effective blade area

[TheShaughnessy]

I read a tip a while back that said you can color a prop with a felt tip marker, run the prop and the parts of the marker that wear away show you the blade area you are using and serves as a guideline for where to remove some material to free up the prop.

Sounded good in theory to me so i colored up a prop ran a set of packs through... ran another set... the marker just seems to stay the same really. Noticed some wear at the tips where i cupped it.

Has anybody successfully tried something like this? Is a sharpie too permanent for this trick. T

the person who posted the tip also suggested a machinist bluing (?) pen. I'm not sure what that is or where to get one.

prop in question is a x645. Work so far includes 1/8th inch back cut(maybe less), tip cupped and i took some tounge out. I didn't want to get too crazy on the tounge cause im looking to use it for offshore and was thinking taking out too much tounge would suffer lower end pull out of the "M" corner or just the corners in general.

conversely i want amp draw to be as low as possible and thought further detounging might achieve a slight amp draw decrease.

motor is a 1500 kv proboat in geico, 120 esc. Eagle tree was reading around 80 amps with the stock 645. I have been waiting on temp and rpm sensors. I want to see what happens with rpm as i try stuff. i had a gps on order but after 40 days on back order i removed the item. Other sensors came in today so i feel better about being able to gauge improvements.

This got a little lengthy. Important question is the first one about the marker.

[ozzie-crawl]

It is mentioned in this article. A bit more than half way down http://www.modelgasboats.com/Knowing_Your_Prop/

I have seen other mentions else were as well.

[ozzie-crawl]

Think the article was Ron Olsen RcUniverse. Someone did mention to me once about doing this but cant remember what he said to use. may have been tippex?white out or simply a paint pen.

[TheShaughnessy]

I read the tip from ron olsens write up on RCU. They mention a red dye in that other article you linked to. I was reading that one the other day but didn't get that far down. Only problem is the red dye mention is brief and I don't know how to duplicate.

[ozzie-crawl]

The Machinist blueing he is talking about i think comes under a few different names. Engineers blue,bearing blue etc.
It is used for making sure a surface is flat.It is painted on, let dry then machine/file etc the area and it shows up low spots.

Try searching also Prussian blue if you cant find it (and no its not the red neck twins)

[tryinotocrash]

Dykem is used in the machine trades , I use it almost daily . It is designed to stain the metal so when you scribe a line it shows up better. The prussian blue is a bit different and I haven't used it so I can't say . It is more to find high spots on things. Not sure overseas but any machinist tool seller has dykem ,you can get blue or red . Not sure if it will do as they say it would but it is worth a try. Mcmaster Carr has it , Enco should have it , Try E-Bay u may find it there.

[Rokcney]

As Tryinotocrash stated, Dykem blue would be a good choice to try. I use it in elevator repair when checking wear pattern on machine gears for proper set up. As the gears are lubed by gear oil, it takes some time to wear off and reveal the wear patten. I think in water on a prop, results would be faster and am going to try it myself. Another possibility could be liquid shoe polish, or artist's paint that comes in the tube. The artist paint will take a day or two to dry,but believe it could also work well with minimal running of prop. Rokcney

[dana]

i would just spraypaint the thing real quick

[Rokcney]

Well said dana. Rokcney