I've decided to make a 1/144 scale model of the John C. Butler class destroyer escort. My grandfather served on the USS Lewis (DE-535) in the pacific in WWII, so I'm hoping to be able to make a semi-scale model for him as a gift, as well as potentially building one to IRCWCC rules as the USS Samuel B. Roberts (if you don't know the story, you should read about it). I bought plans from Floating Drydock a few months ago in anticipation of this project. The boat will be 25.5" long, 3 1/16" beam, and 2.44 lbs as the max weight (1.31 lbs scale), 1 unit. To increase draft for the additional weight, I measured the area of the boat at the water line using the section lines. I then calculated the volume of water for 1.13 lbs, and used the two numbers to find the draft change from the addition of the weight. This came out to 9/16," so I added another 1/16" to account for buffer to come to a total of 5/8." To add the depth without messing up the lines I tried a few ideas, but ended up going with stretching out the portion of the sections from the waterline to just under the deck to keep the shear and bottom shapes (used powerpoint to crop and adjust a scan). Here is a comparison of the before and after. And close up of the stretched version. I will smooth the kink in the bow sections when I transfer the lines onto plywood. For the keel, I cut a copy of the plans at the scale waterline and shifted the upper portion 5/8." This changed the bow and stern angles slightly, but hopefully it wont look too funny. The plan is to make a plug, then mold for fiberglass hulls. Here is the keel drawn out. I made a board to hold the 'deck' of the plug in the shape of the shear. Still need to bend the deck piece on (rectangle in pack of picture) I cut out each hull section in paper thus far. I probably don't need that many frames but I'll give it a shot. And the keel piece with lines for frame spacing. I'm hoping to get the frame put together and full of foam this weekend, though historically I don't often meet my building goals. I will definitely have a lot of questions for this build. I'll focus on the non-combat model to see how weight looks and go from there.
Made some progress over the past couple weeks (secondary/tertiary project) I drew up the stations onto spare 1/8" plywood I had, and also attached the 'deck' piece of the plug to the base. Next step was drawing the overhead view of the deck. I then glued the keel to the board, keeping it relatively straight Then glued the ribs down one by one, with 1/4" x 1/4" balsa strips to aid the glue joints And showing the balsa pieces. I build my boats on top of other boats. Used the 'great stuff' large gap filler foam from generic home improvement store. If was my first time using it, so one side I think will be better than the other. I expect some small pores but overall it should get the job done. Here is the 'blob' while wet And dry the next day. Slightly larger I cut away some this afternoon, I'm planning to get it down to a paint-able shape tomorrow afternoon. Once sanding is complete I will spackle, sand, paint, and repeat a few times until I reach the 'good enough' point.
Cut the foam down. Didn't do a great job with my initial cuts yesterday, but that's what filler is for. Initial pass. Now sanded down to the ribs. Put a layer of paint down. This side was slightly worse on the foam, mainly operator error. Now spackle. Looking better. Stern And side. Went through about half of the little container, but things should be looking a lot nicer after this first layer dries. The goal is to start and maybe finish the mold this weekend. Will do a two piece mold with a flange along the keel.
Got a second layer of spackle down and another coat of paint. Looking more respectable now Stern will need some more work to get the shape right. Added layer of paint to help identify the low areas. I will have more time to get the stem and stern squared away tomorrow. I'm liking the way it is shaping up so far.
More work done on the plug over the weekend. After getting the shape down, I think the underlying foam might have swollen up slightly as one morning the plug looked like the Michelin man. I decided to shift to joint compound to get a uniform surface to paint over. I used two coats, and I was pretty happy with the results. Applied with a new razor blade and sanded with 220 paper. Once it was sanded down, I painted it with two coats of spray primer, and three coats of clear acrylic spray. Hopefully the shape stays until I can get it molded (Thursday/Friday). I'm going to put down a couple coats of wax, then make a balsa wall along the centerline to serve as a foundation of the flange for the first half. I'll seal the balsa with polyurethane, attach it to the hull with RTV, wax more, and spray on a few coats of mold release. The plan to make the mold and subsequent hulls will be using marine polyester resin with fiberglass mat (and maybe cloth for some parts of the hulls).
Polyurithane and Polyester resin don't play nice with one another, don't use Polyurithane EVER (well except on furniture).
The polyurithane will prevent the polyester from curing. It will result in one big uncured gooie mess.
Thanks carlo-san. Unfortunately the plug became slightly 'ribby' over the past couple of days, though ill just consider it the more authentic tin can destroyer escort look.
I know what you mean on less than stellar with the foam. Next time cut a 2X4 (cheap) and block in between ribs. Keep the block edge about 1/4 from the outside of the ribs, then use bondo in a few layers to fill it out. Heavy, but strong and it is all wood so it will swell and contract without massive expansion issues. Another option is fill with pink insulation foam, it is already stable and will not expand on you.
Thanks for the suggestions, I've used pink foam for making a plug in the past, and probably should have used it again here. Oh well. Does anyone have recommendations for internals? Here are my needs/thoughts. Stats: Max weight 2.44 lbs, 1.0 unit, ideally 25rd single shot. Things I have an idea about 1) rudder servo - waterproof micro servo 2) pump - BC micro Things I don't have much of an idea about 1) Drive motors (2x) 2) Battery (assume small LiFePO4?) 3) Regulator/cartridges 4) Solenoid/poppet+micro servo 5) Cannon 6) ESC
http://www.batteryspace.com/lifepo4...mah-19-8a-rate-10wh---un38-3-passed-ndgr.aspx 3.3 amps at 3.2 oz. So 6.4 oz for 2 of them.
Thanks Dave. I have a slight bit of experience with 26650 cells. Back in college I worked on an electric vehicle project, and we had about 10,000 26650 cells donated to us by one of the major manufacturers (just finishing development stage). We did a fair amount of testing, and I made a few battery packs out of 26650 cells for an electric motorcycle project. The cycle performance stats on the website are interesting, we cycled them at 6C charge/discharge for about 1000 cycles and saw a 10% drop in capacity, which was still surprisingly low given comparisons to other battery chemistries. Looks like I should have kept a few extra cells for safe keeping back then...
I put them in my destroyer Im working on, but sailed it in my pool, and forgot to rinse it out. A month later I was going to work on it some more and found the shaft are locked in the stuffing tubes, I got a saltwater pool I forgot.
I try to avoid salt water as much as possible, that's too bad about the shafts. I got a fair amount of work done this weekend. Based on the way the plug looked after sitting idle for a week, I decided that I would try to get rid of the valleys between the ribs. Here you can see the Michelin man look. Sanded it down Added one layer of joint compound And made up the dividing partition Sanded it smooth(ish) next morning, spray painted and clear coated Attached the balsa flange with silicone, which worked out pretty well. Here is the fiberglass layout Used a couple layers of wax and 3 layers of the film on the plug Here is first full layer of fiberglass And after the final layer. Used 4 coats based on the first 3 kicking early. Now with the dividing plate removed, prepping other side The flange came out pretty good repeat above steps on second half More efficient layering this time Three coats of polyester resin down. I used some generic west marine brand, overall happy with the results. I forgot about how the smell tends to linger, I think all of my possessions may now smell like polyester resin. Two halves dry Drilled a number of holes before pulling the mold off. The plug almost survived, but she lost a large chunk in the midships area Two halves screwed together to cut away the extra material on the edges I will hopefully get hull 1 done by the end of the week. I am pleased with how the mold came out.
After you removed the dividing plate, what did you put between the 1/2's so they did not stick together?
I just waxed it and put on two coats of the green film mold release. I have the second coat of the mold release drying now in prep for the first hull, potentially will lay it up tomorrow
Nice, was thinking about making a mold instead of building a wood hull for the next boat I want to make.
