Obeche slips and barrier tape

[David McCormack]

I'm using a hand painted obeche slip that will be in direct contact with the artwork. What barrier tape do folks use on the back of the slip to protect the artwork from migrating nasties? Is cotton gummed paper tape suitable? Thanks.

[Roboframer]

A self adhesive linen tape or somethimg like filmoplast P90 wouldn't make much difference. Personally, for things of value I either don't show slips or put them on the top of a double mount.

[Not your average framer]

I'm assuming that this problem includes the requirement to frame the artwork to conservation standards and therefore I would not favour the use of any kind of self adhesive tape. This is because ALL self adhesives have the potential for out gassing products which are NOT considered as conservation friendly. Also the cut edge of self adhesive tapes may permit direct contact between the self adhesive and the artwork.

I would prefer to thoroughly seal all faces of the bare wood slip with several coats of a suitable polymer sealant before painting the slip, so as to ensure a reliable and continuous seal around all surfaces and edges of the slip. You may need to research your options for a suitable polymer sealer before making your choice, but as a starting suggestion, may I suggest a solution of Paraloid B72 in acetone.

I would suggest that the first application should be a weak solution in order to gain maximum penetration into the surface of the wood, with progressively stronger solutions for successive applications. After painting the slip, I would apply a coat of Picreator Heritage wax. Any concerns as to if any molecular level porosity might exist in the sealing coat of Paraloid B72 will be fully addressed by the Heritage wax coating. Heritage wax is a conservation level micro crystaline wax which results in a "gas tight" non-permiable seal.

BTW, it is worth acquanting your self will the B72 and Heritage wax technical data sheets as these will help to explain my thinking behind this suggestion and may also suggest other uses for these useful products.

This may sould like a complicated proceedure, but I think that from a technical perspective, you will find that the science behind the idea should check out well.

[Roboframer]

There are several conservation-acceptable methods that use DS tape, such as encapsulation and edge-mounting strips and for these I use 3M 889 which is an acrylic based adhesive on a polyester carrier - 3M 415 has similar properties. You could make your own self-adhesive tape for fillets using 889 or 415 and that tape could be made from Melinex and the DS tape would not have to go to the edge of it either. Lineco foil tape is good too, metal is a true barrier. But I still wouldn't class a job with a slip in contact with the artwork as full conservation quality, however it was prepared, sealed or fixed in place...... and you do still have to fix it in place.

[Roboframer]

An interesting discussion on the subject .. http://www.thegrumble.com/showthread.ph ... ts-On-Mats

[Framemaker Richard]

I use Lineco aluminium foil tape on wooden slips that will come into contact with paper. 3M 431 foil tape could also be used, a self adhesive tape which passes off-gassing tests. I am not sure if the Lineco tape passes the same tests but I think it is suitable for most cases. Seal the wood and face with a thin cotton barrier sheet if you want to be very safe but I don't think this would be needed that often.

[Not your average framer]

I've never been able to find out if the paper side of the linco tape is conservation quality, or not. As it is described as a frame sealing tape, I suspect that the paper side is probably not conservation quality, but it would be nice to know for sure.

Edit: The above mentioned Grumble thread indicates that the Linco frame sealing tape is backed with acid and lignin free paper.

[Roboframer]

As far as I'm concerned, regarding tape that is in direct contact with the artwork, including hinges, there is no such thing as a conservation quality tape, be it gummed or self-adhesive.

Mount fillets/slips are visual enhancements and nothing to do with conservation where anything that comes in to contact with the artwork was designed to protect, not enhance; add a slip/fillet and however you choose to seal/fit it, at the highest levels, is damage limitation. See my first reply.

[prospero]

I generally put fillets in the middle of a double mount. Can't remember ever using one right on the edge. But if I had to I think a barrier of mylar with a further sheet of 2-ply rag board beneath. Maybe a couple of mm away from the window edge. The mylar would form a barrier and the thin board would create a gap so that the edge of the fillet would never (hopefully) touch the art. Of course only time would tell if any offgassing from the fillet would jump the gap and affect the art. So anything remotely valuable best avoid a fillet completely.

As Robo says, tapes in themselves may be fairly safe, but if they have glue on the back you never can tell. Even if the tape succeeds in not letting any glue seep though it, there are still the edges.

[David McCormack]

I'm assuming that this problem includes the requirement to frame the artwork to conservation standards and therefore I would not favour the use of any kind of self adhesive tape. This is because ALL self adhesives have the potential for out gassing products which are NOT considered as conservation friendly.

I didn't mention conservation or self adhesive tape! But your suggestion is very considered and thorough Mark as usual, so thank you Is Heritage wax the same as Renaissance wax?

Seal the wood and face with a thin cotton barrier sheet if you want to be very safe but I don't think this would be needed that often.

This job was simply driven by design and not conservation, so was just wanting to know how to offer some protection from the wood slip. I used 500 micron barrier board in the end as suggested by Richard.

Interesting link to the Grumble. I agree about fillets & slips not really having a place in conservation framing. Some may find the attached page from the FATG Tapes & Adhesives publication interesting (section 11).

Tapes_and_Adhesives.pdf

(60.69 KiB) Downloaded 154 times

[Not your average framer]

Sorry, it should be Renaissance wax! It was getting a little mixed up.

Heritage wax is something else which I also have in my workshop, Ii don't even know where it came from, but like everything else, it has it's uses.