Medals and silicone

[Darth Framer]

Hi all. I've just noticed in another thread on the forum a reference to the use of silicone for attaching medals. The inference is that this is serious malpractice. I'm intrigued to know why this is such a no no. I hasten to add this is not how I attatch medals but even so if the process is reversable then why not? Or is that the crux of the matter - is it not reversable, or does it damage the metal? Thoughts please...

[Roboframer]

Firstly, if you believe the process is reversible ....

a. How would you reverse it?

b. Why don't you use it? and ...

c. What DO you use and why?

[fineedge]

Let me hasten to add that I have attached medals with silicone and still do - but it depends on the medal. Old war medals or something of historical nature are treated differently. I often get customers with a bag full of sport stuff,tarnished by sweat and coke etc and these are often arranged in a long strip vertically or horizontally and they get the silicone treatment but lie to cure and off gas over night because of the methyl alcohol which evolves from the contact with air. I have had occasion to redo an arrangement after a year or two because of an addition to the collection and have found that these cheapo medals do discolour where there was contact with the silicone - almost as if that specific patch was polished up with brasso or something. I suspect that those marks happen when the silicone is soft and not beyond the curing process. ( I use the silicone method in these cases because of the many variations of medal shape, date plates on the ribbon , lumps on the back from embossing, lost ribbons, broken and lost loops holding the ribbons etc make it difficult to attach twenty or thirty each in its own way -adding to the cost)

[Not your average framer]

I would not use silicone anywhere near a customers medals and certainly not in contact with the medals.

There are a number of reasons why I would suggest that this is a bad idea:

1. Most RTV (Room Temperature Vulcanising) silicone compounds cure by releasing acetic acid which will attack any copper, or zinc content in the medal, (and I'm not too sure about lead in some metal alloys,)either by direct contact or possibly by "out gassing". This is at risk of damaging the surface finish on the medal and also the appearance of the medal.

2. The patina on medals can also be changed, or locally removed by direct contact with or by exposure to the "out gassing" of acetic acid. Also over time any atmospherically generated tarnishing or forming of additional patina as consistent with age would be uneven due to the masking effect of the silicone where it contacts the medal.

3. As far as I know, at least some types of medal ribbons may contain cotton based materials. If so, any cotton based materials are likely to be vunerable to exposure to acetic acid by "out gassing".

4. There are much better and more professional ways of doing this sort of job, which are completely reversible and fully proven conservation methods. The customer's reasonable expectations are for you to do your best and to avoid doing anything detremental to their property, after all you are supposed to be an expert at your job and that's why they came to you in the first place. In this particular case, silicone falls a long way behind recognised best practices.

Finally the quantity of acetic acid released during curing is significantly more than most framers probably realise.

[JB183244D]

I'd never use silicone near medals, in fact any adhesive should be avoided unless you can be sure the acid content will not effect the metal, as most medals are made of alloys, it would be hard to tell if one particular medal would be safe until it was too late. I always wire my medals direct onto the mountboard.
Alan, if your medals are covered in sweat and coke, have you been framing for Dwain Chambers??
Mark

[Darth Framer]

Firstly, if you believe the process is reversible ....

a. How would you reverse it?

b. Why don't you use it? and ...

c. What DO you use and why?

a. I dont know. Ive never used it. But would it not just peel off? It certainly seems to do that round my bathroom taps

b. I'd never thought about using it til I saw it referrred to in another thread this evening

c. I use wire fed through to the back of the board tied to itself because its reversable. However I'm worrying about this now incase there is the possibility of some adverse metallic reaction between the wire and medal I dont yet know about.

[fineedge]

good stuff Mark. So that causes the discoloration! - found this - http://yarchive.net/electr/silicone_sea ... eness.html -

I think that they are talking industrial here but the amount behind a medal ( 3 or 4 mm blob ) cannot give off acid enough to chow up a medal if the article refers to it only etching aluminium but we will nevertheless consider the melinex strips on the "coins" and sew through the ribbons of the others next time.

So what happens to those thin metal frames ( from years ago and that I detest ) that I have seen sealed with silicone at the back to attach it to a board to prevent bowing?

Does Dwain then actually work up a sweat? Make that coca cola!!!!!!!!!!!!!

[Roboframer]

c. I use wire fed through to the back of the board tied to itself because its reversable. .

Where does that wire go?

It can't go across the face of the medal - you'd see it. So what stops the medal from flopping forward, away from the mounting board?

Silicone would solve that problem?

[Darth Framer]

On a circular medal like a 1939-45 War Medal I use three anchor points, one between the medal and ribbon bar and two on the bar itself.On something like a star I use one anchor point on the ribbon ring and a loop round the bottom star point using copper wire.This last attatchment I agree is noticable but is negligable as long as the wire colour is similar to the medal colour .In addition to the ribbon being fed through a slot in the board and held at the back with ph70 these fixings do the job - no floppage.

[Roboframer]

On a circular medal like a 1939-45 War Medal I use three anchor points, one between the medal and ribbon bar and two on the bar itself.

IC IC - I get the picture - bin there; done that. So, what happens when you turn the frame face down? (just to exaggerate my point)

On something like a star I use one anchor point on the ribbon ring and a loop round the bottom star point using copper wire..

Ah - yes - stars - handy. Why not use the same method as the circular ones then - i.e no support at the bottom? OK the circular ones may have a ribbon bar that the star shaped ones do not - they just have a ring. But, mostly, they will have a ribbon, and you can attach the ribbon to give the same support as you are giving the bar, in which case you don't need that support at the bottom?

[Darth Framer]

The circular medals are attatched at the bottom of the stem between medal and bar and then twice more on either side of the bar creating a triangle. When these wires are wound together at the back it draws the medal to the board. A similar approach could be applied to the stars but it would mean more wire showing hence I go with a loop at the bottom which is drawn up behind and wound to the attatchment above. There are occasions (depending on the medal) where there is a small amount of play when the frame is tipped forward but they settle in position when hanging.
What would your solution be? Just dont say silicone

[Roboframer]

I used to do what you do, but with button thread, very hard to see. Then I did the same with melinex straps, even harder to see. But still had the problem, on circular medals, of them not laying flat.

So now I use Jim Miller's method with melinex - I make a 'spider' of melinex by drawing around the medal on to a piece of paper, then adding 'legs' (straps) to that circle - four in an 'X' is good for a medal.

Tape a square of melinex over that and cut around it with an exacto knife - JUST inside the circle and along the legs so you have an 'X' with a circle in the middle.

That goes over the medal and the straps pass through slits underneath it. You use the waste melinex you have cut that shape out of as a template for the position of the slits. Hope that makes sense.

It's tricky getting a set of loose medals lined up, but if they have ribbons I stitch them first, which makes it easy.

Here are two coins I did with that method.

[fineedge]

A spider !!!!! this is one of those "why didn't I think of that " moments. I did an antique pocket watch the other day and just used two straps crossing each other - hell of a job getting them to stay put while threading through to the back - eventually lightly taped the straps to the front of the watch while working at the back pulling them up tight and then removed the tape carefully but it worked in the end and I actually had to point it out to the customer - she couldn't see them. But then again it was a glass surface they were crossing so they were just about invisible.

[Not your average framer]

good stuff Mark. So that causes the discoloration! - found this - http://yarchive.net/electr/silicone_sea ... eness.html -

Have you checked out data for silicone compounds and sealant from "Dow-Corning"? They are the bigest name there is in silicone compounds and they publish plenty of scientific info and data sheets.

I think that they are talking industrial here but the amount behind a medal ( 3 or 4 mm blob ) cannot give off acid enough to chow up a medal if the article refers to it only etching aluminium but we will nevertheless consider the melinex strips on the "coins" and sew through the ribbons of the others next time.

Etching aluminium is very different from metals and alloys used in medals. Aluminium self anodises through contact with air in the environment and that anodised surface on the aluminium is highly resistant to corrosion, Sorry, but it's not a very meaningful comparison.

Just in case anyone is wondering how these RTV silicones cure, well they are prevented from curing by the inclusion of an alcohol which when exposed to the presence of air rapidly absorbs oxygen and when you add oxygen to alcohol, the result is an acid. Hence the acetic acid, which is there is enough qualities to etch through fine copper wires in electronic assemblies and the reason why other (non-acetic acid) versions of silicone compounds are produced for such uses. I used to work in electronics design - it's a well know problem with some silicones!