Funny how threads wax and wane (this one is on the wane at the moment). I would be interested to know just how many people visiting this thread have actually had a go at casting as well as just having a passing interest. Also, it is sometimes hard to keep track of what is happening and who actually knows who and what is happening with various projects.
Eg, as I understand it, Neil (aka Flettner) supplied the initial casting to Ken for his sliding cylinder arrangement, but I'm wondering if their projects are still closely tied to each other, or have their ideas and designs diverged somewhat?
Willy, youre in a philosophical mode, but absolutely right, these things do seem to go in waves. As to "ideas and designs diverged somewhat?", not really, just struggling with time and competition from other activities and, I'm sure, the same with Neil.
Neil L. The soluble core you are referring to, what is that made of ? We did have a play with salt bonded sand that was set using a metal hot box. This then could be dissolved in water after the casting had cooled.
Anyways, turned out the dyno wasnt really at fault, but the blocked/seized exit water flow control valve. So, completely removed this (& the leaks that came with it) and will control the flows with manual valves. Checked the HT tacho against an optical tacho and it reads at half the true value. So when it reads 1270 it is actually 2540 rpm.
Did a brief run today and looks to be ok. From the smoke I can see there is oil in the fuel, or vice versa.
Made up a spreadsheet, so when I do get it under formal testing, I will use this to manually enter the input values and make the calculations for power and BSFC.
Using this spreadsheet, it can be seen it is running at the 2540 rpm @ 2.9 kW. That is, unless I have made a stuff up somewhere (and that "hawke eyed" Frits embarrasses me again). Also need to fit a calibrated flask so I can measure fuel flow rates and calculate BSFC
"Success is the ability to go from one failure to another with no loss of enthusiasm.
Ken, it was a green water soluble wax that we used. The main wax was red, and was not water soluble. Not sure of the Red wax melt temp.
It came from an American investment casting supply company.
Neil
Ken, it was a green water soluble wax that we used. The main wax was red, and was not water soluble. Not sure of the Red wax melt temp.
It came from an American investment casting supply company.
Neil
Is this the sort of stuff, they do show a green wax in this?
One key requirement would be that this wax core isn't affected by the lost wax when this is poured in. Also, what sort of sludge do you end up with after "dissolving" out and can this be re-converted back to the original wax condition?
Good though.
"Success is the ability to go from one failure to another with no loss of enthusiasm.
We never reused the dissolving wax but over time it did slowly deteriorate. I thought it was called hydrocore or something like that. It was green though.
The main wax used in conjunction was red. If there was no soluble core, the wax we used was Green and was tougher than the red and had a slightly higher melt temp. The red was quite brittle and easily damaged compared to the green tough wax. Ofallon casting in Missouri did the production castings in A356 and were heat treated T6 or T7 I don't remember which, and then with a white acid etc to make them look nice.
Now with 3d printed waxes, they are more accurate than the core arrangement and no dies need to be made. Certainly the engine that won the World F2A champs in Perth last year 2016, was a 3d printed lost wax case engine. They could get much better concentricity in the castings and a better geometry in the exhaust duct than by doing it with cores. Then if you wanted to change anything, it was a computer model change and you could get another lot of 5 or 10 or so done.
Neil.
Ken, a philosopher tends to be someone who knows all about life and how it should be lived, without actually taking part in it! (is that me?)Also they tend not to be noticed till after they die! - So I guess I've got something to look forward to!.
Looks that you are getting places with everything working as it should, maybe we will hear something different as opposed to a much modified conventional bike engine, keep trying.
I did have a little bit of a struggle getting my head around the wax and investment casting puzzle (not having pretty pictures) at first, but I think I can understand it now, and maybe I'm on the right track
Looking at 3D printing (much to Flettner's disgust) but I don't really want to do anything more than some very small castings for the moment and I do think it might come in handy there!.
I have a small Roland engraver (based on a plotter) which could be a basis for one and which could be quite easily converted to 3 axis. Probably would be just as costly as buying one in the long run though!
I've already got an extruder somewhere, ready to fit, plus a couple of steppers. However, it runs on HPGL (plotter language) as opposed to CNC, so a different controller is required, and a motor etc.to feed the filament. - it would be a challenge but I don't know if it's worth the challenge! - got to have a think about it!
Husa that looks interesting, never heard of that one before!
Unfortunately it runs US$2-300/liter which might make it a bit pricey for larger castings, though you could probably honeycomb the insides to stretch the material farther.
Neil, did you ever make use of 3D sand printed molds as from ExOne?
I looked into that several years ago and the price was on the high end for hobby use, but if you look at the price vs several weeks of time spent making traditional patterns it starts to look a lot more attractive (for many of us hobby time has zero monetary value, commercial stuff costs actual money).
No I have never looked at 3d printed sand.
But being at the top end of what we are doing with model engines, precision is the priority over costs.
Otherwise the engines are in the also ran class.
Neil
FormLabs has a resin for the Form2 SLA printer that is designed for use in lost wax casting ..........
the price was on the high end for hobby use,(for many of us hobby time has zero monetary value, commercial stuff costs actual money).
Thanks Michael,
Everything is changing at an alarming rate! and I can see 3D printed sand patterns having a great future in the foundry, but also the combining and (sintering?) process using both metal and ceramic powders is very interesting indeed. A bit early to say maybe but this possibly will eventually (at least partially anyway) take over from the casting process itself - if that hasn't already happened!
I would be happy just to carry on with the traditional stuff but in about 5 years time that might become a ludicrous way to do it! - However, I'll just have to remain as I am I guess, as it's too much of a leap for me! - all very interesting and exciting stuff though.
Unfortunate for me (and others) to be born at the wrong time!
Yes the Steadmens was right after all.
This is a sensible replacement for my ' universal ' crank case. The original was set up for a YZ gearbox, too hard to find. This has a 175 gearbox, smaller, still robust and available. Water cooled crank case and large rotary valve.
Designed for 100 or 125cc engines.
Reeds are for lawn mower engines🤗
Yeah, that is it Ken.
If only I did a simple sketch like just did, could have saved a couple of days in posts.
There is an outfit in England with a printer and offers the service printing and casting and heat treating.
That may be the way to go for a few engines for me. I just have lots to think about at the moment and
have to figure out what we are going to do. There maybe some changes after the F3D world champs so will
hold off work on that project for a while.
Neil
Originally Posted by WilDun
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