bonding by the epoxy resin and glass reinforcement.
Beginning to add material
I started to add epoxy and fiberglass back onto the fender. I had to gradually move back out to where the existing fender used to be. I worked both sides bit by bit and allowed it to start curing before adding more.
Getting the shape back
I actually went a bit beyond the shape I needed. This allowed me to get the surface planes in the right spot, and later return and trim back the proper hood edge.
Back side getting rebuilt
The back side of the repair also got transitioned into the hood and out to meet the front repair area.
Grinding the repair
After most of the rebuilding was complete, some grinding got it back into shape to allow an evaluation of the repair progress.
Grinding on the back
The back side was cleaned up as well, getting the appropriate part thickness back to where it was originally intended. A nice transitioned surface was created, and all sharp edges were removed.
Bodyfiller for cosmetics
I used some bodyfiller to smooth the repair and restore the cosmetics of the hood. I could also have used epoxy, and it would have bonded better. Polyester bodyfiller is less expensive, easier to apply, and easier to sand. I smoothed the surface and feathered it back into the surrounding area to allow for a consistant surface.
Application of Primer-Surfacer
Urethane Primer-Surfacer is applied to the whole area to allow for removing the sanding/grinding scratches and preparing the surface for paint application.
The repair is complete, and the hood looks back like it was original. This repair, and many others, can be detected with some investigation of the back side of the repair area. This will be a very durable repair and will last as long as the rest of the composite body panel.
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