toyotatruckin

Build your own prop balancer and it works better than the durlbro and topflight
materials
1 1/2" x 1/2" wood your choice visit lowes or home depot
2 1/2 x 3/4" wood your choice
1/8" piano rod -- for 1/8 size props
great planes finger tip prop balancer --- all other prop sizes
4--1/2" round high power thin magnets they are silver and can be found at hobby lobby or michaels or ebay "rare earth magnets" what ever you want to call them there very strong little suckers
1"x1" piece of lexan or cut a piece off a plastic battery package

tools I used dremal with router attachment and cut off wheel, drill with 1/2" bit tape measure, saw,2 part epoxy,sand paper, and a bench grinder

Ill start with the posts, cut two pieces of 1 1/2 wood 4" long squaire them up and make sure there the same size, next drill a 1/2" hole at the top of each piece about 7/16" down from the top, easy way to do this is clamp both pieces together and drill straight through both pieces so there in the same spot on each one.Next take two magnets stuck togather and epoxy them in the hole flush on one side try not to get epoxy on the face of the magnet it needs to be smooth, repeat on the other post, reason for two magnets per side is it doubles the magnets power that part is done..

Next cut the bottom aprox 4 1/4" long out of the 2 1/2"x3/4" wood on the top router two slots for your posts to sit in about half way through the base, first you need to measure the finger tip balancer to get your distance to set the posts at add 1/8" to the balancer length that way one end of the balancer is on the magnet and the other is free floating. On the bottom take your router and make two slots about 1/8" deep and a little longer than you balancer rod and drill two 1/2" holes between them for the two balancer cones deep enough to set the cones about flush.

Next take your piano rod cut it the same lenght as the rod in the finger tip balancer rod, make sure it is straight!!!! very important!!! put the piece you just cut in your drill and take it to the grinder lightly grind both ends to a point with your drill going the entire time your grinding that way your point will come out even with no flat spots It will be a little ruff so again with drill going sand the points with 220g and move up to about 800g to make it smooth as possible when your done the ends will look almost chrome.

I place the lexan piece over one magnet held on with a little oil it gives the magnet a very smooth surface for the balancing rod to spin on the other end of the rod should be aprox. 1/32" or so away from the other magnet
Your done stain it paint it whatever you like when your done with it put your rods and cones in the bottom of the base and rubber band it all togather toss it in your field box and go!

Hope this helps someone out the above instructions are not set in stone you can modify or change things anyway you like shoot use oak and stain it cut the wood fancy to give it a custom look just make sure the magnets are directly across from each other!!

unclecrash

Nice lookin home made kit. I forgot I picked up a little magnetic balancer but the shaft aint worth a crap. Where did you get the finger balancer. Ill post a pic of the unit I got. I wonder if the finger balancer will fit inbetween my unit. I can make a 1/8 for it. Dave

toyotatruckin

3 3/16" long I got mine from the LHS but tower sells them to
http://www2.towerhobbies.com/cgi-bin...?&I=LXK247&P=7

unclecrash

I forgot I had this I build a lot of EDF jets and needed a balancer that would balance a little 50mm fan but I got burned out on building jets and never used it its been put away in a box. The finger balancer wont work on it the shaft on mine is 2-3/4 if I remove one set of magnets its 3in. its a nice sturdy unit but like I say the shaft is crap it rolls to a heavy spot every time. Just like that one they call precision balancer how can it be precise if the darn shaft and hubs arnt balanced!!
Dave

toyotatruckin

LOL thats why I quit buying balancers, not worth the money the finger balancer isnt 100% perfect but its real close the 1/8 piano wire shaft I made is balanced I had a topflight magnetic balancer and it wore spots in the face of the magnet making it not balance right plus when you used the set screw to set the magnets they were never straight and the durlbro balancer with the metal disks works good for bigger props but small ones its not sensitive enough razor blades work ok just have to make sure there level...Its hit and miss with all of them..
the one you have in the picture is nice looking and from the same idea as mine I think you should make some shafts for it!!

unclecrash

A friend of mine was telling me find some drill bit blanks. There hardened and they wont bend. I will have to look into that. Ya I might try to make a couple shafts for this one. 1/8 and 3/16 My only prob I dont have a bench grinder. I think I can find someone with one. I tryed to balance one prop and I had a bear of a time with it the other I started Im real close. How do you go about balancing them? I here the berylium is real dangerous to breath. Dave

toyotatruckin

YES, berylium is dangerous to breath!!!! Use a mask when cutting your props, its cheap insurance!! I use a dremal with sanding disks back side only (side with the notch) to get the edge, I get a "hard sloped" dge then feather it out from there try not to take to much meat out and work it to the trailing edge once thats done I hand "wet" sand to get a finer edge and to smooth out the back side also wet sand the cup side of the prop not changing anything here just get it smooth, I dont spend to much time on the hub if there is casting flash on it knock it down with a small fine file, this might differ from some but after its all cut and looks good I go ahead and do a so so polish job to it, clean it then stick it to the balancer. Get a marker so you can mark your heavy side sand a little off the heavy side till when you spin it it stops in a different spot every time then I polish the crap out of it re check your balance when done if its off you can take it back to the polisher and polish the heavy side till its back in balance...

unclecrash

This is kind of hard to explain. The back theside with the slotyou are doing the sharpining. I know you said all you do is sand the front. Do you do any sharpining of the front edges that come down to the hub. Or do you just leave them thick. Hoppe this makes sense. I have a lot of experiance building planes over 20 years but boats not much. Whats the difference between theprops with the rounded tips and the pointed ones. Also how do you tell if an engine needs more prop or less?
Dave

toyotatruckin

here is a picture of what to sharpen I have marked it in black. as far as tips im not exactly sure what effect round vs pointed would have except the way the water came off the prop someone with more knoledge would need to step in on this one most of the props Ive done have been prather or x and y series octura
you asked how you know if the prop needs changed the way I tell is listining to how the engine sounds mainly also how the boat is reacting..If the engine sounds like its working to hard -smaller i go, if its not working hard enough I go bigger thats the easiest way for me to explane it.. Im no expert in props but I can pass on what I have learned from actually doing the work and listining to the people that know more than I do when they try to teach me something new... I hope this answered your questions ok

unclecrash

Thats what I thought. The front you leave alone other than sanding to a polish. dave