Prop Finishing Advice

[SweetAccord]

Greetings,

I was interested in what most are using to achieve a bright polished finish on their Beryllium props? I have been using my DREMEL No. 421 Polishing Compound and that appears to give a nice fine, smooth, polished, reflecting shine. Is there anything else that is better maybe?

Thank you kindly.

[egneg]

I use a air micro die grinder #47869 from Harbor Freight - adjustable from 0 to 56,000 rpm and mibro #6 high gloss compound from Northern Tools. IMHO better than a dremel but a 10 gal or better air compressor is required.

[SweetAccord]

I ordered some Mibro #6, and I'll let you know what I think if it's better than the DREMEL No. 421.

Thank you!

[G Doggett]

Highly polished props are only for BLING.
A smooth satin finish is all thats needed and might even be faster.
Remember the discusion about sanding the shine off the bottom of your boat - same theory applies to props.
Graham.:rockon2:

[egneg]

Andy Kunz thinks otherwise - step 5.

http://www.offshoreelectrics.com/info-pages/sharpenandbalance.php

[ghostofpf1]

As always there are at least 2 sides of every issue.
I've read somewhere recently that a satin finish is preferred to allow air bubbles to form breaking up the waters stiction on the blade .
I've read elsewhere to polish only the rearmost face and leave a satin finish on the frontside...or was it the other way around ???
I've also read of the necessity to religiously polish each and every surface to a jewel like finish .

All seem to have merits on first glance and
for a beginner like me this presents quandaries ;)
If it hasn't already been done someone with a thrust meter,data logger and some unfinished props could put this to rest for all time or at least define the benefits or downfalls of each camps thinking.

ghost

[SweetAccord]

I know there is an advantage as there is a company that sells special finished Octura props gain MPH than regular finishes ones. All the pro racers use then apparently. I'll have to find their site and post it.

[SweetAccord]

Ok, I found the site and they don't polish the prop apparently front or back. Here is the site:

http://www.twistedliquidracing.com/props.html

http://www.twistedliquidracing.com/uploads/DSC05875.JPG <speed bead finish pic.

http://www.twistedliquidracing.com/images/tlrspeedbead.jpg

I don't follow the logic of their statement: "micro dipples allow the water to pass over the prop blades with less drag" but at the same time they state: "Testing has shown the SPEED BEAD props out performs the polished props by 2mph."

I don't feel yet one way or another about polishing, but less resistance make the most logical sence and a smooth surface would accomplish that.

Peace~

[egneg]

Aluminum oxide has long been used as media for bead blasting along with glass, walnut shells, and a plethora of others. Calling it a chemical process is very deceiving as this would lead one to believe it is some sort of etching process. As to the claims made about race events and testing - where is the data. If you look close at the picture you will see irregularities that are easily camouflaged by this process. Also the trailing edge has not been sharpened and I can't tell from the picture but I hope the shaft and drive dog areas were protected as these would eventually wear and become over-sized.

[Avanti]

Also the trailing edge has not been sharpened

I have never heard of sharpening the trailing edge, point me to your source on this.:confused1:

[egneg]

I guess that is a bit misleading - sorry. The trailing edge should be flat with sharp corners and 90 degrees from the concave side.

[Dr. Jet]

Trailing edge sharpening in this case means leaving a nice, flat trailing edge, similar to what you would see in a "wedge" style rudder.

[Avanti]

I'm with you now

[SweetAccord]

Right, the trailing edge is usually not well defined from the factory on props. Most all the area on the trailing edge are not "flat" to allow the water to run off more easily when leaving the blade so when they are filed down to be flat that is what is really meant by saying "sharpening the trailing edge", it's just wording.

[SweetAccord]

Yeah, I don't know what to make of Twisted's products. I would like to know if anyone has used them in compared to a "regular finished" prop and have seen any major difference?

[SweetAccord]

ugh* forget it:

http://forums.offshoreelectrics.com/showthread.php?t=3932&highlight=props

[SweetAccord]

I use a air micro die grinder #47869 from Harbor Freight - adjustable from 0 to 56,000 rpm and mibro #6 high gloss compound from Northern Tools. IMHO better than a dremel but a 10 gal or better air compressor is required.

Got it today, tried on one prop, and the results are I'm sold, Mikey likes it!

[Jon K]

I machined a spike for... my car ... don't ask.... out of 6061 aluminum. I was going to throw it in my vibratory tumbler but figured it'd round all the corners. So, I used a polishing pad on my dremel at like 8 speed and used Mothers Aluminum Polish. I then used this to polish the part (carefully) straight from being machined - no intermediate grits of sanding or anything. Basically, right off the lathe and onto my desk to be polished!

Here are the pics


Before polish:
http://blowneuroz.com/525/Progress/spikeofdoom1.jpg

Post polish:
http://blowneuroz.com/525/Progress/spikeofdoom3.jpg


This polish has worked well on copper previously - so give it a shot! Its a small ~2.75" tub from Pep Boys.

[egneg]

Got it today, tried on one prop, and the results are I'm sold, Mikey likes it!


I liked it much better as well - glad I could help.

[SweetAccord]

The good thing is that I can balance the props much faster now. I can fine balance with a file, get really close and closer and when it's just right with the files, I can buff the file marks right off. The great part is that you don't need a high speed tool to do it either! Using a dremel that is 5,000-35,000 and not even running it full speed gets the job done easily with mirror results.

Thanks again for great recommendation egneg!

[SweetAccord]

So, I'm curious. Does or has anyone here polish the back side of the prop and have noticed any top end speed increase? I read somewhere that it was done on a prop and all else was the same and the gain was 1-2 mph more.