First iron melt - Real time

Very excited guys! I did some floor and tuyere repair today with Bluram and decided to fire. I made some aluminum ingots just to run the furnace and decided to give it a try. Furnace had been running for an hour and I've dialed everything up. I added 8 lbs of cast at 730. Its 809 and I've already skimmed once and added another 8 lbs or so. Going to pour into greensand ingot molds. Wish me luck.

Pete

 

GO PETE GO!!!

 

Well that'll do for now! 1 hr total crucible time. It would have certainly been less had I preheated my second charge.

 

That's way better than the tiny bit of mouse poop I melted first time round.

 

It's actually timely to hear from you Mark. I was melting bronze on saturday at what seemed like my usual oil/air/atomizing settings and it was taking forever. It seemed that the top of the melt was fine but the bottom of the #10 crucible remained slushy. I was able to bring the muck up to the top of the melt and got the whole thing up to 1200C to pour, but it took a stupid long time. I was surely bringing enough fuel and air to the party but I noticed.... my flame goes half way around the bore and then angles straight up the wall toward the exhaust hole. Sound familiar?
So I looked up your disk thread which was very interesting. I read a post in that thread where someone mentioned that they remedied the issue by pointing their burner downward. I really dont want to do that because I'm afraid my nozzle will cause pooling. I discovered this afternoon that the fit of my tuyere had gotten a bit wonky and was indeed pointing at a bit of an upward angle. This put me at a crossroads. I like the idea of the disk and would like to try it, but if all I had to do was straighten out my burner then I'd save myself some form work and ramming. So I repaired the tuyere, resurfaced my floor with a 1/2" of bluram and had a go with aluminum. It melted a #18 just fine and did a second heat in short order. Seemed great. Then I turned up the fuel and air in my already hot furnace and went for the iron. The first few chunks melted quite quickly as i mentioned above. I put one chunk in and preheated the next couple of chunks before putting them in. I was surprised at how fast they melted. It seemed that my burner issue had been resolved. I decided to put the next load in without preheating and of course must have frozen the melt. 20 minutes later the top of the crucible was liquid and the bottom was solid. I was running fuel at about 3 gallons per hour and my blower flat-out so there was really no more to give. I covered my exhaust about 1/3 with a fire brick and crossed my fingers. 15 minutes later it was fully molten so I skimmed and poured.
Long story short, I'll be giving your disk a try.

Pete

 

Way to go, Pete. This sounds a bit like a "breakthrough" moment!

Denis

 

First of all congratulations on your iron melt, it's a major milestone for any oil burner users. While I'd be interested in seeing how another disc in a furnace runs, solving it in an easier way is preferable. I have noticed that the disc does give a fairly even heating to the crucible which should extend it's life in theory. Your fuel consumption is roughly comparable with mine: 5 US gallons in an hour for about 26 lbs of iron in an A25. I have noticed running the furnace flat out (without a disc) makes the flame transition from vertical to spiral.

My next experiment is going to be lining my removable 4" bore tuyere pipe with 3/4"-1" of dense castable and allowing the fuel spray to hit the hot refractory lining once the fire is lit. If it works out as planned it may eliminate the disc and precombustion chamber altogether.

 

Congrats Pete!

 

Thanks for the encouragement guys.

Thanks Kelly. Yes I have a couple of patterns waiting in the wings. A couple of years ago I picked up an ancient Seneca Falls lathe with a broken compound and a cracked link arm in the gear train. I could simply mill these parts out of steel as I have the equipment to do so but I've been advised to stick to original designs and materials. I've just been waiting to cross this particular bridge.

Pete

 

If you need some pictures, measurements, or whatnot from a 1903 let me know; still sad that the spare I had was for an entirely different machine. :/

 

Thanks. Fortunately the parts are complete- just broken- so I've got good references to work with so far. I used a router copy carver to rough out the compound and was able to enlarge it slightly for machining.

 

Today's the day. I'll be pouring my lathe compound and link arm today. Greensand is fresh, molds are made. I'm ready to close the molds and fire the furnace. They're chunky patterns so I designed the molds with large blind risers. I tested the molds last week with aluminum and everything appeared to work correctly, so I'm pretty confident. Update later.

Pete

 

One of my patterns is an 18” long prism with two faces 2.5 and 3” wide. I found it only pours well if oriented pointy side down. Since I drop in a core to form the third side of the prism and I need to feed it from below, I need to use a cope, cheek, and drag. The prism divides 90% of the cheek sand fully in half. Without using screwed-on top and bottom board, flipping that mold without breaking the sand is impossible.

For almost all of my molds I screw on the top and bottom boards as I do my lifts with a hoist or I flip by hand but the molds are too heavy too manage the flip and at the same time keep the bottom board in place. I do find that smaller more conventional molds are OK to flip with floating top or bottom boards or are often not required in the case of a typical gear pattern or maybe a plaque.

Good luck on your casting today. I’ve found that leaving a 5 to 10 pound iron casting in the sand for 5 hours or so allows it to cool down to 300 degrees or so. It can be then shaken out without risk of hardening the iron. Avoid the temptation to use much water to douse flask fires. A light spritzing along the seams can be ok. But I learned that hosing down the wood more freely can result in harder iron. That’s not what you will want for scraping in your compound.

Denis

 

Well that was an adventure. I did 2 heats in a A10 Salamander Super. No problems with that crucible. One was for a 20 lb casting, the second was for a 13lb casting. Both filled completely, so that's a relief.
Highlights and potential topics:

It took a long time to get the first heat melted and poured. At least 90 minutes. As the furnace gets heat soaked (solid refractory, no insulation) the combustion rate changes and after 30 minutes or so I had blower running at top end and fuel at about 30% on the needle valve. Kirby vacuum cleaner exhaust for blower, 20 psi pushing diesel fuel, 10psi atomizing air through a Delevan nozzle. After a full hour or more I had plenty of melted iron but the top layer was 1/2" thick and very gooey. It made for very awkward skimming and I'm not looking forward to inspecting my furnace later this morning. I eventually jacked up my atomizing air to 20psi and was able to increase fuel flow with the needle valve. That was the push I needed. The blower on its own was just not able to give me as much as I needed so I had to augment it with more compressed air.

I had 1/2 oz of ferrosilicon wrapped in brown paper which I plunged into the melt shortly before I was ready to pour and it boiled over like a volcano. Moisture maybe? Startling and messy. i ended up having to add more metal and waiting. Hopefully not too long.

Skimming was extremely awkward and messy. I was using a fence post bent over at the end in an L shape and each skim pulled out a lot of good metal as the dipping end got fatter and fatter. Skimming was not totally effective and I unfortunately saw a bit of slag go down the sprue hole as I was pouring.

The second heat melted straight away. (rain clouds looming) Nice and liquid with less slag on top. I had enough metal for the pour but added one more chunk just for insurance. 4 or 5 minutes later the blower quit! You should have seen that pyro show! I shut the fuel down, unplugged the blower, pulled the partially molten chunk out of the crucible which dragged out the slag, and poured the mold. It filled the mold with very little to spare. In my haste I neglected the ferrosilicon.

I waited about 6 hrs to shake out the molds. Still very hot. I just broke them out to see if they filled. More observations and pictures later today.

Picture shows why my blower quit.



Pete

 

Brushes strike again!