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Undent brass cases


Well-Known Member
I have a few dented cases and want to get the dents out. Who has some good tips? The biggest dents i got out by filling the case up to the dent with sand, and putting in a wooden block, shaped to the case, then putting in a metal rod, and expend the dents. Now i have left a few small ones, any ideas? For the bigger cases i used a hydraulic jack, that worked fine, but they wont fit in a 15 or 17 cm case,



I've used car body dent dollies and bits of round bar with a mallet on the out side but I can only reduce the size of a dent not get rid of it entirely. Could try making up a small screw jack with a short fat bolt and nut with a tube to sit the protruding thread in and the nut to push against. The ends having soft metal/ plastic pads to protect the case and spread over the desired area....... got me thinking I might try to make something up myself. 2pr
Two woods

There is an old post on the forum about this topic but I cannot find it.

One method I tried recently with great success was to get two shaped pieces of wood that fit inside the case over the dent and drive a wedge between them to expand them-you have to be careful on thin cases but it does get a lot of dents out !
Much food for thought here,the mention of using sand by Kees hadn't occurred to me,and I live quite close to a whole lot of that.Driving down a length of hardwood with a suitably rounded end,right where the dent is,
with the case filled with sand,might just do the trick.Working through a 47mm bottleneck doesn't make it any easier for me,fortunately the dent is
at the top,just below the shoulder.It's the same case with the 'ole in a different thread,many thanks for all your thoughts on that,chaps.
When i filled the case wih sand, up to the lever of the dent, i found out that all energy that normally causes the ear damaging sound, and other side effects was gone, and the dent came out much better. Another good thing is when you build up the diameter with wood, and its stucked, just remove some sand and you will get all filling out of it. I'm looking for a stronger hydraulic jack now, at least 5 tons, that will work for the large diameter cases. Problem with the hydraulic jacks is the minimum hight of it. Denting out a 15 cm case is therefor not easy. Right now i'm tring to find a piece of steel pipe with the right diameter, that can be forged in the case. Problem is to get it out again. But for every question there will be an answer. Has anyone tried to get small dents out of cases? like the use of heat, or special kind of hammering devices?
"spreading tee tool"

I'd like to post a pic of it but cant find it. What it is is a Tee shaped tool that the business end goes from 2" to 4". The handle attached to the business end is 1 foot long and has a 3/4" wrench size nut on the end which spreads the head as you tighten the nut, and there are plastic or nylon protective caps covering the tips of the spreading head. This works very nicely for any casing between 2 and 4 inches in diameter. Next week my project around here is to clean the basement/workshop area to prepare for a yard sale and if I find it, I will post pics. I got it from my dad about 30years ago and he has no idea where he got it or what the intended purpose was. My dad has every freaking tool imaginable which someday will be passed down to me (later than sooner I hope cause my dad is the greatest man alive). Anyway this tool works great on little dents but won't take the torque required to take out the biggies. The tool is just too fragile and excessive force would break the damn thing. Takes "the feel" to know when you're just before break point. Those shell casings I display with the dent pointing toward the back and I find that works quite well. He He....Another tool that has been of help is an exhaust pipe spreader. This is a tool that is round and works well on dents higher up in shell casing. When tightening the center nut the whole thing spreads or increases in size and you can really get some torque on this bad boy. That's my 1 squid worth.....Dano
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Here in the U.S. we have small hydraulic tools for use in auto body repair and manufacturing called Porta-power. They usually come as a kit with different lengths of hydraulic cylinders that connect to a separate hydraulic hand pump. Some of the cylinders are only a few inches long.


You might visit an auto body shop in your area to see what the locals are using.


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Kool Tools

Geez John, Like Batman you have the cool tools. I am kind of a tool freak and would love to obtain a porta power. I remember using one back in High School Auto shop. fire dept's use them when they have to un-jam something too small for the "jaws of life" to get in...Dano

Hi thekees, Go to US ebay and type "exhaust expander tool" into search box and there are some detailed pics in there (works good on exhaust also!) Dano
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Saw the tool on ebay.Should be possible to build something like that for 15 cm cases, just wonder if the force needed will be getting out of the construction. Right now i'm using the hand type car jack, but for jacking a dent out, the force by hand is not enough, maybe i can weld a 1/2 inch wrench adapter on it. I guess that's the first thing to do tomorrow.
un denter

Hi thekees, The torque and force put out by the exhaust expander way enough for any dented shell casing, thing is you are very limited in size with the tool, unless you are creative and handy and can make a covering of some sort to up the size capabilities, may be a stretch here, not sure. Hazord has the right idea with the porta power, expensive but the adaptors than comes with it would prove invaluable. Let us know on any strides made with which ever way you go..Dano
The hydraulic set looks very good to me, will look locally for one. I used a small potjack, when i placed it in a case, one meter deep, and found out that the release screw was on the jack, took me a long time to clear the jack (and myself). I wonder how they made the WW1 trenchart? If we found out how the hammered the shells in that shape, it will be ok using that techniek for getting dents out too.
I can neither confirm or deny that I am Batman.

A couple of thoughts regarding removing dents:

The guys in WW I had a lot of spare time on their hands, so they weren't in a hurry, worked slowly, and gradually got what they wanted with a lot of hammering.

You can anneal brass with a torch, to make it softer. When it got dented, it was also work hardened a bit, so the dents will come out easier.

There was a discussion a month or so back about annealing brass, heating it with a torch and then cooling it in water.


If I were actively working on this myself, I would get some round mandrels to go inside the case, under the dent. The mandrel would be as close to the desireable inside diameter as possible, but doesn't need to be a full circle, as you would be pushing it with your porta-power. I would have a curved mandrel on both ends of the hydraulic press to distribute the force, so you don't make a dent towards the outside. If I were you, I would also get an auto body hammer, and as you push the dent out, you gently tap on the brass around the dent.

When you start looking around your area for porta powers, befriend a body shop worker, and have him show you how to hammer out dents.

The best dent removers, are the guys who take dents out of musical wind instruments, like trumpets, etc. When they are done, you can't tell there was ever a dent. You could find the local expert guy that does that and ask him also.

Today i took a visit at a construction shop. The inner diameter of the case was 152 mm. I found a steel pipe, diameter 152 mm, wall thickness 20 mm. So the dead mass i needen was in there (55kg) It was the correct length. Tried to get it in, and after a few good hits it was bottomed in the case. all dents were gone. Only need is some sanding and polishing on the old dent locations. Getting the tube out? A wooden beam in it, and hit it with a 10 kg sledgehammer. About 10 strokes and it was free. This case had dents big more than 2 cm deep. Next step is looking for the other diameter. Before i'll put it in the next case, i'll put some grease on it, will release better i guess.


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On the subject of large brass casings. Any tricks on getting HEAVY tarnish off. Say the kind you might expect from being buried in Iraqi sand for a long period of time?
i use scotchbrite, the finest one (do not know the new color), mine was gray. and with a light hydrochloric acid (diluted to max 3 percent) and wash off the most of it. after this i clean the case with a soda solution, this to neutralise the hydrocloric acid, and preventing turning the case red. After that a good polish with carpolish, or sandpaper (400-800), before polishing, and you have a nice case. Best is to start with a light Hydrogloric dilution, so you cant damage the case. When using the scotchbrite, always use it in line of the manufacture lines on the case. It prevents scratches against the normal direction.
The best dent removers, are the guys who take dents out of musical wind instruments, like trumpets, etc. When they are done, you can't tell there was ever a dent. You could find the local expert guy that does that and ask him also.


They sound like a very good type of person to ask about it. If it was a decent enough case, I wonder if it would be worth paying a musical instrument repairer to do it.
Regarding removing the tarnish, I use a similar technique to "thekeys" but instead of hydrochloric acid, ordinary vinegar seems to work. The domestic pot scourers arent really agressive enough and I also use a scotchbrite pad.

Vinegar works ok too, but when you have "heavy dirt"like 50 or more years sealive, the vinagar seems to get into the dirt, and works the zinc out of the brass. Founo out that in that case it's better to use the acid, it looks to have less effect on the "de"zinc proces, and is better to neutralise with soda. After cleaning the case mostly looks too new. Make a mixture with water and ammoniac and wipe the brass case with it. repeat this several times, and wash the case with water. now you have a clean casem without dirt and corrosion with a aged look.

BTW be sure that you have a few pair of gloves, first your hands turn red, soapy (acid) green and after the ammoniac, they turn black as night. And a mask for your mouth and nose is not to bad idea either.