Hi All,

Sorry if this is a stupid I just want to check something, if when I am using my coal forge I get small blue flames within the fire.

Do I need to be concerned that I am burning harmful chemicals, I have always previously thought that blue flames just indicated a hotter flame. But I watched a video on youtube about harmful gases when heating metals and it mentioned a key indicator is a blue flame.

Thanks,

Depends on what the flame looks like.  Most likely you are just getting a reducing flame; generally considered a good thing; but you do need adequate ventilation.

Another very different bluish flame is burning off zinc which is a clear and present danger.  Avoid putting galvanized stuff in the forge and it's not a problem.

I did think that but just with the warning on the video, I am forging under the open sky at the moment so ventilation is my main advantage.

Thank you for the reply.

May not be enough ventilation for galvanized!  I've had several friends welding stuff outside and still ended up going to the A&E (ER in USA).  Really just easier to ban it from the scrap pile---"In Rust We Trust!"

When burning your coke, incomplete combustion of the carbon and oxygen from your air supply will produce carbon monoxide resulting in a blue flame, among other sources.  Just provide plenty of ventilation as in any forging.