Work holding with Cerro Safe type alloys.

Gordon

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Do any of you guys & gals ever use low melting alloys such as Cerrosafe etc. for work holding instead of Thermo Lock?
 

mitch

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Yes, but not in years. It's super-useful for some bizarrely shaped parts, but a major PITA to use. Done right, you'll never have a more solidly fixtured object, but so few things warrant the trouble.

A few hints- Get an electric lead bullet casting pot and closely monitor the metal until it just melts, then unplug it. the iron pot will keep it plenty warm for plenty of time. a lead pot gets way too hot for cerrometal and will burn it up if left unattended.

i used empty Spam cans for vessels (mmmm, Spam). they provide nice, parallel sides for clamping. you might also try cutting into the side of a round can, then you could rotate the 'fixture block' in your vise jaws.

work over an old cake pan or something in case the molten metal drips or overflows. also, it gets more than hot enough to burn you. it may melt at 'only' 160 degrees or so, but you wouldn't want to put your hand in 120 degree water for more than a couple seconds.

DO NOT LET ANY CERROMETAL COME INTO CONTACT WITH GOLD INLAYS. You will learn the meaning of "stuck like death" and some new cuss words.
 

monk

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#3
blimey ! several years ago i used it to hold a piece of gold jewelry to work on. needless to say that was a disastrous mistake. it ate the gold that was in contact with the metal. istill have the crap in a small salve tin. not sure if it was cerro, or not. i bought it at msc years and years ago.
 

DanM

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#5
The 117F isn't too hot,just put your hand in cold water for 30 seconds then put your hand into the pot of melted alloy and pull it out with a metal coated hand.
 

Stefan

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#6
Thanks to everyone !!!
Now I got it,
1. Experiments are dangerous.
2. Better than sealing wax, shellac and mounting paste, no options
Conclusion--
I will mount the old fashioned way.
 

mitch

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The 117F isn't too hot,just put your hand in cold water for 30 seconds then put your hand into the pot of melted alloy and pull it out with a metal coated hand.
i didn't know they made any that melted that low. iirc, most of the alloys i've seen worked between about 155-170.
 
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#8
I had no idea what you guys were talking about so looked this up on Google. It's interesting, but why would you use this instead of Thermo Lock? Thanks for this post - I learned something new. Diane B
 

pilkguns

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#9
I thought the only real value of Cerro SAfe was to pour inside thin body frames so you don't have any unwanted depressions occurring... either on the gun or in your mind after you discover it on the gun.... I did one time on a Browning BAR ..... not fun to fix
 

jerrywh

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#10
I use Cerrosafe for turning thin barrels. The barrels tend to flex in between centers on the lathe. Filling them with cerrosafe will stiffen them up and help prevent this. It is also good for backing thin metal when engraving, The silver on these patchbox covers is only .032 thick. They were backed with cerrosafe to chisel them out.http://jwh-flintlocks.net/patchbox-cover-js-vegas.jpg
 

monk

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hmmm ! that many years ago i'm not sure if i even used computers. i surely never heard of thermoloc. i'm going to give those suggestions a try. i made amends for the disaster. will do it to just see what happens. what could go ronggggg??
 

dhall

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hmmm ! that many years ago i'm not sure if i even used computers. i surely never heard of thermoloc. i'm going to give those suggestions a try. i made amends for the disaster. will do it to just see what happens. what could go ronggggg??
Seeing this thread reminded me I bought some Cerrosafe years ago, and I thought the characteristic of change in size was intriguing. I, too, have thought about using it as a work holding material, but never found an instance where I chose to go that route.

From the Cerrosafe instructions published by Brownells, copyright 2011:

"Cerrosafe" TM casting alloy is used any time a "positive" copy must be made of a rifle, shotgun or handgun chamber, neck, throat or bore. Chamber casts are used to determine the caliber of an unknown or unmarked firearm, and to verify the marked caliber if it is suspected that the original chamber has been altered. It is also used to check dimensions and condition of the neck, throat and bore to help determine bullet fit and case neck turning requirements.

Cerrosafe shrinks slightly during initial cooling. It then expands to the chamber's original size about one hour after cooling to room temperature. After cooling for about 200 hours, the chamber cast will expand about 0.0025" over the actual chamber size. Cerrosafe is completely reusable; the chamber cast can be remelted and reused after all necessary measurements have been taken.

Cerrosafe can also be used to help remove stuck cartridge cases where the extractor has pulled the head from the case body, leaving the front of the case lodged in the chamber."

The instructions go on to give more detailed information about making/pouring chamber casts and removing stuck/broken cartridge cases and measuring chamber casts.

It doesn't appear as if fixturing/work-holding was an anticipated use of the material, nor in the casting information is the use of any type of mold release agent suggested. The only thing mentioned it that the chamber is to be clean and dry. I'm thinking a silicone spray would keep Cerrosafe from alloying/sticking to jeweler's metals, though.
 

Dave London

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#13
Mitch
Not too long ago plumbers made up joints in lead pipe by wiping molten lead by hand. You had to be fast I used a heavy leather glove and a rag. Some of the old timers did this so much with their callused hands and a rag.
Ha pour some molten lead in to your hand,not for the faint of heart
Lead melts at 641.4F.
 

Big-Un

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#14
Mitch
Not too long ago plumbers made up joints in lead pipe by wiping molten lead by hand. You had to be fast I used a heavy leather glove and a rag. Some of the old timers did this so much with their callused hands and a rag.
Ha pour some molten lead in to your hand,not for the faint of heart
Lead melts at 641.4F.
When I was a certified high voltage cable splicer, we needed to repair or fabricate joints in high voltage cables (4160 volts up) and a lot of them, especially those intended for underwater or a highly corrosive environment, were lead lined. To complete the splice we had to encase it in lead, which was wiped on by hand, pouring the molten lead into your hand, protected by a wiping cloth, to literally form it around the cable. You needed to be fast and fearless, as the lead is IN your hand and you will be burned at some point. As most know, lead has a fine timeline it can be worked properly. Some of my coworkers told me I was crazy, but I loved working with lead; it is an exercise in art.
 

mitch

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My grandfather was an industrial electrician on the REALLY BIG STUFF (hydro dams, etc.). He used to freak out my brother and me watching him work on regular house & vehicle wiring. He would be poking a screwdriver around in a junction box, sparks would be flying and he'd say, "Aw, that ain't gonna hurt ya.."
 

monk

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ok.here goes-- i melted the low temp alloy this am. i could find no trace of the gold that was "eaten". although not a lot of gold was lost, it surely ruined the project, not to mention my nerves.
 

Big-Un

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My grandfather was an industrial electrician on the REALLY BIG STUFF (hydro dams, etc.). He used to freak out my brother and me watching him work on regular house & vehicle wiring. He would be poking a screwdriver around in a junction box, sparks would be flying and he'd say, "Aw, that ain't gonna hurt ya.."
Yep, I used to do that also, would freak out my wife, but when you understand what you're working with, it isn't all that bad. I was working on a live circuit and didn't want to walk all the way to the breaker box and thought I would just short circuit it to blow the breaker. Wrong! It welded my screwdriver to the box, had to go turn it off anyway plus grind my screwdriver off. Electricity is wired that way, sometimes it does what is expected and sometimes it doesn't.
 

monk

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big un: i got nailed 3 times with 440 dc in a coal mine. that was a thrill, to say the least. apologies for getting off track, the other thrill, being trapped for an hour or two by a fire in the mine section i was working in. had to change diapers after.
 

mitch

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"It welded my screwdriver to the box, had to go turn it off anyway plus grind my screwdriver off."

i've got one of those screwdrivers, too. the funny thing is, now it's got a tiny 'shark bite' arced out of the side of it that occasionally comes in handy for hooking a wire and pulling it forward in a box.

when i visit my parents in Denver i like to fix things for them and a few years ago i decided to take care of a couple pull-chain light switches in their basement that had become balky. i announced my intentions to my dad and he starts in with "Aw, gee, I don't even know what breaker those are on, don't worry about it, it ain't hurting anything..." Fathers, right?

so i replaced 'em both hot, which freaked out my dad, but wasn't any big deal. my gramps would've been proud...
 

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