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| sorveltaja:
One thing, that popped to my mind, after writing the previous message, was about using ceramics/glass as an insulator, that nowadays small glass/ceramics quantities can be heat-treated on microwave oven(+800 watts), using a 'micro capsule'(freely translated). At least here in Finland, those are available in three sizes (diameters 70mm(2.75"), 110mm(4.33"), and 160mm(6.29")). Prices are from 99€ to 240€. Anyone else heard about similar things/devices? Microwave ovens do not accept the use of metallic materials, that are an essential part of spark plugs, but how about graphite? It would be an ideal mold material, and mold for center electrode hole could be made of 0.5mm(0.019") re-fillable pencil -rod. Lil' bit of mindstorm to lighten the thread. |
| madjackghengis:
--- Quote from: sorveltaja on May 13, 2010, 03:40:10 PM ---One thing, that popped to my mind, after writing the previous message, was about using ceramics/glass as an insulator, that nowadays small glass/ceramics quantities can be heat-treated on microwave oven(+800 watts), using a 'micro capsule'(freely translated). At least here in Finland, those are available in three sizes (diameters 70mm(2.75"), 110mm(4.33"), and 160mm(6.29")). Prices are from 99€ to 240€. Anyone else heard about similar things/devices? Microwave ovens do not accept the use of metallic materials, that are an essential part of spark plugs, but how about graphite? It would be an ideal mold material, and mold for center electrode hole could be made of 0.5mm(0.019") re-fillable pencil -rod. Lil' bit of mindstorm to lighten the thread. --- End quote --- Hi sorveltaja, now you're thinking along the lines I am! I haven't heard of what you're talking about, however the issue of metal in a microwave is primarily about the life of the oven. I've been the recipient of more than one which was done for, as far as food, and a gift, so I've experimented in more than one with metal without Mrs. jack coming after me with implements of destruction. I was considering using "slip", which is ceramic slurry, used to pour castings, in plaster molds, the process basically filling the mold, letting it set for a bit, then pouring our the liquid, to form a hollow casting. My Mom makes ceramic dolls this way, which is how I know it. I was thinking of making a plaster mold say a quarter size of the insulator of a conventional plug, a two part split mold, putting the center electrode in, pouring in the slip, with a riser as one would do with aluminum casting, as the insulator needs to be solid, and once it is "green", meaning essentially dry, but not fired, and then perhaps hanging each by a wire on the electrode to keep it from losing its shape while firing, and doing a soft firing, then glazing it, and doing a final hard firing. That is the the process with the dolls, the soft firing leaving a porous ceramic, the glaze and hard firing leaving it glassy and totally non-porous. The steel "shell" it goes in typically has a packing of very fine powder I believe is ceramic, to cushion the contact of the insulator with the shell, near the thread end, and at the outer end, a shoulder on the insulator for the copper o-ring to seat against, and rolling the edge of the shell, which is probably twenty thousandths thick, over the copper o-ring and crimped down against the powder packing. I haven't tried it yet only because I haven't gotten to that stage yet. What do you think about that? mad jack |
| sorveltaja:
Madjack, definitely worth trying :thumbup:. To me, even the ceramic-making terms are a new thing, and would greatly appreciate your attempt. I'm sure there is a whole bunch of people(well, at least me ::)), that would prefer using ceramics instead of plastics. I did some searching, and found this: http://www.microwavekiln.com/KILNINSTRUCTIONS.HTM They look somewhat similar to those, that I mentioned earlier. Some have even done small metal castings using microwave oven :bugeye: http://home.c2i.net/metaphor/mvpage.html |
| sorveltaja:
Two Y-pieces made. One for inlet and other for exhaust. I'm going to test a vapor carb, before making an adapter for conventional one. Somehow I feel, that the Y-piece should be as close as possible to the engine, to make sure, that both cylinders inhale the fuel mix, instead of each others inlet tube's content. Gasoline/oil mixture would be an ideal fuel to test the engine, but if the ignition, or timing aren't right, it makes the engine's combustion chamber very dirty, even after short runs. No matter, how small amount of oil is used in the fuel mix. That's what I have experienced during my previous project. Gasoline-based fuel seems to work better on vapor carb, than an ethanol, though. At least on colder winter months. But at the moment, the environmental temperature has rapidly risen to a summery level, so the ethanol just might evaporate bit easier :dremel: |
| madjackghengis:
Hi sorveltaja, what little I know about ceramics comes from watching mom and sisters casting dolls, using plaster molds, and they have made their own molds as well, so I've got some "look see" experience to start with. I figure the plug companies have tried everything, so starting with how they do it is probably the best place to start and attempt to copy. I should be able to turn a pattern with the electrode as a core essentially, and make a two part mold from plaster around that, and with it being a small tubular piece without much volume, let it dry to the point of being able to break off the "sprue", and then fire it with the electrode in place and fire it a second time for the glazing. I'll ask my mom tonight, she knows almost everything. you're looking good on the engine, you should be about going, now, gas has naptha as a primary ingredient, which is far easier to vaporize than alcohol, but the heavier elements in it produce more goo when it doesn't burn completely, and alcohol leaves little but soot and carbon. I used to use lighter fluid, such as for a Zippo, when I was young and had a hard to start engine, it's pure naptha, and a few drops in the intake will usually at least pop off. If you know there's oil on the bearings and on the pistons and rings, a couple drops in the intake won't hurt, but if the engine is dry without oil, it can leave you with scored bearings and cylinders, as will "starting fluid". Good luck on getting the carburetion set up, it seems to be one of the trickiest parts with these small engines. Looking good, and I'm ready to hear it run :thumbup: :nrocks: :headbang: mad jack |
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