Metal Barrier For Conservation

Rob Markoff

PFG, Picture Framing God
Mar 8, 1999
San Diego, CA USA
FACTS standards call for a minimum separation of 1" (in all planes - per Jim Miller's suggestion of language) from wood unless lined with glass or metal. Many framers forget that the plane also includes the area behind the art. Glass is too heavy and cannot be used in my application as the art is shipped and stored and glass also breaks.

This means that if I am using a narrow stem moulding and have a strainer with cross support BEHIND the art, and the art is floated with 1 1/2" AA on a 4 ply board that is backed with coroplast, there is not enough separation between the coroplast and the strainer behind the art to meet standards as it is less than 1" thick. Adding the extra filler boards will not always work as the moulding would then have to be too deep (acrylic, spacers, float board, filler board, strainer all need to be no thicker than 2")

We are using 1/2" - 3/4" spacers to hold up the UF acrylic made of matboard (built up to 3/16" thick) and attached to a metal lined rabbet with acrylic adhesive supplemented with PVA dots.

We have been lining the inside of the rabbet with metal tape (Lineco) and also wrapping the strainer with the tape (which gets time consuming). We are framing original works of means (Jasper Johns, Richard Diebenkorn, Wayne Thiebaud, Robert Mangold) so the materials and methodology is critical.

While at a restaurant supply, I came across large rolls of rather thick aluminum foil that would allow us to line the coroplast with the foil using only one or two sheets of foil.

If I use something like YES! paste and prepare a bunch of sheets of Coroplast and line them with the aluminum foil (overlapping about an inch at the seams), and the coroplast completely lines the back, and the rabbet is lined as well, would that meet standards and eliminate the need to also wrap the strainer? This would be a great solution as we could pre-make big sheets of lined boards and only have to cut them to size as needed. The foil side would face UP (towards the art) and would be inside the framed package anyway so it would not be seen (in the event of a "wrinkle" in the "manufacturing" process.)

I am hoping that Hugh will weigh in here (and Jim and Greg).
or in San Diego

The panels would be about a half inch and would eliminate the acid shortcomings of a wood strainer entirely. All while affording you a simple rigid, one piece unit to replace filler, strainer and coroplast. This also reduces the labor cost of cutting and creating all those individual and separate components.
The only drawback is that we secure the stem moulding to the strainer and attach all hanging hardware to the strainer. The moulding is too thin for d rings, so we need the "wood".
You can use a couple of different methods to attach hanging hardware:
1) pop rivets to install d-ring strap hangers (4 hole) directly to the aluminum
2) pop rivets and z-bar hangers

I believe that the panels from Small Corp can be provided with a wood edge. Check with them as they might be able to recess it in to achieve the 1" no wood zone.

You might be able to get the back skin of the honeycomb a bit wider than the front and the actual honeycomb and screw that to the back of the frame.
While at a restaurant supply, I came across large rolls of rather thick aluminum foil that would allow us to line the coroplast with the foil using only one or two sheets of foil.

I think that aluminum foil has micro perforations in it that would negate its use as a barrier for your job. These perfs are put in during the rolling process at the time manufacture. The perfs may be small enough to keep out water but not gases. I went down that road about 12 years ago.
Aluminum foil can be an effective barrier material, but if it is not coated, it will oxidize and can stain paper that touches it. If the consern, here, is emissions from the wood of the strainer, it is important to remember that the dangerous part of wood is the end grain. If the strainer, or frame, is made of straight grained wood that is free of knots, it should emit at a low level and the Coroplast, itself should function as an effective isolating layer. To create a vapor barrier, a crystalline material (metal or glass) is required, since it will stop infusion of molecules. There are other materials that will intercept and neutralize gases, such as zeolites (Microchamber papers, Artcare boards) or particulate metals (Corrosion Intercept plastic, silver cloth) and these can be most useful. Aluminum polymer composites are available flexible sheets (Marvelseal 360, 1311, Mitsubishi High Gas Barrier, or Alumiseal zero perm vapor barrier) or as rigid composites (Dibond, Alucobond, Alumalite, Econolite, D-lite).
Aluminzed polyester film that is used in food packaging may also be useful. Keeping the cellulose or protein that comprises items we value from gases that come from wood or from air pollution is an important issue and one well worthy of FACTS consideration.

Thanks for the reply, Hugh. I want to make sure that I understand that a Coroplast sheet in between the strainer and the backing board is sufficient to protect the art. This concerns me as FACTS states that there needs to be a 1" separation unless lined with glass or metal.

In direct response to my idea, would the aluminum foil attached to the coroplast provide any benefit, and if "staining" from the metal is of issue, would putting the metal side down against the strainer be a better idea?
As long as we are on this topic -

The housing construction trade uses aluminum tape to seal heat and air ductwork. It is about 1 1/2 inches wide (sorry, dont have a brand name to give you). I was wondering if this too would be acceptable as a barrier tape like the Lineco tape I now use. It is wider, so it may be more cost-effective in some applications.

Just wondering....