Ironclad USS Chickasaw, 1/200 scale, from CAD model

[Roscoe]

Aha, that makes sense.

I'm really interested in seeing how you go about making the mold, so don't hold back on the pics.

Take care,
Dean

[Devin]

Yeah, you and me both! That's going to be... interesting. Never done it before.

[Devin]

Okay, here's one for you Dean (and anyone else that has an idea). Since the lower hull curve got wonked up due to the overly wet wood (Guilty. Right here.) There's a large gap between the two assemblies. You can see the difference below in the photo of the actual, and the crop of the 3D model drawing.

My choices are three, that I can see. One is to glue them together as-is, and then fill the gap. Easiest to do, but the angle will be all wrong, much more curved/blunt than the slop that it should have. Second option is to make a cut in the top of the lower hull, remove material, and see if I can bend it to something more like it should look. I'm not crazy about that idea. I can imagine a large SNAP and then hull go all broke and stuff. Three, the one I'm leaning towards, it to cut the last 1/2 inch or more off of the lower hull, glue them together, lay in styrene to get the correct angle, then back-fill.

[Roscoe]

What about re-wetting the top of the hull, and using your jig again to bend it back? You might have to wet it pretty good so it soaks through to the longerons, at least that way your not cutting and filling. I'd wet it all the way across the surface where the bend is supposed to be to get an even bend. It's worth a try, and if it doesn't bend all the way, you can always go back to idea # 2 or 3.

-Dean

[Devin]

Since I've filled the voids with putty, I don't think it's going to bend at all without at least a cut.

The other option that I've come up with is cutting off the last inch or so, and gluing it and the rest of the hull in place, then filling the gap. That gives the correct slope, termination, and negates having to recreate the entire area with sheet styrene.

[Roscoe]

Doh, I forgot about the putty.
I really don't know much about that type of putty, does it set up hard, or does it remain somewhat soft? And wouldn't the moisture seeping through the sheet soften it somewhat, enough to let it bend without cracking?

-Dean

[Devin]

Yeah, that stuff ain't flexing at all. It's wood putty and epoxy putty. Solid.

Cutting off the end and positioning it correctly then filling the gap will be easy with some Apoxie Sculpt, and the gap won't be that large at all.

[Roscoe]

Well, that sucks. OK, one more for you, how about taking an X-Acto hobby hacksaw, and making a few cuts across the width of the hull, spaced out along the bend area? But don't cut all the way through, that should give you enough relief to bend it back into shape, and you'll only have to fill what little is left of the slots.

-Dean

[Devin]

Long time no post. I've been volunteering at Stevens University here in Hoboken, helping them with their USS Monitor plan collection, and I've had some movement on some writing projects, so modeling time has been at a minimum. I did get some more sheeting done, though. With the sheet for the main deck, things get tricky. Holes for the turrets, the pilot house, and the stack have to be cut. Initially I drove myself nuts for a day or two trying to figure out the center of the circles, then realized that the camber of the deck makes the circles not entirely of the perfectly-round variety. An email to Dean, resulted in a template the the centers marked. I glued that to styrene, and away I went�

A full-sized PDF of the hole centers makes the job a lot easier.


Holes cut for turrets. Even though they're not perfect circles, this is close enough, and I hit the elongated sides a bit with sandpaper to make them match the drawing perfectly.


I'm using the Circle Scribe cutter. I have no idea if this thing is even being marketed anymore, as their website is no longer active. A shame, as this is the only tool I've ever found that does a good job at cutting holes larger than punch-size in styrene.


Top sheeting glued on. The forward edges and the stern will be added from separate sheets, as that's the only way to handle the compound curves in those areas, short of vacuum forming the skin. Here the sheet needs to still be trimmed to the hull sides, which I've already done, but haven't photographed yet.



It's time now to sheet the rest of the deck, filling in those gaps at the bow and stern, fill any seams with Apoxie Sculpt and sand. I can then prime and start thinking about scribing armor plates!

[MartinJQuinn]

Cool stuff.

[Roscoe]

Looking good Devin, I'm glad those templates helped out.

Are you going to add a layer inside the turret cutouts to raise the turrets back into place?

Keep up the fine work!

-Dean

[Devin]

Dean, I am going to use the disks that I cut out to fit into those recesses to keep the turrets at the correct level. One of those "ah ha!" moments I had the other day. I'll punch disks for the stack and pilot house to do the same.

[Devin]

With power out for nearly a week and subsequent clean-up from Sandy, I haven�t done much modeling lately. Yesterday evening, though I scheduled time to work on the remaining sheeting for Chickasaw, and today I trimmed and sanded the result. A little filling and sanding is left, but then I believe I can prime the two hull halves, do a final check for blemishes, and then assemble the two and begin scribing.

The curved section of the forward hull required it be sheeted separate from the rest of the main deck. Here .015" styrene has been fit to the inner curve, glued to the hull with overlap to allow for any slop in fit.


The great thing about working with thin styrene like this is how easily it cuts. I use fabric scissors to cut the excess to within a few millimeters of the hull, and then take it the rest of the way with a sanding block. You can see slight gaps between some of the plates; these will be filled with Aves and sanded smooth.


The stern section has curves in 3 axis, so I had to go with even smaller pieces here to get them all to conform. Vacuum forming or heat stretch "smash molding" would work better here, but I don't want to spend a week figuring out how to best go about that.

[Roscoe]

That's looking really sweet!
You did a really nice job on the sheeting, I'll bet you had a few choice words while doing that aft section.

-Dean

[Devin]

The aft section actually wasn't that bad... the second time. I tried to do it in one continuous strip and it just wasn't going, so I ripped it off and cut the smaller pieces. They actually fit down quite well; I had to massage them down continuously as the super glue set -- and glued myself to the model a few times - but there's very little distortion and gaping.

I think what I'm going to do with the wells for the turrets is just coat that area with super glue to seal up any cracks and leave it at that. Even putting in the thinnest styrene sheeting puts the turrets too proud of the deck.

[Rdutnell]

Fascinating Work!

I just found this WIP, and as an engineer and Chickasaw I really enjoyed reading through your build and how you have resolved various issues as they have arisen.

I look forward to seeing more andfollowing her through to construction.

[Devin]

Not a lot to post lately as I'm at the stage where not a lot changes. Fill, sand, prime, repeat. I'm getting close to being ready to paint, I think, but every time I get it all smoothed out and ready to go, I find another seam or gap or bit, and have to go at it again.

I've realized that going with the .010" sheeting was a mistake. Way too thin. In several places I've nearly sanded through the styrene to the underlying filler or wood. It's going to make scribing a problem. I'm thinking of doing another sheeting coat of styrene, maybe as individual armor plates on the deck, so fix the issue. It'll throw off the scale thicknesses, but if it looks better in the end, it'll be worth it.

I'm also still trying to decide on whether or not to cast up any hulls from this. Right now it doesn't look like it's going to happen. I've never cast something like this before, and I'm not sure a hull this size is something to start practicing on, and with storm recovery costs still adding up here, I can't justify the expense of such experimentation at this time.

[Roscoe]

Looking good Devin.

Sorry to here about the storm damage, who would have thought you would get hit like that in New Jersey, that's just crazy.

Well, if your going to re-sheet the Chickasaw, doing it as individual plates sounds like a good idea, time consuming, but I think it would look great that way.
Have you thought of maybe trying Plaster of Paris to make a mold? I'm not sure how well it would work, and it will probably need some filler to fix any remaining air bubbles, but it's cheap.

Later,
Dean

[Devin]

A brief update. Still fillin' and sandin'. I keep waffling back and forth between either finishing it smooth as-is and scribing the plating detail, or sheeting it another time with smaller armor plates. I've been able to get the stern of the upper hull built up and shaped pretty well (the real problem area), so I think I'll finish up the filling and sanding, then give the scribing a go. If that doesn't work, then I can always go ahead with the plating plan.

Photo shows upper and lower hulls in spray booth. Been having some seam separation issues in certain areas, but they're easily rectified. I think they're from handling of the parts while sanding, causing weak seams to spring, and not an issue with the styrene to wood bonds. I've set nuts in the lower hull for mounting points: once I get upper and lower hulls together they'll allow me to mount it to a sacrificial block for painting, and then I'll switch to shorter screws for attachment to the final base.

[Neptune]

Looking good Devin!
Casting something like this is going to be expensive indeed. Plating would be nice, although you could perhaps do it with Litho or something like that. It's thinner than styrene and has an extremely smooth finish.

Anyway, I'm still waiting for progress on your Carondelet !