does dry ice really work

C

Centerfire

Member
I was looking over the web regarding PDR (paintless dent removal) and wondered if the dry ice they used to remove hail dents in cars would work on a dent on an aluminum scope tube?
Am interested in trying but thought I would ask for some help.
Centerfire
 
* Paintless Dent Removal is a process that reforms metal back to its original condition without affecting the paint finish.
* Our highly-skilled technicians, using specially designed hand tools, gently massage dents out of a vehicle's body from behind the affected panel. The result is a dent free panel with original paint and parts intact.
 
in order to remove a dent from metal, you must shrink it. when it was dented, the metal stretched. many moons ago in auto body school they taught us to shrink metal with a torch, and a wet rag. heat it up hot and quench it, its the only way to do body work without filler. can a scope tube be done, dunno. i'd warm it up with a hair dryer, and try the dry ice. the most your out is the cost of the dry ice.
 
I am going to differ.

You have optics in that tube. If you thermally shock them, they may crack.
 
Well now I have to think about this. The ocular lens edge contacted the concrete bench and now does not allow the lens cap to be screwed on to the scope. It is just flattened a bit. The tube is aluminum and if parts were available I would buy a new part but that is not an option on a Unertl. I thought due to the small area concerned the dry ice might work. Dry ice on the outside and a brass pin pushing on the inside toward the outside. If I can get the lens cap started it might help in rounding the rear of the lens.
My crystal ball is cloudy. Any other ideas?
Centerfire
 
This solution may be a little "out there" so bear with me.

A CNC production turning center typically uses a hydraulic ram to open/close the chuck/collet.

5C collets are commonly available that expand.

IF a guy was jonny on the spot and (had the balls to try it) I'd venture to guess that the collet could be turned to an appropriate diameter, the scope's bell could be inserted and with careful manipulation of the foot pedal and fiddling with the pressure setting (it's totally adjustable from zero to over 1,000lbs on my machines) a guy would swell the ding out from the inside.

The collets are usually made (least the ones I have) from a soft material that is free machining. The "rub" will come with the threads as it's likely going to be inclined to booger the thread a bit. A delrin ring some leather wrapped around it would probably save it.

It's the first thing that popped in my head. Dunno if it'd work or not.

Good luck.

C
 
hi all
a shot gun dent removal tool from brownells will do the trick and not bugger the threads.????

regards ted
 
I think it would be amazing if you are able to repair any dent in a scope tube using dry ice. The metal has been stressed beyond it's elastic ability and it will have to be stressed beyond it's elastic ability in the other direction... and then it will probably be a distortion in the other direction. It is not possible to remove a dent in shotgun barrel without leaving a visible mark on the outside which then can be refinished and disappear. I have done several and never experienced an immaculate conception so to speak.
 
OK, I'm guessing you don't have a lathe....?

IMO the dry ice thing is an absolute no-go, here's what I would do. WITH a lathe I'd turn and thread a mandrel just like your lens cap, I'd thread about a half inch of shaft..... now grind a hunk out of it so's you can get the threads started. Feelin' it? It'll take some fiddling but you will get it started eventually, this WILL iron it out.

Without a lathe I'd whittle/grind a tight-fitting tapered plug. Of course it won't go in because of the ding..... so again, you remove that section and work it in, rotate. This works for dropped thermii....

let us know what you end up doing.

al
 
Centerfire said:
Well now I have to think about this. The ocular lens edge contacted the concrete bench and now does not allow the lens cap to be screwed on to the scope. It is just flattened a bit. The tube is aluminum and if parts were available I would buy a new part but that is not an option on a Unertl. I thought due to the small area concerned the dry ice might work. Dry ice on the outside and a brass pin pushing on the inside toward the outside. If I can get the lens cap started it might help in rounding the rear of the lens.
My crystal ball is cloudy. Any other ideas?
Centerfire
Click to expand...

If the scope is still serviceable, I'd just find a slip on cap, or cover, and be done with it..............
 
Well Al your right I do not have a lathe, well I have a Neilson turner, but that doesn't count.
Thanks to all for the suggestions.
What I do have is a Tool and Die maker with 45~ years experience and have not traveled to his shop, yet.
When I do go there I will take your suggestions as this will be a big help.
Thanks once again,
Centerfire
 
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