1:48 Scale Y Wing

Treadwell

Master Member
RPF PREMIUM MEMBER
I assume the shrinking occurs after the rubber has set? So you remove the donor part and then it's shrinkydink time?
 

Flintlock

Sr Member
OK, I finally got a chance to do this update to my previous posts:

Rear Plate Detail – It WAS pinned down that the Nichimo 1:35 Jagdtiger is the kit for the rear “engine grill” detail. The ESCI 1:72 Jagdtiger is pretty much spot-on, while the King Tiger could also be used. Since the front of the hull is used too, the Jagdtiger would be better, but since I already have three King Tigers, I am just going to use them. These kits are re-released by Italeri. The Revell Germany kits aren’t as close to the Nichimo.

Sides of the Neck – Roden has a 1:72 8Rad that can be used, but it is not completely accurate. I will probably use the transmission part and scratchbuild the rest. My one Roden part got messed in a… an incident…

"Dome Strut Box" – I got an ESCI 1:72 PzKpfw III N/M and it has the dome strut box in it, as well as other parts that the larger Tamiya version has. I am going to use the RG PzKpfw IV Ausf H for the shovels.

The DML Hummel parts arenÂ’t exact, but could conceivably be used.

I am using Hasegawa 1:48 Messerschmitt Bf109 K landing gears for the “dome struts.”

Now for some pictures... Be aware that Geocities might act up again... I am looking for a better way to host pics.

DML 1:35 Hummel parts for the wings:


ESCI 1:72 PzKpfw III N/M parts:




Hasegawa 1:48 Hurricane IIB:


Hasegawa 1:48 Messerschmitt Bf109K:


Hasegawa 1:48 P-51D Mustang:




ICM 1:48 Spitfire 9 Engine Parts:



Roden 1:72 232 Panzerspahwagen:



Revell Germany 1:72 PzKpfw IV Shovel:


Revell Germany 1:72 Tiger I Canisters:


Tamiya 1:20 Tyrrell P34 Six Wheeler:


Now I want to show you a comparison of King Tiger hulls (ESCI is on the left and Revell Germany is on the right):


The ESCI (re-released by Italeri) is better in my opinion, but since you need to use the front of the hull as well as the back, the ESCI/Italeri 1:72 Jagdtiger is the best:


It does not have the round piece on the top/center of the hull. As I said, I am not going to bother getting this kit because I have 3 of the King Tigers and the only real difference is what I just mentioned.

There are other kits that I have and can probably find to detail this thing... like I might need an HO scale Tiger I... I also have an Airfix 1:72(76?) Matilda which contributes nicely... the good thing about that kit is that it is also used on the 32 inch Falcon.

A lot of these pictures were found on http://www.ontheway.org.uk/, since they were nice and I haven't gotten around to take any of my own. Here is one final pic:

Various Parts
 

Flintlock

Sr Member
<div class='quotetop'>(cobywan @ Aug 17 2006, 04:55 PM) [snapback]1302369[/snapback]</div>
I have a technique for making silicone molds that shrink. So far I have tested a ration of 50:50 Silicone to Naptha that really does shrink 50% of volume. The actual ration of dimensional length is some sort of complicated math formula that I haven't figured out yet. But it is something to consider as you go forward with this venture.
[/b]
If my calculations are correct (I've always wanted to say that), then a mold that shrinks 50% in volume would yield a part that is 79.37% of the original in physical dimension. Does this seem right? I need to find that formula and see what I come up with using that. The original post seems to have been taken down.

I found the original formula, I think, in my offline notes. It seems like something is missing from those notes, but from what I have they were getting the same numbers. They had 0.80 (80% instead of 79.37%) for a 50/50 mix of Silicone and Naptha.

So, this won't quite work for my Y, unless either I also do one that is sized in-between the studio scale Y and a 1:48 Y (maybe using the AMT 1:200 Saturn V's and 1:48 Jagdtiger I have) or am somehow able to keep adding napthalene until I get a part that is 50% in linear dimension. Maybe I will figure out what that ratio would be - something like 25% silicone? :)
 

Treadwell

Master Member
RPF PREMIUM MEMBER
Too lazy to do the math, but off the top of my head, if the naptha thing creates an 80% sized result, just recast it the same way like five more times. ;)
 

Flintlock

Sr Member
Now my mind is buzzing with ideas... I take it there would be no significant detail loss by re-casting like that? When I get home I will figure out roughly how many times I would need to shrink it down. Now, if I only had the ability to sojourn into the fourth dimension and turn the parts that I have "inside out", I would be able to cast 3D mirror images of my parts. :unsure
 

Flintlock

Sr Member
OK... I almost asked a dumb question... don't do that.

Here is what I got as far as shrinkage:

80.00% 79.37%
Primary master (original part): 1.0000 1.0000
Secondary master from first 50/50 naptha mold: 0.8000 0.7937
Tertiary master from second 50/50 naptha mold: 0.6400 0.6300
Final master from third 50/50 naptha mold: 0.5120 0.5000
Casted piece from pure silicone mold:

Sorry if the tabs do not hold... The first column is using the estimated 80%, and the second is the percentage I got from a mold that shrinks 50% in volume. I couldn't fill out the last row because I don't know how much a normal mold shrinks. It looks like I can get pretty close with that... what do you think?

Here, this is better:

 

cobywan

Sr Member
The detail should hold just fine. An they will look sharper as they reduce in size. The only real tricks are to make sure your mold are air tight while they set up and that you are VERY carefull getting your pattern out of the rubber. the "thinned" silicone is like jello untill the naptha evaporates.
 

Flintlock

Sr Member
<div class='quotetop'>(cobywan @ Aug 22 2006, 01:49 AM) [snapback]1304798[/snapback]</div>
The detail should hold just fine. An they will look sharper as they reduce in size. The only real tricks are to make sure your mold are air tight while they set up and that you are VERY carefull getting your pattern out of the rubber. the "thinned" silicone is like jello untill the naptha evaporates.
[/b]
OK. I have just a few questions then:
1) What do you mean when you say, "make sure your mold are air tight while they set up?"
2) Do you give the rubber the same amount of time to set as you normally would (without the Naptha)?
3) How long should I wait for the Naptha to evaporate completely, or as close as it can get?

Thanks Cobywan
 

Flintlock

Sr Member
<div class='quotetop'>(Flintlock @ Aug 23 2006, 01:00 PM) [snapback]1305653[/snapback]</div>
OK. I have just a few questions then:
1) What do you mean when you say, "make sure your mold are air tight while they set up?"
2) Do you give the rubber the same amount of time to set as you normally would (without the Naptha)?
3) How long should I wait for the Naptha to evaporate completely, or as close as it can get?

Thanks Cobywan
[/b]
...You there Cobywan?
 

cobywan

Sr Member
1. The mold needs to have a lid or be in a small container with a lid. You need to prevent evaporation while the rubber cures. I build my boxes out of styrene or acrylic and after teh rubber is poured I slap a plate over the top.

2. The set up times are the same.

3. You can tell it's done when the smell of naptha is gone. It shouldn't take more than a day to evaporate out.
 

Flintlock

Sr Member
<div class='quotetop'>(cobywan @ Aug 27 2006, 03:10 PM) [snapback]1307948[/snapback]</div>
1. The mold needs to have a lid or be in a small container with a lid. You need to prevent evaporation while the rubber cures. I build my boxes out of styrene or acrylic and after teh rubber is poured I slap a plate over the top.

2. The set up times are the same.

3. You can tell it's done when the smell of naptha is gone. It shouldn't take more than a day to evaporate out.
[/b]
Thanks, Coby.
 

Flintlock

Sr Member
Re: 1/48 Scale Y Wing

Can't believe I am resurrecting this thread yet again, but here goes:

The body for my 1:48 Y is being printed out as I type. I tried a couple of times scratching it, but got super frustrated. Being a perfectionist is not good when you want it accurate down to 0.010".

The best part about printing it though is that it's being done for free.

I'll have some pictures tonight which I will post here. I will also be updating my blog which you can see here: http://www.eulercircles.com
 

Flintlock

Sr Member
Re: 1/48 Scale Y Wing

Ok I didn't post last night because... well... here's the good and bad news:

GOOD - The top and bottom halves of the fuselage finished printing and they turned out great.

BAD - My digital camera crapped the bed and the pictures I took are atrocious.

I can post them if wanted, but I warned you...
 

Flintlock

Sr Member
Re: 1/48 Scale Y Wing

I am having some trouble casting my fuselage halves - maybe someone can help me. I made two part molds for each half (top and bottom) of the fuselage. The molds came out great. This evening I took the mold for the top half, powdered it with baby powder, stuck it in the microwave on high for one minute, and then poured the resin into my gate. This casting came out very good. I did the same thing for the two-part mold for the bottom half, but it came out terrible. Most of the thing was trapped air. So, I did it again but I used a paper cup and poured a thin stream as slowly as possible to let the resin get all the way in. The second time there was still a lot of trapped air.

The third time I washed both parts of the mold, dried them thoroughly, re-powdered, microwaved, and slushed it. That is, I poured the resin in first and then pressed the male part of the mold on, letting the extra resin squeeze out the sides. This one turned out better, but some of the walls, which are supposed to be 0.080" thick and solid, are mostly air covered by a very thin skin of resin. Also, in this third attempt, there are areas in the solid portions that are darker - like trapped resin that is not curing, even though I mixed the resin as thoroughly as I did the first one.

What am I doing wrong, or what could I do to fix this, aside from buying a pressure pot and a compressor?

P.S. I did cut slits in my mold for air to escape, so that's covered, unless I need more.
 
Last edited:

Flintlock

Sr Member
Re: 1/48 Scale Y Wing

Never mind - I figured it out. The geometry around the gate created so narrow a passage that it was filling up with resin too fast. Meanwhile, the cavity underneath was not getting filled up in time before the resin started to cure. I took my utility knife and made a bigger passage for the resin. This time I got a beautiful casting.

Hey, this is how you learn right?

Oh, if anyone is doing something similar (with two part molds), and if anyone is still reading this thread, I recommend letting the resin cure all the way until it is completely hard before you demold. In this piece I was trying to cast, I have a couple of undercuts and when I pulled it the resin was still somewhat pliable. I ended up with a slightly warped piece. Next time I will let it cure and cool completely.
 
Last edited:

darth_daniel

Sr Member
Re: 1/48 Scale Y Wing

Good luck with it!

I think you should re-do your drawing of the cockpit pod though, if you want to base your build on it. The top of the canopy (the horizontal plane above the "rectangular" windows) actually is a flat plane, there´s no sharp bend in it, it´s just very very slightly (hardly noticeable) bent as a whole. And the whole canopy is much flatter. And it´s quite much wider. If you´re interested, I could provide some - more or less - "ortho" pics of my MR Y´s cockpit pod and canopy. Just let me know.
 
Top