CSS Hunley

[cdavenport]

I know, it was not a CSS ship; folks just think of it that way.

Reading the rumors that Z might dump old threads made me sick that my thread on the Renova Hunley build would be lost.

If there is any interest, I'll repost my build thread as it appeared last year. Otherwise, I decided to post some completed images for your amusement.

[SJPONeill]

I know it's a bit of work but I'd like to see the thread rebuilt over here - it's a piece of paper modelling history and I am very wary of losing material that once gone, is gone forever + I'd like to think there that will be a small chance in millenia to come that alien archeologists will think that's how we built submarines and will waste years trying to get a watertight hull....

[rmks2000]

Thanks for posting the pictures. I have this kit and it will help me when I finally get around to building it. I've got a fair number of subs to build, but the Akula is on the top of my pile.

[silveroxide]

Please re-post this historical ship Sir.

[Ron Caudillo]

Yes! By all means, repost for the benefit of us! It's a shame to lose such great posts like yours!

Best Regards,

[cdavenport]

OK, you asked for it! I'll try to get it in the order in which I originally posted it.

When I learned this model was released I just had to have one (actually two). I have a couple of other resin kits but they are somewhat inaccurate. Renova’s kit seems to be based on the latest information available. I live about about 5 hours from Charleston, SC and have seen the Hunley under restoration. So, it was with great anticipation that I began this project.

You will find my text keyed to numbered photos as if you were reading a zine article. Also, I will share some equipment choices and techniques with you. Though I cannot design like some of our more prolific forum members, I have a varied base of experience in materials, techniques, and processes to share. Though I have started this as a naval thread, you will see I used techniques applicable to other subject areas, too.

Photo #1 Eschewing the shot of the packaging and parts, I’ll start straight with the build. First, I have seen reported a number of problems with 1mm cardstock warping. The simple answer is to stop using the 1mm cardstock we routinely associate with paper modeling and switch to mechanical board, sometimes called “illustration board.” Go to dickblick.com and search for “LetraMax 2000 mechanical board.” It will cost about $7.00 plus shipping for a sheet 30” x 36” that will last many models. Save shipping and go to your local art supply house. The product does not warp. In fact, I have a supply that I have been carrying around the world since the middle 80’s that suffered a bit of water damage recently. The area not affected is perfectly fine; in fact, I used it for this project. It measures a tad over 1mm thick and can be delaminated. However, under regular use, it does not delaminate, fray or exhibit any of the undesirable qualities normally associated with cardstock. I assembled the bulkheads with Tacky Glue. Notice that the edges of the bulkheads are colored. You’ll learn why shortly.

Photo #2 In a departure from normal building procedure and taking a cue from the RC guys, I am cutting sections of closed-cell Styrofoam to size to fit the spaces between the bulkheads. I use the foam in which computers are packed. It is light, dense, and very strong. I am using the “Hot Wire Foam Factory” kit which includes a number of useful accessories to cut the foam. The heated nichrome wire cuts through foam like, well, a hot knife through warm butter.

Precision is the watchword here. I want the foam to fit exactly. If I cut too small, I have to backfill the gaps (acrylic spackle); too large and I force the bulkheads out of square. Fortunately, the hot wire technique is so precise that I can shave off pieces that are a few thousandths of an inch thick if the need arises.

Photo #3 This close-up shows that I have ensured the wire is square with the table. Additionally, I use a draftsman ruler as a fence to ensure precise and constant cuts. Any straight-edge will do. You can make your own hot wire cutter with some wood, a motorcycle battery and 30AWG nichrome wire purchased over the Internet.

Photo #4 Using Elmer’s White glue (PVA glue) to adhere Styrofoam, this is what the hull looks like. It took a few hours to do this, working continuously, but you are going to see that this extra effort up front is going to pay off in spades later!

Photo #5 Using one of the accessories in the Hot Wire kit, I am roughly removing the excess Styrofoam using the bulkheads as a guide.

Photo #6 With an aluminum T-bar and 50 grit sandpaper, I roughed the Styrofoam down and finish sanded with 180 grit. This is where the colored bulkheads come in handy. The second I touch and edge, the color comes away indicating the limit of my sanding. Once complete, the hull is rigid.

Photo #7 The reason for the Styrofoam is three-fold; first, it gives me a solid surface onto which I can glue the hull plates WITHOUT backing strips. Second, the foam undersurface prevents sagging of the paper between bulkheads. Real ships do show evidence of this but usually only after sea duty. Nevertheless, in the scales we build, that sagging is really over stated. Finally, having a solid hull allowed me to really muscle the paper into place minimizing any seams. I used some simple tools, mainly a wooden ruler, to make sure adjacent seams were perfectly flush with each other. The foam carried the load!

More importantly, the Hunley was flush riveted and quite smooth. I didn’t want to see bulkhead bulges and sagging plates.

Photo #8 The proof is in the pudding. There are several seams here. Judge for yourself. This technique actually saved time and effort. I completely covered the hull in about 5 hours, taking my time and carefully aligning hull plates.

General notes:

1. The Renova CSS Hunley is excellent value for the money!
2. The parts fit is superb, in particular the hull plates.
3. There are three main plates in addition to bow and stern plates. Each plate is designed as one wrap-around piece. I recommend cutting each main plate into an upper and lower plate. It is easier to adhere and align them this way. The bow and stern plates are best assembled as is. Their fit is almost perfect requiring just a little filler material.
4. Speaking of filler material, the kit includes extra black and copper color sections for any eventuality that might arise. I used a bit of the black to fill in areas not completely covered by the bow and stern plates.

[cdavenport]

I am working on all the various subassemblies. In this photo, I am using the Reheat Models Precision Punch and Die set to punch out the viewports on the fore and aft hatches. Mike Crisafullis' site indicates that Renova got the viewport placement for the captain's hatch right on money. My intent is to allow light to bleed through the viewports for that extra touch of realism.

The subsequent photo comes courtesy of Mike and clearly shows the raised rivet detail on the coaming flange. Notice the thickness of the flange? Renova got this wrong. The two flanges need to be thicker than the supplied printed parts. No worry, I'll just do a bit of laminating to get it right. I'll shoot a photo and show you how I did this.

[cdavenport]

The Renova kit supplies some hex bolts but gluing them to card then cutting them out individually seemed a time consuming chore. So, I made my own. In the following photo you can see the brass syringe I made from telescoping hexagonal tubing available in five consecutive sizes from Small Parts Inc. Check them out on the web.

I soldered sections together and extruded Celluclay in long sections. Once dry, I gave a section a smoothing swipe with a jeweler’s file, then sealed it with CA.

Of course, I have this syringe for other applications and enough brass tube to make any of five diameters. Pretty cool, huh?

[cdavenport]

1. In this next installment, I am preparing to construct and add the two hatches. Because the real coaming flange is a thick object, notwithstanding the concretization that has yet to be removed, the Renova part is too thin. In order to prevent any cupping or creasing of the part I laminated it to a new part that I formed by laminating two pieces of card together on top of the completed hull form. Notice that I stretched Saran Wrap around the hull to prevent any damage to the hull. Notice also the registration line that allows me to align the printed part to my laminated part. Once I glued the Renova part to the preformed part, I simply glued the whole shebang into place.

2. The next photo shows a close-up of the coaming flange with the hatch and conning tower in place along with the other fitments. Notice the light coming through the view ports. I glued the flange to the hull first, then added the conning tower after ensuring all mating edges were flush. Renova included one bulkhead at the top to shape the tower. I added another at the bottom, which made for a rigid part, easily aligned and mated to the flange.

3. The next shot is an extreme close-up showing the compound curves of the hatch cover. This is a scratch built piece that eliminates the use of the Renova part and, therefore, the appearance of any cutlines. I am working with cgutzmer to try to upload an mpeg video to demonstrate the basic process of rolling paper to achieve compound curves.

4. The final shot shows the hull with both hatches and the keel ballast installed.

Comments: All of the parts fit perfectly with only minor trimming needed. To fit the conning towers to the coaming flange required a swipe of sandpaper to ensure the surfaces mated perfectly. Secondly, I added cardboard reinforcement to the keel ballast even though Renova did not make any mention of doing so. Adding the card made the structure rigid which aided in attachment to the hull. It also gives me a solid base for subsequent mounting.

[cdavenport]

Paper rolling
As a follow up to my last installment, I wanted to back up a bit and show you how I accomplished the replacement of the hatch covers by creating compound curved surfaces without seams. Paper is a flat medium with poor tensile strength and limited malleability. However, even with poor malleability, it can still be shaped into compound surfaces. If you take into account its limitations, you can successfully shape even complex curves like propeller spinners and achieve a round, seamless curve. It just takes some work. For the Hunley’s hatch, I did a couple of videos that you can access on YouTube. They are titled Paper Rolling pt 1, Paper Rolling Pt 2; both are tagged “card modeling.” If you need a better resolution video, PM me with your email address and I will forward the originals to you.

1. In Paper Rolling pt 1, you will see my showing my rolling surface. It is a piece of mouse pad rubber backed with a used section of LetraMax 2000 mechanical board. I have posted about this material as an excellent and cost-effective replacement for the standard cardboard card modelers normally use. You will then see me using a tool I designed and made to roll cardstock. <object width="425" height="350"> <param name="movie" value="http://www.youtube.com/v/-yUJgn3YbWo"> </param> <embed src="http://www.youtube.com/v/-yUJgn3YbWo" type="application/x-shockwave-flash" width="425" height="350"> </embed> </object>

2. In Paper Rolling pt. 2, I have soaked the previously rolled card in Hot Fuel Proof Thinner to soften the fibers without destroying them. Thinner is not compatible with the binders used in paper manufacture. So, the card softens, making it more pliable, but it doesn’t fall apart. Please note that in both videos I am gradually using more force as I roll the paper. <object width="425" height="350"> <param name="movie" value="http://www.youtube.com/v/QCl0dWhT7rU"> </param> <embed src="http://www.youtube.com/v/QCl0dWhT7rU" type="application/x-shockwave-flash" width="425" height="350"> </embed> </object>

3. This is the tool that I made for the big work. The different armatures turn inside the bearings which prevents the card from tearing. You can make similar tools from birch dowel stock available at your hardware store. Shape them to the desired profile with sandpaper and finish sand them to 320 grit. Coat the dowel with polyurethane lacquer so that the dowel rolls around without tearing the card.

4. For the really small work, I still use, from left to right, a dental tool (ask your dentist for used ones), a ceramics detailing tool (ceramics store), and a Letraset letter embossing tool (dickblick.com).