A good tool for scraping is a single edge razor blade. But you need to put a little hook in the edge. Clamp the back of the blade in a vise and use a burnishing tool held at 45 degrees to the horizontal and rub it along the edge, pushing firmly. This will bend the edge over a bit and make the scraper much more efficient. This is what a furniture scraper is, but much cheaper.
I used a 5/16" hardened dowel pin in a file handle for SO students back in the day when solid props were required. I woke up to Ethan Aaron's potential when, at 12 yrs, he perfectly scraped a prop (in balance, too!) in an hour.
I did have some cheap single edge blades that were over hardened and broke with this treatment. Better blades will give you the right curl. They take a lot of material off pretty easily.
Lay the prop on your leg, with the tip toward your body, and scrape from the hub to the tip. Hold the prop up to the light frequently to be sure you don't scrape "windows" in the blade. Don't scrape too much off the blade where it meets the hub, or it will be too weak. Only scrape the top of the blade.
Don't ever sand a plastic blade; just a waste of time and the surface gets fuzzy.
I agree with John, a Dremel is good for the hub, if you are going for something under 2 grams.
Ray
--- In Indoor_Construction_at_yahoogroups.com, "jabiruchick" <jabiruchick@...> wrote:
>
> Wow! Well I will keep scraping the Peck and see what I can get it down to. I could deal with 1 gram. It's tedious and messy but oh well, so are most things in this hobby!
>
> Sorry if my original post was unclear. IF you are using a plastic prop, FAC requires it to be "molded" one piece to stay within the old-timey spirit. Otherwise hand carved or machine cut wood is OK. I've never carved a solid wood prop before and time is ticking, so I was hoping to find a lightweight plastic prop that meets the one-piece MOLDED requirement.
>
> Thanks!
> Katie
>
>
> --- In Indoor_Construction_at_yahoogroups.com, Fred or Judy Rash <frash@> wrote:
> >
> > Modified Ikara props have worked well for the local Science Olympiad
> > students and for me for Wright Stuff planes, but you undoubtedly know
> > and have done that. I've also used modified Ikara props for Bostonian.
> >
> > I've never done Dime Scale, but Don Slusarczyk has already given you
> > what appears to be the definitive word on the FAC rules.
> >
> > At the USIC several years ago, we used to fly an event called Federation
> > ROG or FROG (30-in2 wing, 3.1-g minimum airframe, 6-in max molded
> > plastic prop). I found the scraping to be laborious. Some folks could
> > convert a 9-in Peck P-30 prop into a 6-in, 1.0-1.5 g prop for Federation
> > ROG. Mine were closer to 1.5 g than to 1.0 g.
> >
> > Fred Rash
> >
> >
> >
> > On 5/9/2011 4:00 PM, jabiruchick wrote:
> > >
> > > Hi Guys,
> > >
> > > I know this isn't a pure duration question but since it applies to
> > > USIC prep, I hope someone has an answer for me.
> > >
> > > Does anyone have a good suggestion for a lightweight plastic prop to
> > > use for Dime Scale? I am thinking about an Ikara prop, but I'm not
> > > sure if it fits the "molded plastic prop" rule for Dime Scale. I've
> > > used Peck props for 20+ years, but now that I'm learning how to build
> > > light models thanks to you fine folks, my prop weighs darn near as
> > > much as the airframe!! I tried scraping the prop down but the model is
> > > still going to need a glob of clay on the tail. Maybe it's time to
> > > figure out how to carve a balsa prop.
> > >
> > > Thanks,
> > > Katie
> > >
> > >
> >
>
Received on Tue May 10 2011 - 06:54:48 CEST
This archive was generated by Yannick on Sat Dec 14 2019 - 19:13:46 CET