wefalck

Of course, I did not imply that anyone should ever attempt to drink sulphuric acid ! I tried to point out the difference between 'toxicity' in the scientific-medical sense and other detrimental health effects. Peolple tend to confuse these. Oh, btw, I have a PhD in geochemistry and many years of practice in chemical laboratory work

NB, sulfuric acid is not toxic ! I doubt that you could drink enough to experience any toxicity from the sulphate ions ... sulphuric acid dehydrates and oxidises organic tissue, which is something completely different. It is important to not mix up different categories of hazards. Otherwise, people get worried about things, while in reality materials can be safely handled with the proper procedures and precautions. Having said that, for me there would be certain no-nos in certain working environments. For instance, I am working seated at a wooden workbench. This means that I would shy away from using at this workplace strong oxidising acids, such as sulfuric or nitric acid. A spill is difficult to control on a wooden bench and when seated, you cannot get out of the danger zone quickly - you will have it all in your lap.

Looks good, Chuck, but when one can see the strands like this, one could also really splice the rope

I gather the answer to your question also depends on what kind of vessel and what period we are talking about. Without such information one can only guess, but the real practice may have been rather different.

Moxis, here in my building-log you can see some applications: https://modelshipworld.com/index.php?/topic/8957-sms-wespe-armoured-gunboat-1876-of-the-imperial-german-navy-by-wefalck-–-1160-scale-when-first-commissioned/&do=findComment&comment=465372. I am laminating e.g. MDF with it and manually engrave plate-lines etc. Not easy to see, but some 20 years ago I built the shell of this dinghy from planks cut form 'hard-paper' and cemented together with CA. The reason was that I needed very thin planks and due to the clinker-construction could not really sand the surface: If this Polybak® is less brittle than the phenolic resin-based material, this would be of advantage. However, with a 0.3 mm end-mill at very high speed, but low feed you shouldn't have any problems on a CNC-mill, if the material it clamped down properly. I am using ordinary HSS- or carbide-metalworking tools with it. Single-lip engravers also work well, as do diamond-impregnated tools. One has to remember that these materials, Polybak® and 'hard paper', are laminated materials and not homogeneous. In the very thin qualities you have essentially a very thin layer of pure resin, the resin-impregnated paper, and then another very thin layer of pure resin. The pure resin is rather brittle, which is why one has the paper in between to take up the tensile stresses, just like the steel bars in re-inforced concrete. A tool jerk my cause chipping of the pure resin layer. When machining 'hard paper' in a router, i.e. when generating a lot of dust and heating up the tools and the material, one should have a reasonably good ventilation. I bought a life-time supply of 0.2 mm and 0.4 mm 'hard-paper' sheet from a small company specialising in such materials in Berlin, where I lived at the time. There are various German companies on the Internet that offer the material, but I don't know, whether they would sell in small quantities and to private people. Thicker qualities, 1 mm and above, can be bought in small pieces from electronics supply houses (e.g. Conrad in Germany, Austria, and France).

Interesting discussion. The material would be called 'hard paper' (=Hartpapier) in German and is essentially a variant of Bakelite. It is paper soaked with a phenolic resin and pressed between steel-plates while setting due achieve a smooth surface and uniform thickness. It is commercially available down to 0.2 mm thickness and was/is used as insulating material in electrotechnics. Before being superseded by expoxi-based materials it was also used for circuit-boards. There are other variants of the material that are based on layers of cloth soaked with the resin that are used for making silent gears and the likes. I am using it a lot in my models because it is stiffer than polystyrene and does not contain plasticisers, so that it has a better long-term stability. Basically bakelite artefacts have been around for some hundred years now without degradation. Polystyrene will be brittle by that time. 'Hard paper' has some good properties, but is also rather brittle and may splinter easily when duller tools are used on it. One has to learn to work with the material. This Polybak® seems to be an interesting stuff. Unfortunately, their safety data sheets do not say what resin they use, it is only labelled as 'proprietary' compound. Otherwise, one could look for a similar product here in Europe. I would be very interested, as the phenolic fumes that are given off when machining my 'hard paper' are not all too pleasant and possible not too healthy either.

We don't really know, but popeye2sea is most probably right. However, the question 'bluff bowed' or not is not so simple. You would need to ask 'bluff in the waterlines or in the cross-section'. You can have bluff waterlines and sharp cross-sections or vice versa.

... actually, I would have thought that the part is really U-shaped, or even slightly V-shaped - the position to which the stay will attach is not defined in the way it is modelled; the stay would in practice slip to one of the corners and then pull slightly sideways.

JerseyCity Frankie, that's a good point - haven't thought about this.

Dafi's sail-making technique would also make nice flags ... In another forum (http://www.shipmodels.info/mws_forum/viewtopic.php?f=59&t=163736&start=120#wrapheader) Jim Baumann discusses how he makes flags by printing the design onto ordinary white paper and then splits the paper to only retain the top layer. Two mirror-images of the print-out are glued together. These flags can be nicely shaped. The figure-modelling fraternity uses tin-foil (better, but now difficult to obtain - in the old days chocolates were wrapped in it) or aluminium foil.

Send them an email last nigth, enquiring, whether they could deliver directly to a non-professional. They called me up this morning, curious what I was going to use them for. I had to 'confess' that it was for modelling purposes. We then had a nice chat about the applications and needs. In fact, HORICO did offer the strips and other tools from their range to a modelling supplier, but somehow it did not catch on. They realised that they would need some sort of holder for the strips. I gather, they are thinking about this market. Their carbide rotary tools seem to be of good quality, but rather expensive for us modellers - even when you consider that these burrs my last a modeller's life, there is always the risk that you break a small 25 € tool ... That is probably, why they could not sell to our market. In any case, exceptionally they will send me my strips

At this link you can see the whole range of HORICO strips, both diamond and carborundum: http://www.horico.de/en/praxis/separierstreifen/2-uncategorised/91-alle-streifen.html

Glad to see that my interpretations/guesses were correct. This arrangement with two back-stays and a sort of triatic stay running from the fore-mast top back down to the main-mast cap is rather intriguing. I don't remember having seen this before. It actually makes it impossible to have stay-sail running on the main top-mast stay.

That's the kind of price I saw on Amazon, while dental supply-houses in Germany charge around 4 to 6 € for the dozen plus shipping ... actually the 30x series is not diamond-coated, but carborundum-coated according to HORICO. The diamond ones have a different number. The thin steel backing with a total thickness of 0.1 mm made them particularly interesting from my point of view, as you can widen narrow slots and the likes with them. No other file or sanding-paper is that thin.

How much did you actually pay for these HORICO Stahlcarbo® strips ? The only Amazon-offer I saw today seems to be grossly overpriced. So far I only found suppliers that would only sell to professionals or traders, but not to private persons. May have to contact the manufacturer directly.

Actually, the first drawing puzzled me somewhat: I gather the bow is to the right ? So what is shown in the top of the main-mast ? This means that single or double back-stay goes down from the fore top-mast to the cap of the main-mast ? A rather unusual arrangement ! By the middle of the 19th century iron caps have come into use together with eye-bolts as fastening points for triatic stays and the likes. Likewise, a lot of forged iron-work began to replace certain ropes or chains - less maintenance required. I would interpret these 'square' structures between the stays and the caps as some sort of U-shaped iron rods that are bolted to the middle of the cap and provide the attachment point for the stays, the angle of which adjusts itself. Never seen something like this before, but it makes sense mechanically.

When you fold strips of cloth over the edge of your sail, you end up with a hem on both sides - which is not correct and doesn't make sense really. On the prototype the hem would be folded over to the port side (for fore-and-aft sails) or the back (for square sails). Similarly, the bolt-rope goes onto the port side and back of the sails respectively.

I guess it depends on in which direction you use the tool and on the shape of the file you use. I would have to read up again on file-making, but believe that after being hewn, they would be tempered to destress them before hardening. So there is not that much reason for them to break along the teeth lines really. Perhaps so, if you use really cheap ones. However, files are really hard and therefore brittle. If you turn thme into turning tools they would need to have some hardness drawn from them so that they are less likely to break.

Ad 17: couldn't this be the fishing tackle for the anchors ? I would have thought that the foresails would be running on stay, not set flying. Therefore, there should be another stay between nos. 3 and 4, and 4 and 5. The stays leading down to the jibboom could go around fairleads and then down to the whiskers and back to the stem or the knights. So 9, 10 & 12 would be stays.

Good method and I have used it myself. However, for the period of the ARROW there wouldn't have been metal grommets, but rather ones fabricated by the sailmakers by stiching around the hole. So, you may want to use instead of the CA some white glue on a toothpick that has been tinted a tad darker than the sail. You could also use a light dab of CA and then use some thick acrylic paint of a suitable colour to imitate the grommet. The dab of CA prevents the paint from bleeding into the fabric (which, I assume, is what you use).

Thanks for reminding us of the RB products. Meant to look into them, as I am increasingly use Plexiglas, bakelite and styrene for my projects. Back in the late 1990s and early 2000s, before the Chinese began to flood the market directly via ebay, I did buy a few times at VME. Friendly people and good quality. When I happened to be in the USA on business, I had stuff delivered to my hotel. Working for the UN, importing stuff into the EU was also relatively hazzle-free and the US Postoffice offered a 'surface' service that was reasonably priced (but you had to wait for one or two months, which didn't really bother me). Now there is only airmail at ridiculous prices, which makes buying from the USA very uncompetitive. Sorry for the US trade, but the Chinese seem to be able to ship stuff for next to nothing. While browsing the dentists' and dental technicians' arsenals, I recently came across a couple of interesting tools: - so-called separation strips. These are used to file the sides of teeth or false teeth. They are abrasive material of various grades on a backing of either Mylar or stainless steel. For the time being I got some Mylar ones, which I bought to make sanders for my filing machine and the micro hand-sander I built. I have not being able to identify an on-line source for the steel-backed ones. One may need to buy directly from the manufacturers: http://www.horico.de/en/neuigkeiten/2-uncategorised/91-alle-streifen.html. The Mylar-strips are about 5 mm wide, while the steel ones come in width down to 3 mm. As you can see in the link, Horico also makes fine-toothed steel-strips, i.e. saws. This is how the Mylar-backed are sold and they work very well: - There is also one provider for something like a miniature hacksaw that uses the above steel sawblades or abrasive strips: http://www.ebay.de/itm/172605444198?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT. I have not seen this on offer somewhere else and this offer appears to be rather pricey. Haven't tried this yet. - Flexible abrasive and polishing discs: TT These are quite aggressive and seem to last a while. I have used them as micro surface-grinding discs on my micro milling-machine. I should take some pictures of other tools and materials in my chest from the medical/dental realm ...

This is called a safe-edge in the trade and many files can be bought ex-factory like this.

Looks more like the finish of the small boat production . Some pictures of the construction would be nice ! I think you are a professional. In both senses of the word, in terms of the quality of the products, I gather also economically speaking ?

That was exactly also my understanding of the term. And my memory served my right, there are various illustrations in Underhills 'Masting and Rigging': Figure 87 on p. 85 shows the thing and plates 36, 37, and 38 shows how they are used to keep running rigging from the higher yards close the shrouds and out of the way of lower yards. These thingies, that look a bit like the old-time wooden sewing thread bobbins, have a groove along their length of the diameter of the shroud and, according to requirement, up to four holes lenghtwise.

I have a 1905 book on rigging that was written by the naval architect who build (among others) the 5-mastes-ship PREUSSEN. It gives the dimensions, breaking strains etc. of every bit of rigging. However, it was written at a time, when some form of materials testing already existed and the production processes for steels were quite well-controlled, so that qualities could be produced repeatedly with confidence. This meant the the margin of error was reasonably small and, therefore, safety margins could be reduced. I use this book as a guidance for minimum dimensions. Fifty years earlier they had to work with much larger safety margins, as metallurgical processes were less reliable and materials testing in its infancy. So with time parts become much more 'delicate'. Too me the strap and eyebolt look a bit on the small side, actually. It is not only the static breaking strenght that counts, but also the dynamic strains, when on sea.