If you need balsa block let me know. I have a lot.. 36"x3"x1-3". Once I get the band saw, and drum sander set up I will be cutting sheets as well.
Thanks for the offer. I might need some for the Java plug - the local hobby shops no longer sell 1" balsa.
After applying spackle to the balsa and sanding it I've spent 2 days applying multiple patches of thinned spackle to fill low spots. The first coat of Zinsser primer/sealer went on this morning. As usual, having the hull a uniform colour showed more defects to fill. The transition between the bulges and hull sides between the frames is always a challenge to shape evenly. I hope this will be the last application of spackle before the final 2 coats of Zinsser. With bulged hull plugs it's nearly impossible to get a perfect finish. Once the plug is as good as I can get it in a week I usually stop tweeking it. When I make molds the gelcoat is very thick so I can sand remaining minor defects out of the bulges - any low areas left on the plug will be high areas on the mold. (When I say high or low I'm talking about 1 mm or less.) I found an symmetrical area at the stern, where I'd made a more rounded profile in the balsa on the port side. I took a wood file to it and flattened the curve to match the starboard side, then added spackle. The aft end of the skeg should be 1/8" thick from top to bottom but I had to make it wider where it meets the hull. Otherwise it's too difficult to gelcoat and glass such a narrow space. The skeg will be solid so modellers can shape it to the correct profile.
The stern profile is fixed and the bulge to hull side transitions are better. Unfortunately another day of filling and sanding low areas in the bulges has improved but not eliminated them. When sanding the spackle filler I'm creating some new 'dips' next to the ones I filled, even with fine sandpaper. This problem always happens with long bulges; I recall what a pain it was to do the bulges on HMS Furious, which had almost identical lines though the hull was larger. I'm reaching the point of diminishing (or no) returns for the additional work.
I wasn't happy with the bulges so have been 'spackling' and sanding for 3 more days. This time I ran painters' masking tape along the hull sides at the top of the bulges, got a paint scraper wide enough to fully span the distance between the hull frames and added several skim coats of spackle, working from the lower edge of the tape down. After a few hours of careful sanding I've got much smoother surfaces and the port side of the plug is done. There were two low areas between frames at the transition of the starboard bulge from hull side to bottom. Those have been built up with multiple thin coats of spackle and will be sanded this evening, finishing the starboard side and bottom of the plug. There's a very slight 'knuckle' effect at the frame where the bulge ends and the hull becomes smooth toward the stern. I have photos of other bulged RN ships in drydock and they have that slight bump at the transition from bulge to smooth side. More coats of Zinsser will go on this weekend.
More touch up work with spackle for several hours today, using a hair drier to dry the spackle quickly. I should have thought of that a week ago! Shaping of the hull plug is almost finished; I'm still on schedule to complete the mold by the first week of September.
Hawkins Class heavy cruiser hull plug waiting for the 4th coat of Zinsser to harden. The small ripples in the Zinsser will disappear wiith sanding. Very much a late WWI hull design. Not perfect but as good as I can get it. That bump at the aft end of bulge bothers me but there's a frame there and I can't eliminate it. It won't be as noticeable when the windows are cut out of the hulls and they're sheeted with balsa. Lots of curves in this hull, which made it hard to shape. The Furious and Courageous plugs, which had very similar lines, were just as difficult to build. I had to compromise on the bulge shape. It should be more concave where the top of the bulge meets the hull side amidships. I was unable to shape this well enough to keep it even along the length of the bulge, so after many failed attempts flattened the concave area. It becomes correctly concave fore and aft. On the port side the top edge of the bulge is slightly curved and 1.5mm/1/16" too high in the middle instead of running nearly straight along the hull as in this photo of the starboard side. Enough to be noticeable. I don't know if I dare try to fix it on the plug but could sand the hull side/bulge junction of the mold slightly to make the junction line straighter. Late evening update: the Zinsser was dry and thick enough that with a square cross section Swiss file, a wedge-shaped fine sanding block, and very careful filing and sanding I was able to straighten the top edge of the port bulge without breaking through to the spackle.
The Zinsser was sanded today. There are still a few small low areas on the plug but they're minor and can be sanded out of the mold. I'm afraid I'll break through the Zinsser and have to paint the plug again if I keep sanding. I'll start putting the molding flanges on tomorrow.
Good news from Canada Post. Their maximum package dimensions have changed enough that I can ship any cruiser hulls and any battleship hulls I might make that were less than 800' loa. Canada Post is cheaper than Fed Ex. I had to work today but have the day off tomorrow and hope to finish putting the molding flanges on the Hawkins plug. The stern skeg will be a challenge.
Probably gonna be spring before I have my first mold finished. Good job on this one it looks great so far.
Is there a 1/96 combat group? I remember there was a 1/72 scale group using mostly destroyers and a few huge cruisers. 1/96 scale models would be a lot more manageable. No further progress on the molding flanges for Hawkins. The stern skeg's shape has been a real problem to match closely enough so I've taken a break for a couple of days. I bought enough material this afternoon to make the mold and 3-4 hulls. My goal is to finish the flanges by Sunday, wax the plug and start the mold Monday (Labour Day). It will take 4 days to complete the mold and a couple to fine tune the surface by sanding out minor imperfections.
Battlestations is the format name. Currently a small group but hopefully growing. Dayton Ohio area mostly.
Got the flanges done a day early; 4 coats of mold release wax have been applied and the gelcoat goes on the first half of the mold tomorrow. The Hawkins mold will be finished by Friday evening. Back side of the centerline flange made of 1/4" balsa, attached to the plug surface by a bead of silicone. When the first half of the mold has cured the flange will be removed and the silicone pealed off the plug. It took a couple of hours to shape the balsa to fit exactly into the contours of the stern and stern skeg. Waxed and ready for gelcoat in the morning. The only material I had that would follow the deck's curve was 1/16" balsa; 2 layers were applied. The old masonite waxed up well. I was throwing out a bunch of it at the cottage and found a piece just long enough for the job. It's screwed to the deck of the plug along the centerline where I'd made multiple hard points under the deck to take screws. The balsa section was ca glued on.
The first half of the mold has been gelcoated - I applied 2 layers to make sure I wouldn't break through when sanding the mold to smooth out a few imperfecetions. The fiberglass goes on this morning. I'll have to keep an eye on the weather because the forecast has changed to possible showers late in the afternoon. By then the glass shoud have hardened and the mold can be covered while it cures outside - rain predicted overnight. More wet weather is predicted for tomorrow and Thursday, which will delay mold completion until the weekend. It takes 1-2 days to get the mold surface fine sanded so it will be 9-10 days before the first hull is made, weather permitting.
The first half of the mold has been fiberglassed. It has 2 layers of 1.5 oz chopped mat over the entire surface. A third layer of 2" wide strips was added along the keel and deck flanges, overlapping onto the hull, and along the bulge, extending to bow and stern. After it was curing in the sun for an hour I noticed the area near the aft end of the keel flange had some small soft patches where the gelcoat and glass had lifted off the flange 1-1.5 mm. The outer surface was already dry; the area affected was small enough that I used a pair of c-clamps and pieces of basswood to clamp the soft spots back against the flange. A few drops of dissolved gelcoat oozed out and I applied a bit of catalyst to it. It was solid in 20 minutes. I couldn't see or feel any other soft spots. I think this is something called 'allegation' that can leave odd squiggly marks on the surface of the gelcoat. Easy to fix by filling with gelcoat and sanding. Hopefully there aren't any defects on the hull section of the mold. After the fiberglass has cured for 24 hrs the balsa keel flange will be removed and the other half of the plug and the fiberglass keel flange will be waxed. Gelcoat goes on the second half of the mold Wednesday, then there's a delay Thursday due to rain and the fiberglass goes on Friday evening. If all goes well the mold will come off the plug Saturday, be fine tuned and waxed Saturday-Sunday and ready for use Monday evening.
