I've always sanded the back of the prop and a long time RC'er told me I was wrong and you have to sand the front of the prop so as not to change the pitch.

Does anyone know the correct answer?

Also what about sanding the hub of a prop?

Thanks

Whenever I balance a prop I sand the back of it down.

Also if you use master-ariscrew nylon/glass props I'm told you should sand off the letters "master airscrew" on each side. The letters can come off if fuel hits them, and cause an imbalance, especially if you are flying. An experienced instructor at my airfield told me this, so please don't spam me if I'm wrong. Hope I helped.

-brian

I've always heard that you sand on the back because sanding on the front would change the airfoil shape. I'm also interested in the question about sanding on the hub.

Sand the back side to keep the airfoil shape. I have also sanded the hub to get a good balance you just need to be careful and not remove too much material. Pete

The easy way to balance is to not sand at all. Instead, rub a small amount of 5-min.epoxy on the back of the light end of the prop. You'll be surprised at how fast you will have a perfectly balanced prop. After the epoxy has cured, dull it down with fine steel wool and you won't even be able to see it. Try this once and you will never sand another prop again............Jerry

use extreme caution if sanding the hub. This is the area of highest stress. No matter what, be sure to leave no notches because that's where failures start......even farther out on the blade.

The experts and information on prop web sites, like bolly or others, all say to always sand the front of the prop. If you sand the back side of the prop, you can change the pitch, which is considered a lot worse effect on the prop than changing the airfoil. This subject has come up many, many times.

Does it make a difference when sanding with wodden, glass/nylon, etc.?

I've always sanded the front of the prop. Never heard of modifying the hub or sanding the back. Plus cleaning the flashing off of the tip sometieme goes a long way to balancing.
Rick

how about krylon clear coat

Hello!
I sand the front on all props both wood,carbonfiber and plastic(APC)! The back side should be left alone as this side have a fixed pitch.it´s more easy to sand the front side as this side has a profile that is easy to shape...and you do not alter the pitch!!
This is the way most competition pylon racing guys do it!

Regards!
Jan K
Sweden

Put away the sandpaper and never sand another prop. Use a little clear spray paint to balance your prop. I have used Krylon, 21st Century, and Flustercoat all with good results. Simply spray the light blade until it is slightly heavier than the other blade. Let it dry about 5 minutes, put it back in the balancer, and check the balance. It gets easier with practice. One note, you need a good balancer. I use an old Hi-point balancer for the big props and the magnetic one for smaller props.

I use some light-colored or white paint, and paint my prop tips . . .
this gives a visible arc when rotating for safety, and a way to balance the prop without sanding.

Al

I wish an acknowledged "EXPERT" would weigh in on this one !!!

Perhaps there is more than one "correct" answer?

Al

Every glow engine in captivity is imbalanced, some worse than others, but all of them are out of balance. None of the crankshaft counterweights are sufficiently heavy to balance out the weight of the piston, pin, and connecting rod. So, what is balancing a propeller accomplishing? I think not very much. I think balancing propellers makes sure that we won't make the shivers worse no matter how we mount it on an engine. I suggest using a propeller balancer to find the heavy blade and stick that one on the same side of the crankshaft as the counterweight to help balance the engine. Make the imbalance work in your favor. Of course electric motors are balanced and a balanced prop makes an e-power airplane run even more smoothly.

Hi,folks.I am at my wits end trying to achieve correct balance on my props.Does anybody else find that a certain highly acclaimed 3 letter prop maker doesn't drill the holes in the center??? I use a magnetic prop balancer and,spend ages adding high tack tape to the lighter blade/hub until balance is perfect. Trouble is,remove the prop from the balancer spindle,turn it through 90 degrees and,recheck the balance-MILES OUT!!!!!! Check spindle-replace with a second one,rebalance-same result.How do you balance a propeller properly??? Regards Marc Sommer

Marc,
If you balance a prop, then move it on the spindle and it's out, then that probably means that the spindle is bent.

It happened to me. I Made another spindle for the magnetic balance from landing gear wire. Ground the ends pointy on my bench grinder.

Roll your spindle (without the cone thingies) on a piece of plate glass, and see if you hear a click with every rotation. If so, toss it.

Want to know about balancing props just go to this link
www.bolly.au/book/content.htm
They will splain it all for ya

Link doesn't work

Here's the correct link:

http://www.bolly.com.au/book/content.htm

WOW! That site has loads of information on lots of RC related things! What a neat site!

Let me try the bolly link one more time.
www.bolly.com.au/book/content.htm
Thanks and sorry for the bad link
Don