Props --- Sharpen, balance & polish

[Doubledog]

After having a few PM's sent my way, you're going to get the full story on how to do this. May take a little while to complete, but we'll get there.

This is how I do it. From the sport boaters standpoint, this should be fine.

Today I saw my wifes cooking scales (weightwatchers brand) and decided to see what a prop weights.

Ran 5 different sizes of props. The two Prathers are stainless but it gives an idea. Then three ABC series three blades.

Prather 280
new -- 52 grams
roughed up -- 47
Sharpened & Balanced-- 45

Prather 275
new -- 37
roughed -- 34
s&b-- 33
Barr Cut mod -- 32

ABC 3015-3
new -- 65
s&b -- 57

ABC 2716-3
new -- 31
S&B-- 29

ABC 2616-3
new -- 26
sharp & bal -- 25

[Doubledog]

tools of the trade. *& don't forget the 6 in. needle files:D

.

[Doubledog]

needle files & balancer. Actually I use two balancers. The Top Flight normally used for airplane props & the Zero G' for final.

.

[Doubledog]

Stock Prather 280

notice how flat & thick the blades are especially at the blade root (dog side)

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[Doubledog]

Untouched ABC 3015. This is a heavy prop and as you can see from this side shot, the blades need some work.

*folks just slap these things on & run :rolleyes:

[Doubledog]

Check out these pics. This is after a mild wet sand. Look at all the pits. This one is not bad considering some we've ran across. :rolleyes:

YOu don't have to take this much trouble just for a sharpen & balance. Thats fairly easy for a two blade.

[Doubledog]

Then we start grinding.

I'll take the green carbite wheel & run all over the back sides working close to the edges getting them fairly sharp.

Check balance.

Then run over the back again with the large grit sanding drum, smoothing out the rough areas made from the green wheel.

Check balance.

(Checking the balance lets us see which one needs a little more attention.) :p

I'll work close to the edges with this one & clean the hub lines up while there.


You'll notice once you get the grey paint or whatever it is off the prop, theres tons of imperfections there. Might not effect performance, but they've got to go if its mine. Ya'll asked. ;)

[Doubledog]

Once done with the large grit drum, we'll run over everything with the fine grit drum. Smoothes it out even further. (sounds funny when you read it:D)

With the smoothy on, thens when I like to hit the face & take out those pits. Dremel makes it so much faster. :cool: Look at the tip of this prop. See that pit? Its coming out.


At this point the prop is fairly sharp & is very close to balance.

****while working with the Dremel, I'm wearing a resparator (cartidge type), goggles & have a large Shop Vac right there sucking as we're grinding.****

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[Doubledog]

another shot of the swirl marks.


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[Doubledog]

Look at the blade root closely. Its still flat next to the hub.

Nows the time when I'll set down & work it over with the 6 in. needle files getting a lot smoothed out & start on sharpening. The edges are sharp when done by this stage.

The whole time paying attention to the balance. Dont' want much difference in the sides as its harder in the end.

This is also a good time to say that when sharpening, you can decide the profile. Some like it super thin, or I'll keep mine with a little meat on there. Not thick, but fair.

[Doubledog]

LET THE FUN BEGIN (not) :o

Take about a foot of 320 sanding cloth, roll it up tight & start working those Dremel swirls out. To do one prop will take me about 3 hours. :eek: When Im done, there's no wave's, dips, swirls, pits, nothing. They get worked out. We'll most of them.:D

After your'e done, find a peice of wore out cloth & run back over an area real good. Then do it again for a few minutes. The shine will come. Actually, you can do a prop that way, managing how much pressures applied & bring it to a good mirror shine.

If not satisfied with that, take some 1500 grit wet sand paper & cut you a 3x3" peice. Stick it under a dripping faucet & go to town. Once the paper almost wears out, put a drip of dishwashing liquid on the paper. Have a look after a few minutes :eek: :eek: :eek: :eek: BLING BLING BABY. :cool:

To finalize, check the balance again & run a file over the trailing edge to square it up.

Not that hard was it? :)

Thats my method in a nut shell & maybe it helped someone.

Best Regards,
DD

[Doubledog]

few more pics.

/

[Watercadet]

Nice idea for a thread DD. I am sure this will answer a lot of questions and bring up a few more :p . I really like the "prop working tool" (stick). Do you use a flex shaft on your dremel?

[Raydee]

Nice Post DD.

[Doubledog]

Thank you. Thank you.

Its not as much of a mystery as some thought. Just elbow grease & a good Dremel. :) I've got a wand, but still prefere not to use it.

We'll come back to this thread later & show how to balance a three blade. :0 There's some stories to be told about them. I've got one now that will not balance to save my life. Makes me wonder how much more can be removed before it questions the strength of the blade. But we'll save it for later. Gruss, DD.

[Ron Olson]

Prop thinning is critical on lifting props. A buddy of mine likes to take his props to the extremes but found out the consequences on his .21 'rigger. He had them so thin that with the prop lifting the boat that it bent the blades!

[ejp]

What do the cuts by the hub do????

[ejp]

So, to polish a prop do you have to rebalance it??

[Doubledog]

E', always try to keep a prop in balance no matter what you do. I like to get them spot on balanced before starting the polish & check throughout the process. Like I said, to do a gas prop in SS takes about 3+ hours just to polish to near perfection.

The cuts by the hub help the prop to accellerate & rev quicker plus reduce a little lift. Such as if a prop is falling off the pipe in the turns, try that cut. Its not going to hurt performance.

[suck my wake]

nice post dd its basicly perfect timing cuz i just ordered a few props and am gonna try to balance em up nice. I was just wondering (anybody can chime in) what do you think the best balancer is to have ive heard people asy use an octura one if your a beginner and then a top flite once your a bit expeirenced. any comments appreciated.
nick

[Watercadet]

I went right for the Top Flight- just follow the instructions to balance the shaft first.

[Ron Olson]

There are cheaper and more expensive ones than the Top Flite but that's what I'm using right now. My old one that I still have is a Robart.
You'll find that the Top Flite is really sensitive to any little bit if work that you do on the prop so don't drive yourself crazy trying to get one perfect. One little part that can throw the whole thing off anyway is the drive dog and loose fitting bushings in the strut.

[Burkey1000]

Just one note to add on this, i would always advise to thin the prop, i dont mean the whole blade, just when you you sharpen it, start from the middle of the blade, and a gentle taper to the edge, and they must be sharp, these to things can have a huge affect on the boat, prop walk etc, i know ive been there lol, well we all have to learn, just i learned that the hard way lol :D

[Pagemaster]

Excellent post DD. Some people are just afraid of trying to tackle this.

You can also buy the right prop balanced and sharpened from the start. Sure you can save some money buy sharpening your own, but you cant save time. I know its a shameless plug for me! :-)


Steven
www.OffshoreElectrics.com

[Ron Olson]

Steve, if you're going to do a shameless plug, you ought to be pushing your pix and video site too. www.rcflix.com , I love it! Upload your vids in there with no limit for free! You've done us boaters a great service with that.

[Pagemaster]

Thanks Ron.

[Ron Olson]

Steve, just watch out around Memorial Day weekend, we'll be uploading a LOT of pix and vids on your site. :D

[rico3]

so the master has spoken..DD nice work about the props....as im writing this, my printer is printing this hole thread.... soon i will have another 4 props 2 modded and 2 just balanced and sharpened.... well it looks like ill be having a try on moddin props myself....cheers m8 for the info.... ;) ;) ;)

[Doubledog]

Thank you many times over for the words. We're currently on vacation & 'puter time is very limited. Give you guys a little break from my jabber mouthing for a few weeks. LOL.

Need some help from you while at it:
Where can I buy 3M Blue Roll sanding cloth? Our local store once stocked it & have since quit. Been to the Home Depot, Lowes, and many others in search of this only to draw a blank.

Reason for asking is because that particular brand (the blue cloth) doesn't load up nearly as fast. Found some 3M in the beige (tan) colored cloth & its a bear. After a minute of rubbing, its loaded & going through lots just to do a small area. 320 grit is perfect.

Happy Prop Work to you.:)

[bufferoo]

DD...question for you.

What's the best way to get balance, polish AND sharpening all at the same time? :mad: I'll be buggered if I can do all three. Sure I can get a real nice & shiney prop that is razor sharp...but way out of balance. Or I can choose to have a prop that is perfectly balanced and shiney...but about as sharp as butterknife. I've even managed to have a balanced prop that was sharp, but not so much as a lick of a shine to it.

What am I missing?

Bufferoo

[Doubledog]

Very good question.
Balance, Polish & Sharpen at the same time. Humm. Don't really know how to explain it other than being prepared to spend some time.

Another method than what we've described earlier would be this:

Take a new prop & check the balance right off. That way you'll see which blade will require immediate attention.

1st heavy blade: Start by bringing the heavy side (blade 1) to a good edge with 6 inch files. Check balance. Might still be heavy on blade 1 so you'll need to work the back side removing material with little amounts. Checking balance often.

Once blade 1 gets close, you know you still have to remove (sharpen) blade 2 (lighter one to begin with) therefore throwing the balance off again. So now you'll have to go back to blade 1 & remove material from the backside again to get it in balance. Dancing back & forth between blades.

For final, hit the trailing edge with a good flat file & square that baby up making it flat, but sharp. Check balance. You should not have to remove much material to get it square. Reason we want it to be that way is so the water will release clean.

Thats just to get it S&B.

Okay, now we've got a perfectly sharpened & balanced prop right...? Yes, now its good to go & can be ran.


Start with the polishing.
Taking some of the 320 grit (or you can choose to wet sand) start removing the imperfections on both blades. Keep checking the balance often. You'll be surprised how much difference a little sanding will reflect in the balance. After seeing which side is heavy, give it some attention with the paper.

For final sharpening, I like to use the 320 & work the edges. Once the 320 is loaded good, it'll polish very well or you can choose to wetsand with 1000 or 1500. When using those grits & their loaded up, you're not removing that much material so it should stay very close.

To S&B a two blade prop normally takes less than an hour. To get the full effect of S, B, & Polish requires some time & patience.

*Note*
How many times have you taken a new prop out of the package & seen many dingle berries (mold lumps etc..) along the edges? A lot of them are that way. Another key point is to look closely at the mold lines of the prop. A lot of times there are divots or what looks to be steps.

I've taken a new prop & made a mold of both blades only to find out that one blade was slightly larger due to this. Having measured them with calipers in the same areas, some have been found as much as 1mm difference. Sounds silly but true. It really becomes tricky now making both blades the same shape. Usually you can see this with the naked eye before starting, but when in doubt, pull out the calipers & check it out or make a template or even a mold if your that serrious.

****Balancers*****
I like the Top Flight for all around. It gets you very close.

Since using the Zero G balancer, this thing is a nightmare because its so sensative. When mine arrived, the first thing I did was go back & check props we'd already done with the TF. Most all were out.

Please keep in mind that the Zero G will almost make you want to pull your hair out due to the sensativity & caused some restricted language to occur. One of the problems I face with it is when doing Steel props is the magnetic field seems to throw it off especially on the larger Prathers. Thats when I start juggling between the TF & the ZG. For non magnetic props (berrylium copper) the ZG is the best in my opinion, but much more of a headache. I've seen one on another website where there's two metal tabs bent (rolled) upwards & what looks to be a stub shaft center ground on both ends. The prop is slid on the stub shaft then rested on those tabs without the use of magnets. This seems like it would be very good but where to buy one & form my own opinion.

Hope that helped a little bufferoo.

[bufferoo]

Hope that helped a little bufferoo.

Sure. Why not? ;)

When you say the back side is that the side of the blade the is moving forward INTO the water or AWAY from the water. I can NEVER get this part straight. I'd think thta the FACE is forward and the backside is facing the stern but then again I think a LOT of things that turn out not to be true. :D

Should the trailing edge be squared to the blades or angled in some fashion? Does it really matter and if so, how would it affect the running.

Lastly, from what I understand from what you wrote, I should only be using the files to sharpen the blades rather than the paper? Maybe my files are too coarse since I get definite file lines when I do this. That's when I break out the 400X and get a razor edge. I've tested this too. A nice close shave. Mr. Gillette would be proud. :D Problem is this kills my balance...again.

So...tell me if I'm correct here. I shape and smooth and balance (I can do all that ;) ) and then use the paper to remove any file marks. Recheck my balanc and polish while periodically checking balance (I think I can do this too). If the balance is off I need to work the side of the blade that is facing the rear of the boat until the balance is right. If I can keep the balance pretty much in the ballpark during all this I shouldn't need to do much polishing on the backside to keep the balance in check.

Sound good?

I tell ya...with all the cuts and hand cramps, those jet drives are looking REALLY good right now. :D

Thanks for the help DD.

Bufferoo

[Doubledog]

:) Shoulda' said this in the beginning. Sorry for any confusion. :)

Backside = drive dog end (negative pressure)
Positive pressure side would be the nut end (prop face) as water is being forced against it.

Home Depot, Builders Square, Lowes, Scotties or most home/hardware stores will carry 6 inch metal files. I like a good quality set as the steel will wear them out under much use. They come with 5 or 6 different shapes (round, flat, flat tapered, triangle, Half round & square) in the pack & are my choice because they allow you to get to the hub & remove the casting lines along with the blade root. They also don't leave a ragged edge like the larger files as they are finer.

Those will do a satisfactory job of thining & sharpening.

To do a professional looking job, yes, I like to use the paper for final sharpening.


Sharpening the trailing edge = the nut side
(someone correct me if I'm wrong) but the trailing edge needs to be square to the angle of the water coming off.

Lets visualize a prop sitting on a table with the nut side facing upwards; The trailing edge will not be flat with the table or 90* angle to it, but at the angle of the water coming off. (man, its hard to write without having a camera to take pics).

I feel that if you use the files moderately on the egdes, then there should not be much final sanding involved.

In a few weeks we'll start doing some mods that have been proven to work if you feel like cutting up a perfectly good prop. :)

[Burkey1000]

the trailing edge needs to be 90 deg to the back of the blade, very flat and must not curve at all, you know when its right you should have very sharp edges, one thing that maybe should be mentioned here and i dont want to confuse the issue, and if any replies come from it i will let DD try and explain lol :D cheers DD lol, is when you balance the prop, the heavy part always falls to the bottom, you always remove metal from that part below the spindle, trying to explain this is not easy, ok if looking from above you see the prop and the shaft its on, the bit right below the shaft is where it needs to be removed, if it falls in the middle of two blades it might need to be removed from the tip of one and the toungue of the other, and also the barrel part, now that will confuse someone im sure lol. All questions to be answerd on a postcard and send to DD, lol sorry mate but its hard to explain this lol.Maybe you try explain it too, good luck :D just thought id mention it incase they think only remove metal just from blades.

[Doubledog]

Good input for sure. :)

[bufferoo]

Okay!! I think I have it! :eek: So if I'm looking at a prop that is mounted on the boat from the rear I am looking at the face of it and the reverse (?) would be the back. I guess that makes sense since the "face" is where the water would seem to build up the most pressure as it is beign pushed back by the prop. This actually makes me wonder is are the blades pushing the water back or pulling the prop forwards? My head hurts. :o

So if what I am thinking I have read is true then I do believe that I'll get through this...finally.

So now let's assume that I have a prop that is nice and shape and mirror shiney but slightly out of balance. Since I really don't want to touch the blades and take off the shine or sharpness, can I just take a little off the hub as I think Burkey1000 suggested? That'd make my life a little easier.

I took a closer look at my files and I think that my problems come from the fact that the tooling seems to be in the wrong direction. I'm right handed and when I file I get marks. If I do it left handed I get none. Maybe I bought left handed files? Do they even exist? I'll start looking for a different set I guess.

Bufferoo

[Doubledog]

can I just take a little off the hub as I think Burkey1000 suggested? That'd make my life a little easier.

You're getting the hang of this now. :)

Also, check the trailing edge. Thats always a last resort, but if the prop is very close, then take a little off of it and you won't have to worry about
re-polishing the hub.

[Burkey1000]

i know what ya going through we have all been there at one time, try and get an old prop and work with that, bit of pratice fist, once you get started its not that bad just takes time thats all, the prop spins through water pushing the water back, therefore pushing the boat forward, its 3.11 am here, i think i got that right, if not im sure somebody will let me know lol :confused:

[Burkey1000]

can I just take a little off the hub as I think Burkey1000 suggested? That'd make my life a little easier.

I did say you can remove metal from the hub, but only if it needs to be removed, you do not remove metal from anywhere that doesnt need it, what i was saying is sometimes it falls in the middle two blades and may be the hub as well as the blades.

[suck my wake]

i know this sounds stupid but where do i take off material when the end of the blades are level would i take it off the tip right where the drive dog is

[ejp]

So, can the topflight balancer do 1/8 inch props too???

[Doubledog]

E', I just measured mine & its 1/8th exact but the cones are larger. Might not need them but it makes me wonder would it be sensative enough to do such a small prop?

[ejp]

Well, if that won't, what balancer will???? Octura???

[Micho523]

I have heard problems with the topflite's cones being off balance. I the one i just ordered is ok! :eek:

[Burkey1000]

when you get a new one you always balance the shaft with the cones on first, before you even put a prop on it.

[Doubledog]

Not trusting many balancers for true-ness, I'll rotate the cones a wee bit, then check it. File a little, check, rotate the cones & check again. Same with the highly sensative Zero G' balancer.

[Doubledog]

Sorry haven't had much time to mess with this thread and promise to show better detail in the next couple of weeks. There's a couple of fresh three & four blades in the works you want to try your skill.:)

In the next few posts, I want to share something..........DO NOT TOSS A BUSTED PROP

Reason is we've created something good out of what looked like a bad deal. This was the 275 that came from Enforcer when I bought the 'G. A few dings & meeting with a rock later, it almost got tossed in the trash. Reading threads like this lead to an experiment with the files & cupping tool. It was ate up pretty good along the leading edges and tip.

So to get the idea for a blade design came from looking at other props on pages like this: Prop Mods 1 (http://rcboat.com/prop.htm) and Prop Mods 2 (http://www.rcprops.com/rcprops/index.html). The hard part was coming up with template. Some thin flexi plastic and shears allowed the design to fit perfectly into the hub & be consistant. Scribe & start removing material.

First was removal of the tounge & scuffed up areas along with rounding the tip. Ran it. Did ok but slipped mad. Tried a back cut as you can see next to the hub and a little cupping. Turns out to be the best prop for my 'G with the 230. Amost afraid to mess with it any more including cleaning up the hub.:)

Have a look.

The one I'm referring to is the copper 275. Check out the stainless one too. It got busted REAL bad & is now a fast prop. Its not as fast as the copper one (guessing because its a bit smaller dia. & less cup.).

[Doubledog]

side shot. It shows a good back-cut & a little cupping.

See, they don't all get polished. Be easy on me about the hub area not being cleaned up too. :o

[Doubledog]

Here's whats planned once we finish this segment up. Don't forget a few three blades with good detail. :eek: :p Got a hot mota' for my cat to run these on if time permits.:)


.

[737mech]

who sells / where can I buy a "Top Flight" prop balancer?

[Ron Olson]

If your LHS doesn't carry them or can't get them, you can order it through Tower Hobbies.

[Ron Olson]

If you haven't gotten one yet, the latest issue of RCBM has a great article on sharpening and balancing props by our own Moderator in here, Rick Eyrich.

[ejp]

Is the topflite a better balancer or the Dubro Tru-spin??

[ejp]

Hows this for a shoping list.
http://www2.towerhobbies.com/cgi-bin/wti0001p?&W=000601842&I=LXDS07&P=K
http://www2.towerhobbies.com/cgi-bin/wti0001p?&W=000601842&I=LXNM83&P=K
http://www2.towerhobbies.com/cgi-bin/wti0001p?&W=000601842&I=LXHY61&P=K
I know that the prop is more expensive but I don't want to have to pay shipping for just a prop:D Should I get brass or stanless on the prop???

[Ron Olson]

The Du-Bro isn't bad, it's similar to the Robart that I used for years. The Top-Flite you might find to be too sensitive for most users. It might drive you over the wall because you'll have problems getting a prop too perfect.

[ejp]

So, would you go with the Du-bro???

[Ron Olson]

For ease of use they are the same. You might like that the Du-Bro isn't so sensitive.

[ejp]

But it is sensitive enough to balance a prop well??

Also, whats better. A stainless prop(harder to work with) or a Copper????

[rico3]

stanless steel is harder to work with,but i think it looks better..copper is more easy than steel but watch out for the dust when filing the prop its DANGEROUSE ... anyway look in this months issue of rcboatmodeler...theres a few pages on prop balancing and sharpening....but if i was you id get a prop modded already for you straight away even if it cost alittle extra... :D :D

[ejp]

Where can i get a modded prop???

[ejp]

And do stainless props run better then copper or will I not notice a difference between the two??

[rico3]

i no of on in USA hang on ill look for the web address.. stanless steel is harder (stronger)they say you can throw these props around a dont worrie to much if you hit some thing with them..... they both run the same i think,just that stanless steel is stronger :D :D check this out he doesnt sell props but have a look at these ejp..http://rcprops.com/rcprops/index.html :D :D

[rico3]

ill have to look for that web address for the modded props that you can buy... give me a little time ejp ill get back to you .. ;) ;)

[ejp]

I'm going to order a balancer and prop so I will just experement with that:D

[Ron Olson]

www.cmdracing.com has a Prop Wall that has props on hand and ready for shipping. It is updated daily so if you don't see what you want, keep checking in or request one. I might get into doing some prop work this weekend. A LHS is going out of business after being here in town for a good 20 years. Myself and a friend are probably going to get every prop that they have on the wall. It's to bad as they were the only one out of 3 that kept boating supplies in stock.

[ejp]

Better then what I have. 0 out of 0 here carry boating stuff:D

[Burkey1000]

Theres no difference in stainless or berylium as far as performance goes, but rico is right, watch out when ya mod those bronze ones, the dust is realy bad for ya. Word of warning, before ya mod a prop get alot of info if ya dont know what ya doing and make sure all the blades are the same size and shape and ballenced right otherwise you will just go through flexis every 15 mins and lead teflon bearings too, you have been warned.

[ejp]

I just plan to do the bar cut so I can get it to rev out faster. I also want to clean up the hub real good and thin the blades some, also give a a nice polish job.:D Thanks for warning me.

[Micho523]

How do you keep the props from tarnishing??

[Doubledog]

The only ones I've had success with not tarnishing is the SS. Copper is going to tarnish a little so keep some polish handy.

[rico3]

ok ejp heres that link for buying modded props....http://hometown.aol.com/tpw033/thepropworks.html :D :D :D

[Doubledog]

While the glue dries in the radio box for the Fighter, may as well cut up a prop. :eek: A bit of experimenting. :p


Prather 280

Before even running, it got a huge Barr Cut. Thought the Sikk would like it but it doesn't. Speed was way off and didn't rev. So we'll try something else.

Look at the left side of the prop and you'll see the orriginal cut. The right side is being worked & will show more in the next pic.

.

[Doubledog]

Notice something missing from one blade?

This is the tounge area as its referred to. Its leaving town. :D

Look close & you can see where the trailing edge of the "R" side (of Prather) is getting blended into a back cut now.

The Barr Cut and tounge removal are two good mods that help them rev quicker.

[Doubledog]

More blending. For experimenting purposes, I'm going to keep it rounded on the trailing edge.

.

[Doubledog]

side shot.

Scribe lines along the trailing edge where the planned back cut will be. (like said above, the plan is to try a rounded back cut this time)

[Doubledog]

Tounge is now removed and rounded on both blades. Scribe lines are visible on the trailing edge again. Its going to be blended into the edge of where the Barr Cut used to be.

Two ways to do this....

Round them slightly and run it. If it doesn't work, then can always come back and finish the Back Cut. Lines will be there. :rolleyes:

.

[Doubledog]

Back side.

These are some thick blades. I knew when working this prop the first time that I didn't thin it up too much and then after cutting the tounges off, MAN THIS THING IS thick! Of course there's going to be a lot of work done now to get them down good and sharp.

[Doubledog]

Last one for now.

This shows the scribe line that'll be used to reduce diameter and round the tip.


Too easy.
How?

AA battery.:D

The work begins after this. A little filing, Dremel work and loads of fun. :) I'll bring this back to the top after its done and maybe a few runs.

.

[ejp]

So, how do you make both blades the same??? I was thinking about modding the prop I am getting. I was thinking a good bar cut, then cut the tongue. That is if I can get it balanced and sharpened first:D But how do those two things sound??? Any help would be great.

[ejp]

Also, would rounding the ends do anything for me??

[ejp]

Ok. So heres my first prop:D It is balanced pretty well I think and sharp enough to cut my finger when it sliped while I was polishing the dremel marks out.:D Should I make my barr cut deeper???

Its not perfect yet.... I still have to get some finer grit paper and work on it a little longer.

[Doubledog]

Looks nice. I would not use the dremel any more on the face (nut side), but the sandpaper with light grit (say 320 at the roughest). Try not to distort it. You can make the Barr Cut a little wider and deeper. Go back and read through this post again to get the measurements.

Btw,
Before making any more changes, RUN IT and see if that mod helped. Do one at a time when experimenting.


ps,
Barr Cuts... the described best way to do one is to cut straight into the metal with the trailing edge.. Not at an angle like you and I have done. Making the cut at a slight angle and blending with the prop face is a style of mine. Some might disagree.

[ejp]

So, Go in at the angle of the trailing edge??

[ejp]

I don't see the measurements on the post

[ejp]

What kind of resporator do you all use??? I am using a Aearo AOSafety. The cartridge says it is good for organic vapors, chlorine, dydrogen chloride, sulfur dioxide, clorine dioxide, hydrogen fluoride, and P100 particulate filter. Effective against all particulate aersols.
Will this one block the dust???

[Burkey1000]

The barr cut needs to be done square to the back of the blade so you have a full indent, also i flow mine alot more that you all seem to do. I flow mine throught 2/3 of the blade so the flow of water has a smoother path. thats my way anyway and it works for me.

[ejp]

Well, I'm done using beryllium copper!!!!! This stuff is beyond dangerous. :eek: I'll pay the extra money for stainless. I didn't relize what the stuff does to you. :( http://www.berylliumdisease.net/

So, do you have a pic of your barr cut???

[ejp]

what do you mean "flow" yours more???

[Doubledog]

Measurements vary.

For any noticeable difference, 5mm wide and 5mm deep is usually where its started and worked larger from there. (can be a good or bad thing). 7mm both ways seems to be the majik number for my G' & the stock 275.

Yours looks much smaller. For you to say that you've seen an increase in perf is probably the engine getting broke in good for such a small cut.

Flow the cut along the face? Blending & smoothing the blade. Not the trailing edge. Go back & look at your cut v/s the one done on the 280. See the face how its been smoothed out ie, blended ?

<sigh>

[ejp]

Well, I made mine 5mm by 5mm and thats when I tried it and said it made a difference.:D What about the beryllium thing:(

[Doubledog]

Well, I made mine 5mm by 5mm :(
Hate to disagree in open public but its not that large of a cut. (maybe combined). 1/4" bore = 6.35mm. So looking at the size of the bore next to the cuts is pretty obvious. Others will tell you that when the engine breaks in good, you'll see an increase in speed. Before modding that prop any further, I'd try some different ones instead.

Working these props in a well ventilated area & wear gloves. When filing, its not that bad because they're taking large bits of material where sanding is churning up the dust. For sanding, a drop of oil on some wet sandpaper does the trick or wetsanding under a dripping hose, but then you've still got to be careful with it getting into the skin.

[ejp]

I know its not that deep. I had my stock one on then I changed to this prop. 30sec. and it was back in the water so something couldn't have changed other then the prop:D My mom said she could even see a difference.:D

[Doubledog]

Good stuff Eric. Proved me wrong no doubt, but still good. :)

[ejp]

So, DD. Do I have to worry as much if I use a SS prop instead??? I really liked messing with a prop until I figured out how dangerous it is.:o

[Doubledog]

Heres a new one for you.

Prop Shop 7016 ss

This was a good one with the rc230. Didn't get around to testing much because it got banged up after a few minutes. Dang rocks.

Notice how its got a backcut designed into it.

.

[Doubledog]

Front.

Check out how its got the tounge removed also. What else do you need from it? :p


Forgot what the pitch is. :o

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[Doubledog]

last of this prop.
Just kicking around today.