Author Topic: Restoring a Roman bronze  (Read 3409 times)

0 Members and 1 Guest are viewing this topic.

Offline Figleaf

  • Administrator
  • Honorary Member
  • *****
  • Posts: 31 539
Restoring a Roman bronze
« on: June 14, 2010, 01:32:51 AM »
This coin was discussed and identified here. What follows is the discussion on whether/how to fix it up.



I agree. This coin was improperly cleaned. Giving it a long (weeks) soak in pure olive oil may help.

Peter
« Last Edit: June 15, 2010, 12:27:41 PM by Figleaf »
An unidentified coin is a piece of metal. An identified coin is a piece of history.

Offline ghipszky

  • Moderator
  • Honorary Member
  • *****
  • Posts: 1 170
Re: Restoring a Roman bronze
« Reply #1 on: June 14, 2010, 02:47:41 AM »
Good idea Peter I will give a try. Maybe that would take some of the grey look out of it.
Ginger

Offline sminnoch

  • Senior Member
  • ***
  • Posts: 311
Re: Restoring a Roman bronze
« Reply #2 on: June 14, 2010, 02:48:57 AM »
I wouldn't bother.  It's been stripped because of the lack of detail, nothing more will come out of it.  It will get a more natural patina over time, which is likely the only medicine for it.

Steve

Offline ghipszky

  • Moderator
  • Honorary Member
  • *****
  • Posts: 1 170
Re: Restoring a Roman bronze
« Reply #3 on: June 14, 2010, 02:52:03 AM »
Steve should it be out in the air vs the flip folder?
Ginger

Offline sminnoch

  • Senior Member
  • ***
  • Posts: 311
Re: Restoring a Roman bronze
« Reply #4 on: June 14, 2010, 03:06:08 AM »
Steve should it be out in the air vs the flip folder?
Ginger

Well it's up to you, I don't think it makes much difference.

Offline ghipszky

  • Moderator
  • Honorary Member
  • *****
  • Posts: 1 170
Re: Restoring a Roman bronze
« Reply #5 on: June 14, 2010, 03:21:50 AM »
Thanks Steve, I'll just leave like it is then. I don't hold out too much hope for it in the near future.
Ginger

Offline Arminius

  • Procurator Caesaris
  • Honorary Member
  • *****
  • Posts: 1 178
  • Varus - may i show you our forest?
    • Arminius-Numismatics
Re: Restoring a Roman bronze
« Reply #6 on: June 14, 2010, 10:46:53 AM »
Boiling in soda solution may help to regain the ususal bronze coloration and will remove all acidic residues from stripping.

After a short boiling you should leave it in the slowly cooling solution for a couple of hours.
« Last Edit: June 14, 2010, 10:58:31 AM by Arminius »

Offline ghipszky

  • Moderator
  • Honorary Member
  • *****
  • Posts: 1 170
Re: Restoring a Roman bronze
« Reply #7 on: June 15, 2010, 04:43:12 AM »
How much baking soda should I use??
Ginger

Offline Arminius

  • Procurator Caesaris
  • Honorary Member
  • *****
  • Posts: 1 178
  • Varus - may i show you our forest?
    • Arminius-Numismatics
Re: Restoring a Roman bronze
« Reply #8 on: June 15, 2010, 09:04:34 AM »
How much baking soda should I use??
Ginger

The concentration of the soda is less important than absence of chlorides and acid plus a long interaction at elevated temperature.

I may use concentrations at a rough estimate of 1-10 %.

regards

Offline lusomosa

  • Senior Member
  • ***
  • Posts: 291
Re: Restoring a Roman bronze
« Reply #9 on: June 15, 2010, 09:23:29 AM »
I'm not a chemist..... I prefere Olive oil.

LP

akona20

  • Guest
Re: Restoring a Roman bronze
« Reply #10 on: June 15, 2010, 09:55:05 AM »
As a coin cleaner with some experience I suggest in reality that the coin be left as is (subject to bruce's advice) and you move on.
I am not particularly liked in the ancient coin world because I like my coins bright and shiney but hey, that is just my liking.

Art

Offline Figleaf

  • Administrator
  • Honorary Member
  • *****
  • Posts: 31 539
Re: Restoring a Roman bronze
« Reply #11 on: June 15, 2010, 12:43:44 PM »
I think Arminius' advice is meant to neutralize the remains of an inappropriate (acid-based) cleaning process. Lusomosa and I were thinking more about restoring a natural colour. The two approaches do not seem mutually exclusive, but you should do the soda treatment first.

On whether or not to fix it up, the underlying thought may be that in this state, the coin has little value. I look at this differently. First, "don't judge what someone else collects" applies also to grade. It is obvious that Ginger enjoys this coin, so for that reason alone it is worth fixing upping. In addition, treating the coin will give Ginger valuable experience with restoration. I appreciate that pollution will in the long run also improve the coin's looks, but I think that process is less fun and less educational.

Just MHO.

Peter
An unidentified coin is a piece of metal. An identified coin is a piece of history.

Offline Arminius

  • Procurator Caesaris
  • Honorary Member
  • *****
  • Posts: 1 178
  • Varus - may i show you our forest?
    • Arminius-Numismatics
Re: Restoring a Roman bronze
« Reply #12 on: June 15, 2010, 06:29:36 PM »
I never use natural oils (like olive oil) as they may contain chlorides or acids - and thats a basis for bronze disease (BD).
In addition after some decomposition of these oils they may be a basis for a "living" surface associated with further decomposition of the coin.

If oil at all i sometimes use alkaline weapons oil.

The best way to find out is to make your own experience treating some slugs and observing them.
In natural oils you will need some months to see a change with the risk of BD.
Heating and cooling down slowly cleaned bronze in soda usually takes 2-3 days to darken the surface significantly without BD risk.


Offline tonyclayton

  • Senior Member
  • ***
  • Posts: 479
    • Coins of the UK
Re: Restoring a Roman bronze
« Reply #13 on: June 15, 2010, 08:26:42 PM »
Looking at the state of that coin carrying it about with your other loose change for a couple of months should fix it 8)

Offline ghipszky

  • Moderator
  • Honorary Member
  • *****
  • Posts: 1 170
Re: Restoring a Roman bronze
« Reply #14 on: June 16, 2010, 01:28:21 AM »
Thanks Peter,
I was so excited to get this coin with the coiled snake reverse. I just think it is different from what I have in my collection to date.
I am going to to try Arminius baking soda restoration, for the experience.
When I first started in this hobby I got uncleaned coins. I tried cleaning them myself for a few months, but I learned quickly that I wasn't very good at it.
Hopefully I can get good results. When I am done I will post another picture of it.
Thanks for the input Tony.
Ginger
If I try this once and there is no noticeable changes, I will probably leave it the way it is. Even though I don't think I can hurt it worse.
« Last Edit: June 16, 2010, 01:39:12 AM by ghipszky »