Beware. It is so "easy" to redesign, you may allow for yourself, to make each one a little different if you fail with previous one. Stack of cases which i left as a memory how hard it was, and how quality improves over time..
Help Support Homebuilt Aircraft & Kit Plane Forum:
I wonder if you use a de-gassing agent in your aluminum melt, available from most casting suppliers?
Casting aluminum part 3: Degassing - Bing video
Casting aluminum part 3: Degassing - Bing video
You want my story of hobby backyard casting ? In short it was long, with a lot of downhill and uphill moments. I come into all this metal working due to want/need building of practical Striling engine. For myself and as a kit form, i still do have a lot of ex connections with cnc metalworking.. And there is a fixed niche for that 200-1000 watt engine to build into your stove for remote areas like mountains/ wilderness etc.. All parts could be milled from billet, but this costs your in 500-800 usd of bill per one engine + some 100-300 for heater.
This part is only about metal casting. Read some book, looked into some fancy videos of lost foam casting in loose sand (drop you foam in sand, pour your aluminum from ~ 3 feets at least to give it momentum). Tried, result was aluminum blob reassembling your foam pattern with a lot of impurities/porosity. And it look nice on video - a lot of flames
0. Lost foam casting as per youtube channels in loose sand - lesson learned i can melt some aluminum using charcoal.
1. Start setup - i was lucky to get some bentonite from guys who drill wells, mix it with crushed silica sand, got perfect and standard mixture for green sand casting. And came to undesrstanding that for one of for prototypes it is a no go - making wooden patterns was to much time consuming.
2. Tried lost foam with some diy coverage made from plaster of paris / gypsum etc - found same problems as all others - foams gases goes up throut you spruce. Some better result with thicker shell and melting foam before pouring. But still too long time to make and not stable result.
3. Read some patents on lost foam casting - in the beginning it was tried in slightly rammed green sand. Tried it with eps and xps foam - Blobs was starting too look more like a part, with some sand embeeded, but it was much better than 0 and 1 step. Bottom part in my previous post. stable with eps, xps was not stable, but hard on tooling - too much sand for a tool. And still not possible make part with minimum machining. Ok with porosity.
Did stop here for a long.. You cut your part with hotwire cnc, fire you foundry, while aluminium is melting sieve your green sand and you have part ready in an hour or so. But it have to be cleaned/sanded from all sides. And still wanted to have that nice surface as in big foundries.
4. Bouth an thermocouple to measure temperature before melting - i was always on cold side. Upped it to 750 degree, and all parts in xps started to cone nice. And much better surface - its does not embeed so much sand a eps inside. Mid part from previous post. Did stop here too, but with feeling to have it better was still with me.
5. Spent some time on reading shoolar articles on lost foam PAINT. A lot was concerned on a gas permeability and building your gating to push all gases to your loose sand via your paint.
6. Experimenting with coating. Tried some more diy coatings, tried to buy ready made (no luck to buy less than 200 kg....). Then i was able to see one "Gentleman" , Luciano who was making diy paint for lost foam casting from plaster of paris and latex paint. And his paint was really thin. Tried that recipy - much and much better. Still some porosity due to embedded water in gypsum from plaster of paris, but still good. Changed plaster of paris to chalk, latex paint to drywall sealer, yes it need some soap to wet your foam, but it worked much better again. But not for big parts. It was very relying on dynamic stability - you head of molten aluminum have to be in certain margin to push all of gases via paint into sand, you have to reheat your aluminium to have enought heat left after evaporating your foam to fill all parts and avoid cold aluminum oxide bridge etc.. But it was on way side - then all went as it could, all was perfect. My alloy was stopper here, so i bought myself an graphite-clay crucible and some degassing tablets, because porosity was an issue again - we are cooling in a dry sand which is an thermal insulator itself.
7. Hated to handle that molten aluminum in crucible, "invented" handle, which was absolutely superb and easy to make :
8. Pouring cup. It is used for green sand casting for better control of turbulence, but it was used by one big lost foam caster to improve quality..
And this was a game changer. No "buble porosity", no embedded sand, no special effects while pouring :
This one with special efects :
And i was limited by quality of my foam patterns - if you score your foam with 120 grid paper before painting it will show on you final part. So for complex parts i have added some wax fillets and all turned out nice.. I am castings parts from 4-5mm thinned wall, like cylinder with 120m id and 70mm long easy. I could go lower, but this make foam pattern too soft to handle it correctly.
9. argon gas bubbling. What nitrogen tablet did not work...
Top part in previous post.
10. Convert from gas furnace to waste oil one. Lets do it in a proper way for Mother nature. Just too small amount of black smoke and too much hydrogen from lpg.
Last edited:
That makes 2 of us with similar experiences. I think I'm probably somewhere between B and C at the moment. .
Still trying to figure out how to make the parts I want in foam so I can get away from lost wax. Al203's videos have been inspirational.
Edit:
Started with charcoal as well. Building electric at the moment, with Argon cover, to avoid all/most of the H2 problems.
All yes if you have ingots to buy nearby. Mine ingots are in the form of broken car alloy whell or engine intakes/heads..
You can make you own ingots from scrap (wheels/heads of known alloy) that are nearly as good as commercial - if you are meticulous with the preparation. I used old VW heads and pistons that I had laying around.
Even back in my charcoal days I managed some good H2 free ingots, and resulting castings. I used a cover flux and degassed with sodium hypochlorite.
My biggest problems were sand and oxide inclusions...............due to caveman quality sprues, runners and gates. Hope to do better in the future,
Even back in my charcoal days I managed some good H2 free ingots, and resulting castings. I used a cover flux and degassed with sodium hypochlorite.
My biggest problems were sand and oxide inclusions...............due to caveman quality sprues, runners and gates. Hope to do better in the future,
But it is worse with lpg. I try to vaoid that nasty fluxes as i can. Especially fluorated ones.
Fixed that for ya.
Woodenwings
Well-Known Member
Spoke to SW.
Download and install before December 31st. It is just the same version as the Education version anyhoo. Having used CATIA, SolidEdge, SolidWorks, Inventor, OnShape etc. SolidWorks is the best for what we do with aeroplanes.
I teach it now (how lucky am i) it was my choice out of the lot. Have 20yrs experience with it.
Feel free to bug me about it!
Download and install before December 31st. It is just the same version as the Education version anyhoo. Having used CATIA, SolidEdge, SolidWorks, Inventor, OnShape etc. SolidWorks is the best for what we do with aeroplanes.
I teach it now (how lucky am i) it was my choice out of the lot. Have 20yrs experience with it.
Feel free to bug me about it!
I started with SW98 and prior to that started with Autocad 10 in college. Got a job using Cadkey Datacad, Next job used Mechanical Desktop and then in 98 we switched over to Solidworks. Never looked back.... However SW does suck for complex Surface Modeling where class 1 surfaces are needed. I avoid surface Modeling like the plague...
Woodenwings
Well-Known Member
Hi Addictedtoclimbing,
Im interested in what you use for surfacing! I struggles with SW for surfacing early on. Nobody to ask for help etc. I feel pretty confidant i can model most any shape in sw now. There is only one shape that has caused me grief. But it was for my own silly fun, not for work.
Can you tell me what you consider class1 surfacing. It is a term i have never heard in my career!
Im interested in what you use for surfacing! I struggles with SW for surfacing early on. Nobody to ask for help etc. I feel pretty confidant i can model most any shape in sw now. There is only one shape that has caused me grief. But it was for my own silly fun, not for work.
Can you tell me what you consider class1 surfacing. It is a term i have never heard in my career!
Scottiniowa
Member
Not sure how the wheels worked with the EAA Solid Works, but it seems now that perhaps it was a bait and catch kinda thing. I taught it for two years at OSH, and it certainly exposed a lot of folks to the capabilities. Been doing some kind of CAD work since Cadkey 97, and SW's just a few years later. Been interesting to say the least. Like anything, the more you use it, the better you'll become, and if used seldom, the cheat sheets are even more valuable.
As for help, I have found just about any question one would have, someone, somewhere has tried to answer on YOUTUBE, if not there, on the SW's forum site. Once in awhile the answer can not be found, but that is seldom.
Best of success
As for help, I have found just about any question one would have, someone, somewhere has tried to answer on YOUTUBE, if not there, on the SW's forum site. Once in awhile the answer can not be found, but that is seldom.
Best of success
I have never been able to get my EAA version to load. The loader hangs. Windows 10. Have no idea where to get any help.
piepermd
Well-Known Member
- Joined
- Oct 22, 2019
- Messages
- 58
Which version do you mean? I paid $99 to a reseller for a 2021-2022 version because that one was not yet available for EAA members…
Would have been nice to know about this 'feature' ahead of time. I went straight to 'installing' Realthunder without installing Freecad, and it was somewhat disconcerting to discover that while it seemed to open normally, there was no evidence that it existed after I closed it (not in the 'start' menu).
Anyone know the logic of structuring the program this way? Does Freecad operate the same way?
1. Just install it or press right click, choose open with, tick always use this program, press other and browse to your downloaded folder with freecad.
2. Which structuring your need ?
Thanks, but I'm not talking about a created file; I'm talking about the program itself. Starting it feels like I'm back in the previous century's DOS days, and it's a bit disconcerting when clicking on 'runfreecad.bat' opens cmd.exe which then automatically opens Freecad Link Branch.
Woodenwings
Well-Known Member
Have you tried logging in as the administrator before installing?
Moving from windows 7 to 10 makes this more annoying. I really hate win10.
Oh well!
AJLiberatore
Well-Known Member
Tallank...
Here's what worked for me.
* Turn off your Firewall / Spyware for greater than an hour or until you say so.
* Go to your Modem/Router (yes I have one of those combo ones) and literally use the old school ethernet cable to connect and turn off your computer Wifi button.
* Ctrl/Alt Del & Stop any processes you might have running that would mess with the download / boot.
* Follow their directions / prompts to a tee when you launch the download.
* I am wondering if it is a disk space issue on your end.
BTW you are not alone, as a volunteer I have had this question asked a lot. I wonder how many EAA-er's never got passed the download, I talked to a number of them.
AJLiberatore
Well-Known Member
I am here to bug you Woodenwings!
* I Downloaded 20/21 before OSH & "The announcement"
* purchased not a laptop but a workstation because the Horsepower you need to run it is not cheap, ouch.
* So I have been using it to brush off my skills a little each day.
* Hoping to attack Weldments and the Sheet-Metal modules since I have an old school design (drawings) given to me by the owner of the rights to said design that I'd like to model it to learn those modules.
* By the way look into what those cost for a 1 to 3 day class from a local value added reseller, they are not cheap and those modules have a bit different way of doing things.
With that as a background today I get the message, your license expires on 1/1/2022. When this "whole thing" went down, I was told or heard it incorrectly, you load it before the switchover it will be good for a calendar year. Obviously not so. Look, I am a luddite, I don't want to send my files up to the cloud, and that goes for other EAA-er's especially those that do or have worked in sensitive arenas. I am currently working for a firm where I assemble prototypes for inventions, and the design team uses OnShape. Ya it's kinda cool, but I want the native program and my files on my machine, that's the way I and I bet a lot of folks here roll.
If I am reading here correctly, older files will not load? All those models I'd like to look back on and refresh my mind as to my design tree methodology are now gone? All that for what? Many are the more complicated models I used (and perhaps many here did) to get ready for the CSWA. I was an Instructor (Pre-Solidoworks Class) and Assistant in the non-profit arenas, are all those files I used for training now boat anchors?
I'd like to be able to run this version till next August, I am not ready to do this cloud thing. I don't mind paying the same amount for what I am doing now, I just want it on my machine. It is not "just us" upset w/ Dassault Systems trying to out OnShape on OnShape, I get why they did it but this is not going over good, enough said....
I look forward to your reply.
