My Ideas on balancing a prop

[FE_Chris]

I just started to do my own props not to long ago. I have not really gotten on them to much....I sharpen them with a file, Then I give it a balance. After that, I start with the 400 grit sandpaper and work up to 1500, toss her on the balancer again to check it....If needed use some 1500 to remove a little to get her balanced again, and i'm off to the pond. All wet sanded by the way, I use a towel on my lap and a bowl of water. I soak the sand paper in the water constantly, and I always dip the prop and file every few seconds. Never wore a mask...This bad to now where a mask? Hmmmmmm.....

On smaller 3/16th props it has been taking me around 30-45mins to do this, and it seems to work well. Atleast better than running without doing anything to the props.

Speaking of that, I have read you can and will damage something on the drive line if you use the props right from the cast. No work. Anyone ever trashed a boat doing this?

[seabassturd]

i use a dremel for the slag, but everything else with a set of good needle files, a half round tapered sharp point is my weapon of choice, i thin them a hair, and detounge them, make sure the tips are sharp, on appropriate blades, and .
1. dremel casting marks
2. shape blade (three blades or modified props)
3 thin and sharpen out tips
4 sharpen and shape the cutting edge (file)
5 heavy sand paper 220 grit (remove file marks) all balancing is about complete
6 finish polish with 400-600, then 1500 grit, and crocus resin paper. makes em slick!!!
7 recheck balance
8. rip it up!!!!!!!

[Ocean Racer]

Is it ok to have ur prop as harp as a knife???

[Eyekandyboats]

that the only way i have them.
after a several runs or so the water will ware them down and may need a possibly re sharpening

[Fluid]

Water does not "wear down" a BeCu prop. I have props I have raced for several years which are still shap enough to cut - and I have the scars to prove it. If you run in mud, muddy weeds, up the bank, etc. then you can expect the sharp edge to dull.

Safety Note:
I would caution those who use power tools to work on their props without a resporator that they are exposing themselves to a toxic material with serious side effects. The problem with self-appointed health 'experts' is that they do not understand all the hazzards involved. The real issue is NOT beryllium poisoning, but the health effects of colloidal copper:

Copper fumes may cause "Metal Fume Fever" with symptoms of metallic taste, chills and fever, aches, cough, and chest tightness. The symptoms may be delayed for several hours after exposure and usually last a day or two. Repeated exposure can cause chronic irritation of the nose and may cause ulcers.
* Copper may cause a skin allergy. If allergy develops, very low future exposures can cause itching and a skin rash.
* Repeated, very high Copper exposures can damage the liver.

Two members of my former FE club were admitted to hospital emergency rooms for MFF after using a Dremel on BeCu props. Do not let it happen to you. Wear a real resporator, not a paper "dust mask"





.

[ReddyWatts]

METAL FUME FEVER from copper fumes
Zn ZnO
OVERVIEW
Metal Fume Fever is the name for an illness
that is caused primarily by exposure to zinc
oxide fume (ZnO) in the workplace. The main
cause of this exposure is usually breathing
the fumes from welding, cutting, or brazing
on galvanized metal. Metal Fume Fever is an
acute allergic condition experienced by
many welders during their occupational
lifetimes. Studies indicate that the most
common cause of metal fume fever is
overexposure to zinc fumes from welding,
burning, or brazing galvanized steel. Since
galvanized steel is more and more common
in industry, the chances of welders having to
work on it are occurring more frequently all
the time. Other elements, such as copper
and magnesium, may cause similar effects.
EFFECTS OF OVEREXPOSURE
Zinc oxide fumes cause a flu–like illness
called Metal Fume Fever. Symptoms of
Metal Fume Fever include headache, fever,
chills, muscle aches, thirst, nausea, vomiting,
chest soreness, fatigue, gastrointestinal
pain, weakness, and tiredness. The symptoms
usually start several hours after
exposure; the attack may last 6 to 24 hours.
Complete recovery generally occurs without
intervention within 24 to 48 hours. Metal
Fume Fever is more likely to occur after a
period away from the job (after weekends or
vacations). High levels of exposure may
cause a metallic or sweet taste in the mouth,
dry and irritated throat, thirst, and coughing
at the time of the exposure. Several hours
after exposure, a low–grade fever (seldom
higher than 102_ F or 39_ C). Then comes
sweating and chills before temperature
returns to normal in 1 to 4 hours. If you
encounter these symptoms, contact a
physician and have a medical examination /
evaluation.
HOW TO AVOID THE HAZARD
• Keep your head out of the fumes.
• Do not breathe fumes.
• Use enough ventilation, exhaust at the arc,
or both, to keep fumes and gases from your
breathing zone and the general area.
• If adequacy of the ventilation or exhaust is
uncertain, have your exposure measured
and compared to the Threshold Limit
Values (TLV) in the Material Safety Data
Sheet (MSDS) for the galvanized material.
• Never take chances with welding fumes. If
none of this is adequate or practical, wear
an approved respirator, air–supplied or
otherwise, that adequately removes the
fumes from your breathing zone.
Page 2 Fact Sheet No. 25 – 1/02
SUMMARY
Here are the main points when dealing with
galvanized metal:
• Metal Fume Fever is the result of
overexposure to zinc fumes from welding,
cutting, or brazing on galvanized steel.
• Metal Fume Fever is a short–term illness
with classic flu–like symptoms.
• The permissible exposure limit (PEL)
according to OSHA is 5 milligrams of zinc
oxide fume per cubic meter of air––always
monitor and measure your breathing air.
• To avoid the illness, keep your head out of
the fumes and do not breathe the fumes.
Use enough proper ventilation and/or
exhaust. If uncertain about the ventilation,
use an approved respirator.
• There are no known long–term effects of
this disease.

[Jeepers]

interesting.

[Team A-Hull]

Thanks ReddyWatts!

That solved that problem, and that was extremely helpful!

[ReddyWatts]

Ok, be careful.


Prop performance mod tips

http://www.rcboat.com/prop.htm

[ecoovert]

Water does not "wear down" a BeCu prop. I have props I have raced for several years which are still shap enough to cut - and I have the scars to prove it. If you run in mud, muddy weeds, up the bank, etc. then you can expect the sharp edge to dull.

Safety Note:
I would caution those who use power tools to work on their props without a resporator that they are exposing themselves to a toxic material with serious side effects. The problem with self-appointed health 'experts' is that they do not understand all the hazzards involved. The real issue is NOT beryllium poisoning, but the health effects of colloidal copper:

Copper fumes may cause "Metal Fume Fever" with symptoms of metallic taste, chills and fever, aches, cough, and chest tightness. The symptoms may be delayed for several hours after exposure and usually last a day or two. Repeated exposure can cause chronic irritation of the nose and may cause ulcers.
* Copper may cause a skin allergy. If allergy develops, very low future exposures can cause itching and a skin rash.
* Repeated, very high Copper exposures can damage the liver.

Two members of my former FE club were admitted to hospital emergency rooms for MFF after using a Dremel on BeCu props. Do not let it happen to you. Wear a real resporator, not a paper "dust mask"





.

Does doing this by hand or without power tools reduce the risc?

I usually wear a mask and goggles when I work on my props but must admit there have been a few times where I took the mask off. When I do this I always hold my breath and take a few steps away from where I did the sanding before inhaling. I also only use hand tools. I know it takes longer but it seems safer to me.

[siberianhusky]

I do my prop work all wet, just a dish drying tray to work over and a tupperware dish of water to keep dipping things in.I don't want the dust being spread around the house, everything just gets rinsed down the wash tub when I'm done.
A screwdriver with a 3/16 shaft with a spare drive dog and 3/16 wheel retainer makes a great prop holder.
Great walk through of the basics of a proper balance and sharpen!I'd love to see somebody do the same sort of thing with bending, I've seen a good one someplace about the basics of cutting a prop.

[2vdave]

Spin the prop in a balancer and if it stops with one of the blades lower than the other? That blade is heavier. Mark it and spin it a few times to make sure it continues to stop lower than the other. File some metal off the back of that blade until the back edges of the prop blades become level for a balanced prop.

You're almost there at this point, but, you actually want the prop to come to rest at any random position. If it keeps coming to rest with the back edges of the prop blades level, it can still be very unbalanced. Imagine that the leading edge of one blade is heavy, and the trailing edge of the other blade is also heavy. It will tend to balance with the back edges of the prop blades level, but will clearly be unbalanced overall, as there is a lot of weight on the low side.

My advice is, once you have the prop balancing level, turn it 180 degrees so that again the blades are level. Does it stay there or rotate itself 180 deg again? If it stays there, set it in motion on the balancer and it should stop at any random position. Your prop is then balanced. If it keeps stopping in one position, level or not, you still need to remove more weight from the low side, until it will stop anywhere.

I hope this helps, and has cleared up a few things, and I realise I've come in 4 years too late.

Regards,
David

[dana]

i agree that doing most or all of the work "wet" is a good way to go. i only do the initial heavy filing dry with a hand file and a good respirator. then its all working out of 5 gallon bucket full of water and wetsanding paper. make sure to dry prop off before throwing on the balacner when working.

[Rich]

You're almost there at this point, but, you actually want the prop to come to rest at any random position. If it keeps coming to rest with the back edges of the prop blades level, it can still be very unbalanced. Imagine that the leading edge of one blade is heavy, and the trailing edge of the other blade is also heavy. It will tend to balance with the back edges of the prop blades level, but will clearly be unbalanced overall, as there is a lot of weight on the low side.

My advice is, once you have the prop balancing level, turn it 180 degrees so that again the blades are level. Does it stay there or rotate itself 180 deg again? If it stays there, set it in motion on the balancer and it should stop at any random position. Your prop is then balanced. If it keeps stopping in one position, level or not, you still need to remove more weight from the low side, until it will stop anywhere.

I hope this helps, and has cleared up a few things, and I realise I've come in 4 years too late.

Regards,
David

Thanks David! I had that problem before now I know I am almost there!

[ecoovert]

Thanks guys. I liked the idea of wet sanding but knew the water would throw the balance off so never used that method. I should have realized it was as easy as wiping off the prop with a dry rag. I must say when I took the mask off I was working outdoors and always moved up wind before inhaling. I used to race bicycles so I am able to work quite a while while holding my breath. I have only done this at the end of balancing a prop. One of the times was when I had the prop balanced after having removed the mask and I dropped it on the cement floor. This threw the prop slightly off balance so I had to re balance it slightly. I was kind of in a hurry so I just finished the job without the mask.