Prop polishing?

[Megabiker98]

I would like to polish a couple of props but have a couple questions, I know u r supposed to use 600 grit wet sandpaper but, is that all? U just wetland till its shiny? any issues I may need to take into account, things to be aware of??

[hydro_pyro]

Stay off the trailing edge... Don't soften the sharp 90 degree edge.

You can carefully finish with a high-speed buffing wheel on a Dremel with a suitable wax-brick buffing compound.

[Megabiker98]

I'm probably gonna start on my stock proboat one, then my octura x642 then my newest m445 if in capable, ill upload pics so u can point me in the right direction

[detox]

I use these with my Dremel
http://www.dremel.com/en-us/Accessories/Pages/ProductDetail.aspx?pid=511E

[hydro_pyro]

I used small sanding discs and soft abrasive wheels on my Dremel tool to do mine.

[Megabiker98]

I'm not gonna use a Dremel, I'm using sandpaper, that works right? Do I NEED a mask when working with an octura prop, even though its gonna be submerged in water???

[Rumdog]

No. There won't be any airborne dust while wet. Especially so when just polishing.

[Megabiker98]

No. There won't be any airborne dust while wet. Especially so when just polishing.
Ya I was pretty positive I wouldn't need it, but hey safety first so u might as well ask! Hahaha

[Megabiker98]

I can't seem to get my pics uploaded from my phone right now, website isn't cooperating. I did one blade on the stock and might need a little more wetsanding but, want to know ur guys opinion, ill try and get some pics if I can get around the problem

[Megabiker98]

I got one, if u guys need more I can try again in a little while, seems like its because I was trying to upload 2 at a time

[egneg]

That is fine ... I usually stop at 400 grit.

96106

[JimClark]

Ok I just got to ask Is the reason you want to polish the prop that you think it will go faster?

[Megabiker98]

Ok I just got to ask Is the reason you want to polish the prop that you think it will go faster?
No, I just want one to have a couple shiny props. The stock proboat is gonna be the one I put on when it's on my desk

[T.C.]

Question for people smarter than me..................
Most people scuff the bottom of the hull (make it a dull finish) so the water wont stick to it thus slowing the boat.
If water sticks to a shiny slick finish then why would you not want a polished prop ?
The prop is the wheel,gear,traction for the boat, so wouldn't you want a surface that grabbed the water ? (shiny)
T.C.

[Megabiker98]

Question for people smarter than me..................
Most people scuff the bottom of the hull (make it a dull finish) so the water wont stick to it thus slowing the boat.
If water sticks to a shiny slick finish then why would you not want a polished prop ?
The prop is the wheel,gear,traction for the boat, so wouldn't you want a surface that grabbed the water ? (shiny)
T.C.
I would have to say that a polished prop doesn't give u anything because its already spinning so fast that it doesn't make a difference whether its polished or not, anybody correct me if I'm wrong! That's just a guess from me

[egneg]

I would have to say that a polished prop doesn't give u anything because its already spinning so fast that it doesn't make a difference whether its polished or not, anybody correct me if I'm wrong! That's just a guess from me

:iagree: Do what you like ... It won't make enough of a difference to matter.

[mtbenjamin77]

scuffing the bottom of the boat creates a thin layer of air pockets on the bottom of the boat. the boat is actually riding on air, not water, thus reducing friction/drag. the prop however needs the friction to move the boat forward, atleast on one side, the face of the blade. the back of the blade doesn't move the water. I polish the face of the blade and satin finish the back. this helps the face of the prop grab and move the water, the satin finish on the back side helps reduce drag and allows the prop to spool up.

[T.C.]

I don't mean to hijack the thread, just curious as to what the reasoning some have for not polishing ?
I would think a non polished surface would promote air bubbles and thus cavitation ?
I would also think any and every little speed trick you could think of would add up in the end ?
It's the whole combination not just one part that makes these run and the prop is a big part of the combo.
What do real boats do ?
T.C.

[Megabiker98]

My dads (real) boat prop is polished both sides. I think it's mainly all just preference and what u like

[hydro_pyro]

In the "real world" of performance boats, the fastest props have a fine satin finish created by straight grit lines in the direction of water flow over the blade. Polished props are only for cosmetics.

[skidbump]

In the "real world" of performance boats, the fastest props have a fine satin finish created by straight grit lines in the direction of water flow over the blade. Polished props are only for cosmetics.

I have been working on surfboards for 20 years and this is what the science behind a sanded/satin finish is in the pro surfing world(should apply to any hard surface to water scenario)

A sanded/satin finish causes water to stick to the surface of the object, the idea is that water on water is less resistance than a water to surface scenario, so effectively, having a sanded finish will cause a water on water planning effect, this should be the slickest way for any object to pass through water. Hope that makes sense.

[martin]

Skidbump your spot on re scuffed surfaces on hull bottoms, the scuffed surface allows a thin membrain of water to attach to the hull surface. So you end up with the water attached to the hull sliding over the lake water rather than a shinney surface of the hull which has more drag.

[kevinpratt823]

scuffing the bottom of the boat creates a thin layer of air pockets on the bottom of the boat. the boat is actually riding on air, not water, thus reducing friction/drag. the prop however needs the friction to move the boat forward, atleast on one side, the face of the blade. the back of the blade doesn't move the water. I polish the face of the blade and satin finish the back. this helps the face of the prop grab and move the water, the satin finish on the back side helps reduce drag and allows the prop to spool up.
Maybe I'm reading you wrong, but this doesn't make sense to me. The back(rear) of the prop is the part moving the water, not the face. It throws the water back and outward, creating the thrust cone, and when this is happening, the face of the blade (in a partially submerged prop anyway), is making very little if any contact with water because as soon as it hits the surface it is scooping water and throwing it back. This is precisely why when balancing props we remove material from the face, not the back, so as to avoid effecting the pitch. It is the pitch of the prop and the sharpness of the leading edges more than anything that count, and also the thickness of the blades, not so much the surface. The idea is to allow the prop to cut through the water with little resistance, allowing the pitch to move water back, not create friction.

[domwilson]

I've found that McQuires Mag wheel polish works great.

[hydro_pyro]

Maybe I'm reading you wrong, but this doesn't make sense to me. The back(rear) of the prop is the part moving the water, not the face...

Indeed, you're reading it wrong. When someone talks about the "face" of the blade, it's the side of the blade that exerts force upon the water. The term "back side" of the blade refers to the low-pressure side which is facing forward, so the term can be confusing. Material is generally removed from the "back side", while preserving the shape of the "face."

[kevinpratt823]

Indeed, you're reading it wrong. When someone talks about the "face" of the blade, it's the side of the blade that exerts force upon the water. The term "back side" of the blade refers to the low-pressure side which is facing forward, so the term can be confusing. Material is generally removed from the "back side", while preserving the shape of the "face."
Thank you for clarifying, what is your interpretation on the whole "the prop however needs the friction to move the boat forward, atleast on one side, the face of the blade."
that sounds counterproductive to me.......? Unless you were looking to widen the thrust cone.........

[Heaving Earth]

so many theories ive heard over the years. ive tried polishing and not polishing without any noticeable difference between the two.

[Rumdog]

Yup. Polishing is just wasted energy. Looks nice though.

[martin]

Yes you would be better off spending the time doing something more productive on a boat else where than bothering with highly polished props, they do look nice but i wouldnt bother. Just making sure their nice & sharpened & balanced does me.

[mtbenjamin77]

Skidbump your spot on re scuffed surfaces on hull bottoms, the scuffed surface allows a thin membrain of water to attach to the hull surface. So you end up with the water attached to the hull sliding over the lake water rather than a shinney surface of the hull which has more drag.

What you're talking about is called laminar flow. But the issue is not really drag its that the hull needs to be able to freely separate from the water.

[Brushless55]

I use these with my Dremel
http://www.dremel.com/en-us/Accessories/Pages/ProductDetail.aspx?pid=511E

do these give a nice polish ??

[TheShaughnessy]

Those work ok, need a finer grit then 280 though, the finest I've found is 320. You do have to be careful with Em though, they have a tendency to grab and wrap/hook around the edge. However it does say right on the packaging of octura props not to dry polish but rather wet sand to finish