Cleaning up seams on Rotary Engine halves?

[AlbertD]

I'm building a WnW Sopwith Pup with a 100hp Gnome Monosoupape engine. It's my 4th WnW kit and my second rotary engine. On the first one I didn't really do much to take care of the seams between the two halves. On this one I want to do a better job. How do you guys clean up the seams on the cooling fins? Is it even really possible?

[Bughunter]

You can try to use a fine etched saw, those are sold often as resin saw.
Really pity that RB Productions seems to be down at the moment, because they had very nice sets of those saws.

Cheers,
Frank

[AlbertD]

You can try to use a fine etched saw, those are sold often as resin saw.
Really pity that RB Productions seems to be down at the moment, because they had very nice sets of those saws.

Cheers,
Frank

Great idea Frank. I have a couple of very fine saws and will give it a go.
Thank you

[PrzemoL]

I use the fresh 300 and 600 grade sanding paper - the edge of a small piece usually fits finely into the gap between the cooling ribs and does its job. When the edge is worn I just cut off a strip and have the fresh one.

[Umlaufmotor]

I'm building a WnW Sopwith Pup with a 100hp Gnome Monosoupape engine. It's my 4th WnW kit and my second rotary engine. On the first one I didn't really do much to take care of the seams between the two halves. On this one I want to do a better job. How do you guys clean up the seams on the cooling fins? Is it even really possible?

Hello @AlbertD ,

I think @Bughunter and @PrzemoL have already given you very good and helpful answers.
Maybe I can help you out here with pictures (I think so in the way you will do the same @PrzemoL)?

I myself use two different grits of sandpaper.
Starting with 300 or 400 depending on which I have available.
Then the "final sanding" with grit 600.
I think the following pictures explain the steps.
No matter what grit of sandpaper you use, the steps are the same.







Here are two rotary motors (1/32) from Roden and Mir.
Both engines are not completely finished in the pictures, but you can see the way to clean the cooling fins.
Of course, sanding is done before the intake manifolds, valve actuation or ignition cables are mounted.







Servus
Bertl

[Umlaufmotor]

The trick with the sandpaper also works on the cylinders of the inline engines.
Here the engine of the WNW HB29





And here a Mercedes engine from Wingnut Wings .... very faint sanding marks can be seen between the cylinders.
However, these are only visible in the makro, the human eye does not perceive them without aids (strong magnifying glass, etc.).





However, with in-line engine cylinders, it is not always necessary to grind every glue seam - check against original pictures.
The cylinders of water-cooled engines were encased in sheet metal.
Between the cylinder liner of the pistons and the sheet metal jacket was water for cooling.
The sheet metal jacket was welded.
It is possible that the glued seam on the model is in the same place as the welded seam on the original.
In this case, the adhesive seam must not - or should not - be ground away completely.

I think and hope you can see the way in the right direction with the help of the pictures.
.... wish you good luck with the built of your Wingnut - Sopwith Pub.

Servus
Bertl

Translated with www.DeepL.com/Translator (free version)

[WD]

Great stuff here everyone, thanks for the explanations, etc.

WD

[AlbertD]

Thank you all for the great ideas. I'm finding little details can really add to a build.