I'm sure this will give those in industry yet another opportunity to jump on me...
I've been refinishing my wooden prop once or twice a year for the past decade.
previous owners removed the brass leading edge protection and sheathed the blades in fibreglass to render them resistant to light rain.
the sheathing worked but the absence of a metal leading edge has meant that any appreciable moisture in the air erodes the paint at the leading edge.
so...
when the leading edge paint gets eroded I get sick of the 5 knots knocked off the cruising speed that this causes and off comes the prop for a refinish and rebalance.
I'm assuming you have a prop that was competently manufactured.
this means that the blade geometry will be symmetrical.
if you rub back the finish confine the rubbing back to the varnishes used on the prop. do not erode the actual wood. this will keep the original blade geometry intact.
on my prop I have realised that the leading edge paint will always be subject to erosion. even using two pack polyurethanes will not prevent the erosion.
so I have taken another tack on my finishes. I use acrylic enamels that can be wiped off with a bit of elbow grease and either acetone or MEK.
when the prop needs refinishing I simply wipe off the damaged paint back to a level and rebuild the paint layers back up to the desired finish.
balancing the prop is quite easy.
I use a half inch diameter shaft with two machined aluminium washers that have tapers that can press into the central prop hole and hold the prop absolutely concentric to the shaft.
two six inch wide boards are placed on my absolutely level dining room table.
all air movement in the house is suppressed.
the prop on its balancer is placed on the boards and allowed to rotate.
I balance my prop by adjusting the paint.
typically I spray another coat of matt black on the back of a light blade.
I check the balance both ways on the jig and when the prop can be placed either way without any tendency to rotate it is balanced.
this sounds crude but a post it note stuck on a blade will rotate it easily.
the take home message is that you should never neglect your wooden prop.
if you can't find a commercial prop shop that will do the job for you
you can do it quite competently yourself.
W8