Wooden prop carving questions

[smperry]

Having given up on paper for making props, I ordered some light and dark veneer and am anxiously awaiting it's arrival. I wanted to practice carving a wooden blank, so I made one out of 1/64 plywood strips. I used alaphatic resin wood glue. Has anyone found another type of glue to be better for this purpose?

Since I am working in 1:48 on this model, my prop is smaller and I am having fits trying to trace an outline of the prop onto the blank. Anyone have any ingenious tips for doing that easily?

And finally, do you taper the blank first and then cut to the outline or do you do it the other way round and cut to the outline and then taper the blades?

Thanks for any input
sp

[maddog]

You could try tacking the prop down and using your airbrush to "overspray" the whole thing leaving a negative outline.

[lcarroll]

sp,
    I cut the outline first as the tapering phase requires a bit more accuracy. (Leave your outline "oversize" until the tapering is done as well) As for glue I don't know if it's the best however I have had great success with Carpenter's wood glue over the years. Last, I clamp the Kit prop to the blank, then do a rough pencil outline and carve and compare from that point.
Cheers,
Lance

[smperry]

Thanks y'all. I got the shape traced by taking a #11 blade to a wooden pencil and exposing a longer section of lead than usual. That helped going round the edges that were off the surface. I also learned that 1/4 " strips are too narrow for 1:48 props. I will use 3/8" strips in the future for 1:48 and 1/2" for 1:32 scale. Glad to learn that on a practice blank instead of the real thing. Next up will be figuring how to taper it and not destroy it. Thanks again
sp

[Bughunter]

I glue the veneer to a block at first, because there is always a light movement between the layers while put the block under hard pressure in a vice with wood glue. I approach from both directions and compare again and again with the template.
I showed my procedure in some build reports here.

Cheers,
Frank

[smperry]

Frank
I noticed that tendency for layers to slip and my work around is to glue up the layers and put a piece of clear plastic wrap around both sides of the blank. I can then line up the layers with my fingers. I use two clamps to apply pressure, the pads of which are 1.5" long and cover half the 3" blank. I hold the stack together and apply one clamp and then the other keeping the layers aligned as I do. When dry, just a few licks with a sanding stick squares up the blank. I had been pressing between two heavy steel bars and shifting layers was a problem. Not so much now.
sp

[smperry]

Another dumb question.
On props with alternating layers of light and dark wood I am seeing 7 layers. The 1:48 kit prop is a little thicker than 3mm, so I want layers about 0.45 mm thick. The veneer is nominally 0.6mm so a little sanding, which is needed anyway, will put me in the right range. The dumb question is: Does the odd strip in the center of the blank need to be dark or light wood? I have looked at photos, but without turning the prop over in my hand, I am not good enough at visualizing in 3D to decide for sure.

sp

[Bughunter]

It depends ....
I have seen 6, 7 or even more layers.

The dark one was mahogany, but Germany was under embargo and has not enough. So the used local wood in addition.
Often, but not always!, the outer layers was hard mahogany for mounting.
So, if you have seven layers and a dark one outside:
dark - bright - dark - bright - dark - bright - dark

If your prop has bright outsides, then the opposite.
The only hope is to have good pictures of the machine to build.

Hope it helps,
Frank

[smperry]

Indeed it does help Frank, thanks for the quick reply. I will have to do some checking, I am modeling a well documented Jasta 5 machine. I am sure there are some profiles, and maybe even a photo or two that might give me an idea which order to laminate. If I can't fine anything definitive, I will simply make one blank with a light center and another with a dark center and see which one looks best.

This could not have come at a better time for me as I had drilled rigging holes and was about to install the lines prior to attaching the top wing and was not looking forward to that chore so fooling with prop blanks is a great diversion.

I have re-read Lance's great tutorial and your helpful additions to it and I'm now ready to go cut some veneer strips as soon as the shop cools down a bit.
Thanks
sp

[Berman]

 The best reference books on German propellers were written by Bob Gardner. He published four books. "The German Propeller Industry 1914-1919" and the three volume set "German Propeller Makers of WWI".
   Available through www.aeroclocks.com

[smperry]

He seems to be out of stock on most of his books.

I did a picture by picture look at the D.III datafile and near as I can tell there was not a set number of laminations even from what appears to be the same prop maker. I guess I will make up a few blanks and vary the order and number of laminations and see what looks best. (if any :-)
sp

[lcarroll]

sp,
    As Frank has indicated it varies from prop to prop, type to type. I try to determine the number of layers or laminations and the "light/dark sequence from study of the machine I am modelling if photos are available and then work from there. My theory is that, like colors and markings, there are no set rules and nothing is ever for sure! It's kind of akin to the real color of PC.10 IMHO! I completely agree with Frank, if photos of the machine you are building are available then it's an easy decision! Otherwise, go with the nearest "comparable"!
Cheers,
Lance

[smperry]

I guess a hundred years on from a time when aviation hardware was just being invented and by no means standardized, a best guess is as good as it gets in lieu of a clear photo. Trouble with WWI photographers is they were photographing airplanes or men in front of airplanes, not props, cockpit interiors, hinges and strut & wire fittings. We do the best we can, although I would like to hear some mechanics of the day pass comment on some of our plastic masterpieces. Just as well that is no longer possible :-)
sp