So... what to use for an anvil?
Funny you should ask... I have been writing on field expedient and/or cheap anvil substitutes this week. Many folk say I beams or a section of rail. If you go this route, wrap it in heavy chain, bolted fast. The chain will deaden some of the very high pitched ring and help save your hearing (but still wear hearing protection when you can). If the loop of chain is loose enough, it can be unslung and used as a carry handle. Coating the body with something like rubberized truck bed liner or the like also helps, but may catch fire if you are unfortunate. If it does, throw some sand on it and keep working.
Other handy items;
-a section of thick plate; check any machine shop that has a water jet cutter. Or scrap yards that service them. A 4" round section of 1" plate will work reasonably well, though it is going to bounce. Glue it to a decent block of wood with rubber cement to help reduce the bounce and get it up in the air a bit so you are not stooped over trying to work. If possible, file or grind the edge into a radius; it is more serviceable, will allow you to use it to shoulder hot stock, and is far safer to the user than a square edge is.
-a large section of heavy walled pipe with a disc (as mentioned above) welded to one end. Fill the pipe with sand, then weld on a base plate with angled braces to build a "post" anvil. The sand adds weight and reduces ring. Very hard to pack in though.
-make a portable anvil. Again, a heavy bit of steel, preferably about 4 to 6" long by half as wide by 1 1/2 to 2" deep. Drill a 3/8" hole into each side (opposite each other), and mount a bail handle to carry it or tie it to a pack (then dig a ground forge and work on site). I am screwing around with a pack in kit that is a tweer (air blast pipe), a backpack mounted bellows, a small portable anvil, two pairs of tongs and two hammers, all mounted to a canvas pack for bush work. Such a rig would be fired with charcoal made on site (which is usually better than store bought) and as such, the kit will require a small camp axe for charcoal making. Of course, a proper fire kit to light it all would be in order as well, though a lighter and paper is a bit quicker.
-other heavy bits can be used as an anvil in a pinch. In the past, I have used a section of car axle (hard to keep from rolling, great for drawing points, not worth a crap for big flat work like blades), a manhole cover (cast iron, while heavy, tends to crumble under the hammer), and the ball from a tow hitch (the flat spot on top was about 1" in dia... it was a field expedient repair that had to be made, I wouldn't suggest this unless you are only doing small things like arrow points or fish hooks). Even smooth bits of granite can be used, and some Scandinavian anvils were basalt or granite (wear decent eye protection and an apron, a missed blow with a hammer can cause a spray of chips and debris, and do bad things to your "anvil"). In an extreme pinch, concrete can be used, but it WILL crumble under the hammer.
The trick is to use the correct hammer for the "anvil" used in these cases; a smaller hammer puts more force in a small area, hopefully keeping the anvil bounce to a minimum. It makes the smith work harder however. A larger hammer, used gently can be used on a smaller anvil. The usual rule of thumb I've often heard from the old timers was 50lbs of anvil per pound of hammer. That said I use a one handed 10 pounder on a 125 pound anvil at times. Somewhere I have a photo someone took of me that shows a clear 1/2" of light under the anvil, making it appear to be floating that shows just how much wasted force I was putting into bouncing the anvil that day. Ah well, it looked great to the boy scouts and parents watching!
The big trick is think creatively; "can I hit that and not break it? Hit it a LOT? Can I carry it about?" if all these questions are answered with a yes, that should work. Granted, a proper anvil is a highly specialized tool, with a number of features that an anvil stand in will not have (a horn, pritchel and hardie, cutting table and radius shoulders - all very handy), but it will get you out there and making things, and that's the best way I know of to learn! Read, study then DO IT! Have fun!
Thanks for reading my long ramble here! I'm going to go make a bit of weird damascus.