TIE Bomber Scratchbuild

Keiko

Sr Member
Hello everyone.

Minor update as I make tiny rivets on tiny things. I'm sure I'll be glad I did when I'm done. I've started the bomb chute redo.
blakeh1: I doubt any could be mailed my way due to regulations, but if you see any liquid cement, grab it for yourself.

Cheers all,

K.

DSCN5751.JPG DSCN5752.JPG DSCN5753.JPG DSCN5754.JPG DSCN5755.JPG DSCN5756.JPG DSCN5757.JPG DSCN5758.JPG DSCN5760.JPG
 
Last edited by a moderator:

Keiko

Sr Member
Hi guys,

Next update is minor and ends in tears. I made some error while doing my replacement bomb chute, complete with embossed rivets. The detail looks good and I was liking my result, but a mid-component sub assembly revealed the mistake. I have to start over on that piece for a 3rd try. I'll do it a little differently this time - first build shape, then add details. The whole notion behind doing them separately was to facilitate symmetry. Obviously I missed that boat! I'm only out by 0.25 mm, but at this small scale, it would be very obvious if I didn't start over.

At least when I redo things, it's faster the second or in this case third time.

A few pictures anyway.

Thanks for looking,

K.

DSCN5761.JPG DSCN5786.JPG DSCN5787.JPG DSCN5788.JPG

On the other hand, my helmet is coming along nicely:

Helmet 5.JPG
 

stevielewis

Sr Member
Sorry to hear about this. Yes, it will proceed faster this time, but just having to remake this chute again, it's got to be frustrating. Good luck!
 

Keiko

Sr Member
Yeah, it was an aggravation to discover I'd made a mistake. Doubly so because it's something straightforward and easily avoided. I went through all the seven stages of grief, culminating with Acceptance. I moved onto the helmet as a consolation prize but will get back on the bomb chute horse tonight. I was really hoping to be hitting the RTV this weekend, but it wasn't to be. That's probably what made it a tougher pill to swallow - it was my last step before molding and I was expecting to be there yesterday.

Oh well, now isn't the time to accept less than my best, so I'll take another lap.

Cheers,

K.
 

Keiko

Sr Member
Hello everyone,

I'm back at it again/still. I have to admit, I'm getting burned out and stumbling around the finishing chute. After the debacle of bomb chute #2 being a screw up, I didn't touch anything for a few days before getting back on the horse for bomb chute #3. I still have a few minor details to add on the front and rear plate, but overall the hard stuff is done and acceptable. Not perfect, but I'll live.

I also have a few finishing touches on the thruster part that goes on the back of each fuselage. I decided I wasn't 100% happy with my first attempt, so I rebuilt the entire inner piece that features the fishing line raised ribs, too. There were a few strands on my first attempt that hadn't been taut enough when I glued it and they cured in a wavy shape. I decided to redo that too. I'm not replicating the red LEDs that are in the studio mini though - instead leaving an open hole that resembles the thruster part on my other TIEs.

I'm sooo close to molding now. Getting the rivets done on the final chute was huge to me.

Cheers and thanks for looking.

K.

DSCN5806.JPG DSCN5805.JPG DSCN5803.JPG DSCN5802.JPG DSCN5798.JPG DSCN5791.JPG DSCN5808.JPG DSCN5812.JPG
 

Keiko

Sr Member
Thanks blakeh1.

For cutting larger circles, >1.5"/5 cm, I have a cutting compass I use. I'd have to check, but I think it might show up way up thread when I made the outer cones for the rear thruster segment.

For smaller circles, I just draw them on sheet with a template and cut them out with a straight cut knife, going from square to octagon to hecadecagon etc, then sanding. In one of the pictures in my last post, you can see I'm just starting that process on the backing plate for the ribbed cone part. With care, I can get pretty good results. The key is holding the knife perfectly vertical when doing the cuts of course.

Cheers,

K.
 

Keiko

Sr Member
Hello again,

Back at it and re-energized after a great extended weekend getaway to San Francisco. My personal highlight: touring the WWII through Apollo 12 Aircraft Carrier, U.S.S. Hornet. Just a great day. A break is a great motivator, and since being home, I went back after the inner ring detail on the rear thruster cone area and got that done. That leaves only:

-drilling a few more rivet holes - forward section of weapons fuselage and on bomb launcher
-minor details between ribs of bomb chute
-minor details on missile guides that go around opening on front of weapons fuselage.
-molding.

It's a 3 day weekend for me here, and I expect to get it all done. Meanwhile, I'll post some more pictures, picking up where I left off on the ring detail. That's right, this whole post is me making a circle.

Thanks for looking!

K.

DSCN5813.JPG DSCN5827.JPG DSCN5828.JPG DSCN5829.JPG DSCN5830.JPG
 

gedmac66

Sr Member
Cool update Keiko , with more brilliant ‘ how to ‘ idea’s shared . Thanks .

In photo #2 is that a magnet you’re using to keep ‘ pressure ‘ on and holding in place , the newly glued joint while it cures within the template ?
On finding a stockist for your preferred glue whilst on holiday . Can you get them in via mail order or will you bulk buy when in the area again ? , either way Congrats !

:cheersGed
 

Keiko

Sr Member
Hi Ged,

No pics yet, but I'm done all the rivet drilling and bomb chute details. All that remains is the missile guides, then mold time. I'm waiting for a missile guide part to cure before I move onward with them. My back is killing me though - I'm on the tall and wide side and airplane seats destroy me. I'm still recovering from the San Francisco flight.

To answer your question - you're exactly right - that's a piece of magnet on the inside of the ring, keeping the seam hard up against the ID of the template. I have a bunch of rare earth magnets and after a while, some of them get broken, usually from the impact of them flying out of my hands and sticking to metal parts or each other. They're great for clamping and whatnot though.

I was super stoked to find that liquid cement. 2 bottles is 10+ years' worth, assuming I don't spill it. I've been a klutz and spilled at least 2 bottles of this stuff in the past. I had no idea it would become so rare. Maybe it's still widely available outside of Canada, maybe I got almost the last of a small store's old stock. I'm not sure. I'll definitely be peeking in on hobby shops whenever I'm in the USA. I'd have bought the third bottle too, but there's always the fear of Customs taking away my new found loot and I had to draw a line of how much money I was able to risk. We put it in my wife's checked toiletry bag and I'm sure it looked like nail polish or some make-up product on the X ray.

I expect to start making my mold boxes and layouts tonight. (It's 2:10 p.m. here as I write this). Stay tuned!

Cheers,

K.
 

Keiko

Sr Member
Hello again everyone.

Another update this evening. I got all the building steps I mentioned completed and have started gluing parts down to their backing plates for the one piece molds, as well as starting on the work for the two piece molds. I'm not much of a garage kit maker, so my molding skills are pretty rudimentary. In order to avoid seam lines, I've made many parts with the intent of using one piece, open faced molds on them. This always means a little more work in the removal of the base plate or pour stubs, but it makes for a nicer piece.

For 2 piece clamshell molds, I usually embed half the part in clay while pouring the first half of the mold. Then I remove the clay and pour the second half. However, with the wing, I don't want to put any clay in the fine details nor the mesh pattern of the solar panels. Therefore I'm manually building a dam to hide the details of the second half from the rubber pour of the first. That might be a little confusing. Hopefully the pictures help it make sense with this and upcoming posts.

Thanks for looking as always!

Cheers,

K.



DSCN5831.JPG DSCN5833.JPG DSCN5834.JPG DSCN5836.JPG DSCN5837.JPG DSCN5838.JPG DSCN5840.JPG
 

Keiko

Sr Member
Hello again,

Wow, I spent all day playing with Lego. Seeing all the parts in one place at one time makes me wonder if I have enough RTV on hand for the whole ship. It would be just perfect to discover I need a run to Viking Plastics. I'm pretty burned out now, so I'll do the pour tomorrow morning.

Thanks for looking!

K.

DSCN5841.JPG DSCN5843.JPG DSCN5844.JPG DSCN5845.JPG DSCN5846.JPG
 

gedmac66

Sr Member
Hey Keiko ,

Not being familiar with the casting / moulding process personally , just wanted to let you know that I really appreciate your sharing this part of the build too !

A few of questions if I may , I have seen people using foam card to ‘ house ‘ the part that’s being moulded ( YouTube ) , and others with pieces of wood - what’s the advantage of using LEGO bricks over them ?

Secondly , I’ve not seen the clay ‘ support ‘ method for the parts as demonstrated , is this a necessary step for delicate , intricate pieces or is it used due to the casting material you’re using ?
What type of clay is are you working with , could products like ‘ Green - Stuff , Aves Apoxie or Super Sculpey ‘ be used instead ? . Asking cause these are easily sourced here in Aus should I ever attempt this process myself ! ,... are they even appropriate for this type of casting ?:facepalm


:cheersGed

p.s. I realise that you consider yourself a ‘ Novice ‘ when it comes to casting , if so then compared to me , you invented the process ! :lol
Also your hints , tips and advice are ... respected ;)

p.p.s. What’s RTV ?
 

Keiko

Sr Member
Hello again.

Here comes a mixed bag update. I did some calculation and measurements on my molds and knowing that 1 cubic centimeter = 1 ml of volume, I estimated my RTV requirements and came up with a volume greater than what I had in stock. Past experience has taught me the hard way that new RTV will bond to old perfectly, so I decided to chop up some old molds from old projects and mix them into my supply to "boost" it. This reminded me of movies when I saw coke dealers cutting their supply with baby formula, but I forged onward. It was tedious, cutting up the old molds, until I realized I could raid the kitchen for a spice cutting tool of my wife's. Even though she will ultimately benefit from this, she does not need to know.

Then disaster struck. My RTV, which has been in the basement for perhaps a year has gone bad. No molding today. No need for boosting a supply either - I'll just buy more and in enough quantity. The bad part is that the store I get it at is a 9 to 5 M-F affair, and it's hard to get there from work. This could be a multi-week setback. I'm a little gutted.

Anyway, that was my Sunday morning. Time for a run.

To Ged's questions:

Lego is cheap, quick and easy for building a mold box, but a properly constructed plastic or wooden one is every bit as good, probably better.

Clay: for 2 part molds, one half of the part being molded must be buried in the clay during the pouring of the first half of the rubber. Most people make a clay bed and push the parts halfway into that and then build a mold box around the whole thing. I do that, but then trim away most of the clay so that the part is on a raised "island" of clay. This way, the parting line of the mold itself is not in line with the parting line on the part. This allows for a large depression to exist in the final mold, into which I pour my resin for the part before putting the "lid" on. It makes the mold less leaky and easier to use. This is probably confusing without photos - I'll have some when I get there though.

The clay is just children's modeling clay. The particular stuff I'm using is Crayola brand (same as the crayons) from the crafts section of Walmart. I've heard some clays are not compatible with RTV, but I don't know the reason and this stuff is fine. Unlike the other products you mention, this stuff does not ever cure and stays flexible for years. It's cheap, too.

RTV: Room Temperature Vulcanizing (Rubber). It's the mold product itself. The stuff I'm using, which I like a lot (spoilage notwithstanding) is an A + B system by Smooth-On. It is mixed from 2 equal amounts of 2 components. Other systems are catalyzed via a the addition of a small amount of catalyst to a larger volume of rubber, say 10:1.

Anyway, here are some pictures of what turned out to be a disappointing day.

Cheers,

K.

DSCN5847.JPG DSCN5848.JPG DSCN5850.JPG DSCN5851.JPG DSCN5852.JPG
 

robn1

Master Member
I've heard some clays are not compatible with RTV, but I don't know the reason and this stuff is fine.

The problem is sulfur, some clays have it and it prevents the silicone from curing. Sorry about your problem there, I had the same issue with paint recently. It's a 2 part auto paint and the activator had solidified in the can, like a hunk of rubber.
 

gedmac66

Sr Member
Thanks for your in-depth replies Keiko . Umm ... whole heartedly agree regarding the actual casting procedure ... pictures = enlightenment for someone like me !:lol

So , the clay you use never cures / hardens . How does that affect the impressed details though when removing the parts / pieces from the clay - isn’t there any distortion ? ... apologies if I’m not getting it right in my mind , and asking stupid questions .:facepalm

Re; your RTV situation , I’ve had something ‘ similar ‘ but not - quite happen recently .
Had a hardly used bottle of Zap-a-Gap medium glue sitting on my work table ( out of direct sunlight ) over a rather hot summer over here .
It had been properly sealed with the provided cap ... went to use it couple days ago , and couldn’t . The remaining glue ( almost full ) had solidified ?
Not sure how or why - maybe weather related , or perhaps a bad batch !? . it wasn’t due to a long , unused period of time that’s for sure !.
Trouble wasn’t only the money wasted ( $12 ) , but having to forego organised / set to spend ( a couple of hours ) constructive ‘ me ‘ time on a quiet Saturday afternoon .

:cheersGed
 

Keiko

Sr Member
Hello again,
robn1: thanks, that was exactly what I heard before about certain clays. I of course forgot all the details and only retained the equation of "some clays = bad".
gedmac66: I think I see what's confusing you. The clay is only used during the mold-making process. There is no clay in the final molds, only cured flexible rubber. It's like this:

1) embed half the part in clay, build a dam/mold box around it, pour in RTV rubber (pour #1)
2) rubber cures.
3) remove mold box and clay, leaving part in the RTV.
4) build new mold box around rubber from pour # 1, but this time with part facing up. (upside down relative to its orientation for pour #1)
5) pour RTV (pour #2) over this.
6) pour #2 cures.

This way you will have a 2 part mold that opens to reveal the master part. The master is removed, and now there is a cavity to pour resin for duplicates.

It was a true heartache to literally be ready to mold and open my jars and discover they had turned to jelly. The bigger frustration than the waste of money is the waste of time, just like you and your spoiled Zap.

With a lot of items, it seems they leak air and spoil by off-gassing some critical chemical component. My usual solution is to store many of them upside down. I figure the bottom of a paint jar, being glass, is impervious and the air gap inside the bottle cannot breathe that way to the outside. Obviously I didn't do this on my RTV, but it is my habit with my paints.

I'll find out of the plastics store where I get the RTV is open on Good Friday. I might have a chance, but I doubt it. That leaves my next opportunity until April 13. Arrgh!

I consoled myself by working on my 1:1 R2-D2 last night.

Cheers,

K.
 
Last edited by a moderator:

Keiko

Sr Member
Hello again,

I had a great weekend getaway in Jasper for a half marathon in the mountains. It is supposed to be Spring, but is definitely winter here. On the other hand, we had some great winter hikes atop of normally rushing rivers and enjoyed looking at frozen waterfalls and other great sights. I've never been there in the winter before.

Since I played hookie from work on Friday, I stopped at the mold making supply shop on the way out of town. When we got home yesterday evening, I promptly went into pouring mode and then demolded this evening (Monday) after work.

There is still a lot left to do, say at least 2 more pouring sessions before I'm done all my molds, but I'm happy with my first set of results. The fuselage mold was pushing my luck in terms of undercuts, but I got away with it, and am very happy.

Next up is building new Lego mold boxes for the pouring of the second half of the molds on the ones shown here, as well as first pours on a bunch more still downstairs.

I did my best to photograph the process, but at certain critical phases, my hands were full, so you'll have to guess what happened.

Thanks for looking as always!

Cheers,

K.
DSCN5876.JPG DSCN5874.JPG DSCN5872.JPG DSCN5870.JPG DSCN5871.JPG DSCN5877.JPG DSCN5878.JPG
 

blakeh1

Sr Member
Thanks for the details on the molding process. I might be starting down that path myself and it's always good to see what others are doing!
 

Your message may be considered spam for the following reasons:

  1. Your new thread title is very short, and likely is unhelpful.
  2. Your reply is very short and likely does not add anything to the thread.
  3. Your reply is very long and likely does not add anything to the thread.
  4. It is very likely that it does not need any further discussion and thus bumping it serves no purpose.
  5. Your message is mostly quotes or spoilers.
  6. Your reply has occurred very quickly after a previous reply and likely does not add anything to the thread.
  7. This thread is locked.
Top