World of Coins

Collecting coins => Cleaning, conservation and storage => Topic started by: Figleaf on June 14, 2010, 01:32:51 AM

Title: Restoring a Roman bronze
Post by: Figleaf on June 14, 2010, 01:32:51 AM
This coin was discussed and identified here (http://www.worldofcoins.eu/forum/index.php/topic,6650.0.html). What follows is the discussion on whether/how to fix it up.

(http://www.worldofcoins.eu/forum/index.php?action=dlattach;topic=6650.0;attach=8928;image)

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

Peter
Title: Re: Restoring a Roman bronze
Post by: ghipszky 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
Title: Re: Restoring a Roman bronze
Post by: sminnoch 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
Title: Re: Restoring a Roman bronze
Post by: ghipszky on June 14, 2010, 02:52:03 AM
Steve should it be out in the air vs the flip folder?
Ginger
Title: Re: Restoring a Roman bronze
Post by: sminnoch 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.
Title: Re: Restoring a Roman bronze
Post by: ghipszky 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
Title: Re: Restoring a Roman bronze
Post by: Arminius 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.
Title: Re: Restoring a Roman bronze
Post by: ghipszky on June 15, 2010, 04:43:12 AM
How much baking soda should I use??
Ginger
Title: Re: Restoring a Roman bronze
Post by: Arminius 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
Title: Re: Restoring a Roman bronze
Post by: lusomosa on June 15, 2010, 09:23:29 AM
I'm not a chemist..... I prefere Olive oil.

LP
Title: Re: Restoring a Roman bronze
Post by: akona20 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
Title: Re: Restoring a Roman bronze
Post by: Figleaf 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
Title: Re: Restoring a Roman bronze
Post by: Arminius 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.

Title: Re: Restoring a Roman bronze
Post by: tonyclayton 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)
Title: Re: Restoring a Roman bronze
Post by: ghipszky 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.
Title: Re: Restoring a Roman bronze
Post by: ghipszky on June 30, 2010, 09:00:46 PM
I have not decided if it is worth it to restore this coin.
Ginger
Title: Re: Restoring a Roman bronze
Post by: andyg on June 30, 2010, 09:04:36 PM
I have not decided if it is worth it to restore this coin.
Ginger

It looks pretty nice at the moment Ginger (I don't think anyone can get it better!)

Andrew
Title: Re: Restoring a Roman bronze
Post by: ghipszky on June 30, 2010, 09:09:58 PM
Thanks Andrew for that. I just this coin has already been messed with enough. I got it for the reverse, one like this in my price range anyhow.
Thanks to people for the suggestion of how to restore this coin.
Ginger
Title: Re: Restoring a Roman bronze
Post by: romeo on July 16, 2010, 01:47:55 PM
I know this is a older thread but I was thinking, maybe in this instance olive oil would not be wise to use, sure it wouls darken the patina but as already been mentioned it is slightly acidic which can only lead to problems with a already worn coin. If you did want it a darker tone, without using repatination products like Dellers or Jax then how about using a product like Renwax. Not only will it protect your coin but it will darken it slightly and once its dried and maybe after a couple of light coats you could go over the high lights of the coin with a cotton bud, buffing gently which will bring out detail too.
Just a thought, best regards romeo
Title: Re: Restoring a Roman bronze
Post by: Figleaf on July 16, 2010, 04:06:16 PM
Since Ghipszky is not in Britain, she will not be familiar with British brand names. Can you convert them to generic product descriptions?

Peter
Title: Re: Restoring a Roman bronze
Post by: romeo on July 16, 2010, 04:52:02 PM
Hi, very sorry i didnt realise. Im not sure if there are other names for these products since they are available internationally. Infact i order mine from Kevin at Nobel Roman Coins. I will try and find out the chemical make up and ingredients though which may be of interest.
best regards romeo
Title: Re: Restoring a Roman bronze
Post by: Figleaf on July 16, 2010, 05:05:09 PM
Found it here (http://www.herbeau.com/Products.aspx?Item=RENWAX). Priced in USD, so I guess you can get it in the US.

Peter
Title: Re: Restoring a Roman bronze
Post by: Prosit on July 16, 2010, 06:54:58 PM
It is available online from stores in the US.  Usually called Renaissance Wax, never noticed it as renwax but I may not have been paying attention.  That name makes sense  ;).

Dale


Found it here (http://www.herbeau.com/Products.aspx?Item=RENWAX). Priced in USD, so I guess you can get it in the US.

Peter