Metal Casting Zone

This is continued from the New Casting Member Introductions forum to here as the thread is starting to get quite long.

I ordered the 3D-printed patterns and core boxes yesterday and they should arrive tomorrow. After a trip to a foundry supply to get the goodies for a larger furnace, we should be ready to pour a cylinder to compare to that made with the traditional wooden patterns.

One thing for certain, money aside, the 3D printing process is a LOT faster than the traditional wooden pattern making.

Spent some time investigating heat treating 356 aluminum castings to at least a T6 condition. Sounds like 1000 degrees F for 6 hours followed by a quick quench and then another 4-6 hours at 300-320 degrees F. May try to find an inexpensive commercial service to do this although we do have a time/temperature controlled furnace. The quench sounds a bit tricky and things can go wrong that would ruin the casting.

Anyone know of a good burner design I can build? The burner is needed for a 5-gallon bucket furnace that has already had the refractory material cast in place. Natural gas is the preferred fuel although I could use propane if necessary. I have a machine shop so nothing is probably beyond me in terms of fabrication. In my first searches of this Web site, I didn't find burner designs. No top for the furnace so I'll have to make one of those too.

And larger tongs and larger crucibles to do the base of the engine which will be about 14 inches long.

I would build a burner that runs on propane, to my understanding the NG supply to most places is regulated down too low on pressure to use as a good burner although you can have a high pressure regulator installed.
The burner i am useing is based on the Ron Reil burner, it is naturally asperated and easy to build. I will post a picture later on, the old pictures on here under elcheapo 1 are my early attempt at a burner, my newer design is much much hotter although almost the same as what i had before...
Then again maybe with a blower you dont need high pressure? just volume?

Here are the plastic patterns and core boxes I received today from the 3D printing service.

These are very hard plastic and should handle very heavy use in a foundry.

Pros: Much better looking patterns than the wooden patterns we first used. The base of the engine which is very complex will be much easier to do in plastic than wood. Turn-around time was 1 day. I sent them the files late monday, they printed the parts on Tuesday and expressed them back to me on Wednesday. Got them today.

Cons: Expensive. If I had to pay for these, they would be about $850. There are slight longitudinal lines running down the patterns and core boxes from the printing process. These can be filled in with sanding primer or sanded down.

Overall reaction at this point is they are cheaper than hiring a pattern maker although someone has to do the 3D CAD to get the files. They can be reprinted at any time if we want to hand the casting task over to a foundry to make commercial quantities of the castings. Can ship the 3D files overseas and have the patterns replicated anywhere in the world.

Sometime in the next few weeks we'll pour a cylinder from these patterns and core boxes.

I also have to come up with a larger furnace to pour the engine base. Of course I first have to draw in in 3D CAD. It is very complex with no real obvious parting line since the top surface of the base does fall below the bottom of the engine mounts (like an integrated oil pan in 3 places)where you would expect to find a parting line. I'm in favor of doing the base using the lost wax method. But I think we'll end up with a sand casting attempt first.

Moving on, I hope to be able to cast the base to the engine in the next 30 days or so. I have a furnace and blower, just need to connect the 2 and add in some gas.

The base is quite complex as you can see in the 3D PDF I've attached. The question that is uppermost on our minds is not can we get a pattern but what pattern? Do we do this on a match board? Where is the parting line. We think the original followed a meandering path on both sides and the ends.

This model is not completed but is getting very close. You click on the PDF file with the left mouse button and then you can spin it around.

Any input or comments would be greatly appreciated.