Silicone adhesive - advice

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JonathanB
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Silicone adhesive - advice

Post by JonathanB » Wed 25 Nov, 2020 10:18 am

Morning everyone -

I need to be able to fix a very light piece of aluminium to mountboard. Whatever I use must be non-corrosive and removable if necessary. Superglue or anything like it is out. I'm thinking clear silicone and was hoping someone might have a recommendation.

Any thoughts?
Thanks
Jonathan Birch GCF (APF)

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Re: Silicone adhesive - advice

Post by Not your average framer » Wed 25 Nov, 2020 11:41 am

Silicone adhesives are almost certainly not very conservation friendly, not only that but silicone tends to migrate from one place to a other a bit. Most of the easily obtainable silicone compounds, used as adhesives, or sealers are acetic acid curing, so if you are thinking acid free, well think again. There is an alternative type which is an alcohol curing type, but it is much more expensive.

A possible issue with the alcohol curing type is that you only have to add oxygen to alcohol and the alcohol becomes an acid. That's how you get vinegar, leave a bottle of wine, or cider open to the air for a while and it turns in to vinegar. The more common acetic acid curing silicone will out glas acetic acid for months and even years, dispersing an acidic vapor throughout the inside of the frame affecting just about everything within the frame. Sorry not very conservation friendly!

I'm much more inclined to suggest a double sided adhesive film, or double sided tape based on an acrylic self adhesive. Acrylic self adhesives come in two types, either acrylic hot melt, or acrylic solvent based. The acrylic hot melt varieties tend to have more grab and a heavier coat weight and are particularly longer lasting. Try to avoid self adhesives which are based on synthetic rubber solution compounds, as these can breakdown in to various harmful acidic by products which are not exactly good news.

Another name used for self adhesives is "pressure sensitive", which is because the strength and the long tern effectiveness of the bond obtained is related to the level of pressure applied at the time of application. So, if you can, really solid pressure is a good thing. If you ever need to remove the aluminium from the mount board at a later date, heating the rear of the mount board with loosen the adhesive and make it so that you can peel off the mount board and remove any residue adhesive from the back of the aluminium with a suitable solvent.
Mark Lacey

“Life is short. Art long. Opportunity is fleeting. Experience treacherous. Judgement difficult.”
― Geoffrey Chaucer

JonathanB
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Re: Silicone adhesive - advice

Post by JonathanB » Wed 25 Nov, 2020 12:06 pm

Thanks very much for your reply Mark. I think I might have given slightly the wrong impression about this job. You wisely highlight the issues with adhesives like this, but I should have mentioned that the item is of little value and the job is overall a 'commended' project where small blobs of silicon are acceptable on non-absorbent objects. I'm a bit concerned about double sided tape failing, and was hoping for a brand recommendation from one of our colleagues about a product they've used successfully in the past.
Jonathan Birch GCF (APF)

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