I need a quick flask to make some stove parts and was able to fabricate a steel cope and drag from some 3"x1" rectangular hollow steel after splitting some lengthwise to get two 3"x 1/2" steel channels. The steel did bend like a banana once split but the curve really wasn't that bad over such short sides so I haven't bothered to straighten it. The corners were mitre cut with an angle grinder and the steel sides were nicked with the grinder to get a sharp fold. I used a ratchet strap to keep it all in shape, and tack welded the corners once it was all square and sitting flat. They look reasonably straight and lie flat so there's no twist and they should last ok with a coat of paint on the inside to slow the rust. They are also surprisingly rigid for their size and resistant to twisting forces. Welds are all ground smooth and all edges deburred. Bottom frame has to be tack welded yet.
Made some progress and finished up the locating pins, will have to use grub screws to lock the pins in place.
Welded with flux-core? Is that metal galvanized? (Upon second/third/4th look, probably not. First picture looked like it at first glance.)
Hopefully it’ll be rigid enough to lift the cope without flexing too much when full of sand. You may need gussets in the corners, but time will tell. Pete
It's just painted blue from the steel merchants, welded with flux core MIG wire. I'll try and use them tomorrow and report back on the results.
Don’t paint them inside. It will form a thin layer of rust that significantly improves the grip on the sand. But it will not rust enough to cause thinning. With the rail at the top and bottom of each flask, sand retention will be good anyway. But paining (IMHO) will ad nothing. I have a couple steel flasks I have been using over and over for a couple years. They are great. No burning on iron pours and nice and stiff. No matter how you fabricate them some warpage is inevitable due to welding of angle rails to flat bar, bending rails onto flat panels, or sawing out sections like you did. In my case I used a jack to bend the 40” long sides back to more or less straight. That was a somewhat tedious procedure. A little side-to-side bowing doesn’t seem to matter. One of the reasons for casting aluminum flask panels was that welding/forming bowing issue. I also really like using the aluminum flasks for iron. [BTW, I was worried that dribbling iron onto the aluminum flask my cause local melting. Someone here assured that would not be a problem. They were right. The aluminum is so conductive that the iron freezes before any harm is done to the aluminum.] Denis
Mainly to allow easy replacement if the pin or the holes get wear over time, avoid any welding distortion of the pin alignment and I can fit longer pins if I have a particularly difficult pattern geometry to extract after ramming up. I did have to do some final bending of the box frame to keep the pins parallel in the end.
I did this about 30 years ago. It might have been a galvanized metal stud. I overdid it on the flanges because I didn't have a good way to trim them at the time.
We have an expression in Australia for stuff like that: "Built like a brick shithouse" or massively overbuilt. Well the flask performed beautifully, there was even an old aluminium matchplate whose width fit between the pin spacing. My green sand on the other hand wasn't strong enough and I was having problems with the sand drying in the 50% humidity, so I was constantly spritzing it with water while in use. I'm mixing it up in a wheelbarrow at the moment.
Awesome trowel. Much like the one I made years ago, and hope to make several more in the future for Foundry.
That trowel was cut to size by a German foundry worker name Wolfgang, not sure of the last name, the handle has WW carved in it. He gave to my friend Peter not long after he retired from Northern Iron and Brass to work on an island resort as the gardener.
I made mine from scratch, being ignorant of other possibilities at the time. Wish I still had it. It had good spring.
In post 7 above I mentioned how the inside of my steel flasks after quite a bit of use had rusted superficially inside. I took a pic the other day. I think the slightly corroded surface is perfect for sand retention. And I think it would take 50 years for deep rusting to occur. Denis
I managed to mix a decent batch of green sand and after several tries made a decent sand mould. Also I carved the runners on the wrong half so the iron would have to flow above the join. My iron was way too cold but I did learn how to tune the furnace properly at last.
