im new at forgeing metal i have so far made one knife that sucks but thats okay its my first one.
i started with a piece of leaf spring i heated it and cut out the shape with a chisel and hammer took a few hours .

but my question is when i stated the thing was about a quarter inch thick
and after its now almost one eight inch thick did i heat it up to much
or is this something that will happen no matter what

The slate colored scale that comes off it every time you pull it from the fire is another layer of steel lost to oxidization.

You can cut your blank with a hacksaw a lot more quickly and easily than chiseling it out like you are.

If you'll click on "User CP" at the top of the page and edit your profile to show your location you'll probably discover there are folk close enough to you to help directly.

Frosty

Ninja Style: if your steal starts sparking you are getting it way too hot and will lose a lot of steal that way. As Frosty said though each time you remove it from the fire you are going to lose some to scale. It will help if you keep the piece in the more reducing (less oxygenated) portion of the fire but it will take longer to heat up. The closer to the air source the more scale you will form as a general rule.

i don understand? ya wallel the heck out of it! or sounds like ya cookrd it off well tis a question to you- what happened? i tore up leaf spring and never got reduction like that in 10 heats- please let us know,... jimmy

some questions to help us better answer your question.

is the metal sparking when you pull it out?

are you useing a hammer and anvil and forgeing?

if you are useing a forge whare in the fire are you putting the steel?

is there any othe info you have about what you were doing?

You offered it up to the fire Gods as a sacrifice and they accepted it :)

don't use to big a blower less o2= less scale and less loss. so keep it realitivley cool. orange in sunlight is hot enough. and little scale. it works for me.

if you are going to forge the blade then you don't need to chisel the shape out, cutting a crude point is more than sufficient

as others say, watch the temperature and the amount of air and the scaling will be reduced. get the metal to the right temperature and hit it hard and you should get more work done with less wastage.

as a side note on hot chiselling, I was teaching a couple of guys last week and amongst other things we made a trivet. Nice simple thing (as simple as I could think of!),which involved splitting a 2x1/4" bar of mild for 15" along the centre. OK, it was mild and not spring steel, but I was able to hot cut it much faster than the others did with angle grinders! it surprised me anyway.

chiseling is not worth the time unless you need a perfect point in a perfect shape. and if it is sparking it is WAY too hot. that is ruining the steel and you can't make a thing of it.