Mylo's Type VIIc/41 Continued....

[mylo]

Not sure why, but page 12 of my original thread just kept growing, and growing, ...and growing. It's been giving me some weird problems as of late, so I decided to start this continuation thread.


[b]Step 69 ]


The construction of the scopes was kind of a two phase situation. The first being, ....what to make the scope tube out of, the second, what to make the scope mast heads out of.

It seems to me that the actual scope tubes on these subs is stainless steel, so I figured it would make sense to have the scale scope in stainless steel as well. According to the plans, my scale scope tubes are 5/16" in diameter. I decided on a length of 6" for the attack scope, and 3" for the observation scope tubes. This would give them an overall length once the mast heads were added of 9" for the attack, and 5 1/2" for the observation. I chose this length in particular for the attack scope because it would then be the proper length to use with the schnorkel in the upright position, with both the schnorkel and the attack scope being close to the same. All this is out the window when it comes to the construction of a functioning retractable scope, but for now, this will do. It turns out that 5/16" stainless steel tubing isn't so easy to get from my searching every local metal supplier I could find (another day spent). Stainless ROD is available, but not tubing. I wanted tubing for the weight factor. I did not want to use heavy solid rod made of steel that high up on the tower, especially since it is also pointing straight up, in effect, creating more leverage in the event the sub is rocking slightly from wave action. I decided to abandon the stainless steel idea and opt for my second choice, which was aluminum. 5/16" aluminum tubing was easy to find not to mention cheaper. The weight is basically non existant. However, I was not happy with the appearance of the dull aluminum tube. I experimented by polishing it a bit, which produced a pretty decent result, more of a shiney stainless look. That combined with some actual grease lightly smeared on it should produce a convincing looking scope tube. I used a pipe cutter to cut the lengths but in doing so, tapered the ends "in" a little. I later discovered that this made attaching the mast heads impossible because a small portion of the bottom part of the mast head is tapered slightly for a nice fit INSIDE the tube. I remedied this tube problem by chucking the scope tubes in my drill press and using my reamer to clean up the inside, allowing the mast heads to fit properly.






As for the mast heads, nothing innovative. Dimensions from plans, masters made, rubber mold, resin castings. The optical lens was molded into the observation scope to give it a little better appearance. Looking at the attack scope mast head, it was interesting to see just how small the head of the scope is in relation to the rest of the sub.







More to come.

Mylo

[mylo]

Step 70 ]



I almost

[b]Step 70 ]



I almost overlooked this little antanae. It was made by grounding down two sides 90 degrees apart on a piece of 1/8" brass. 1/16" holes were drilled in the rod with 1/16" brass rod inserted in each. Screen door mesh was then wrapped around these two "arms", forming a circular screen antanae. A drop of CA sealed the deal.






More to come

Mylo

[mylo]

Step 71 ]


The dash

[b]Step 71 ]


The dash on the tower enclosure, the little "shelf like" part at the front, was made out of .060 styrene. Like the proceedures before it, the plans were used to make a template out of MDF. The template then used to trace onto the .060 styrene. The styrene was then cut out.

TIP ** After cutting your paper template out of your plans, test the fit on the actual piece. You will see from the pics that after cutting the template out of MDF and sanding it to shape, I test fit it inside the tower enclosure to ensure the template was accurate.











I thought now would be a good time to give everybody a few pics of how the boat is shaping up. As I build the parts, I am placing them on the plug to get an idea of it's overall look. With all the bits and pieces added since my last overall sub pics, I thought I'd post some updated ones. The tower is shaping up nicely with all the detail parts added. The parts are very delicately just set in place....one little wiggle of my work bench, and the whole thing will fall apart. This placing will account as to why things don't look "just right", or slightly out of alignment.

....she's starting to look like a type VIIc/41.












More to come.


Mylo

[mylo]

Step 72 ]


The first

[b]Step 72 ]


The first part of making the wind deflector was not much different than any other part. I took a casted tower enclosure and traced an outline onto a piece of 1/4" hardboard. Once I had this outline, I drew another line freehanded that was the same distance from the traced line all the way around, creating the small gap between the tower enclosure and the wind deflector. With the measurements obtained from the plans, marks were made all along the now freehand drawn line. I then drew another freehand line by "connecting the dots", giving a uniform width deflector. With the shape drawn, it was time to hit the band saw to cut out the rough shape and the followed up by a bunch of different sanding tools, both power and hand, to get the beveled shape. The master was then complete.














The casting of the rubber mold for the deflector was going to be the same method used to cast the hatch covers. The master was glued to a piece of malamine. A sufficient mold box was made. The lid with the glued master was put in place, duct taped up, and RTV poured. The resulting mold turned out really well, but the master was destroyed in the process of removing it as the taper was acting to hold it firmly in there. No loss, as the master did it's job and was no longer needed. The mold was cleaned out real well to get all the little bits of master out. Time to pour.








Pouring the wind deflector was easy, but the trick is to make sure the rubber mold is level in all aspects. The Smooth Cast 305 resin was poured in, a little bit in excess, and let cure. Once cured, the rubber mold was peeled away from the casted part to start. Once started, the part came out easily by both pulling on the part, and peeling back the mold. I probably could have saved the master had I used this technique. With a little bit of clean up afterwards, the mold produced a very nice casting. A test fit on the tower enclosure showed that there is enough flexibility in the wind deflector to allow for the supports to be inserted into the enclosure, and the wind deflector fitted to them. That will be done once I begin to assemble a prototype conning tower.












More to come


Mylo

[mylo]

Step 73 ]


Initially, I

[b]Step 73 ]


Initially, I was going to make separate molds for the Wintergarten ladders, lower conning tower hand rails, and the grab irons (steps leading from the deck up the side of the conning tower to the top level). Luckily, I discovered that the width of the grab irons was the exact same distance between rungs on the ladders, which meant that I could use the same castings for both, just trim them differently. With this discovery, I decided that I would also use the same castings to form the lower tower hand rails. In short, I only need one mold for all three parts. Wooooo Hooooo, a time/money saver.

I made a mold that would hold as many "ladder" castings as possible to fit into my pressure pot. From these generic castings, I would trim the three separate parts that I needed. To make the mold, I drew lines with marker onto what would be the lid of the mold box as this mold was going to be made in the same fashion as the hatch molds. Once the lines were drawn, I cut 1/16" brass rod to fit. Each rung had to be cut and ground separately, taking several measurements to fit, which reminded me of the tedium of the rivet placements. Once all the brass was cut, I ran a very fine bead of glue on my drawn lines and smeared it around with my finger. The brass rod was then placed in their spots. Once the glue was dried, this lid was then put on the mold box and the rubber RTV poured in. Once cured, the lid was peeled off the mold box but all the brass remained in the rubber. This brass was picked out of the mold, which was done without any problem.






With the mold done, I poured in the resin. Once cured, the resin was peeled away from the mold and each ladder casting roughly cut out. The excess was sanded off the backs of the castings and then cut out around the ladder.














This ladder casting was then trimmed into the parts needed.











The entire process for making the ladder castings was very labour intensive. Nonetheless, it is much quicker and cheaper (have you priced out brass lately ?) than making these parts from soldering brass rod together. I had tried the "injection molding" method with my turkey baster but was finding that due to the intricate shape of the casting, the rungs were not getting filled with resin, or there were voids in the castings (even the smallest void would make the casting useless). I scrapped those molds and decided to go with the "direct pour" mold method. Lots of time, but at least it worked. It's not shown in any pics, but in casting some of my later molds, I scraped off excess resin with a business card just after pouring instead of letting it pool on top. Doing this saved me the sanding step that I mentioned earlier. Sometimes, there is no quick and easy way.


More to come.


Mylo

[mylo]

Step 74 ]


With all

[b]Step 74 ]


With all the little stuff pretty much done, it was time to get into making the larger parts, which includes the conning tower. The process for creating the conning tower castings is different that what has been covered so far with the smaller pieces. In theory, the exact same method could be used, but you would have to put a second mortgage on your house to afford the rubber molding material that would be needed. Instead, what is done is to expose 1/2 of the master at a time in order to make the mold for 1/2 at a time as well. The master is placed in what is called a parting board which is basically a board with a hole cut in it as close to the shape as the master as possible, with the excess gap filled in with Clay to make sure it is totally sealed from the other half. In the case of my tower, what I actually made is more of a "parting box". I built a box because I was then able to fill it with cat litter to act as a support for the master to assist in making sure that only 1/2 the master was exposed. Why cat litter ??....because it was the closest thing to sand that I had, as I figured something like sand would be a real good support to conform to the master......I was right, the cat little work excellently. Before placing my master in the parting box, I marked the dead centre of the master all around and then lined it with 1/4" masking tape. This tape is going to make an indentation in the mold which will show the exact centre. This is going to be important because when the casting is trimmed/sanded down to get rid of the excess fibreglass/cloth, a reference mark is going to be needed to know where that centre is. This tape line also acts as a real nice reference as to how much of the master to expose. Once the master is taped and placed in the parting box, it was ready for the rubber molding material application.



* Close look at the photo and the green masking tape line can be seen marking the centre of the master *


A thin coat of the rubber RTV is brushed over the master tower. This coat only needs to be thick enough to capture the fine details such as the rivets, weld lines, flood hole markings, etc. Once this thin coat, or "glove", is cured, 2 more coats of a thicker rubber material is applied to give the glove a little more support. I used stuff called Rebound 25 made by the same Co. that the Smooth Sil 920 rubber RTV product that I'm using. These materials were suggested to me by Kevin McLeod for their quality and ease of use, not to mention their availability here in Canada. Kevin was right on the mark as these materials are first rate......but by no means cheap. ($130/gal.). Once the Rebound 25 has cured, it was time to make what is called the hardback.




The hardback is simply a rigid support for the rubber mold. Since the rubber is obviously "bendy and floppy", there needs to be something to hold it in the proper shape, basically an exo-skeleton. I decided to cast a fibreglass hardback right over top of the Rebound 25. This technique worked very well. When the fibreglass hardback cured, I just peeled the rubber mold out of it very easily, no stick, and no release agent needed. Others have used plaster hardbacks, but I found the fibreglass one that I made much lighter and easier to work with. This will be REAL important when I make the hardback for my hull molds (8'9" long x 15" wide). Since the hardback is basically of the shape of the master, I would have to build stands for the hardbacks so that they can sit in the proper position to cast the tower parts.




These stands were of simple 2x4 and hardboard construction with a hole cut out for the hardback to fit into. I cut the hole just slightly smaller than the hardback. I forgot to mention that when I made the hardbacks, I put a 1/2" lip around the perimeter so that the hardback would rest on this lip in the stands. Once in the stands, the rubber molds encased in the hardbacks were very secure. The molds were now ready to cast some parts.






Casting the tower halves was a matter of applying two thin coats of fibreglass resin in the molds, letting the set up well before coats. These thin coats of resin are going to capture the details of the master without any fibreglass cloth distorting them. Once the two thin coats cured, two complete applications of resin/fibreglass cloth were applied. Once all was cured, the rubber mold was removed from the hardback and then easily peeled off the resin casting. The casting was then trimmed and sanded, using the now visible line from the tape as the reference. With the two halves made, they could now be assembled into the complete tower. Before this was done, all the flood holes were drilled/filed out.

As hard as I tried to make these two castings mate up PERFECTLY, ....they don't. A little bit of grinding and fiddling is required to make that happen. Once I was generally happy with how I had them fitting, they were "welded" together using a thin bead of the fibreglass resin while held together with clamps. Once this resin cured, I applied a layer of short hair fibreglass over the top and bottom of the tower. This layer was then sanded to a perfectly flat surface. Both of these areas are not crucial because the bottom surface is not going to be seen, and the top is going to be covered with a planking casting as well. The end result is a fibreglass tower that is impossible to tell that it was once two separate parts. I was pleased with how well the resin castings captured the fine rivet detail of the molds. I then added the tower wall enclosure, wind deflector, and grab irons to the tower, giving the whole thing a coat of primer. Since I was not happy with the look of my casted "square looking" grab irons, I decided to use bent brass rod instead. I like the look much better and it was very easy to do. The prototype tower is now ready for some planking castings for the deck surfaces before the application of the smaller detailed parts.












More to come.

Mylo

[mylo]

Step 75 ]


If I

[b]Step 75 ]


If I was building a one off sub, I would have laid each real wood plank (likely scale balsa) one at a time, stained, then varnished to make water proof. However, since I'm building this baby as a kit, I thought it would be much nicer for the modeller if they could just install one piece decking quickly and easily. I decided to cast these one piece decking parts out of the plastic resin using molds, much like every other part on this sub. I build my masters using templates and glued my scale balsa, plank by plank, down on the templates. Again, one a one off project, I would have just stained and varnished this master that I built. Instead, a rubber mold was made for the plastic castings.






The rubber picked up the wood grain detail of the balsa quite nicely, but to add just a little more definition, I added some "simulated wood grain" by scraping a fine toothed saw across the resin castings. Once the "wood grain" was made, each casting was spray painted with just a medium brown flat spray can paint. Once dried, the parts were given an "oily wash" using black acrylic paint diluted down with rubbing alcohol. This was to simulate the treatment that the actual wood planking would have received on the sub. The wash settled nicely between the planks, filling the gaps black. The excess wash was mopped up with a rag until the desired effect was obtained. Once this was done, a final wash with india ink diluted with alcohol was applied to fill in the tiny wood grain details. The look I was going for was a "semi weathered" look with the decking still quite dark, but starting to show fade/wear. Overall, the final deck pieces are very convincing as being exactly that, ...wood planking that has been treated, but is weathered. If I didn't tell you they were plastic, you would never know. The bonus is, along with these three parts being very quick to install, they are cast from plastic and so are not subject to water damage as real wood might be. These deck pieces do not come painted in the kit as different builders are going to want different looks, but anyone following my explanation as to how I did it will produce some very nice decks and get very different looks by just changing the base colour or wash colours.








Before installing the deck pieces, I decided to drill and sand a bunch of lightening holes (not to be confused with lightning holes) in both the upper and lower faces of the tower. I want this tower to be as light as possible given that it's entire weight is going to be above the water line when surfaced (obviously). The holes made a considerable difference. There is no doubt now, the tower is well ventilated.










More to come


Mylo

[mylo]

Step 76 ]


This step

[b]Step 76 ]


This step was fun because I actually got to build the model instead of building parts for the model. This step completes the conning tower assembly and detailing, with the exception of the Flak guns. I'm looking most forward to see this with the AA guns mounted. I'm currently waiting for some 20mm and 37mm Flak diagrams before I begin building the guns for installation onto the tower. Those of you very familiar with this type of U-Boat tower will notice that there is a part of the railing absent from the upper wintergarten. Ooooops, for whatever reason, I haven't built it yet....not really sure why. Rest assured, it will be built and added to the railings.

I'll let the photos speak.

** NOTE ** The rust in the photos shows up as a bright orange, when in actuality, the rust is toned down much more than it appears in the photos. I think the bright lighting used to take the photos made the rust....flourescent....or something. Anyway, on the model the rust has a much more subtle look. As well, both sides are weathered/rusted equally, yet they don't appear that way in the photos. I don't have an explanation for that....must be the angle the photo was taken, lighting, ...or something.
















I'm going to be away for a while and not able to get at the sub. Very soon upon my return I'll be casting the BIG hull parts.....Oooooo...exciting. Until then, enjoy these pics.


More to come....just a little later, that's all.

[warpatroller]

Mylo,

Your VIIC/41 is coming along

Mylo,

Your VIIC/41 is coming along nice! Thanks for sharing the pics of the sail and the wooden deck planking too.

If you had used actual stained wood planks on your model, you might have had to scrape the algae build up off them after several patrols in your local lake Your model is so big you'll have to moor it lakeside and keep it there for a few weeks at a time, or perhaps build a scale Uboat bunker for it alongside the lake...can you picture that?!

Steve

[mylo]

Steve,

Yeah, the boat is

Steve,

Yeah, the boat is coming along nice......but man, ....the time. It's not looking like I'm going to get it in the water this year as hoped. I've been working on the fit and finish of the other conning towers and it's been eating my time, 40 hours last week alone.....that's a full time job. I'm already 325% over my estimated build time and WAY over my estimated cost. ....must be a government contract.

I'm happy with my decision to cast the deck planking out of plastic. It looks just as good, without the upkeep hassles with models that are in and out of the water.

The model is 8'9", I sure wouldn't want it any bigger. It's been a handful at times to deal with the plug in my basement. It will weigh 50lbs (or so). Not for those with back problems. Leaving it moored to develop a real scum line would be cool As for the 1:25 scale concrete U-Boat pen........it's not looking very likely.

This whole thread, along with the pics, are for us sub heads to enjoy and maybe learn something from, or more accurately, save someone from making the same mistakes. Just doing my part to keep the hobby alive and thriving.

I'm busting my ass to get this thing in the water this year (with/without the r/c "guts"). ....if for nothing else, a nice photo shoot. I'm up at 4:00 AM pretty much every day to get time in on it. Would somebody please phone the mental health authorities and have me committed before I hurt myself.


Mylo

[mylo]

Message to followers of this

Message to followers of this thread:

I'm waiting on supplies. Namely, 60' of 3/32" brass rod so that I can complete all these tower railings. I've been burning up the butane on all this soldering. Unfortunately, the wintergarten railings are just long enough that I have to make each upper and lower railing, of each upper and lower deck, from a full 3' long piece of brass rod. In other words, I had to order a whole ton of 3' lengths. I believe I mentioned something about over budget in my last post.

That, ....AND.... my West Systems Epoxy order. I'm going to be casting the hull parts out of West Systems Epoxy instead of the resin that I did the towers out of. I'm not thrilled with shrinkage......of any kind, much less my castings and the resin does shrink ever so slightly. With parts as large as I'm making, it is significant. I'm thinking that it will save me HOURS of the kind of labour I had to put into my towers to get them just right. The casting of the tower halves out of resin was just an experiment anyway. I find the castings to be pretty good, and the resin captures the detail excellently, BUT...the added labour of getting the halves to match up perfectly is more than I care for. Now that I know the results, I will be casting any large parts out of Epoxy. My understanding is that there is no shrinkage. I should be able to cast very nice parts with the West Systems stuff and eliminate a ton of work. The cost is a little more, but not a whole lot.

That's the update from the ship yard.

Mylo.

[landlubber]

Mylo's type 7

A super and informative build Mylo. Thanks for sharing your work
with us. Where did you learn so much about molding ?
Regards Kent.

[warpatroller]

Mylo,

Your like a one-man shipyard!

Mylo,

Your like a one-man shipyard! If your sub isn't in the water before winter, so what...Think it is better to not rush through it and make sure everything is done right and to the best of your ability. At such a large size and heavy weight I'm sure you'd prefer that it be totally seaworthy in addition to looking as bad ass as can be, before the maiden voyage.

I am impressed that you have not lost interest at this point, and are still pressing on, well done! You still have till next May before the Russians close in and halt your operation so the boat doesn't have to be ready to set sail till next spring if necessary! haha

Steve