First core bonding attempt

[rossi]

I am trying to bond my first bullets, using .22 RF cases turned into jackets.
I poured a few drops of bonding agent into the jacket and then dropped the core. I used a torch to melt the cores. I am getting a bond, but the jackets become all black and “dirty”. I think it is the bonding liquid that burns onto the jackets.
Corbin writes in his book to place one or two drops on top of the core, but even if my cores have a loose fit in the jacket I have noticed that the drop sits on top of the core and does not run down along the inside of the jacket.
Has anyone any experience to share on this subject?
Maybe wetting the inside of the jacket with a cotton swab might be enough for bonding?

[Drilling Man]

I am trying to bond my first bullets, using .22 RF cases turned into jackets.
I poured a few drops of bonding agent into the jacket and then dropped the core. I used a torch to melt the cores. I am getting a bond, but the jackets become all black and “dirty”. I think it is the bonding liquid that burns onto the jackets.
Corbin writes in his book to place one or two drops on top of the core, but even if my cores have a loose fit in the jacket I have noticed that the drop sits on top of the core and does not run down along the inside of the jacket.
Has anyone any experience to share on this subject?
Maybe wetting the inside of the jacket with a cotton swab might be enough for bonding?

  I remember waay back when i was trying to learn how to bond bullets.  I had Corbins book, and even made several calls to Dave.  I don't believe at "that" time Dave had ever bonded a bullet and then tested it...  What he failed to tell me was, (and from out phone conversations, i don't think he even knew)  even if you did get it bonded (and i did) the jacket material was all wrong for bonding, and would crumble and break up on big game.  Anything the bonded bullet did work on, didn't require a bonded bullet in the first place...

  DM

 

[talon]

 Drilling man must be speaking of .22rf bonding, which I've never tried. However, on .243s up to .458s, my bonded bullets seem to work very well. I use jackets from .014 to .065 in thickness, not the very thin ones found in .22rf brass. The lead holds to the jacket. While the slug sometimes seperates on hitting bone, the lead still holds to its part of the jacket. I do hold my bullet speeds at or under the 'common' velocities used in hunting cartridges.

[Drilling Man]

Drilling man must be speaking of .22rf bonding, which I've never tried. However, on .243s up to .458s, my bonded bullets seem to work very well. I use jackets from .014 to .065 in thickness, not the very thin ones found in .22rf brass. The lead holds to the jacket. While the slug sometimes seperates on hitting bone, the lead still holds to its part of the jacket. I do hold my bullet speeds at or under the 'common' velocities used in hunting cartridges.

  Actually i said and ment "exactly" what your experience has been too.  "If" you hit bone the jacket breaks up especially at high velocity...  Yes, the lead will be still stuck to the pieces of jacket, but the jacket has come apart...  If the jacket comes apart, it doesn't matter much that it has a small amount of lead bonded to it...  A proper big game bonded core bullet should stay together even in tough situations...

  I wanted to sell big game bullets, and i did, but you can't use ordinary jacket material if you want a bullet that will do the job when the going gets tough.  I just had to do the research and testing on past where Corbin left off...

  I think it's always bugged me that he didn't just come straight out and tell me he didn't have the answers...  Instead he had me calling back, wasteing my time and energy running in circles...

  DM

[talon]

 Needless to say there's a bullet type for achieving any goal. For my 'Rhino stoppers', I swage solids out of copper rod, but only for the .416. However, for all American big game, a bonded core using a .030 copper jacket traveling at reasonable velocities will do the job as well as, if not better than, more complex and expensive to make jacketed bullets. While you will have 3 sigma occasions where the  bonded bullet, having struck a massive  bone, will break apart in many small pieces, you can usually count on the bullet holding together, or at least 2 or 3 large pieces of copper 'protected' lead holding together. On a non bonded core jacketed bullet ( plain vanilla type), the jacket most often strips off even hitting a soft bone like a rib and then the much softer lead comes apart like a bomb. While there's something good to be said about the killing effectiveness of this last instance, I prefer deep penetration through the vital area without waisting several pounds of meat. I've never experienced a .065" walled bonded core bullet shedding its core material on impact, but using that type of bullet on American big game, except for the big bears, is gross overkill.

[rossi]

So far my first experience.
I have bonded .224 bullets made out of 22RF jackets and ha tried them on wet telephone books. The bullet broke apart like a non bonded commercial. I shot some Hornady SX as comparison on the target and noticed that both bullets behaved the same, but the bonded one had lead pieces attached to the broken jacket.
So far my experience confirms what has been written on this tread.
The .22RF jacket is simply too thin. I will try a harder lead core, melting lead shot, but I do not expect far better results.

Anyway, I am still getting extremely dirty bullets out of my bonding process. How do you clean them? Tumbling for 2 hours didn’t remove al the backed on mess.

I mad the bonding flux myself. It works. What do you use to bond?

[Lead pot]

Bonding the core is no different than soldering a copper pipe fitting.
Chances are when you formed the jacket you used lube to do this.
You must remove the lube before the lead core will bond to the brass or copper jacket properly.
The rim fire cases must be cleaned with a carbon tetrachloride or a similar degreaser because the lube that the rim fire bullet was coated with.
Two drops of flux is more than needed, I would put it in the jacket before placing the core in.
To much heat on the jacket will change the flux and it will act like a oil and you will not get a good bond.
If you have swage lube on your fingers when you handle the lead core you will have a problem getting a good bond.
A little tin will be a plus with a rim fire case. I like to use a 1/20 alloy when I form .22 or 6mm bullets, they will take a higher velocity with out exploding in flight do to high rotation in flight, and the added tin will lower the melting point of the core. A lot lower than pure lead.

Take it from a plumber that has learned how to solder from past mistakes.

I don't use a acid flux for bonding I use a rosin flux, it is much cleaner.
Use a low heat when you heat the jacket it will save you a lot of problems.
If the jacket turns red before the core melts you just about lost the game.

Kurt

[rossi]

I have used acetone to degrease the cores and the jackets. Perhaps it is not an adequate product for this job. I have noticed that when I heat the jackets with a torch to melt the core, sometimes fingerprint marks are burned onto the jacket. 

My bonding solution is a selfmixed brew. I didn’t want to wait weeks for receiving a bottle of core bond solution from Corbin (I live in Italy), so I looked up the ingredients in the msds. An msds is not a formula but I found a nice book talking about goldsmiths and reporting a lot of formulas on how to prepare soldering solutions. The book says that rosin (colophony) can be used if a clean solder between lead and copper alloys is desired but also gives a formula containing zinc chloride and ammonium chloride, which are the ingredients reported on the msds. The book says that this solution gives a better bond, so I tried this for a start. I mixed them in the given proportions an tried the solution. It works well, and is much cheaper than buying the finished solution. I will try colophony too. Even if I now have a few gallons of acid solution left. The price was slightly more than one big bottle of Corbin solution. 

Heating the jackets evenly with a torch is a pain to me. I have drilled several holes in a fire resistant brick for holding the jackets. It is difficult to tell how much heat is sufficient. The lead melts from the outside to the inside, and I don’t now how long I have to hold the flame on the bullet to guarantee a complete solder.
Reading Corbin’s book it says that the lead should form a concave base. This is a sign for a good bond. In my case the lead formed a deep hole in the middle of the bonded jacket, not only a small depression.
I even tried an furnace. Mine reaches 900° F  (500C°). I left the bullets for 15 minutes at 450°C (aprox 810F°). The cores showed a depression on their top, but not a deep hole as with the torch. Perhaps the temperature was too low and the time too long, and the solder evaporated. 

Does anyone use a furnace to bond the bullets? My feeling is that I need a much higher temperature and a shorter time, but I have no way to try this.

[rbt50]

i have bonded 22 cases by useing corbins core bond by putting one drop in the bottom of the jacket and heating it with a tourch just to when the lead mealts. then put the core bond jackes in vinegar for a few min and all came out with a light copper color.

[rossi]

My latest bullets where better. I used too much bonding liquid, and while heating, it ran out and down along the jacket, where it burned.
Anyone got any suggestions concerning the use of a furnace?

[Reed1911]

Well,
I cannot comment to bonding bullets directly, but I can comment on bonding in general.

First of all Rossi, you need to figure out what temp your lead mix is going to melt, then go about 10-15 deg higher on the furnace to get a complete bond, time is not critical but temp is. Too hot and you will loose the bonding and end up with a layer of corrosion between the case and core. Depending on the mix, I'd add a bit of tin to it to act as a draw, I'd also stay away from acid based flux and keep to the rosin based or "green" natural flux (apricot seed I think, don't remember) .
 As for a core that will hold together well, I can say from experience that high-temp soldier is a good way to go with the rim-fire jacket, I believe it was a 96/4 tin-lead mix but I may be wrong, the melt temp is 780-800 and unlike lead you'll never get that shiny surface effect. The big drawback to the HT is that with such a high tin content they are a bear to point up.

as an aside where in Italia are you? Spent a lot of time in the North.

[Lead pot]

reed.

95-5 solder melts at 475*

[Reed1911]

Sounds about right for regular solider, If you'll notice I was talking about high-temp specific soldier.

[edgemark]

Have you settled on a formula that works best? I have considered giving it a try ONCE , just to see how it works.

Do you mind sharing your recipe?

Thanks,

edge.

I have used acetone to degrease the cores and the jackets. Perhaps it is not an adequate product for this job. I have noticed that when I heat the jackets with a torch to melt the core, sometimes fingerprint marks are burned onto the jacket. 

My bonding solution is a selfmixed brew. I didn’t want to wait weeks for receiving a bottle of core bond solution from Corbin (I live in Italy), so I looked up the ingredients in the msds. An msds is not a formula but I found a nice book talking about goldsmiths and reporting a lot of formulas on how to prepare soldering solutions. The book says that rosin (colophony) can be used if a clean solder between lead and copper alloys is desired but also gives a formula containing zinc chloride and ammonium chloride, which are the ingredients reported on the msds. The book says that this solution gives a better bond, so I tried this for a start. I mixed them in the given proportions an tried the solution. It works well, and is much cheaper than buying the finished solution. I will try colophony too. Even if I now have a few gallons of acid solution left. The price was slightly more than one big bottle of Corbin solution. 

Heating the jackets evenly with a torch is a pain to me. I have drilled several holes in a fire resistant brick for holding the jackets. It is difficult to tell how much heat is sufficient. The lead melts from the outside to the inside, and I don’t now how long I have to hold the flame on the bullet to guarantee a complete solder.
Reading Corbin’s book it says that the lead should form a concave base. This is a sign for a good bond. In my case the lead formed a deep hole in the middle of the bonded jacket, not only a small depression.
I even tried an furnace. Mine reaches 900° F  (500C°). I left the bullets for 15 minutes at 450°C (aprox 810F°). The cores showed a depression on their top, but not a deep hole as with the torch. Perhaps the temperature was too low and the time too long, and the solder evaporated. 

Does anyone use a furnace to bond the bullets? My feeling is that I need a much higher temperature and a shorter time, but I have no way to try this.

[rossi]

The ingredients I used are zinc chloride, ammonium chloride and distilled water.
I looked at Corbin’s MSDS and found these two ingredients in their solution. But an MSDS is not a formula so, I went to the library of  the University of Padova (the town where I live) and found a nice book about goldsmiths with a lot of  “old “ formulas.
In the chapter “soldering and brazing” I found the formula about how to produce zinc chloride and a comparison between several fluxing agents.
You don’t need to make your own zinc chloride, just buy it ready!!!   

The book said that a good fluxing solution for soldering copper and lead (and its alloys with low tin percentages and other elements) is simply obtained by dissolving 300grams of zinc chloride (a white powder) in one liter of water.

I am European, I use metric units…don’t ask me any conversions please   

When heating this solution the water evaporates first, and then, at 262°C the zinc chloride melts, forming chloridric acid which dissolves the oxides on the surfaces of lead an copper and makes the bonding possible.

A far better solution is obtained adding ammonium chloride. This solution is better because its melting point is much lower and the decomposition of the oxides starts way before the metals begin to melt. Thus the surfaces that are in contact are more clean once they have to bond.

The formula is

Water 300 grams
Zinc chloride 71 grams
Ammonium chloride 29 grams

The two elements (not the water) form an eutectic solution when mixed with this percentages, and melt at 179°C.

I have paid for 1 Kilogram of Zinc chloride 97% pure 45 Euros, but the nice lady of the chemistry shop found a cheaper brand, which unfortunately was not available at the store, for 30 Euros. I took what they had ready on hand. Ammonium chloride was 20 Euros for 1 Kg at the local pharmacy. To make 0,5 liters of solution I paid something around 6 euros, included a brown bottle for mixing the chemicals.

To neutralize any residues of the solution the book suggested to use baking soda (sodium bicarbonate).

I have bonded some bullets made of .22RF jackets, loaded them in a .222 Rem,  and fired them into wet telephone books. The distance was 20 meters (I had no better range) and the bullets where completely smashed. But the pieces of the jackets I found had  lead firmly soldered on them. I think that the jacket did not separate from the core, thus the bonding was good. The bullet where simply to fragile and the distance to close to hope to recover a someway intact bullet.

I will have to find a better range or wait until the hunting season starts (in September) to test fire in the woods.


@ Reed1911

I live in Padova, 30 Km west from Venice

this week I will try to bond using a furnace.... I don’t know if I should select a high temperature and heat for a short time (minutes? seconds?) or select a lower temperature and heat for some more minutes. The highest temperature on my furnace is 500°C (lead melts at 340°C).

Any ideas?

[edgemark]

Thanks, that is great info

Keep us posted, it sounds fairly easy.
I never tried to bond them, but if it works well I will have to give it a go!

Corbin website seemed to indicate that faster was better.

Thanks again.

edge.