Underwater Pipe Repair
An epoxy and fiberglass wrap can repair steel pipes while submerged underwater. Repairing small holes in pipes by wrapping them is sure to be much less expensive and disruptive than replacing bad sections of pipe. Divers must have access to the whole circumference of the pipe and the pipe must be free of its contents to prevent contamination and allow for the wrap to seal the leak.
As always, surface preparation is very important, and is demonstrated in the video with the grinder. The epoxy must form a good bond with the substrate material, not the rust and scale that is on the outside of the pipe.
Jeff Longmoore of TFT demonstrates how this repair is performed in a Youtube video, but does so in a dry environment rather than the actual underwater one. Very interesting.
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.
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