Scratch-built 1/96 Virginia Class - Pete's second boat

[pirate]

After about three years of research, and countless changes of original plans of mine because new information on the progress of the real Virginia trickled out bit-by-bit, I finally decided that I could not keep up with it, and I should just start making the model with the info that I had. Besides, no matter how long I waited to get more detail, when I would make mine, someone else would soon make a more accurate version anyway.

So with this thread I will show where my journey to Virginia took me.

I started by laminating 3/4" pieces of MDF board together to the length and width of a 1/96 scale Virginia model. I decided I would make the master plug in one piece, and from that make a 2-piece urethane rubber box mold by pouring one half up to the midline, let it cure, then pour the other half to get my two parts. This meant my halves would be perfectly registered, with no chance of the two master halves becoming distorted before the mold halves were made.

I glued up the MDF with Gorilla glue, and clamped them tight to cure for about a week.

Now I realized a significant problem. At scale, this boat is 44-1/2" long without the pump jet attachment, and 4-1/4" wide. My wood lathe is only 36" long.

Seeing as how this boat is the same diameter for most of its length, I decided to turn the front and back tapered portions only, no where near 36" long. And I found a standard PVC sewer pipe with an exact O.D. of 4-1/4" wide that I would use to fill in between. Violé. Problem solved.

Here I am turning the bow section in my garage. Hey, no jokes, it's pretty cold in Indiana in January. What us sub nuts won't do to build a boat.

[pirate]

Here is the results of

Here is the results of turning the two ends. These are sanded down, primed and filled, and sanded some more. I kept them on their turning blocks to be able to keep putting them on the lathe and work on them.

I turned them both 1" longer than the section I intended. Then machined a 1" lip onto the ends, which will fit into the end of the PVC pipe I'm using for the mid-section. These lips not only give them a way to join to the PVC, but because my pieces are close to true round, they will force the 3/32" thick PVC pipe to be closer to true round where they join.

Next, I'll show how I joined the ends to the PVC pipe.

Pete

[raalst]

very nice.

That's a wood

very nice.

That's a wood turning lathe, right ?

what are those deep cuts for ? surely the final hull does not
possess such features ?

[pirate]

Virginia Build Ship's Log
3-20-06

After pretty

Virginia Build Ship's Log
3-20-06

After pretty well finishing the two turned ends, I created a male-female interface between them and the piece of PVC pipe to be used between them.

Once each end was seated properly in the PVC pipe, I drilled holes at 60° intervals around the pipe to secure the bow and stern sections to the pipe with countersunk wood screws. I then applied epoxy to the lips and inserted them togehter, and fixed with the screws leaving to cure. I set the pieces up on end while they cured, using gravity to help hold them in place and not shift off the hull center.

Remember to always rough up surfaces to be joined with adhesive to get rid of repelling surface finishes and give some tooth for the adhesive to grip.





I then used that really thin fiberglass cloth, I think it's like 2 oz., the stuff that nearly disappears when you put the resin on it, around these joints to make sure they didn't move later or develop any cracks in them as I worked to a finished surface.

Once the epoxy resin and glass was cured I worked around the seems withauto body filler. Then sanded it down to shape, primed, and added scratch filler to fill in the last marks and uneveness.





Then prime and you've got a nice smooth boat hull, torpedo, missile or falic symbol worthy of the Egyptians (just seeing if you're paying attention)





I first marked the parts with a center line on the top and 180° around on the bottom to keep things aligned, and as the process proceeded I ccontinued to remark this line. This was much easier to find and make square on the open ended PVC pipe than it would have been on the finished hull. These center lines would be used to line up and measure from for the detail parts to be added.

The Virginia is the first U.S. nuke to have a chin sonar, so this was the next main detail to form into the hull shape. This was fun because it morphs right into the hullshape. I'm an artist by profession and do sculpture, so this was right up my alley. I call this model building sculpture with a purpose.

The chin sonar dome started out as a round disc. The i placed a piece of sandpaper over the area where the chin sonar would go, giving it the shape of the hull. I cut away some excess from the dic, then ran it over the paper until it conformed to the shape of the hull, fitting in perfectly. I attatched it and filled around the seem, filleting it in seemlessly as on the real boat. I would later add the little tab that extends and retracts from the dome with a piece of styrene using the same sandpaper shaping process.

[pirate]

Raalst,
Yes. It's a wood lathe.

Raalst,
Yes. It's a wood lathe. Very old and rickitty, but she's good enough on pieces this big around. Any smaller and things vibrate out-of-round.

The deep cuts in the initial slug are at reference marks for the different diameters. I turn them all down to their prospective diameters first. Then I go back and turn the sections in between them from one to another. This give reference points to turn down to little by little, and you don't have to keep measuring with a micrometer until you get very close.

Pete

[pirate]

Virginia Build Ship's Log
3-21-06

Next is

Virginia Build Ship's Log
3-21-06

Next is to create recessed areas that can be cut out or left for static display as holes in the hull. These would be the main ballast drain holes on the keel.

I did these by taking a printout of the vent pattern from my printer and spray mount gluing it to a wide strip of masking tape. I put the adhesive side of the tape down on a sheet of wax paper. I then proceed to very carefully cut along all the lines of each drain hole on a cutting board, without popping out the pieces of tape.

Once they're all cut, I place a piece of airbrush friskit over the top of it all. This is a clear masking medium with a light adhesive on one side. This will act as a carrier of all the cut pieces so they stay together.

I then flip the whole thing over to reveal the wax paper facing up—a sandwich of masking tape, paper print out, and the friskit now on the bottom. I carefully peel the continuous piece of masking tape around all the ballast drain vent pieces off and away from the friskit. This leaves only the pieces of the ballast drains on the friskit in there proper alignment and configuration.

Then I carefully remove the pieces of wax paper stuck to the bottom of these pieces of tape with an exacto knife, without pulling the tape pieces from the friskit.

Now I can flip it over and position it in the right place on the bottom of the hull, and press it down so all the drain vent holes are in their right place. Since the adhesive on the masking tape is stronger than that of the friskit, after burnishing all the pieces down to the model surface, I can peel the friskit back leaving all the tape pieces behind, still stuck in place on the hull.

Always peel making tape, or masks of any kind, back from the surface at a negative 45° angle or greater. Or I guess as you lift it from the surface being 0°, 135° or more. This leaves a clean line against paint, and makes the pulling effect of the tape move on a line parallel to the surface instead of away from it, reducing the chance of pulling up the suface.

Next, I paint over these pieces of tape with a scratch filling auto primer. Many coats to build up a thickness of paint, letting it dry in between. I spray it only around the area where the pieces of tape are, and gradually taper away for a short distance around the area. No need to build up the paint on the whole model.

Once this is completely dry, I peel off the little pieces of tape revealling indentations of the main ballast drain holes.

[pirate]

Virginia Build Ship's Log
3-22-06

Time to

Virginia Build Ship's Log
3-22-06

Time to add the side aperture arrays.

The side aperture arrays on the Virginia were originally depicted as being very much the same as those on the Seawolf. On the Seawolf they are very rounded, sloping and tapered presumably for better hydrodynamics.

But as pictures of the actual Virginia construction started coming out they were actually more geometrically shaped. They are rectangular and protrude more from the main hull shape than those of the Seawolf. And all of them are pretty much the same size and shape. So this would allow me to build one master and slightly adjust each casting to the specifics of where it would go on the hull.

Using the stock PVC pipe for the hull turned out to be a real blessing here, because I could use a generic cut off piece to make my master on.

Instead of building up material on the pipe and then sculpting it down to shape, these arrays are so geometric that i could make straight cuts on a bevel and achieve the results I wanted.

At this point I needed some kind of material that would cut easily and then form just as easily to the pipe shape. What I found was some rubber gasket material found in sheets at the local Do it Best store. This gasket material is used to make custom gaskets for plumbing and is found in the plumbing department. There are even varying thicknesses available.

So I used two layers of different thickness to simulate the differnet thicknesses of the parts of the array. I measuered and marked the pieces, then cut them with a utility knife along a steel rule on the appropriate angles to create the bevels.

I then adhered them to the pipe, one at a time, with contact cement. They conformed to the curvature of the pipe perfectly.

Next I built up a mold dam and poored RTV over the part to create a mold.



When I poored the casting for these, I used another piece of PVC pipe to push down on top as the second part of a two-piece mold to create the backside curve needed to fit flush against the hull. Before the poored pieces were fully cured, and still soft, I pulled them and put them against the actual hull so that they took the actual shape of the spot they would go in, giving me perfect registration and minimizing any filling of the seams when I attached them.

(I use Alumilite White to make a lot of my prototypes, as well as finished part reproductions. It cures very fast and strong, and machines and glues up with CA very well. So when prototyping a complex shaped item, I usually break it down into simple shapes, mold and cast each, then piece them all togehter and make one final mold for the finished piece. I learned long ago that it's not a question of how hard you work, but how smart you work. Saves a lot of headaches.)

When they did fully cure, I made the unique cuts in each to reproduce the proper shapes for each array.

Here's how they turned out.

[pirate]

Virginia Build Ship's Log
3-25-06

Now onto

Virginia Build Ship's Log
3-25-06

Now onto the details.

On the last model, Seawolf SSN-21 (see www.geocities.com/submarineworks) I used scribing to do all the detail. It does look accurate to scale, but it sure is hard to see when it's down in the water moving around. So I wanted to do something that would play off the light a little more, creating some harder highlight and shadow lines making the detail show up a little better. After all I thought, if you're going to spend so much time adding it, shouldn't it be able to be seen?

So this time I wanted to try something new. I saw on F/X/Models website some of the things they were doing was making the details project off the surface. I liked this effect, soI decided to make the details on my boat raised as well.

What I did to get everything equal and symmetrical from one piece to another, and one side to another, was to make as much as I could from photo-etched metal. This is the last, most detailed thing other model makers offer to get the most detail on their models, so I would just build them into it.

I found a wonderful little do-it-yourself photo-etching system on MicroMark.com. Only about $120 or so. As long as you can print decent quality black and white prints from your desktop printer, this thing works beautifully.

These are a sheet of detail parts that are additional to add to the sail and bow decking to add to the model right before painting.


I decided to do the MBV, vent gratings, VLS hatches, capstan, countermeasures launch tubes, bow plane openings, torpedo tube doors, escape trunk hatches and other deck details this way. Some of them I then used scratch filler around to eliminate a lip on the edges, and then primed over if there wasn't any detail in the surface, like the torpedo tube doors.






More to come.

[pirate]

Virginia Build Ship's Log
3-25-06, later

Virginia Build Ship's Log
3-25-06, later in day

To do the hatches, I first found a wood boring bit that was the same size as the flat decking around the hatch. I used this to drill don onto the top of the round hull just deep enough to accept a circular piece of 1/16" styrene plastic. When placed in the space left by the boring bit, this would become the flat deck section around the hatch.

I he filleted up the edges around the plastic disk so that it smoothly transitioned into the contour of the hull around it. And so if moving along the top of the deck along its longitudinal axis, there is no rise or fall when moving over these hatches.

Then I made photo-etched metal pieces of this same deck area with the hatch details in them. CA glued them in place, and filled the edge around them. I took out the hatch portion s themselves to prime over, as not to fill in the fine detail with paint any more than necessary.




For the Advanced SEAL Delivery hatch, I used a straight flat-file, filing out the space on the deck perpendicular to the top of the deck where a rectangular piece of styrene would go. Then same process to finish off.



Now for the towed array fairing.
I figured the full diameter of what the fairing would be if it were a complete tube. Then I found a piece of PVC pipe the same diameter. Luckily there was one. A piece of wooden doll rod would work too, but the PVC glues down the the tapering shape of the hull at the stern much more easily. I set up guides on my band saw and cut the PVC pipe length-wise to the same size as the fairing.

Then I got some doll rod the same diameter, and using a disc sander, I tapered down the ends of a piece I cut off (long enough to get both ends of the fairing out of) to match the fairing ends. Then I ran that through the band saw to get the same size cut-off as the PVC. Then I just cut off the ends to lenth and attached them in the front and rear of the PVC pipe on the hull. Used filler to fill in the gap between all of these parts.

I next used the previously mentioned tape method to get recessed areas, to get the safety track denoted down the length of the fairing. Built up the primer, removed the tape, and there was the safety track. You can just barely see it in the last picture, and the next two. That area is the lighter tan color of the bare PVC pipe.

[pirate]

I shaped the sail out

I shaped the sail out of a piece of MDF. Carved the notch in the front under the sonar panel and primed and sanded it smooth. Then, again used the taped method to get denotation of the panel hatches along the sides of the sail. Once the scratch-filling primer was built up sufficiently, I removed the taped pieces and had nice details. Once the real boats get there sound deadening materilas applied, these hatches do end up recessed because there's not any coating applied over them. I will use pieces from the photo-etching picture above to add detail to the diesel exhaust ports and the fairwater vents at the bottom edge of the sail when building the actual model. I scribed in the detail on top for the hatches and masts.









With all the detailes applied to the hull, I was ready to make the mold.
First step was to make a two piece mold box. I used melamine board to build it out of because the white plastic surface is hard to get anything to stick to, so pulling and putting a mold out and in would be easier. I used simple drywall screws to hold it together. And joint discs to keep them registered with each other.




Next came time to poor the mold.
From the centerline marked on the hull when turning it, i drilled 1/8" holes in each end where i inserted 1/8" brass rods long enough to hold up the plug on the walls of the mold box. I also drilled holes in both ends of the mold box at the center lines to receive these brass rods. THis would allow the plug to float in the mold box with its centerline perfectly aligned with that of the mold box so material could be poored in right up to it.

I had to make sure the mold box was completely level so the centerline would be straight before pooring the mold material.

I used Por-A-Mold Hard Urethane rubber which mixes 2 parts at a 1][/url]

[pirate]

Once cured, I attached the

Once cured, I attached the top half of the mold box to the bottom, taped around the seem so the mold material wouldn't leak out, then removed to top of the box to poor the second piece of the mold.

Here is a picture of the mold pulled apart and the plug removed.



This picture shows the detail captured by the urethane rubber. I didn't mention, but this 2-part urethane is much less expensive than RTV rubber in the quantities needed for this size of mold.



To cast a copy of the hull, I use epoxy gelcoat and resin 2000 from Fibre-Glast. Very nice stuff, and very forgiving. It must be mixed accurately by weight, but the gelcoat can be applied with a brush up to a 1/8" thickness if desired, and it pretty much self leveling, even on vertical surfaces—amazing. You can also let it sit overnight before applying the resin and glass coats to back it up, without having to sand the surface.





Next was the glass lay-up.



I made the control surface pieces out of the MDF too. Really great stuff for this kind of prototyping. Then I made RTV molds and cast Allumilite pieces to which I added the towed array pod to the dyhedral plane for example. And the brass tube for the towed array port on the port stern plane. I then made final RTV molds. After each is cast I can cut apart the plane from the elevator, and the towed array port to make the starboard plane. And cut off the towed array pod off the dihedral to make the starboard dihedral.

[pirate]

I made molds for all

I made molds for all the smaller pieces out of RTV rubber. Following are pictures of the pulled hull castings and other parts as they turned out.

[koeze]

I have to ask this.

I have to ask this. I don't know the Virginia in detail but aren't those raised and recessed details out of proportion? I have seen photo's of the seawolf before the tiling was put on and it had the same explicitly raised details but after the anechoic tiles were stuck on this was much lessened.
I'll have to dig up some of those photo's to be sure...


Erik Jan





Edited By KOEZE on 1143642929

[pirate]

Erik,
If you're asking about the

Erik,
If you're asking about the VLS hatches on the top of the bow, yes mine are exagerated. I wanted them to be so they cast more highlight and shadow so they'd show up better on the water when the model is running 10-15ft away.

If it's the sail hatches you're talking about, they become more recessed after the coating because the coating does not go over the hatches themselves, making them appear lower the the rest of the side of the sail.

As well, these areas are more than actual because once a couple of coats of paint go on the model, much of the detail gets covered up, or filled in with the paint. This will keep some of the differences from doing that.

Pete

[mermaid]

Dear Pirate]http://www.subcommittee.com/forum/icon_question.gif

Dear Pirate]http://www.subcommittee.com/forum/icon_question.gif[/img]