Prop coating

[Ray Sametz]

Just curious, what's the coating on this prop????

 

[SayMikey]

Just curious, what's the coating on this prop????

No coating just look close it says ANDY BROWN on the hub

 

[Bigbird]

Just curious, what's the coating on this prop????

It looks like a spray to help see cracks.

BB

 

[glenng]

Just curious, what's the coating on this prop????

It looks like a spray to help see cracks.

BB

BB, It;s been many years-used to do dye penetrant testing on non-ferrous metals. Best that I can recall red dye was applied and wiped down-then the part was sprayed with a chalky white substance. red dye would bleed out of the cracks and show up in the white outer coating. Glenn

 

[Mike Rappold]

Just curious, what's the coating on this prop????

It looks like a spray to help see cracks.

BB

It appears to be similar to what we use on drag boat props. It is a quick way to check for cracks. After the prop is cleaned, degreased, etc. you spray on a dye penetrant that is typically red. The pentrant soaks into the metal pores and any cracks. You then wipe off the excess pentrant and spray the prop with a developer, which is a white color like shown on the photo. The developer has almost a chaulk type of consistancy. If there are any cracks in the prop, the penetrate that was left in the crack after wiping the excess off will bleed through the developer - thus more easily reveiling the crack. It shows up as a red crack or spot on a white surface.

Mike

 

[jayt]

Then again it could be a ceramic coating to reduce heating. Full scale race props get very hot when running (their tip speed can be almost three times higher than ours), sometimes hot enough to soften and lose pitch. Perhaps a ceramic coating would reduce the heating of the metal.

Why check for prop damage with the prop mounted on the boat, making it much more difficult to even see any dye? The white is clearly glossy, not chalky.

.

 

[Mike Rappold]

Then again it could be a ceramic coating to reduce heating. Full scale race props get very hot when running (their tip speed can be almost three times higher than ours), sometimes hot enough to soften and lose pitch. Perhaps a ceramic coating would reduce the heating of the metal.
Why check for prop damage with the prop mounted on the boat, making it much more difficult to even see any dye? The white is clearly glossy, not chalky.

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Jay,

The red dye shows up very well on a white background. It is very easy to see pits, pores, cracks, etc. in the 1/64 to 1/32 inch range. The dye penetrant method is a quick way to check for damage that can be done on or off the boat. It is always easier off the boat where you are not bending down but can be done either way.

In the photo orginally attached, it appears that the prop is off the boat. On the unlimited's trailers, they often have a "holder" to mount the props on while checking, changing, or whatever. This what appears is being used. Look in the background and you can see the strut, minus the stub shaft and prop.

Mike

 

[moparbarn]

i've used the dye & developer on auto cylinder heads for crack locating. also used various "developers" to check for the source of fluid leaks. all were flat white, almost powdery. the coating on that prop sure shines??

 

[miniczar]

The photo shown with the white stuff on the prop was part of a two stage system to check for cracks on the props, not anything near ceramic coating. I did this many times on Ken's crew when I crewed with my dad. I remember my dad telling me about the first time he used that stuff. It was a windy day in Detroit, and he put it on the prop to check for cracks. After he was finished he looked up at the Smokin' Joes which was pitted next to them. The side of the Smokin' Joes was covered with the red spray... lesson learned. Ha ha ha. We had many laughs about that one.

 

[Ray Sametz]

The photo shown with the white stuff on the prop was part of a two stage system to check for cracks on the props, not anything near ceramic coating. I did this many times on Ken's crew when I crewed with my dad. I remember my dad telling me about the first time he used that stuff. It was a windy day in Detroit, and he put it on the prop to check for cracks. After he was finished he looked up at the Smokin' Joes which was pitted next to them. The side of the Smokin' Joes was covered with the red spray... lesson learned. Ha ha ha. We had many laughs about that one.

Thanks Dave. B) B)

 

[Tom Foley]

EXPENSIVE !!

 

[jayt]

Jay, The red dye shows up very well on a white background.

Thanks Mike, that makes perfect sense.

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