Adding weight to a post anvil

[navasky]

I'm planning to sink a sledgehammer head into concrete to make an anvil. I'd like to increase the density of the concrete by adding steel scrap. What I'm wondering is how big the pieces of scrap can get before the strength of the concrete starts to become compromised. Ideally I would just toss a ton of railroad spikes in with the concrete but I have a feeling they might weaken it. Does anyone have any experience with something like this?

[Glenn]

If you put a 20 pound sedge hammer head on a 200 pound stand you still have a 20 pound sedge hammer head as an anvil. It can and will do wonderful things but is not a 220 pound anvil.

[ThorsHammer82]

The concrete will eventually (quicker than you'd think) break down and be useless. You're better off using a metal or wood stand.

[Geoff Keyes]

A number of knife makers (you didn't say what you want to do), Tim Lively and Tai Goo come to mind, have used post anvils set in concrete and it works for them.  For something as small as a sledge hammer head I would take a 4x4 wood post and carve a hollow in the top.  Fit the head to it and then run a strap through the eye and bolt that to the post.  Embed the post in a bucket of concrete.  I think Glenn is right, it won't be as good as a #200 piece of steel, but blade smiths have been working on small spike anvils all over the world, and doing good work.

 

Geoff

[Jim Coke]

Greetings Navasky,

 

Mounting the sledge in concrete not such a good idea...  I think it would be best to mount it like a stake anvil in wood...   What ever you do use caution hitting hardened steel with hardened steel yields small chips that fly off and can hurt...  Don't miss... And by all means wear safety glasses... 

 

Forge on and make beautiful things...

 

Jim

[navasky]

Thanks for all the suggestions guys. I actually have the sledge head attached to some large pieces of steel that go all the way to the bottom of the form so as to take some of the load off the concrete. I was debating whether to coat all of that with silicone caulk like >this guy did in order to reduce vibration. Now back to the original question, I know that adding weight to the concrete won't be the same as having a heavier anvil, but even if it only helps 1% I'd still like to do it. Can anyone weigh in on how big I can go with the steel "aggregate" without making the concrete weaker? Thanks.

[Charles R. Stevens]

I wouldn't go any bigger that 3/4", as thats about what a bag of redymix has. You might consider a loosely rolled peice of old fence. kind of ferro cement. Cement wouldn't be my first choice either. But let us know how it works out for you.
As far as hitting a hammer on a hammer, two observations. Even tho it's not recommended, note that the best anvils and hammers have hardened faces, and the new hammers you buy at the big box stores aren't very hard.

[DSW]

Concrete filled with steel bar often breaks up easier than solid crete with no steel in it. Take it from someone who has broken up quite a bit of crete in his career. Crete almost always breaks away from the steel 1st.

 

I guess small bits of steel like crushed stone might add some weight, but it's probably marginal at best. Also note that concrete in general is moderately corrosive to uncoated steel. This is especially true if it gets wet ( concrete IS porous and WILL absorb water). When the steel starts to rust, it acts like  a wedge and helps split the concrete ( it's why you often see steel exposed on road bridges and so on where the crete has spalled.) If you wanted to add mass, the best way would be to use a very fine "sand" of steel vs larger chunks. The finer particles would allow you to add more steel vs using bigger chuncks pound for pound. Down side is this would rust much faster than larger pieces. The end result probably wouldn't be worth the effort. Lead shot would probably add more mass, work in better, and have less corrosion issues. Even then I seriously doubt it would be worth the effort and expense.

[navasky]

Thanks DSW that's exactly the information I needed, I guess I'll be skipping the steel.

[Glenn]

Now if you were to WELD the hammer head to a big chunk of steel then,,,,, Oh wait a minute, that means you have a big chunk of steel to begin with.
 
Look for something with a mass of 50 to 100 pounds that you can beat on. The positive and negative shaped come in handy for swaging. Search for Brian Brazeal and look at his striking anvil.