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### Help Support Home Model Engine Machinist Forum:

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1. ### Improbability Drive MkII

I have a sudden hankering for a bottle of Old Janx Spirit. :D
2. ### 1/3 Scale Ford 289 Hi-Po

Wow! Just Wow!
3. ### Teflon as spark plug insulator

You could have just said you thought it was too expensive Steve.:rolleyes:
4. ### Teflon as spark plug insulator

Why would anyone use Teflon in a spark plug when this stuff is readily available? McMaster-Carr If that is too spendy, there is also this stuff. McMaster-Carr
5. ### Sodium Silicate for Foundry Sand

Actually, at room temperature of 20 deg C it will be about 830 PSI.
6. ### Steam engine lubrication

Hi Steamchick, I was following through your calculations, but there was one bit that I didn't understand. In this line: So this 7.6cu.in/min. of water = 7.6 cu.in./min. x 3.13 = 23.9lbs/.hour. Where does the 3.13 come from? I did it like this: 7.6cu.in/min x .033Lb/cu.in. =.251Lbs of water...
7. ### Ambitious ORC Turbine

That makes sense. I was reading through your earlier posts and noticed you are planning to drive a turbocharger compressor with your engine. What happens to all that high volume/ medium pressure air from the turbocharger compressor?
8. ### Ambitious ORC Turbine

I looked at the table, and I do believe you are interpreting the volume correctly. Are you planning to superheat above 183 C? Keep in mind that as the gas expands and cools, it will be dropping into the wet region under the "steam dome." At this point, some of your steam will have started to...
9. ### Ambitious ORC Turbine

Hi guys! I've got to jump in here regarding PV=nRT. You cannot use PV=nRT when dealing with a Vapor according to my thermo book. This is why we use the Steam Tables. There is no simple mathematical expression for pressure, volume, and temperature when dealing with vapors. The vapor temperature...
10. ### Help with Mach3 and 4th axis machining

You can take out G28 without any problems. G28 rapids all axis to their home position which I find can be kind of dangerous if you are unsure of what path the machine will take to accomplish this. Personally, I never use G28 for this reason. I like to use G00 Z4.000, or G01 Z4.000 F10 (if you...
11. ### Using a CNC Mill as Lathe

That is REALLY cool! I gotta try this.
12. ### Small engine dyno

Wow, it sounds like your to do list is as long as mine! I look forward to pictures of what you're up to. I've never tried using stepper motors for dyno brakes, it will be interesting to see how well that works. Do your turbines have proper DeLaval nozzles in them? If so, they may not use much...
13. ### Small engine dyno

Thanks, I'm glad you liked it. I will be adding better instrumentation in the future so I can feed the data into a laptop, but right now I've got a big list of other things to do first. I would be happy to help whenever you're ready to build your own. Cheers!
14. ### Small engine dyno

You guys have made some cool dynos! So far, I've found the easiest way to make a dyno is to use an AC induction motor as an eddy current brake. It is literally already made for you, and any AC induction motor will work. You simply feed DC to the windings to increase the braking effect. Here is...
15. ### aluminum 4032 piston material heat treatment

Why not make the piston out of something that really IS heat treatable like 7075? I don't know if this would work, but it might be worth a shot.
16. ### Casting fun

I've been casting aluminum, and some iron, in my backyard for years, and in my experience, degassing is rarely necessary. The main gas that aluminum absorbs is hydrogen which comes from incomplete combustion of your fuel. The trick is to fire slightly fuel lean. In order to do that, you fire up...
17. ### DoAll Bandsaw for Brian

Hi all, Have you checked whether the motor needs to be wired in "star" or "delta" for the VFD you are using? That could set a fault. Also you want the motor and the VFD to be close together because long wire runs can set up weird harmonics that do bad things. I hope that helps. Cheers and good...
18. ### "Steam eater"

Hi F.Wissink. I think sometimes it gets forgotten that this is a HOBBY engaged in for fun, self education, and a way to express our artistic creativity or whatever. If it doesn't work, so what! I personally have learned far more from my failed attempts than I ever did from my successes. Anyway...
19. ### First Fire

Hi Bovine, Looking at your rig, I can see one problem. Your exhaust vent holes are probably too small. Don't forget that when you heat up air to 2500 F or so, it expands quite a bit, so you must allow enough vent area to get this "bigger" air out of the furnace or you will choke down the...
20. ### Need opinion on truck

Hi Ranger, Sounds like the truck is a total basketcase at this point. Don't buy it. If you offer your friend \$500 (way too much, this thing is scrap) he will be insulted because he paid waaayyy to much to get it back. They only made a bazzillion C-10 Chevys, so if your heart is set on this...