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I need help with scratch-building small parts
Shrimpman
_VISITCOMMUNITY
Dublin, Ireland
Joined: August 14, 2016
KitMaker: 51 posts
AeroScale: 38 posts
Posted: Sunday, January 29, 2017 - 10:57 AM GMT+7
I have managed to complete my little Kukuruznik. The scratch built parts are not great, but am nevertheless very happy with the results. Building them turned out to be really satisfying, especially the ammo crates. They're balsa wood with styrene strips. The exhaust pipes are brass tubes. I messed them up a little bit, but that was the best I could come up with. When wife saw the ammo crates she said they're cute and told me to make another pair, so she could make them into earrings. I also made the looking glass, an improvised rear mirror fixed with duct tape, so fitting in an all-female squadron (thank you Namabiiru for taking those pictures for me, they were invaluable!) I will also post more pictures in the Soviet Phoenix campaign post.








Namabiiru
#399
_VISITCOMMUNITY
Virginia, United States
Joined: March 05, 2014
KitMaker: 2,297 posts
AeroScale: 268 posts
Posted: Wednesday, December 28, 2016 - 12:58 AM GMT+7
My pleasure. Let me know if there is anything else you specifically need photos of.

Shrimpman
_VISITCOMMUNITY
Dublin, Ireland
Joined: August 14, 2016
KitMaker: 51 posts
AeroScale: 38 posts
Posted: Tuesday, December 27, 2016 - 09:56 PM GMT+7
I got the photos! Thank you so much! It's a real treasure for me.
Namabiiru
#399
_VISITCOMMUNITY
Virginia, United States
Joined: March 05, 2014
KitMaker: 2,297 posts
AeroScale: 268 posts
Posted: Monday, December 26, 2016 - 08:40 AM GMT+7
Shrimpman,
Took a bunch of photos of the PO-2 today. PM me your e-mail address and I'll send them as a couple of zip files.

Namabiiru
#399
_VISITCOMMUNITY
Virginia, United States
Joined: March 05, 2014
KitMaker: 2,297 posts
AeroScale: 268 posts
Posted: Sunday, December 25, 2016 - 01:03 AM GMT+7
No problem! I don't actually work there--I just volunteer there when I'm not otherwise at work. My work isn't that much fun...

I'll be out there tomorrow and will take lots of detail photos of the engine and exhaust.

Shrimpman
_VISITCOMMUNITY
Dublin, Ireland
Joined: August 14, 2016
KitMaker: 51 posts
AeroScale: 38 posts
Posted: Friday, December 23, 2016 - 09:49 AM GMT+7
Thank you for the hints, I really appreciate your suggestions. Now I have some ideas on how to begin.
Namabiiru, what an amazing coincidence! This would be tremendous help for me. And what a great workplace you have! If it would not be too much trouble, would you mind taking some pictures of how are the bottom exahausts connected to the cylinders? The instructions sheet is quite vague about that and I was unable to find pictures that would clearly show this part. I am sure I would also need some photos of the rigging, but that would be for much later stage.
Namabiiru
#399
_VISITCOMMUNITY
Virginia, United States
Joined: March 05, 2014
KitMaker: 2,297 posts
AeroScale: 268 posts
Posted: Friday, December 23, 2016 - 12:15 AM GMT+7
Shrimpman,
We have a PO-2 from the Night Witches in the museum where I work. If you like, I can get some detail photos of the engine and any other areas you would like.

As far as scratch-building the exhaust, I would use pieces of sprue or other styrene rod cut and bent to roughly the right shape, filled out with epoxy putty, and filed/sanded to fine shape. Crates I would make from a small block of wood covered with thin balsa strips used for planking wooden ships (if you don't have any of that, use a plan balsa sheet and score it with a knife blade).

rdt1953
_VISITCOMMUNITY
New Jersey, United States
Joined: February 06, 2015
KitMaker: 523 posts
AeroScale: 472 posts
Posted: Thursday, December 22, 2016 - 09:44 AM GMT+7
Hi - The exhaust manifold would be best made of rod or tubing bent to shape . Brass rod of the appropriate diameter made in two pieces and joined at the flared exhaust nozzle either by solder or epoxy. The exhaust opening could be hollowed out with a Dremel bit or simply painted black. Plastistuct also makes plastic rod with a wire core in various diameters that may do it for you . I would drill out the exhaust ports on the back of the cylinders to accept the manifold if possible. You may want to attach the engine to the fuselage and insert your chosen manifold material and then bend it to shape . I would use sheet or strip styrene for the crates . Epoxy putty such as Milliput or the equivalent might be used to sculpt the bags. I have used polymer clay in the past for similar purposes and while I have had no bad interaction between the clay and the kit it does shrink a little during the baking.
I have also had it bleed through acrylic paint on occasion leaving a shiny appearance. Hope this helps and please post some pictures of your project- I'd love to see it!

Good luck - Richard
Shrimpman
_VISITCOMMUNITY
Dublin, Ireland
Joined: August 14, 2016
KitMaker: 51 posts
AeroScale: 38 posts
Posted: Thursday, December 22, 2016 - 06:15 AM GMT+7
Hi
I am building a 1:72 Po-2 by ICM at the moment and although the model quality is excellent, I have noticed an important, very visible part completely omitted. Looks like ICM forgot about the exhaust pipe for top and left pistons. It is the one in the circle in the picture below.


At this angle it look like a straight tube with bent ends, but it is actually curved around the nose. So far I have only ever tried to scratch build very simple straight rods out of sprues by grinding them down with a file until I had a required thickness. This technique will not work for such an out of shape piece. I was thinking that maybe I could try a tightly rolled piece of paper instead? Do you have any suggestions on how to approach this thing?

Also I wanted to build my Po-2 as a Battle of Stalingrad machine from 588th Night Bomber Regiment, the famous “Nachthexen”. I have recently seen a documentary that showed Po-2 used to air drop supplies to 62nd Army. The plane had crates and sacks tied to the wings and fuselage. The backseater would lean out and cut the rope with a knife to drop the goods. The plane looked so much cooler with this improvised contraption than with those purpose-built containers that we see on the box art. What materials would you use to attempt to build the ammo crates and sacks of food? Polymer clay comes to my mind, but I think it might react with the plastic.

I enclose picture of the containers and a (very poor quality) screenshot of the stuff I would like to scratch build.