'Cast' copies of originals..

[Biro]

I would really appreciate some help on this subject from anyone in a position to do so.

I recently read an excerpt from ''Orden und Ehrenzichen" - the journal of the BDOS - expressing concern over a sharp rise in appearance of a particular item in the 70's and that they were beleived to be fake 'castings' from an original.

I realised that it is any area I know VERY little about, and particularly dangerous when giving a or opinion from a picture only...

Is there any other way of discerning between an original and a casting from an original other than the crispness of the detail? ... that bit I understand..

If someone is able to post picture comparisons of features (striations, marks of any kind) or point me in the direction of a good thread that would help me understand this better, I would really appreciate it.

I'm specifically referring to tell tale signs of fakes 'cast' from originals..

Thanks

Marshall

[Dietrich Maerz]

Hi Marshall,

it really depends on what kind of casting method is used. The regular method (and the cheapest) is to make a wooden model of the medal in question, form fine sand around it, take the model out and cast. This will give you a fairly good representation.

I guess that the better method to use would be 'lost form' casting wheras the model is made of wax embedded in very fine sand and when the metal is poured in the wax is replaced by the metal. This is for finer parts.

Ther are other ways but thats basically the principle. Now with all casting methods you have two things:

- the medal will need to be cleaned, especially the reminder of the casting channel and the raiser need to be cleaned of. This will leave a mark.

- a casted part is always smaller than the original unless the 'faker' are very carefull in constructing the model. Normally, the shrinking factor between the hot metal and the cooled metal is 1.5 -2.5%, depending on the material. This is the factor the faker have to make the model bigger in all dimensions or tthe casted peice will be smaller by that percentage (which is normally the case)

A casting surface is never as good as a die stamped surface. You will have very small surface bubbles and in more clear cases you can see the sandy surface of the form. In other words, it's rough. There are also limitations in the details, they just don't come out very sharp.

Hope this help a little bit.

Dietrich

[George Stimson]

And I'd like to add that cast copies have been made of many of the different awards which we include as "Crosses of the Wehrmacht"!

[Biro]

And I'd like to add that cast copies have been made of many of the different awards which we include as "Crosses of the Wehrmacht"!

Yup - but thought I'd get a quicker response here about the casting process rather than the particular (admittedly Imperial) item.

To elaborate a little before I'm shifted over to the correct forum.. - this cross of the wehrmacht spange below I am fairly certain I can now spot as a cast copy. But really only because the detail is awful.

Any idea how this process would vary for an enamelled award like.... the Order of the German Eagle... and if indeed any part of such an award would/could be 'cast' as opposed to re-made from scratch??

Dietrich - thank you mate ... that is indeed a very helpful summation of the process. The info about dimensions in particular.

Marshall

[tinmantis]

out of interest: do you have a pic of the reverse?
regards
jon

[Biro]

out of interest: do you have a pic of the reverse?
regards
jon

Jon

Of the Original? Yes - it was posted by Bob Hritz - the lucky owner - in a thread started by me entitled (ironically ) L/12 marked EK2 spanges. Do they exist???

And yes - as is evident now, they most certainly do!

Of the cast copy? No - you would only see two prongs sticking out of some ribbon anyway.

regards

Marshall

[Tiger 1]

Biro,

Just a bit to clarify Dietrich's description.

The process is 'lost wax' casting. The wax pattern is invested in a slurry of plaster. Casting runners and vents are also added to the wax pattern. After the investment is dry it is fired to burn off the wax pattern and to 'set' the mold. Hence 'lost wax'. The hollow pattern that remains in the mold is then filled with molten metal. This type of mold is generally used with a centrifical casting machine to fill in all the voids and details of the mold using G forces produced by the spinning arm.

Sand casting is slightly different from 'lost wax' in that the pattern is impressed in a fine oiled sand instead of an investment plaster. The pattern is pressed into both halves of an indexed sand mold and there is no burning out of a wax pattern, as there is none. Usually this type of mold used by pouring the molten metal into it. The oiled sand mold is basically compressed sand with oil being the binder and it would not withstand any centrifical force. Sand casting generally leaves a coarser finish to the cast object and is used for larger items in industrial manufacture that don't require a fine surface. Much of the sand casting process has been replaced by die casting in many industries. Die casting is just that. Forcing molten metal, or plastics into a metal die under pressure and ejecting the finished product when the die has cooled. Plastic models for the hobby industry are made this way.

'Lost wax' is used in the jewelry trade and dental labs to make bridges, crowns , etc.

Just some further thoughts.

Tony

[Biro]

Hi Tony - and thanks... some more useful info for the archives!

Casting itself I know is a genuine process used to make finely crafted originals from a die... so a 'crudely cast fake' could equally be described as an 'extremely finely made cast fake' depending on the expertise, care and attention devoted to the process by the faker... including allowances for the dimensions due to shrinkage... and be all but imperceptable?

The article I referred to at the top of the page described the fake cast item being essentially indestinguishable from a true original except under something like 50x magnification and then only by the slightly 'rounded' edges..

We are truly in a world of hurt!!

Marshall

[Tiger 1]

The article I referred to at the top of the page described the fake cast item being essentially indestinguishable from a true original except under something like 50x magnification and then only by the slightly 'rounded' edges..


Marshall

Marshall,

Are we talking about die struck versus die cast? Or die struck versus 'lost wax' casting?

Your quote would hold true to some degree only if the original item was also cast to begin with. If the object was originally struck in a die then compared with a 'lost wax' casting the differences would readily apparent at a much lower magnification. 10x should be sufficient magnification to distinguish the surface texture between the two.

Tony

[Biro]

Thanks Tony - I don't know which method of casting is referred to.

I'm only being remotely 'cagey' about 'the item' because strictly speaking, it's Imperial and this is not the place for specifics on it. As casting is an across the era's process though, I was hoping to get some information on that process here in this section where the feedback is a little more immediate.

A brief secon hand synopsis of the article is here, in the correct forum..
http://www.wehrmacht-awards.net/foru...0&postcount=30

Thanks to your and Dietrichs help - I now have a better idea of the process.

Marshall

Marshall,

Are we talking about die struck versus die cast? Or die struck versus 'lost wax' casting?

Your quote would hold true to some degree only if the original item was also cast to begin with. If the object was originally struck in a die then compared with a 'lost wax' casting the differences would readily apparent at a much lower magnification. 10x should be sufficient magnification to distinguish the surface texture between the two.

Tony

[Steve Conway]

Hi Biro,

There is also another method for making cast copies using tin and or lead, it may also be possible to use pewter. Silicon rubber moulds can be used in a centrifuge to produce pretty detailed items. I used to make Dungeons and Dragons figures commercially in the 80's using a centrifuge and silicon moulds made commercially for us by engineering firms. These firms also used to make badges for schools or for national events as mementoes and these were sometimes enamelled or painted and made of a variety of metals. I have seen at least 3 of these disk shaped 2 piece moulds of medals for sale on e-bay.

I have also seen dental suppliers using plaster of paris moulds to create copies of medals for collectors as display items instead of having the real thing on display. The quality of the output often depends on the experience of the person doing the casting.

Hope this helps, by the way are you back in NZ now as the last time I looked you were in Britain.

Regards

Steve

[Tiger 1]

Steve is also correct.

I did not mention RTV molds for our discussion because they are basically low temp compatable and would not stand up to the much higher tempertures needed to melt and cast silver.

Just some further thoughts.

Tony