Bob Blarney
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Posts posted by Bob Blarney
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On 12/29/2018 at 12:36 PM, Jaager said:
Bob, for removing hide glue, try ethyl alcohol - the rubbing alcohol in pharmacies - not the isopropyl.
Heat and ethanol denatures the protein - changes its shape and no longer bonds.
Denatured alcohol is ethyl alcohol mixed with methanol (and possibly other noxious substances) added to make it poisonous. The proportions vary from 30-60% either way. Pure ethyl alcohol is consumable and taxable and hence much more expensive.
Hide glue will also denature and release with steaming water alone, but that might cause problems with warping.
- mtaylor, thibaultron and Canute
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Is there a 'best'? Maybe. I've used -
1. 3M SprayMount (low tack) and 3M Super 77 (high tack), and Weldon Contact Cement. All of these can be removed with spirits of naptha. residues can be a problem
2. rub-on glue sticks, ok but only for items where I didn't worry about removal
3. Elmer's glue - water removes it but can stain
4. Shellac - a traditional adhesive that can be removed with denatured alcohol, and should not interfere with finishes
5. hot hide glue (not Franklin!) - hot water / steam soluble and does not interfere with finishes
- thibaultron, Jaager, Canute and 1 other
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If you have an air compressor, have you considered an air pencil grinder?
I have a related question. How are the flexible shafts lubricated? Are they permanently sealed or do they require maintenance?
https://www.amazon.com/Astro-218-8-Inch-Pencil-Grinder/dp/B000RH36WU
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22 hours ago, vaddoc said:
Very nice videos
However, I looked for 01 steel blanks in the UK, cheapest 3x3 mm x 500 mm is £10 when a high end chisel is less than £20. Not worth the effort
I forgot to mention that spade (paddle) drill bits are a convenient and good source for the tool steel. You may already have a few spares, or could find them at a boot sale or the local home center.
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If you have a smartphone, there are apps which can measure both the lumens and color temperature using the camera, so you can get an idea of what your prefer for different tasks.
I found that I like color temperatures in the 4000k-5000k range, with 1500 lumens for general area lighting, and between 2000-4000 lumens for detailed work. So over the bench, I have a strip LED and two architect task lamps that can be positioned as need. Also, a whiteboard mounted on the wall can be used as a reflector and also to make notes.
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This item was advertised as new in the box. Perhaps a wide internet search will turn one up for you.
https://www.worthpoint.com/worthopedia/plank-bender-wood-ship-model-building-458501085
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A dull blade can be an issue. A zero-clearance plate will help - you could try making a zero-clearance plate with model plywood.
1. Cut twice: Make a slight scoring cut first, just grazing the wood, and then draw the wood back, raise the blade, and cut through.
2. First place a sacrificial board down and then place your stock on top that, and then cut through both of them.
3. If the wood is friable (I've never cut that species), you could give it a wash-coat of shellac (Zinsser Seal Coat, diluted). This will harden the surface somewhat and will also keep the wood clean. The shellac can be removed with denatured alcohol and/or light sanding. Try on scrap first!
As for safety, there are a few things to keep in mind. This saw is not particularly powerful, but a kickback is a never good thing. Obviously, keep your body parts away from the line of cut.
a. never cut warped or twisted wood.
b. never push wood through with the miter gauge while the wood is also in contact with the fence --- ((re)move the fence).
c. if possible, make and use a sled that registers in the miter slot or against the side of the table.
d. never reach behind the blade - use a push stick - a common pencil with an eraser will work for these small saws.
e. to catch small pieces, cover the nozzle of a vacuum cleaner hose with cheesecloth or window screen - the vacuum will catch the small piece.
f. avoid cutting thin pieces from a board close against the fence - put the board against fence and cut the sliver from the wide piece.
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In situations where a large amount of fine dust is generated (e.g. such as my basement workshop), this might be a useful feature. I wonder if the sensor is reusable. I would guess that it may be a pressure sensor that transmits the furnace plenum's internal pressure, which the phone software app compares to the ambient air pressure. As the filter clogs and the airflow decrease, the internal pressure will go up and the app will indicate the minimum airflow as 'end of life' replacement time.
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That's a neat solution. PVC pipe also works, but cutting it is somewhat more difficult.
- Canute, thibaultron and mtaylor
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In the past, I made a set of small knives from old hacksaw blades. It's really not so hard to make them. The steel is quite good enough for this purpose and they can be readily sharpened, and the blade and handle shapes can be easily customized to suit the purpose and the hand. A heavier blade can be made from a reciprocating saw blade, or even heavier yet from power hacksaw blade.
- paulsutcliffe, Canute and mtaylor
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About the glue - I have been known to make mistakes, but maybe I'm wrong about that. Still, there were times when I thought it necessary to disassemble something that I've made. Almost all glues will release with heat and/or water (steam), while others can be softened with vinegar or another solution. TBII is fairly resistant to these procedures, while Elmer's GlueAll is not so resistant and is adequate for many purposes.
Incidentally, guitar builders and repairmen have come up with some interesting methods to disassemble instruments.
One way is to cannibalize a coffeemaker and attach a rubber tube to the boiler element, and then plug a hypodermic needle into the rubber tube. Then the needle can be placed in the joint that needs to be loosened and steam applied, e.g. the dovetail joint between the body and neck. (Hmm, I have a defunct Keurig in my junkplie that would just dandy for this!).
For very small joints, and to steam out small dents in a soundboard, I'll fill a syringe with water and install a hypodermic needle of the appropriate size (20-27ga). Then I'll place the needle where needed and then heat it with a soldering iron to produce a pinpoint jet of steam.
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Odd, I was just admiring one at Lee Valley. I've heard very good things about them, although the price isn't attractive. Still, as my mechanic said about his SnapOn tools, "It ain't what it costs, it's what it does."
You might also consider a jeweler's saw frame & blades such as these:
http://www.crhill.com/sawframesandsawblades.aspx
I have this one: https://www.zakjewelrytools.com/products/swiss-saw-frame
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4 hours ago, Popeye67 said:
All good info guys, thanks! I guess I will have to slow down and get use to not having the benefit of instant cure glue! I need to work on my patience I guess.
I am going to assume, in regards to white glue, Titebond II is still a decent choice?
Popeye
No, I wouldn't use TBII - it's an aliphatic resin glue that is highly water resistant. Try good old Elmers school glue first.
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Adequate lighting is absolutely essential, especially for those of us who are not so very young. Although heat from an incandescent bulb is often useful (especially to the cat), there are other ways to manage that.
I'm fortunate to have an old Luxo architect task lamp from the 1960s. It's has a 45" reach on a swivel base, and is perfectly balanced and will hold any position without any tightening or loosing of knobs. It has a porcelain socket, and so I can install an LED, incandescent, or infrared lamp as desired.
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White PVA glue is a good choice for many situations, but there are also alternatives.
As a builder of acoustic guitars, I've used a wide variety of glues. Whenever possible, I've used hot hide glue because it does not interfere with any finish and is fully reversible, and yet is incredibly strong and creep resistant. But I expect that most modelers would not want to deal with its preparation and handling. In this case, Old Brown Glue might be a good alternative, and for my next instrument I'll use it. (But I've never met any instrument builder who would willingly use Franklin/Titebond Liquid Hide Glue.) You can read about Old Brown Glue here:
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It makes me want to re-engineer my electric toothbrush.
- Roger Pellett and mtaylor
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For ideas of workbenches and their accessories, here's a couple of links from Yesteryear when modelmaking was a common activity for leisure hours.
In this one, note the plane fixture for accurately thicknessing in wood. Using a sharp plane is quicker than sanding and will give a much crisper surface. (Oh, and check out the toy rubber-powered tugboat a few pages down! a great kid's toy)
In this one, there's a vise, and anvil, a bench pin, a groove for shaping masts with a block plane, plus a mount for a Dremel.
And here's a basic explanation of bench hooks:
https://www.wonkeedonkeetools.co.uk/bench-hooks/what-is-a-bench-hook/
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Tools can be acquired as needed, but don't pass up a good deal when you see it > but only if it's on your list <.
One tool that I consider essential, and that hasn't been mentioned above, is a stable work surface (or table/bench) that is equipped with a vise, an articulated lamp (architect or gooseneck), and maybe a birdsmouth and a bench hook. It could be a piece of 3/4" MDF or plywood about 20"x20" with these items attached, and be stowed away somewhere if you don't have a dedicated workspace.
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As in many situations, it depends on what kind of material that you're working. For most woods, I'd stay with steel files because there are many tooth patterns and shapes that allow quick removal of wood, and the final tooling marks can be removed with abrasives. For metal, diamond files might be more suitable because of the hardness and random arrangement of the diamond particles reduces tooling marks. Also, my diamond files have grits that are too fine for quickly shaping wood.
For myself, I only use diamond files and stones for sharpening metal tools, and use steel files that I clean with a plastic or wire brush. One thing that I try to avoid, is using a particular file for both wood and metal, because sometimes metal fragments that are in a file's surface might be transferred to the wood.
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It looks stylish and I'm imaging uses for the ball end. However, surgical scalpel handles are usually flat, such as this beautifully finished one from Miltex:
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My experience with bending wood is for musical instruments, and this is usually means hardwoods in the range of 2-3 mm thickness. I use an electric blanket and bend the wood dry clamped on a form, or the same after a light misting with water and wrapping with aluminum foil. The temperature is somewhat dependent upon the species of wood, in the range of 250-400F. Generally, I think that softwoods won't bend as well as hardwoods, but that may not be so because guitarbuilders don't bend softwoods.
However, you don't need to do this. You could use a clothes iron, or pieces of pipe fitted to a heatgun that is clamped in a vise or fixture. As you draw the wood across the hot pipe, you'll feel it relax and can shape it as you go. This will take practice but it will work. Also, wood bends in compression, not expansion, so fractures may occur on the outer side of the piece unless it is reinforced while bending.
One other thing, the output of a heatgun (or blanket) can be regulated by using a 'router controller' from Harbor Freight costing about $20. Most lamp dimmers are limited to 600 watts, so don't use that instead.
I hope this helps.
- thibaultron and Canute
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Hello, this video shows a machinist turning a barrel 'for fun'.
- Richard Griffith, JpR62 and Belco
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Hmm, were you applying the CA glue straight from bottle? That can certainly create problems. Instead, try putting a dot of glue on a card, and then use a plastic toothpick as an applicator. A tiny amount can be placed by using the sharp end, and slightly more with the brush end. Also, select an appropriate viscosity, and maybe try an accelerant. As always, develop new techniques on scrap material first.