engraving on cast metal problems

[Billox]

hello,

beginner engraver here, currently practicing using hand push technique.

i've been practicing and improving allot on copper sheet mostly and some silver sheet too
but just go a horrible shock when trying my hand on a cast silver ring, and it was brittle and 'crunchy' for want of a better word.

i knew there was a difference in the quality and properties between cast and forged/milled metals but it was a bit of a surprise at disappointment how dramatic and it was and the effect it had on the finnish,

was wondering if anyone here has any tips and experience on improving the workability of the metal

cheers

 

[Roger Bleile]

No tips but it is an age old problem. Recently, I was examining a Winchester 1866 engraved by John Ulrich in 1868. It was in pristine condition but there was a tiny hole in the background where his background punch hit a void in the bronze casting.

 

[Chujybear]

I engrave/recurve all my cast stuff.. it does not have the density of milled metal.. i chase everything.. front and back if possible.. that will tighten it up considerably.. you should also hunt an y voids or pits and lay in a bit of weld ... you can smooth it all down after... or carve through your hammer marks.. there are tactile differences depending on what you do, depending on how flat you have plannished your surface

 

[Billox]

I did have a little go at planishing it which helped a little but the hammer wasn't the most suitable,
i'm going to invest in on and maybe be a bit more brave with my whacking,

thanks for getting back to me

 

[monk]

i did a lot of work on parts for front stufffing rifles and revolvers. some of those parts were sand castings. this technique produces voids, some of which cant be seen by eye. the "kit guns" were notorious for castings. most of the custom makers for which i worked had enough sense to buy premium parts that were not cast.
btw, you should be very wary of engraving plated objects. even the finest (expensive) plating can chip or flake away during cutting. when this happens, you got a disaster to deal with. try doing a nickel plated zippo. you may find out the hard way! !

 

[707chrisa]

Welding is an option as Chujybear said , I am lucky and have a Orion plasma arc welder, works real good on silver and it is ease to use on large items. With that said I wish I had a laser welder like the one I used at the lab. A good welder with the right machine under a microscope can cover an are of a dime in about 15 to 20 min depending on cool down of the item being welded even at 120$ per hour this can be a life saver. If you all ready had the set up and knew the metal you where working with and heat was not an issue you could triple the area . When you hit an inclusion the fun starts and you will need filler metal of the same alloy . Ps Thank you Monk for the tip on plating . LOL I know welding wont fix that.

 

[allan621]

Trying to engrave a badly cast ring is like trying to drive straight on a road with lots of potholes. The top may seem smooth but if you turn it over and look at the underside of the top of the ring that's where you can tell. There may be tiny dots, a few are okay, but if you see a lot, that's trouble. Porosity is air in the casting metal, which turns to holes on the surface and empty divots in the body of the ring. Sometimes its only the surface and that can be taken down with a fine emery board. But if you keep going deeper and more holes appear, now that's a real problem.

You can't improve on the workability of the metal. But the more you work on this kind of ring, you begin to get a feel about how to engrave it. The result is never as good as it should be, but it may be okay to the customer.

Allan