Endo

Arkie,

It might be due to uneven heat as the stock is somewhere around 1.375" thick round. It's been a few weeks so I don't remember the exact measurement but it is over an inch.

On that the technique that Charles has illustrated for me is the info I was looking for as I have experienced this on smaller stock also.

Again thanks.

Charles, 

 

I was thinking it was something like that. I remember watching a video that explained how to prevent that but when I needed the knowledge couldn't find said video.  Thanks for the quick reply

hi everyone, I have a problem that seems there should be a simple remedy to. I am going to attemp to forge a tomahawk head and when I have forged flat an end of bar before I end up with a hollow in the end I am drawing flat. So what prep do I need to do to prevent this.

Thanks in advance

Nice one ,it looks a cracker .

 

How long did it take to forge ?

 

 

Rob 

 

Rob, it took me about 2 hours total to forge. this is including waiting for my forge to get to temp. Castable refractory does take a bit longer to get to temp. I had to keep it really hot so I once I drew out the edge I had a very short open time where I could move metal easily so I was dancing with this thing getting it hot than back in the forge.. 

 

ausfire, I heated the cutting edge up to austenite than quenched it in what oil I had which was only a quart of cutting oil and ended up boiling that but to my advantage as I didn't want to have to temper the thing it hardened it enough to where a file doesn't bite like when it was soft and my good quality sandpaper doesn't do much cutting either. I also dropped it when I was quenching it and thought it would have broken and it just made a decent spark on the cement and didn't do much damage. 

 

all in all I am pretty happy. cant wait to use it.

this is my first tool. Made out of some unknown shaft material but it has a high hot hardess as it had to be almost white hot to forge.

Alan it did not crack. There was some light spalling at the mouth where the castable is at its thinnest. Interestingly the top of my burner was sweating a few times during initial heat up. So far I have only gone to 20psi which gets it plenty hot and I know extended use at that pressure will freeze over my 20# tank.. I need a 40# tank atleast.

A couple more pics. I added some doors to

So I finally got her time and guts to heat this thing up. I am very happy with how things turned out.

So I fired the burner for 10minutes than shut it off till the steam stopped than repeated but shorter firings the next few times as it didn't take much for it to get steaming again. When I finally let it go for a while what I thought was steam was actually the paint and adhesive starting to gas out.

Some pics for fun.

This is at 10psi


This is at 15psi

If it puts your mind at rest…the first time I came across castable was when I was given a few bags by the foreman at a drop forge works that I bought a Massey hammer from.

 

When I used it to make a furnace base, I looked up the handling spec. which referred to incrementally raising the temperature 15 degrees every hour for days.

 

I phoned the foreman and asked how to control the temperature increase. The answer was "Ignore it! when we are going to recast a furnace we turn it off after the shift on Friday night, smash it apart, recast it, light a small flame on Saturday morning, leave it burning over the weekend, Sunday night it is turned up flat out and is ready to use by the Monday shift…sure they crack, but they still work fine with the odd crack"

 

My first castable furnace lasted for 15 years and we only replaced it because we were idle while waiting for a project to get under way. It had tonnes of steel through it in that time. It was cracked and worn around the mouth but I did not notice any increase of efficiency when we recast it.

 

Alan

 

 

 

 

thanks that really does put my mind at ease. Once I get the feet on it I will fire her up!

Here are some pics of the forger.

First the burner, I am pretty excited about this guy.


The forge, it is missing some hardware namely the legs which I hope to get welded on later today.

Last castable I made put a heat lamp in one endand blocked off half of the other end so moisture could escape. Left it on 24/7 for 4 or 5 days.
First fire only for about 10 min. Next few fires each a little longer then go for it.

This sounds more reasonable, as I said it has been sitting drying for 2 weeks I have left it to get as hot as it can in the sun so any moisture on the surface has been driven out. I just need to bring it to operating temp slowly without any explosions. I do expect it to crack as it is a continuos cylinder and there is one thinner spot at the top but I don't want it to spall.

I will take a picture a little later.

Hi Everyone,

 

I am building my second forge, my first being made with ceramic wool, This new one is a castable forge using kast-o-lite 30. I poured the castable in the forge about 2 weeks ago and it has been drying since, I have been making some of the hardware to finish the forge and also building the burner in that time. So I have the burner built I just need to get the castable fired for the first time. I have no way of controlling temperatures for extended periods just able to fire my burner on and off to sustain a temp. Any ideas for heatup on fresh castable?

 

Thanks in advance.