Using SketchUp to Create a 1:72 Scale Model of an Iowa Class 16" Battleship Turret

I’m glad it is interesting to you. If a marvelous and kind of magical process, but not without its frustrations. I’ve been active with it for almost three years and pretty far up the learning curve, but still get into jams. The software driving the machines continues to evolve to making it a bit easier.

I now have the open yokes complete… not perfect… yet, but complete enough to use. The T-handle and operating lever, while they printed didn’t hold up in the cleaning. I’m going to replace both of them with metal substitutes. It’s this kind of stuff that makes me think a commercial version of all this is probably a non-starter.

The yokes printed with a drawing error… at least I thinks it’s one since it occurred exactly the same on all three. It was an easy fix with Bondic and some careful sanding. As I’ve said before, since Bondic is chemically the same as the resin being printed and therefore makes strong and completely integral patches.

After sanding, you can see the Bondic patch, but after painting it will disappear. I believe the color of the yoke looks like Haze Gray.

Here’s a look into the breach. I really like that all the little details that are attached to the yoke face resolved beautiffully, including the very fragile Salvo Lock and the gas ejector control valve. You can see the yoke on the left still has its operating lever, but no T-handle. The one on the right has half a lever and no T-handle.

I got nice prints of all three powder doors; one open and two closed. I originally drew these about 30% too large and it was causing problems in ‘decorating’ the rest of the gun compartment rear.

Here’s all that detail. I’m going to print the whole deal in one part minus the cradle/spanning tray. It will help in controlling support placement and removal. There’s more smaller diameter wiring/piping than this, but in 1/72 it won’t be seen nor paintable.

For the above, I really am going to wait until my field trip to finalize it. I’m not sure about the side entrances in the outer two gun rooms. There also appears to be steps from that door to the operating floor and I’m not certain about their height or placement.

The modified gun girder is finished, washed and waiting for final sanding and cleanup. This new printer is just doing great.


I’ve got a problem and it’s one that’s occurred before. While doing mods to the gun girder part (5th iteration… ugh!), the middle section closed up on the bottom and I can’t get it to open. I’ve done the usual trick of tracing over all the lines, but it would respond as a flat surface and wouldn’t let me delete just the false floor in the open sections. This has happened before and it drives me nuts.

The opposite seems to happens when you can’t close a space and keep making smaller and smaller triangles until it finally clicks shut and then you can go back and start erasing all the triangles since it was a flat surface in the first place. Can someone help me here?
Gun Girder Challenge.skp (595.1 KB)

It’s hard to know exactly what’s needed or not with a part like this but here’s shot in the dark.
Cleaned up a bit and purged.
Hope it helps.
Gun Girder Challenge 1.skp (556.6 KB)

Can’t open. I’ve got SU Make 2017. Is it possible to save in older version? I’ve made the decision to finally go Pro now that I can’t open anything on the warehouse either.

I back saved it just now. I’m sorry about that. It’s a mistake I’ve made before too. :blush:

You could open it in SketchUp Free and download as a 2017 file…
Same for Warehouse models…

All good. While I was waiting for your new version, I killed that model and copied the un-modified one from my master plan. I then found what I thought was the culprit. One of the notches for the powder chases was not perpendicular to the bottom surface. When I pulled this wall face to change the dimension, it created the filled bottom situation and because it was coming down as an angle, it was no longer a co-planar surface and therefore couldn’t properly close. When I rebuilt that one wall surface to make it truly perpendicular, the bottom surface was cured. Thanks for all your help. I will take a look at what you did to see what I can learn.

It’s been a week, but I’ve been busy; mainly reprinting things that weren’t right or fixing things that broke. I’m printing the fifth iteration of the gun girder. It seemed I could never get the spacing correct. I also realized that it could be wider to better fill the plastic parts. This time I think I’ve got it.

I had to reprint the back bulkhead because each change in gun spacing changed the spacing of some of the doors in that bulkhead. The bulkhead print looked great until I started removing all the supports. The Slicer auto-positioned it almost completely vertical which reduced the supports just to the edges of the raised details. I use heavy supports and then go back and delete those that are on small details, not needing the beefy supports. Except I missed one set. These were attached to the individual lights on the gun-ready panel. The supports clustered together on such tiny details formed a solid resin mass whose removal also removed all the details.

Rather than reprinting another nine-hour job, I decided to try and fix it. I had all the scrap bulkheads so I cut out the good part on a scrap one and grafted it to the area needing replacement on the good one. I really didn’t matter the shape of the insert piece as long as I made the opening in the good bulkhead to fit it.

Again, with the help of Bondic I fused the new piece into the bulkhead. Even though you’re not supposed to use Bondic on blind joints where the UV light won’t get to it, it works great on UV resin parts since they almost transparent to 405nm UV light.

Here’s the piece fit in place with Bondic.

And here’s the bonded graft before finishing. I also had to replace the port hole cover since it too had heavy support damage.

On this iteration I chose to not print the open portholes (to accept glazing). I was going to drill them out. I used a couple of small drills to start the holes and then used drills of the correct size. I was having trouble using the #20 drill for the large portholes so, like an idiot that I sometimes am, I chuck the drill into my DeWalt monster drill. When the drill grabbed the resin as it was exiting the hole, It fractured the wall completely through. Another repair!

Again, with Bondic, the joint was made with almost the same strength as the base material.

And here it is after final finishing with the portholes open. After painting it will look just fine.

I also had a mess fixing one of the guns. I was working to get the yoke to fit tightly against the rear of the slide portion, when, after applying too much force in removing the un-cemented part, I fractured off both counter-recoil cylinders AND the gun captain’s foot pad. I first tried to drill and pin the broken cylinders and glue them back on, but it wasn’t working well. Again, since I’ve been keeping all the reject prints, I had an ample supply of intact cylinders which I could surgically remove and graft to this particular good gun. I was “good” becasue it was not warped.

I cut off the sacrificial cylinders just aft of the support clamp, and using a diamond burr, removed any material on the good gun so it was an even surface at the bracket. I then spent a lot of time preparing the yoke so it fit nice and tight and square and glued it in place. I then glued the graft cylinders on top. I was also able to glue the foot pad back using Bondic alone. I had to trim the back of the foot bracket since it was pressing on the breach spring assembly. That contact point was probably stressing the foot bracket and may have contributed to its breakage. Whew! Dodged another bullet.

The only problem with the above is the air feed pipe on the yoke is on the wrong side for this particular hand of gun. I will add some actual wire piping to correct this.

The new gun girder is in the ultrasonic getting cleaned up. I’m anxious to see if I’ve finally corrected the errors.

Right now I’m attempting to print two of the complete loading sections of the turret compartment. It took a ridiculous amount of fussing to get them reasonably close to what it should look like. Lots of piping details to print and support. Each compartment’s is different in both orientation and where the piping runs go.

That’s all for today… Happy Spring!


Had a rare Saturday session and got some good progress. Finally got a good gun girder part with the gun-to-gun spacing correct for the Takon turret housing. Parallax makes the left spacing a bit off. Take my word for it, all three are centered over their openings.

An additional test with the girder part and guns in place show good centering and I think my gun sleeve length is just about perfect. Later in the day I did a test with one of the bloomers and the gun installed and that worked okay as well.

You can see in this image why I had to reduce the gun’s tail diameter so I could shrink the O.D. of the gun sleeve to fit betweens the Kit’s opening. There’s parts of the bloomer assembly that had to glue to that inner step. If the diameter wasn’t reduced, the wall thickness of the remaining gun sleeve would have been too thin to function.

To give gun sleeves access to the gun tail I have to open up the backs of all three bloomers. I did one using the tried and true “Drill-a-lot-of-holes-and-cut-the-stock-that-remains” method as shown here.

I finished all three guns and they’re ready to paint (today??). I made the real wire hand grabs for the counter-recoil cover, retrofitted the wire air piping that was now on the other side of one of the guns, and grafted a good breach lever onto one of the open breaches that was missing.

First the piping. After I took the picture I added some wire formed clamps. I’m not going to model the globe valves and swivel joints that are that those bottom curves. They will not be visible in the final model. I did model them in the printed version, but even then, some of it broke off in the cleaning process.

To replace the broken breach lever I did some minor surgery with the dremel and a diamond coated cutoff wheel and removed the lever stump and the rest of the mechanism behind it. It was scary because I had already glued the yoke onto the gun slide and if I screwed it up, wouldn’t be able to get it off. I would have to reprint the slide and the yoke again. I did the same surgery in reverse on one of my reject yokes that still had an intact handle. Once remove I trued up the mounting surfaces with some careful filing with a riffle file and diamond coated flat jeweler’s file and adhered the job with Bondic.

For the hand grabs I measured the spacing with a dividers and marked the drill spots. I bent the 0.022" Phos-bronze wire using a small needle nose at the point of its tapered jaws that matched the hole spacing. It took a couple of tries to find the exact spot on the jaws, but once found enabled me to replicate all the handles.

Here’s the undersides of all three completed guns. You’ll notice a pocket to the side of the recoil piston rod. That’s going to be the upper junction of the elevating screw. I may hae to adjust the hand-made piping if it gets in the way of the trunnion mount.

I printed all three load area composite parts. Two of three were perfect. The center gun’s had a drawing error. The pipe array on one of the side walls wasn’t actually attached. It was about 1/16" away. I went back to the drawing and fixed it. The mistake arose when I was readjusting the wall placement vis a vis the new girder spacing dimensions. I had moved the piping group off the wall, but neglected to put it back in the new position. The printer never lies. It prints what I draw, good, bad or very ugly.

The detail on this print is astounding. The new printed is dynamite! Painting all this will be fun. Many of those pipes are actuall standing free of the wall. You can’t do that with injected molded parts. These parts would all be relief moldings stuck to the walls or they would have to be glued on separately. Either way, printing is superior. Notice: the powder bags are already in place, ready to be rammed into the combustion chamber.

Fun Fact: The operating pressure inside the combustion chamber reaches 40,000 psi at peak pressure. That means the projectile is being accelerated with 8 million pounds of total pressure on its rear end. Awesome!

More work will be done today on fitting the girder, bloomers, and cleaning up those load area prints.

I’ve put together a detailed list of questions/details i need for successul project completion for my USS New Jersey field trip. It’s a once-in-a-lifetime visit and I have to make the most of it.


All three plastic bloomers are now modified and I tried all of them in place with the barrels and the rest of the gun behind them. They work!

All three load area prints are done, cured, trimmed and final finished. I then spent a lot of time doing a final fitting of each into their respective slots in the gun girder. I knew during the design process that they would need “field” tweaking. In the two with the spanning tray in the load position I positioned the gun in the trunnion and slide the tray into the breach in the position it would be when loading. I used that position to determine the depth that the part needed to be in the girder slot. It turns out that my design was right; the final position is with the part’s bottom level with the bottom of the gun girder’s bottom.

lHere are all three in place (not glued).

I explored different ways to fasten the girder part to the kit’s plastic floor and decided to screw it in place, not glue. Gluing resin to styrene is iffy. CA sometimes doesn’t bond well. I know from experience that Bondic has trouble holding to styrene, and that also goes for epoxy. It sometimes breaks loose from styrene. CA is much more secure on the resin.

I spent a lot of time ensuring that the girder was positioned properly before clamping it for the screw installation process. I used Quickie Clamps to hold it secure. There wasn’t much space to actually drill and screw it together. I used a #56 drill for the threads and a #49 for the clearance hole in the plastic. I then countersunk it just a tad so the brass flathead screws would be flush.


And here are two of the four fasteners after assembly. They hold very tightly.

The door frames for the powder hoist compartment impinged on the load area parts and had to be trimmed. I can’t move them any more since they start affecting all the other details on that bulkhead in the officer’s cabin. Trimming worked and again, folks won’t notice.

This view does show the relationship between the bulkhead and the load parts. I printed that false back wall instead of attempting to print all that piping on the bulkhead directly. While this isn’t prototypcially correct, but it was pragmatic. I had much more control of the printing process by making it a separate overlay.

I have to decide on the order of assembly and painting at this point. The load area parts have a lot of details that has to be picked out and it would be much easier if they WERE NOT all assembled. But, having them in their raw form makes it much easier to glue them all together. I will accept opions on this decision.

I did one more thing. I decided to NOT install a round filler piece to build up the recessed ring. It was unecessary since in real life it’s open all the way to the pan deck between all the partitiions (which I will be installing). Instead, I just put in some strategic pieces of thin MDF to give more base upon which the load area parts can rest and sit squarely.

These will be unseen and I made sure I didn’t block the hole for the projectile chase.

I’ve been 3D printing for three years this June and it still blows my mind when I look at a real part that is a direct 1:1 relica of the drawing that I made. This project could be build old school, but it would most likely lack the depth of detail that it’s going to have. As I’m getting some it ready for assembly and it’s looking as I wished it would, it’s giving me confidence that it will be built and be worthy.


Very cool!

With every post my respect for your modeling skills and determination to get things “right” grows by leaps and bounds. I’ve said it before truly epic !

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I just found out that our daughter and son in law both tested positive for COVID. We were in their company last night and my wife hugged our daughter today after exchanging Mother’s Day cards. They were masked, but… we’ve now been exposed to active cases and therefore have cancelled our trip back East that was supposed to begin tomorrow. And that means cancelling the New Jersey tour. Bummer. We’re had the 2nd booster two weeks ago and that makes us pretty safe, but nothing’s perfect and we were scheduled to see a lot of people in Philly.

To reinforce your comment about my determination “to get things right”, I wasn’t really happy with the rear bulkhead. That’s such an important part of the gun house that it was annoying that it was so cobbled together. Then I found that in my master drawing, the bulkhead was updated once more and had better door spacing. So I printed another one. I think that was number four (or was it five). This time I made sure that the supports didn’t screw up any details by putting all the supports in as LIGHT and then going back and adding HEAVY supports at the base or on large mass details. This worked great! As you see, after doing 3d printing for almost three years I’m still evolving better techniques.

I tried it on with some spring tweezers holding it firm to the load area components. I had to cut some relief in the corner of load area part on the right so it would seat against the door frame. My door frames are a bit exaggerated so it would seen at this scale.

I’m turning my attention to the gun house shell trying to determine assembly sequencing and how and where to do the cutaway/transparent parts to show the most detail without killing structural integrity. The ports for the training and pointing telescopes needed to be opened and the armored outer bulges needed to be opened as well. Opening the holes in the walls was not difficult, but opening the closed weather hatch on the bulge was not viable. I would have to make a scratch built door in the open position. So I careful measured the kit parts… there are two differently shaped bulges based on whether they were positioned fore or aft of the gun house side crease. And they were right and left handed.

There are no right angles on the mounting surface since the gun house walls slope in two directions. I used the digital calipers to carefully measure the lengths of all four corners, the overal side and the position and sizing of the opening and the wall thickness. I then drew both versions on SketchUp. I created the right and left hand versions in the slicer using the MIRROR function and printed two full sets. Took a little over an hour to print.

I cleaned up one unit before post-curing just to test it out. We’re heading out to Philly over next week and I will finish these up when I return. My homemade version will work perfectly well. Again I used heavy supports on the bottom and light supports on the open door.

I’m struggling with figuring out how to install the pointer-trainer stations in the gun house wings since their scopes have to peek out of the gun house into the bulges. I wish I could make the entire roof removable which would simplify a lot of this assembly work. Some of the roof will be either transparent acrylic or cutaway so those items in that area could be accessible.

I also decided to install screw blocks into the gun house corners and screw that part down like I did with the base. It will make the insides accessible in case something comes loose.


Major bummer! I hope that you are able to reschedule the trip sometime, ideally soon enough to make a difference in your amazing ongoing modeling work.

That’s the plan, but after finding that the electric deck was strictly off limits and not human compatible, I probably will go with how I’ve been doing it so far. Ryan and I agreed that we will reschedule during our next visit later in Spring/early Summer.

UGH! We’re going to do the first test tomorrow. My brother in law (the pediatrician) says we won’t catch it. I’m not sure I share his optimism. But we are double-boosted, so there’s that.

Well, for me, there’s a silver lining to staying home… more time in the shop. Can’t say that for my patient wife. We were both looking forward to seeing the family and that field trip.

After the realization that fitting the complex stuff inside the gun house with a solid roof would be very difficult, I woke up this morning with a decision to remove most of the roof and replace it with acrylic once all the interior is finished. The acrylic will be screwed onto the model so it can be removed. I didn’t want to remove the entire roof for fear of destroying structural integrity.

I marked the plastic with a Sharpie where the cut would go. Then I made a strathmore pattern of the cut to perfect it. I then traced this pattern back onto the roof for the finalized cut line.

I just bought a water color drawing pad that was 90 pound strathmore, which is perfect for crafting in out model world. I chasse to go the tablet way instead of a large sheet becasue it was easier to handle and had lots of pages. It was less than $20 USD.

I have a long-throat jeweler’s saw that I bought probably 30 years ago (or longer) to build wooden ship models. You need such a saw to cut out the frames (if you don’t have a scroll saw which I now have). I used it very, very rarely, but today it was PERFECT. It’s hard to handle and I broke two fine-toothed blades before switching to a bigger toothed blade. I will have to reproduce the locations for the gun house periscopes which I will print.

I made sure I cut well inside the lines so I could sand and file up to the line and get nice clean edges. I briefly entertained the thought to use the Dremel with a 1/16" carbide router, but that thing is prone to going wild and digging in. Besides, when cutting styrene the plastic melts and gums up the bit making it non-functional.

After doing the rough cut I couldn’t help but stuff some things inside and see how it all worked. It worked great! I found that the aiming stations do fit okay, but my captain’s cabin monster asssembly print needs to be shorter front-to-back and adjustment around the rammers. I also needed to trim the rear bulkhead to fit nicely. I will have to install a lip under the cut edges to support the acrylic. I’m in the process of refining the back assembly’s design so finding out all of now is a an eample of good timing.

Looking long-ways with the aiming stations in their respective positions. After I took these pictures I started cleaning up the cut edges, but didn’t finish before dinner.

I’m going to install some LED lighting under the remaining roof parts. I’m still going to make the partitions for the left gun out of acrylic to display the sides of the gun slide assmblies. Making all solid partitions would effectively hide all that cool stuff.

I have the aiming bulges in the post-cure box and am printing the powder chases down through the electric deck. I had to split the chases to fit the printer. I was going to cobble these together with styrene, but then quickly realized that this made no sense. Printing them from the drawings lets me fit them perfectly. I hollowed them out on the slicer to reduce the amount of resin they were consuming.


The acrylic window in the top of the gun house will be great! And some interior lighting would be fabulous.

I’m holding off on the acrylic for now depending on how the model will be protected in the final display on board ship.

work continues even though today is the day I would have been on the actual ship. I got a final officer’s cabin print that fits in all the right places, has two entry passages (although I’m still not sure of the positioning of the narrower on). I lost a couple of the seats and the large handwheel, but careful surgery and transplant from the reject ones that were still floating around the shop and I have now have a fully complete and successful print. I also added the sprinkler system cisterns. The system in the Iowas works by gravity and these tanks would flood whatever space that was afire.

Another view:

I finished up filing the cut edges of the gun house roof. Nothing really to show, just lots of craft work.

I got good prints of the upper two sections of the powder hoist trunks. I printed some keys that would attach the sections since I ended up making two female joints and forgot that one had to be male.

And here’s the separately applied assembly key.

I cleaned up and attached the four aiming station bulges to the gun house.

There’s a curved bridge girder that supports the cradle and shelf deck at the rear of the gun pits. I drew this and printed them, and put them on today. Again, I used Bondic as the adhesive. When possible, it’s the best possibel one to use since it literally welds the UV resin together with the same material. The fact that it stay completely fluid until the UV hits it (5 Seconds) is another benefit allowing adjustment. With CA, and the action of the UV resin acting as a catalyst the working time can sometimes be ZERO!

The ladder that comes up from the pan deck floor attaches to this part at its top.

The last item today was preparing the parts to screw the upper and lower gun houses together. It’s a bit more complicated than I envisioned due to the interference of the officer’s cabin floor and sprinkler tanks with the mounting blocks. As a result, the blocks aren’t all that big and I will have to be careful in drilling and screwing the parts together.

I had to shape the blocks to conform to the rise of turret house floor rear. I then had to carve them to conform to aspects of the cabin floor. These will be epoxied in on a roughed up surface.

When I’m not in the shop, I’m probably on the computer (much to my wife’s chagrin). At least I’m doing it on a laptop sitting in my Eames chair in the great room keeping her company. I’ve got the projectile flats detailed with projectiles and all of the equipment therein. There is a motor-hydraulic pump-hydraulic motor arrangement driving a pinion which drives a ring gear that rotates the independently rotating inner projectile storage deck. This is controlled by a crewman to bring ammunition around to be par-buckled into the projectile hoist. The inner ring is for active storage. The projectiles on the non-rotating outer ring are secondary storage. That ammo would be moved inward as needed. This is necessary to keep up the 30 second firing rate of these guns.

The projectiles are slid across the smooth metal decks with ropes wrapped around gypsy heads thar are also driven by a motor in the inner circle of the projectile flat.

This is my rendition of the part of the flat that is connected to the gun house rotation. This keeps all the hoist trunks in line with the guns that they feed.

Just for fun, here’s what the cutaway looks like now. The work remaining is: Electric Deck Machinery, Pan Deck Finalization and Powder Handling Deck. Of the three, the latter is the least complicated (I hope).

Little by little, day by day, this monster is coming together.


Beauty and the Beast! :slight_smile:

I guess you could say that.

I got the third gun reprinted and finalized. it wasn’t without its challenges. Again I had to cut the counter-recoil cylinders off one of my rejects, surgically remove the distorted ones and graft the replacement in. I also had to replace some segments of the airpipe that got whacked in the clean up process. It is now correct with the foot rest on the left side to receive powder bags coming from the right partition.

In this instant it was easier to remove part of the slide along with the two cylinders and glue it in (with Bondic) as a unit. There was some chipping that I had to fill along with the joinery.

Here are the pipe repairs.

I added the hand holds and the gun is now ready for priming and final paint with the other two.

I got all all the mounting blocks epoxied into their respective locations; the front two into the forward corners of the gun house uppper section and the rear glued to the base shelf.

The fit is so nice that the top holds to the bottom on its own.

I printed the entire middle projectile flat that rotates with the gun house.

It was a massive print for my small machine, but did reasonably well. That is, except for the gun hoist frames which actually were in contact with the base in the drawing and therefore printed rather poorly. I decided to salvage the base since it used some much resin, and would print the hoists separately. There were some remnants of the hoists which I sanded off.

This gave me an opportunity to spend more time detailing the hoist frames and I did thusly. I printed them separately and they game out perfectly. I printed six since there are two projectile flats that need detailing.

I’ve subsequently edited all the rest of the drawings for the inner projectile flat cylinder, the machinery therein (separate print) and the array of 16" projectiles printed in four groups. I will start printing these on Monday. The outer stationary ring is too big to print and I’m either going to make it out of styrene sheet of have it laser cut out of ply or MDF. I can do the cutting at University of Louisville’s First Build Makery, but need to reseerve the time. The outer projectile array will also be print in four groups.


Moving along…

Started the print for the interior cylinder of one of the two projectile decks. This is a complex five-hour print that will determine the process going forward. It will be done before 8 p.m. tonight. While that was printing I cleaned up the projectile hoist prints and installed them on the previously printed rotating middle projectile ring.

I’m not certain about the placement of the hoist control stand. In the one detailed image I have of one of these appliances, it was facing perpendicular to the ring’s circumference.

Now let me give you some details of how I did this part. There were no marking on the finished ring to show the precise location of each hoist. The entry point of each hoist must be facing forward towards the outer ring’s walls (I think… I could be completely wrong in this assumption. Like I said, I have no good reference information of the full arrangement of all the hoists and may not be able to visit this deck in June.

I made a paper pattern of the ring’s face and scaled it correctly. I then marked the center of each hoist chase to give the hoist frame locations.

I drilled some shallow depressions to locate each hoist and drilled the same kind of holes in the center of the hoist channel. I applied Bondic the bases of each hoist and fastened them down centering the two holes. Here’s the alignment looking straight down the hoist frame.

I had to make sure that the hoist didn’t extend too far inward since it would make fitting the internal cylinder very difficut. As it is, there is overlap on the outside and I will have figure out what to do with the outer ring’s fitting.

I also fit the screws that are holding the gun house together. I’m using some nice brass wood screws. After doing all the drilling and fitting the four screws, I took it apart and applied some thin CA to each now-threaded hole to harden the threads so the screws can be taken out and applied multiple times without stripping the threads.


After the projectile flat center cylinder print I will print the machinery that lies within plust the ring of projectiles themselves, and that will equal one deck. There is another of the same design, although I am led to believe that some aspect of it might be of a smaller diameter since the barbette stack narrows at the bottom corresponding the the reduced ship’s width as it nears the keel.