I finally decided to start a build thread for my French light cruiser Emile Bertin. At present time, she is almost ready to sheet, so I will begin at the beginning - It will take me quite sometime to get this thread caught up to the current progress. The design of this ship is documented HERE. It is around 5 or 6 pages in before Emile Bertin was decided on as the ship to design. There were PDFs and DXFs available on this site for download, however, since the site migrated I'm not sure if they are still available. I will hunt around and see, and If they aren't, I can try to upload them. If they are, I'll edit this post with links.
Using the DXFs that were downloaded, and a borrowed industrial laser cutter, several complete kits were cut out. Ultimately, most were sent to other forum members for research and development. Here's a picture of the pile of laser cut parts:
Due to the fact that this was cut on an industrial laser used almost exclusively to cut steel, and the fact that we were rushing due to a limited time slot, we had some issues dialing in the power settings and such. We wound up with a bigger laser kerf than we anticipated, which resulted in some pretty poor fits. I was considering scrapping the whole mess, but with some prodding from another on the forum, I decided to at least attempt a glue up to see how it would turn out. Here you can see the gap between the rib and corresponding slot in the sub deck:
The ribs were carefully glued to the sub deck one at a time. I used large sockets on either side of each rib to hold them square while the glue dried.
There is a lot of trial and error that goes into getting the right slot widths, even if you know the laser kerf. I like your improvised jig to glue in the ribs.
We definitely should have been more conscious of the kerf issue. I think what made it worse on this ship is that we had cut an Iowa class battleship immediately beforehand, and had dialed in the laser to "close enough". We never thought to check it again when we switched from the 3/8 plywood used on the battleship and the 1/4 used on this. Potentially aggravating the situation more is the fact that I drew up the cad data for the battleship, and accounted for the actual plywood thickness in the size of all the slots, and someone else had drawn the cad data for this ship.... And I foolishly never checked to see if the slots were drawn to a nominal 1/4" or to the actual size of the plywood. Lessons learned: Verify twice, laser once.... but only laser after you have verified that the laser is lasering where you want the lasering to take place...
The "assembly jigs" got even more intricate as things progressed.... I needed to hold the deck flat while the keels and water channel pieces dried.
The bow block was whittled out of a piece of 2x4.... Totally high tech ....... Also note the equally high tech rib alignment fixture to the left.
My Preferred method of bottom construction is the sanded balsa bottom. Although it may be a little more time consuming than covering with thin plywood, it is very easy, and also results in a bottom that perfectly follows the contours of the ribs. I had just started here.
Because I'm impatient, and like a little kid with a new toy, I couldn't wait any longer to see what it was going to look like.... oh, wait, I meant *because I'm diligent and needed to verify proper placement and progress* I sanded what was there before adding any more blocks.
I left a few of the areas to be done later. This would allow better access while figuring out the rudder and propulsion system. The last thing to do was the solid stern section. Laziness took over, and the easiest method in mind at the time was to glue several stacked pieces of balsa onto the area and sand them to the proper contour....
