At the Quorn swapmeet of Autumn 2000, after looking at the large 1993/94 brooches for sale it became apparent that many from the set had started to yellow where they should have been white. It was most apparent on large areas of white such as those found on the pilot and the chef. However, the rugby player's ball and other smaller areas also showed signs. I put this down to them having been stored in sunlight. On arriving home I checked mine and convinced myself that the whites were still white. However, in August 2001 I had cause to check again and found the truth was quite different!
Considering the pre-war fruits have survived in excellent condition since 1932 and yet the 1993/94 set have started to deteriorate so soon after manufacture, I set out to try and understand the problem and sought opinions from the sources mentioned below. Please note that no firm conclusion or evidence has been reached. However, it provides food for thought, and hopefully will help you consider carefully how best to store yours.
Anybody who can tell me how their set has faired and how they store them may help to reveal the cause.
With thanks to everybody who has contributed.
The Bizz Badge Company say that the 1993/94 set were steel stamped badges with epoxy coating. After 5 years or so, epoxy will start to discolour especially quickly in direct sunlight.
Colin Dodds offers an explanation that the most likely causes are oxidation of the coating causing yellowing, with contact with air being a cause almost impossible to stop! The oxidation could well be speeded up by light, as for example the rapid browning of old newspapers which needs air and light to go rapidly. The plastic coating is set by a catalyst or more strictly an accelerator. If too much accelerator is present, then it can help in continued oxidation of the coating. This could also explain why some badges seem OK after an equal length of time. It seems to affect some batches more than others.
The Bizz Badge Company advise that after 5 years or so, epoxy will start to discolour especially quickly in direct sunlight and so to minimise this yellowing, always avoid sunlight.
However, several members of the Yahoo! group display their collections on a Robertson's Golly scroll and can see no sign of yellowing. In fact one members says, "I've always kept them in my kitchen and its south facing so you always get the sunlight in it" and adds "mine have not discoloured at all!". (Thanks Louise).
If keeping them in the dark was the answer then it would not explain another members' experience who has always kept them "in their packaging and stored away in a treasure box" and yet describes the white parts on her Chef and Skier as having turned a "manky yellow". (Thanks Susan).
The Bizz Badge Company also advise that for long term storage of the Golly collections, if you limit the times you actually handle the badges this will help to keep it's long term quality.
Presumably this is general advice rather than specific to the 1993/94 set because, as Colin comments, it is not obvious what in body perspiration would speed up the yellowing process.
The Bizz Badge Company commented that keeping them in the polybags may help cut down on the oxidation of the epoxy a tiny bit, but my [Bizz Badge Company] gollies are kept behind glass (out of the polybags as they also deteriorate) and there is only a tiny bit of yellowing against the white enamel.
Colin offers the explanation that in the polybags the amount of oxygen in the air is limited, and once it reacts with the epoxy resin will not be so readily replaced as in free moving air. Out of the bag the process will be quicker, but badges in confined spaces should last better for these reasons.
However, several members of the Yahoo! group display on a scroll and have no sign of yellowing, whereas those who store in bags do.
Charlie Panting says, "I have two sets that have been stored in their original plastic bags in the dark. It would appear that there were two types of plastic used for the packets. One has a plastic feel to it whilst the other is quiet brittle. In all cases with my sets, the badges stored in the brittle plastic bags have yellowed".
A member of the Yahoo! Group also confirms that from his experience "the discolouration seems to take place in those badges that originally came in the crisper cellophane bags... rather than the softer plastic type." (Thanks Andrew)
However, Colin adds that the Horizontal backstamp versions came in the 'cellophane' type of packet and the Vertical backstamp versions mainly in the flexible PVC type and that the obviously yellowed ones are all the Vertical backstamp versions in his collection. This is the opposite way around to the other collectors' experiences.
Colin considered whether there could be some interaction between bag and epoxy resin. PVC is actually very brittle. For this reason the PVC has a material called a plasticiser added. The plasticiser acts like a lubricant and allows the plastic to bend rather than snap. PVC itself is chemically pretty inert as is the plasticiser. It seems unlikely that either of these could cause this reaction.
Colin feels it may be that when the Horizontal to Vertical backstamp change over took place something else was different e.g. base coating or lack of it or different epoxy mix.
This sentiment was echoed by another member of the Yahoo! group (who prefers to describe the new colour as ivory). His badges are in their plastic packets inside plastic photographic slide storage pages but still thinks it may not be the plastic causing the problem and that it could be due to some aspect of the production process as earlier sets stored in the same way do not seem to show the same problem. (Thanks Ron)
Another member of the Yahoo! group suspects it may occur when the coating is applied too hot by the maker. (Thanks Will)
The Bizz Badge Company state that the 1996 Limited Edition were a better quality production than the 1993/94 set; photo etched using gold plated brass and epoxy.
Colin has observed that the yellowing also seems to affect the Pro-Pat design coating.
Without several different examples of both horizontal and vertical backstamps stored in different conditions over a period of time (in original bags, in the wrong original bags, in the dark, in the light) it is going to be extremely difficult to be sure if the cause was in the manufacture of some but not all brooches and whether storage can only at best slow down the visible signs of ageing.
Since seeking peoples' opinions I have decided to remove my set from plastic bags but keep them in the dark. Others have expressed the view that without displaying their collection on a wall for all to admire, then the point of collecting is lost. From what I have heard, these people seem to have faired best so far!