The first thing a propeller repair shop like Nettle Props does to your prop when they get it, is to sand blast off all the old paint and crusty buildup if aluminum so they can start to work on it. Once they have sand blasted the boat prop down to bare aluminum they read the part number and or the size stamped on the propeller so they know what the pitch size should be. Most stainless and nibral props do not need sandblasting. The propeller is then put on a pitchometer to determine how far off the damaged blades are from a new prop pitch wise. When the blades are hit, that will most times throw off the pitch angle of the prop.
The boat propeller is then taken over to a stand where the blades are set on top of a pitch block, which is a block of metal, that has the exact blade configuration the propeller should have stamped in the block. The tech performing the propeller repair then uses various types of hammers to actually bang the propeller up against the pitch block until it is back to its original blade shape. This is done to all the blades one at a time. In some cases the blades will need to be heated to high temperatures in order to bend it back to the desired shape, the heating is generally not done for aluminum prop repair.
The boat propeller is then put back into the pitchometer and measured for accuracy. If it is off a little the pitch block is used again and then re-measured until the blades have the right pitch based on propeller manufacturer specs.
When the propeller is back to its original shape and pitch corrected, the blade edges might be missing metal (aluminum, stainless or nibral) and in need of new metal to be welded on to the blades. As part of the propeller repair service, new metal is welded on to the blades and grinded down to the correct blade shape on a stand alone grinding machine.
The boat propeller is then tested for balance. Metal is ground off the back side of the heavier blade or blades until all blades are all uniform. The blade edges are then grinded to make a clean edge with no burring. After final quality control and finish touches the propeller repair is now completed and the boat propeller is then ready ready for use again.
We can help you no matter which direction you decide to go… at JT’s Discount Props we have a variety of new boat props and with our propeller repair shop at Nettle Props we are able to provide you with quality propeller repair services.