don schad

Boom! and Safety issues

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I had a very interesting experience yesterday, which I would like to share. 

 

I have a typical routine for starting up the power hammer (LG) which includes wiping down the hammer dies from the oil and scale which builds up over night from dripping out of the ways.   My routine was interrupted yesterday, and I hadn't cleaned the dies when I pulled a 2"x 3/16" flat which had some minor cupping in the end out of the fire.  I saw the mess, but I didn't want to waste the heat, and I didn't think too much about the messy dies.  My intent was to take a couple of gentle hits to make it flat, so I continued and put the piece on the die cup down, and made a firm blow - boom!  

 

I was completely surprised to have an explosion occur at impact!  It was like someone popped a large balloon, complete with a shower of oil and scale sprayed across the room.  It took me a moment to figure out what happened, not relating the explosion to a routine power hammer strike, something that otherwise should have been a crisp wack.  

 

In the end I figure that the oil was trapped in the cupped area getting super heated/boiling, when I brought the head down the compression of the cup caused the oil to flash and it blew up.  

 

It was one of those times that you know your safety glasses were a good investment.

 

don

 

 

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Thanks for sharing that.   I guess it also proves the point that safety should always be first and foremost on our minds.

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No different that putting a bit of water on your anvil before forging,to blow the scale off while the hot metal contacts it during the forging. - not an uncommon thing. It's been done for years by many. - steam related and yes safety glasses are good.

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I expect a couple drops of oil would add a dramatic fire ball to the old blacksmith's trick for getting attention or adding a bit of drama to demos. If you do it with clean steel and move fast enough scale doesn't develop its relatively safe.

 

If you don't use so much oil your LG won't slobber and stray oil all over the place My 50lb. LG only drizzles a little from the main bearing oiler cups. It takes a few days for all the oil to seep through the felt and mains so I get a bit. If I get carried away I'll get a little dripping next to my bottom die.

 

I oil mine with Oregon or Stihl chainsaw bar oil dosed with Duralube at about 1/4cup per gallon. Bar oil is designed to be sticky and high film strength lube. Duralube is an extremely high film strength lubricant, both have this quality without high viscosity. The mix gets where you need it, sticks and is such a good lube you do NOT need it slobbering and spraying all over the place to do an excellent job.

 

Seriously, P drip 2-3 DROPS in the main bearing oil cups and 1 drop each in the other oil points. The grease zerks get white lithium grease. Graphite grease is slicker but THAT stuff travels worse than silicone lube, even touching the grease gun will have it creaping past your elbows in short order. I save graphite grease for lubing my punches, drifts etc.

 

Frosty The Lucky.

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There is another explosive experience that must be avoided.    Hollow drill rod can explode with catistrphic results if forged.  I refer to the  rock drills  that have a bore down the middle to provide compressed air at the drill point .   They are sometimes confused with jack hammer points/tools which are a good source of tool steel.  Our newer members should be fore warned about the dangers these drills being used as a source of tool steel.  

 

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Ive had similar when pattern welding every now and again ! just the metal reminding you to respect :)

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This can be an issue in a press as well....   I have had the "flash" burn the skin off my arms when I trapped a bit of oil between a tool and the hot part in the big press.....      the biggest explosion I had in the shop I am still not really sure how it happend.   I poured some molten copper into the slack tub and it created a steam bomb somehow and more or less emptied out the 30 gallons in there....   But I have tried to recreate the explosion with no boom.... (Ok so I am a kid, it really was a big boom!)

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