What is the strongest archival or conservation grade glue?

[bang]

I have a job in where I have been asked to mount paintings that have been done on mdf and thin wooden panel to a backing and then add a frame. Kind of like a tray frame of sorts.

Not for this job as being archival for it isn't a worry for my customer, but I'm curious what the strongest glue is out there that is still archival or reversible, which could bond a panel painting to a backing. Would it be a starch paste? Or could a conservation tape be used to act as a barrier between the bonding agent or tape and the backing.

[Not your average framer]

That depends! What are you sticking to what? Also the glue bond does not want to be strong enough to cause the failure of the material of the artwork to more easily fail than the glue, or the fixings that retain the artwork in position. It is not uncommon that we can prefer to retain the artwork in position without using glue to secure the artwork at all. For example sometimes an artwork may be secured by means of a platform mount, or even a deep sink mount, where the artwork is secure by containment but nothing is in any way glued to the artwork at all.

[bang]

Mdf to mdf panel, or thin wood panel to mdf.

Thin wood panel to foam core.

[Not your average framer]

It's not very easy to define the longevity of an MDF panel and it particularly depends upon the environment situation in which it it likely to be displayed. It is usually expected that the longevity of an artwork on MDF would not be necessarily mounted by means of a conservation grade glue, but very often by means of PVA glue, which is not always the easiest glue to full reverse. What wood were you thinking of for wood panels? There are types of wood panels with have quite reasonable longevity, compared to MDF.

Sometimes artwork on wood panels are supplied by the artists with support frames as part of the original artwork so that they cam be secured by means of wood screws into the support frames and therefore do not create problem with separating artworks which are glued into their frames and are likely to be problematic, if the need arises that they are to be re-framed. In this case, archival framing usually assumes a reasonable degree of reversibility with regards to how the artwork is to be secured into the frame.

[fitz]

I would be happy to simply use PVA for this. If the painting is already done onto MDF depending on how thick it is it may not require a further backing board? If it is onto thinner, say 2mm mdf board I would back it onto 5 or 6mm board. The method I use I picked up on this forum. Place an even layer of PVA onto the baseboard (I use a small gloss paint roller for this) and allow it to become tacky. Then apply another layer either on to the back of the painted board or the backing board and lay the artwork onto this. Pop a similarly sized piece of board (thin MDF or foam board) on top then apply very heavy weights evenly over the piece. I leave it for at least 24 hours to set and flatten. You can then create a tray frame or frame conventionally based on customers choice.

[Not your average framer]

Hi Fitz,

That is normal procedure for most artworks on MDF, but describing it as conservation framing is stretching it a bit. It is no longer in original condition as it was supplied by the artist, which is a major goal of conservation framings. Added to that, if the artwork is glued into a tray frames, this becomes a further issue and removing the artwork from a frame where it has been glued in place, may require pieces of the frame to be removed from the artwork by cutting away pieces of the frame with woodworking tools and effectively destroying the frame. I'm not saying that it can't be done, but it's not going to be quick and easy, therefore it is likely tobe a risky thing to do and also potentially quite expensive. When claiming that such an artwork has been conservation framed, I think that there should be some caveats defining the limits of what the the customer is told regarding what is meant by conservation framing in that particular regard, as it is not truely what can be genuinely defined as truely conservation framing in the strictest sense of the word.

Added to this, atmospheric humidity has a detremental effect on the longer term condition of unsealed MDF and over time can cause some deterioration of the MDF, whch may effect the potential resale value of the artwork. This rasises the question of whether any sealing is best applied before, or after gluing the MDF with PVA glue, as the the sealer may affect the effectiveness of the bonding of the PVA glue to the MDF. Aternatively using the PVA before coating the MDF which a waterproof sealer, may reduce the performance of the sealer. I would suggest that there is much to think about concerning how you are going to do this. A much superior material would be baltic birch plywood. 18mm thick baltic birch plywood would in fact be very similar to the normal thickness of many stretched canvases and would therefore be quite easy to fix into a normal depth of canvas tray using wood screws instead of using glue. If the piece of baltic birch plywood has been properly prepare and sealed before painting, with nice cleanly cut and finished edges, the level of presentation could be to a high standard and could justifiably and rwasonably be called prepared to conservation standards.

[prospero]

If it's MDF then I wouldn't worry too much about 'conservation' aspects.
It's a relatively recently developed material so no one can know the long-term longevity of MDF.
I'd go so far as to say that it's at least as 'archival' as any other artist's substrate. MDF does not
fare well when exposed to very damp conditions. The trick is not too get it wet.
As for glue, I would be quite happy to PVA it. But the non-archival aspect lies not in the glue itself
but in the fact that it is glued.

[Not your average framer]

MDF sucks up airbourne humidity quite quickly if you don't adequately seal it. To describe it as being of conservation quality is not really true!

[bang]

Thank you for your advice and thoughts on this everyone!

It was the current job I have on that got me thinking about if there is a way to do it that would allow removal of the work in future - in a way that wouldn't risk harming it.

It seams the use of MDF would require I advise the artist to seal it with GAC100 or similar to stabilise their work on it, one of the panels I've got in the studio is bowed quite a bit on one side... perhaps sealing the other will draw it in a little and put less stress on the panel when I glue it to a backing.

I notice many of you mentioned PVA, I know there's a component of PVA in wood glue, but they are not quite the same thing. Are you discussing wood glue and PVA interchangeably, or is there a reason not to use wood glue?... I mean, does it have more potential to cause damage to the work than PVA?

I was thinking an acrylic gel medium could work quite well for something like that, again some of you may be aware of reasons not to use that which I'm not aware of.

[Not your average framer]

I am not aware of any detremental issues with using PVA glue, once it has set there is not anything which ca escape and cause any problems. Many framers already use PVA glue for framing, so it reasonable to assume that it's o.k.

[vintage frames]

Gac100, PVA, wood glue - they're all the same, based on some sort of acrylic mixture.

If you want to stick an MDF panel into a frame and have it reversible then you need a natural reversible adhesive first.
Refined hide glue is reversible. Use Rabbit Skin Glue,(RSG).

Seal the back of the panel first with 50:50 diluted PVA. It's MDF, so it won't matter.
Stick a same size sheet of mountboard to the MDF using lukewarm RSG.
Repeat with another piece of mountboard.

Now stick all of that to a thicker board using PVA/wood glue as Fitz has advised and go on to complete the frame.

To reverse it all, pull off the mountboards from the thick board first, then tear away the mountboards as much as possible before gently releasing the RSG with warmed water.

[JFeig]

One question to ask the artist is: "Is there an isolation layer between the paint and the MDF?" If not the MDF is part of the art and cannot be separated from the paint layer by a conservator. The artist did not do their due diligence regarding preservation of their work.

You are being asked to to conservation framing on a "banana taped onto a wall". It will rot regardless of conservation processes.

P.S.
There are conservation grade PVA's and EVA's.

[bang]

I enjoyed the analogy of the 'banana taped to a wall'! You're right!

Interesting advice regarding the rabbit skin glue, I used a lot of it in my art student days to make traditional gesso and to size canvas. I hadn't thought to use it as you suggested.

Thanks again! This was mostly hypothetical, but I have a better idea of how I would approach a similar job in the future, where longevity and reversal of the adhesives is an issue.