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Post by 92220 on Aug 12, 2023 21:15:53 GMT
Hi James.
Phosphoric acid is way better than Kurust. At least it was when I tried Kurust many years ago. Maybe they have changed the formula since, and made it better, but having got a small, very effective, bath of phosphoric, I'm not going to change from something I know works well.
Keep, up the good work. Your post is really interesting to follow.
Bob.
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Post by 92220 on Aug 12, 2023 14:25:50 GMT
I've found this a very interesting post. Then wagon ism really coming along well. I notice a bit of corrosion on the mild steel strips and shapes. If these get painted without any treatment for the corrosion, within about 12 months, the paint will start flaking off. Can I suggest a handy solution that I learned as an apprentice many years ago (DON'T ask how many years!!!): a bath of about 15% phosphoric acid is an ideal treatment. Just dump all mild steel parts in the acid bath, rusty or not, and the surface of the metal turns a subtle shade of grey, and all the rust has been totally neutralised. It is only the surface molecules that are effected so there is no change in dimensions. The surface, having been coated with a layer of ferrous phosphate acts like a primer and is also an ideal surface to paint. Phosphoric acid used to be available off ebay but it doesn't seem to be now. However, I did find this place, on the internet, where it is readily available along with a number of other acidic rust removers. They are all reasonably priced too. This is the website I found:- www.rust.co.uk/product/cat/diy-vehicle-restoration-start-here/complete-vehicle-restoration/rust-removers-and-converters/ Note that after treating the steel, the items should be rinsed with warm, to hot, water to remove residual acid from the surfaces. As long as the surface has got it's grey coating, the water wash will not cause re-rusting. Bob. Edit. I've found Phosphoric acid available on the internet. It is called Clean And Clever Professional Phosphoric Acid Toilet Cleaner, and is reasonably priced at around £12 to £14 per litre. Bob.
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Post by 92220 on Aug 6, 2023 12:15:57 GMT
Hi Roger.
Chris does make a good point about trying to remove a line too soon after making the previous one. The previous paint line, if not left long enough, will still be removed by white spirit, and most other solvents. You are right, also, about leaving the masking tape on for too long. A lot depends on the type of masking tape. With most paper based tapes, the problem will be that the adhesive comes away from the paper tape and sticks to the paint surface. Then it becomes much more difficult to clean off. The plastic, 'low tac' masking tapes work better but whatever is used, should be tested before hoping you can release it without problems, after a day, and a week, to be sure you are safe.
Bob. Edit:
I note you think the paints will work for you, but just in case it is useful, here is what I have got hold off. The marker refills I have are Edding refill ink permanent marker. If you search for that on Amazon, you will see lots of other brands come up as well as lots of different colours. The white refill was 'Jackson' but I got that one from an art supplier, but can't remember who.
Bob.
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Post by 92220 on Aug 6, 2023 8:14:51 GMT
Hi Roger.
Draughtsman's bow pens can be sharpened. The first operation is to get the drawing edges EXACTLY the same height when the pen is at right anglers to the surface. Once that is done, the blades should be sharpened so that they almost cut paper. Once you get to that, just run the stone around the edge to JUST take off the sharp edge so that it doesn't damage the surface when drawing. That is how the pens should be sharpened for use with indian ink, and drawing. That was how I kept the bow pens working for the tracers at a large company I worked for in Cheltenham many years ago. Use with paint may be a bit different but must be somewhere near. Something that might be worth checking out is refill inks for marker pens. I have a 50mls bottle of white and black and they are runny like ink and are extremely dense in colour. I also found a company on the 'net, that sells a whole range of colours so it should be easy to match the lining colours and apply them with the bow pens. I will look out the bottles and let you know the manufacturer if you think it might be worth looking into.
Bob.
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Post by 92220 on Aug 2, 2023 15:55:56 GMT
That's interesting. Another possibility is to use a single plate portable induction cooker hob. I use one to heat water for cleaning flux off silversoldered parts. I must try it for hardening and tempering. Anything steel can be heated on one of these, right up to red heat. Ther only problem might be if the heated plate of the cooker is plastic. If so, then a sheet of 1/8" ceramic fibre paper, would insulate it enough.
Bob.
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Post by 92220 on Jul 30, 2023 8:17:44 GMT
Forming springs from hardened and tempered spring steel is no problem. Clock springs are hardened and tempered but if you watch "The Repair Shop" on BBC one, you will see that Steve, the clock repairer, bends the ends quite easily by hand, with just a couple of pairs of pliers. Bare in mind it is tempered. It is NOT so hard that it can't be formed, otherwise it would snap when bent. If it was in that state it couldn't be used as a spring because the first loading that bent it would snap it.
Bob.
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Post by 92220 on Jul 29, 2023 8:27:32 GMT
I agree with Chris. The leaf springs on my 9F were all made from hardened and tempered spring steel strip. Any machining you might want to do is easy with readily available carbide milling cutters and twist drills. If you have decent industrial quality HSS tools, they will also cut the spring steel in it's tempered state, though carbide is always much easier, and quicker.
Bob.
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Post by 92220 on Jul 22, 2023 9:43:50 GMT
We have all done it!! Probably many times!! Looked at something we were looking for and not seen it. The eyes can actually see items that are in full view, but the brain just does not register them at the time. Go away and do something else and the brain will then register what the eyes see when the item is next seen, just because it is not being stressed to see the particular item. I think it is just a fact of getting older but we can be a bit embarrassed to talk about it. It happens to me very often in the workshop!! I look for something and don't see it even when in full view. I go away and do something else and turn around and there is the mic I took 15 minutes looking for but didn't see.
Bob.
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Post by 92220 on Jul 4, 2023 7:46:23 GMT
Oops!!! I didn't see that. Must get an appointment at Specsavers!!!!
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Post by 92220 on Jul 3, 2023 11:01:24 GMT
The guy that took over Hewson Model Supplies sells CS70 in the annealed state. He also gives instruction for heat treatment after machining to shape. I bought mine years ago, from Doug Hewson, and machined the leaf sections with standard HSS cutters. If you want to check this guy, just Google D.Hewson Models. This comes up as the to[p listing. Just click on it and thie Doug Hewson catalogue cover page comes up and at the right hand side is a red box that say "Current Catalogue". Click on this and you get the available listings.
Bob.
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Post by 92220 on Jun 17, 2023 8:34:06 GMT
Compare the introduction page that shows magazine staff, and their positions, in both an old mag and the latest. That should indicate any changes.
Bob.
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Post by 92220 on May 31, 2023 7:58:39 GMT
Hi Tom.
Yes. That's the stuff. Ceramic fibre is a superb insulator.
Bob.
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Post by 92220 on May 30, 2023 15:34:18 GMT
Hi Tom.
You would do better putting a sheet of ceramic fibre 'paper' under the tank, rather than a foil 'heat shield', which wouldn't insulate anyway. A 1/8" thick sheet would insulate the tank almost completely. It is available on Ebay at very reasonable prices and even though it is far eastern made, it works just as well as the UK made 'paper'. It is called 'paper' but is just a well compressed fibre blanket. I have tested it by lifting a large saucepan of boiling water off the cooker hob, by hand and it just felt warm. Not even hot.
Bob.
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Post by 92220 on May 26, 2023 10:56:12 GMT
Hi Nick.
Thank you. Very informative!!!
Bob.
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Post by 92220 on May 24, 2023 9:21:01 GMT
Do I understand this right? When 3D printing in a metal, like brass and stainless, there is no plastic involved it is purely metal, so the resultant part would react to heat exactly the same as if machined from solid metal?.....Like Oilite bearing bushes, but without the oil?
Bob.
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Post by 92220 on May 9, 2023 9:57:33 GMT
Hi Roger.
Mixing paint: The best way of mixing a paint thoroughly, is to use a propeller type mixer. I use a plastic model boat racing prop for mixing tins of paint. I have had the prop for probably around 50 years and it is still as good at mixing as it ever was. This is what it is listed at now:- GRAUPNER 2 BLADE RACING PROPELLERS. The prop is about 2.5" dia and about 6" pitch, which is quite a lot, but it works well as a mixer. They sell for around £4.00. There are also 3 and 4 bladed 'racing' props available. but these are nowhere near as good as the 2-bladed Graupner props. I use a piece of 3/16" dia 316L stainless rod, about 10" long, for paint, but I also have a 3/8" dia 316L stainless rod, which I can use, for mixing thicker materials like casting plaster, for making short run press tools.
The Graupner prop will thoroughly mix paint in about 1 to 1.1/2 minutes. Being plastic, depending on how settled the [pigments are, in the tin. It is OK to move it around in the paint while touching the sides of a tin. I usually run it at around 1000 to 1200 rpm. Less than that, as a starting speed, for a new tin of paint, to make sure it doesn't overflow. The prop should also stay in contact with the bottom of the tin until used to using it in paint, otherwise it can overflow.
Bob.
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Post by 92220 on May 5, 2023 13:53:30 GMT
I wouldn't use gold size. If you do, depending on the manufacturer's makeup of the gold size, if you want to take it all apart in the future, you may have difficulty actually getting the faces to separate. The general method of sealing flat faces, on cylinders, is as suggested above by Jim and millman, brown paper soaked in oil, or use proper gasket paper. Then you won't have problems dismantling, and the seals will work well.
Bob.
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Post by 92220 on May 2, 2023 8:11:30 GMT
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Post by 92220 on Apr 25, 2023 12:59:54 GMT
Hi Millman.
That's good. If the paint/varnish is more time in air, and dried with heat, than under water, it should be fine. Unless a paint is designed to be completely waterproof (very difficult) the water slowly infiltrates the structure of the paint/varnish coating, and over time the paint/varnish will break down. As long as there is more time in air than under water, the water will have time to creep back out and not do any lasting harm.
Bob.
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Post by 92220 on Apr 25, 2023 10:39:56 GMT
Just a small word of warning about marine paints and varnishes:- Bear in mind that boats are anticipated to be repainted and re-varnished very regularly, and at relatively short time cycles. That means that the paints don't have to have a long life, unlike automotive paints do. Often, UV inhibitor is lower than what is required to provide a long life. Saves money!!! I came across this problem often, in the 30 years I had the paint business. Modellers would use marine paint or varnish and after one or two years, the paint or varnish coating would be in need of replacing as it had either badly discoloured or had also started to lose adhesion because they had used the wrong base coat or primer.
Formulea might have changed over the last few years, since I retired, but I certainly wouldn't risk using marine products on a model because there is no incentive for manufacturers to make the paints long-life. There are specialist paints and coating for most requirements, so it is a case of look for the one you need, and be prepared to pay the higher cost of a longer life coating.
I pulled this off the internet to show this is not just what I think:-
THE LIFESPAN OF BOAT PAINTS March 2021
Marine vessels need a special type of paint that will provide them with the right type of protection. Protecting the boat, ship, yacht, and other vessels and equipment that meet brackish, freshwater and saltwater means using durable and long-lasting paints.
Taking the cost and the time it takes to paint a marine vessel into consideration, the marine paint or coating should last for several years. However, several factors come into play when it comes to marine paints.
How long do marine paints last? The owner of any marine vessel expects an exterior marine paint to have excellent protection against corrosion, UV rays, abrasion, as well as retain its high gloss. Likewise, they want long lasting boat paint.
Technically, marine paints and coatings should last between two and four years.
Bob.
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