bartley
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HM Cutter Cheerful 1806 by bartley - 1/48 scale
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brass black
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brass black
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mtaylor reacted to a post in a topic:
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Shipman, Oxygen is the culprit in the decomposition. This may sound like a cop out but oxidation is one of the most difficult processes to understand so it is difficult to predict what the products are. Firstly liver of sulfur is not a single chemical substance . It is a complex mixture. amongst the products of decomposition are sulfates which colourless but also sulfur itself which will be insoluble. In its pure state it is yellow but it tends to pick up impurities and and is often green or brown. If the product has been used there will be copper and other metal present so th
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Yes indeed, shipman, this is true. Liver of sulfur is a complex mixture of sulfides and polysulfides. Over time in air these decompose to in active sulfates. Shelf life may be less than a year, Strangely it works well on copper but not very well on brass which is 60% copper. John
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Yes, Kurt this "sharp rap" is somehow different. Many years ago my son was sailing in a small boat constructed as a "klegicell sandwich" . This is foam core with kevlar fiber on each side. It was like rigid like a sheet of steel with respect to movement against the water but once coming around a mark, the boom of an another out of control sailor hit the side of his boat. Punched a neat hole straight through. So, very strong in one sense but very poor impact strength. John
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Dave, My experience is that if it is bare wood there is usually some staining (depending on the timber and how long you leave it in contact). However, if the timber is painted there is no problem. These bolt heads were blackened after installation. John
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Shipman, A couple of extra tips: A clean surface is the key. You obviously know about pickling but don't overdo this step. Pickling id etching the surface of your brass so 10 min at 60 C is usually enough. Don't handle with your fingers now. So, into your soda bath to neutralise the acid, rinse under the tap, drain and into the blackening reagent. Don't immerse your items into the bottle of reagent. Put a small amount into another vessel which you can seal so you keep the original solution uncontaminated. Neat Birchwood Casey reacts pretty fast (10 sec) so to give a bit
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OK shipman, Shelf life of the blackening agent should be indefinite if you keep the lid on. Pickling solution: make it up about 8:1 of the water to solid. Note: add the solid (sodium hydrogen sulfate) to the water not the other way round. The soda water: it doesn't really matter; I add the bicarbonate to the water until there is a little left undissolved. This is called a "saturated solution". John
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Dave, I have dealt with this disposal issue here. If you search my thread you should find it more on this. As I have mentioned also here the Birchwood Casey product is a little different from the other brands in that it contains both Selenous acid and Molybdate so it reacts with both copper and zinc- both of which are in brass. So it reacts a bit more quickly and probably forms a deeper black. Also it will react with any alloy containing either of these metals John
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Question regarding the base of the mast
bartley replied to DaveBaxt's topic in Masting, rigging and sails
Although I did not end up using this, I did I believe produce a good simulation of the canvas covering by using tissue paper -
bartley reacted to a post in a topic:
HM Cutter Cheerful 1806 by bartley - 1/48 scale
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All credit to Glenn. His Cheerful build is magnificent. Great workmanship! but we must credit Chuck Passarro for the invention of this weathering method. From chapter nine of his cheerful monograph:- "I also weathered the black backstay plates ever so slightly. This was just a matter of brushing on some weathering powder and buffing it off. I prefer to make all of the metal elements have a different texture and look than the black painted areas of the hull such as the wales. Its very subtle and can be overdone very easily. So if you want to give this a try it’s a lo
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There are really only two versions of Artistic Wire to consider: "black" and "bare copper". The black is quite glossy and in my opinion does not look like rope. Bare copper can be blackened with one of the selenium products like Jax Black. The plated versions are coated and could not be blackened this way. Alternatively, you could use Chuck Passaro's method where he paints the item black and then uses weathering powder to make it look more like metal. Incidentally, this wire is not stranded. It is essentially copper wire with an enamel coating (except for "bare copper" of cou
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Post 50: Constructing the Mainmast All the deck features are now complete and it is time to start on making the main mast. The mast itself was made from 13/32 square boxwood. I decided that it would be easier to establish the square section at the head of the mast before rounding it. Once this was done I first planed the edges to form a hexagon using the 710 7 rule and then turned the lower section on my home made lathe powered by a hand drill as described earlier. The next task was the curve
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Actually, too long Tom. Being a chemist I know a bit about the technical side of this. The selenium in the blackening agent etches tiny pits in the brass and black selenium is deposited there. If you continue another layer deposits on top of this and this rubs off easily. There is a kind of happy medium between incomplete blackening and too much flakey stuff. The exact time depends on how much you dilute the reagent. Incidentally, watch out for this flakey stuff. It is selenium and is toxic. Wear gloves and wash you hands well afterwards if any gets on your fingers. John
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Yes, there is no adjustment on these. Our x and y are perfect - easily adjusted but nor sloppy. However, the z one is tight as you describe. Maybe a bit of dust which might blow out with compressed air or very small touch of lubricant. Good work my the way - certainly surpasses mine. John
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Glenn, I think I mentioned this once before but all machine knobs like this have backlash. This is like a kind of deadspot where rotating the knob dos not change the setting. It is very small but on fine readings it can make a difference and means that if you set a reading by rotating the knob clockwise you will get a different setting than if you rotate it anticlockwise. so you should always approach a setting from the same direction. John
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This is true, but if you use a cow hitch at the first and last it kind of simulates this. John
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