S.M. U-1 (a new RC project)

[DrSchmidt]

Got the molds for the lower hull going and Friday I laminated the second piece. Took it out today and turned ot quite good...one more to go.

[DrSchmidt]

Working on the fleet....

[DrSchmidt]

I've made molds and a few sheets of PE....so probably more than one. But I'm not a good producer for others. The little time I have for my hobby is mostly reserved for myself. Producing a kit is probably 20 hours of work.

[redboat219]

Will this be a one-off or will you be making more?

[DrSchmidt]

I have laminated the first deck section of the U1. Went quite well, despite the tight radius here and there. I used 3 layers of 80g/m^2 glass, the middle layer diagonally to give the deck some more resistance against twisting. Looks good and the conning tower fits perfectly. Going through the effort of making the three piece mold for the conning tower was quite worth it.

[DrSchmidt]

While I prepped the mold for the second conning tower, I printed the housings for the air intake masks. Turned out quite good.....optimized for little water displacement.

Then I made the second conning tower. Got me new surface resin and a better color for the resin. So this went better than for the first one. After brushing in the surface resin, I poweder the resin with cotton flakes to provide a good coupling surface for the GRP. And the second tower is quite good. The first one was O.K., the second one is good. Less bulky, a bit lighter, no voids. So the next ones will be made to match this one.

[DrSchmidt]

Working on the acrylic covers to get a nice edge to the hull parts. So far so good....

Meanwhile: I pulled the second part out of the coning tower mold. Worked well. Still a bit on the heavy and thick side of things, but besides that, quite O.K.. I'll make a few more. One will go onto the RC version, one on disply model, and one for someone else....

[DrSchmidt]

Actually I hought a while abut the control planes. The original ones were very thin, and to properly reporduce those in that scale....3D-printing is the ideal approach.

https://www.der-lustige-modellbauer.com/t5991-u-boot-u1-im-deutschen-museum-munchen

[He Who Shall Not Be Named]

That always evident German slavish pursuit of perfection to the most basic of items.

[DrSchmidt]

laminated the second conning tower today. First try wasn't perfect with voids here and there. So it's a second one, this time with thinner, more flexible glass and some more thickened resin in the corners. Worked well, we'll see the result in 36 hours...meanwhile: I printed control planes, hatches, and some accessories....

[DrSchmidt]

I finished the molds for the conning tower and opened them. Went reasonably well, but again, I had little section of surface primer stuck in the mold, that had to be removed with brute force, resulting with partially rough surfaces. Not really happy about it, but I guess the mold will be able to produce good parts. We'll see. On the bright side: The PE sheets have arrived.

[DrSchmidt]

While making molds, I have to take care of the additional parts that will be needed. On example are the sub deck structures that house the air intake masts. In my first U1 these were 3D-printed and I'm going for 3D-printed parts again, but with a big difference. The first ones were thick-walled monsters that displaced allot of water and that's above surface. So they contributed to the problem of having large enough ballast tanks. The new ones will be cage like structures with much less volume and only rigid walls, where they are needed, e.g. where the bearings for the mast axis will be set in.

[DrSchmidt]

On Sunday I laminated the first halve of the conning tower mold and filled the box with a mixture of resin and quartz sand. Literally it makes for a rock solid mold. Today I removed the box and the parting plane. Worked out quite smoothly. Then I set up the box for the second halve of the mold. Quick job with such a small mold.

[DrSchmidt]

Finished the box and set the alignment bolts (10 mm steel rods). Then I applied the surface resin and covered everything with cotton flakes as a coupling layer.

[DrSchmidt]

This time applying the epoxy filler and the consequent sanding worked well. So I'm currently setting up the parting plane for the first halve of the mold. Good thing: I have the conning tower design in the CAD. So it was easy to print the silhouette, glue it onto the parting plane, and cut it out using a padsaw. The two grooves for the periscopes were ct using a bench saw. Then I set up the plane, leveling it with stacks of printing paper, and finally gluing it into place using hot glue. Finally I closed the gap between plane and master using candle wax. Alignment pins and box walls next and we are good to go....