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Casting a Model Westinghouse-Type Twin Steam Engine in Iron

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ironman:
Pushing a steel rod into molten cast iron is still the best way to test for temperature just do not stir it otherwise it will dissolve. If you pull out the rod and slag, iron sticks to it your iron is too cold to pour. Another way to test the temperature is to look at the crucible to see if is brighter than the molten cast iron, if it is it needs more time to get to pouring temperature.

vtsteam:
Oh, okay, great tips Ironman. I'll be sure to check both next iron pour. :beer:

I have a couple questions about slagging. I know you slag in the furnace at least once -- I'm guessing just before adding ferrosilicon. What is the end of your slagging tool made out of? It looks relatively thin, and must be some heat resistant material -- stainless steel?

I find that in my furnace, the ITC HT-100 reflective coating soon gets covered with a brownish glaze -- I'm guessing from vaporized slag, mainly from slagging in the furnace. A little slag always escapes the slagging tool.

The brown slag glaze on the furnace walls reduces the reflective property of the HT-100 and melting time goes up from the initial very fast melts. I think my first few melts were 20 minutes long, now that are around 40 for the same 6 to 10 lb melts in an A6 crucible.

To try to see if I could improve that, I've re-coated the furnace with Satanite as a base over the blanket, and then a paint coat thickness of ITC-100 over that.

But, because of the slag glazing problem I'm wondering it the ITC 100 really is worth it on a foundry furnace (as opposed to a forge where people use it a lot), and maybe just the Satanite would give about the same results after the first few melts. It's much less expensive and also seems tougher and more heat resistant than the ITC-100.

Finally, speaking of looking at the crucible and iron to compare temps, I'm curious about what you use for eye protection. I see you use a face shield with a filter -- I've tried filters and it seems like a shade 5 is too dark for safe maneuverability, so I'm thinking of a shade 3 filter. What do you find works for you?

Thanks for all your advice and information over the years! I still have a copy of your early website from nearly a couple decades ago when I first saw it, where you were melting with oil, and also a cupola.

ironman:
Yes you are right it is stainless steel, 2mm thickness 40mm wide and is bent to a simple "L" shape. Welded to it is 6mm dia rod about 2 meters long. I do scrape off the slag just before adding ferrosilicon but I try to keep my hands as high as possible on the steel rod to keep them as far as possible from the exhaust vent. I try not to put the stainless too far into the molten cast iron as chromium absorbs carbon many times quicker than steel does. After about ten melts the stainless steel has absorbed enough carbon to make it brittle and also looks like swiss cheese so I cut that piece of and rebend another "L" shape. The stainless scraper part starts out at 200mm long but ends up a lot shorter after many melts.

I have never tried ITC HT-100 to coat kaowool and the same goes for satanite but I have heard a lot of good reports about satanite. I still have half a 25kg tub of zircoat and would love to try satanite but it will not be happening soon.

My face shield is a shade ten filter and is great for working around the furnace but when I get into my dark shed with my pouring trolley it is a blackout, way too dangerous. So before I push the trolley into the shed I put on cheap safety sun glasses which has a light tint and a clear face shield. I have tried lower filters but my furnace gets so hot and the glare hurts my eyes plus they are briefly dazzled which can cause a nasty accident. Here is a tip when using a shade ten filter, as soon as I don't need to look at the furnace I lift up the shield to see where I am walking.

That was not my website, I was featured on another metal casters website who took all  the photos.

vtsteam:
Thank you again, Ironman.  :beer: I think the shade number on some of my headgear is off. I have some gas welding/brazing goggles from Harbor Freight that claim shade 5, but they are darker than the Shade 9 setting on my same brand auto-darkening arc welding helmet. Hard to see anything out of the goggles except the furnace barrel. Too hard to maneuver,  even outside

Actually I've discovered that the auto darkening helmet seems to work well for me in iron melting. At the lowest setting, it dims the open furnace enough not to be blinding, and when the furnace is closed it reverts to a light green shade that seems right for carrying the crucible to the mold.

I have a couple more questions for you if you have the time:

First, do you adjust your furnace for a neutral flame, or do you vary that a little either way?

Second, I remember that you use copper wire to lower additional iron into the melt. I'm guessing transformer wire from scrapped gear. Is there any advantage to copper wire vs thin ferrous wire (like thin uncoated florists iron wire -- which I happen to have -- I don't have any scrap transformers).

Thanks!

ironman:
When melting iron I adjust the flame to be slightly reducing.

The copper wire is from the field winding from a car alternator. I found through trial and error that if the wire is too thick it takes too long to melt so burning my fingers even though I have gloves on. If the wire is too thin there is not time to aim for the crucible and the wire melts too quickly.

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