Historic flag press mount

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farmgirl1

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Oct 13, 2002
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Centreville, Va
I have framed several historic flags for a good customer. He is very knowledgeable and does the mounting himself, thank goodness. He has a new acquisition, a very fragile silk flag that requires a press mount and no stitches. He has it placed on black cotton velvet which is attached to coroplast. It then is covered front and back with OP3 acrylic. When placed in the frame, we are concerned that the pressure in the center (size is 44x31) will release somewhat and the flag will slip. Any ideas on how to maintain the center pressure? My only thought is 1/4 coroplast on the back that is more rigid. Any other thoughts?
 
Sounds like he is somewhat knowledgeable, and is on the right track, but missing a detail or two.

With this type of mount, the gentle overall pressure is provided by a layer of polyester batting or a similar material (Rebecca will be along to provide the name of the material soon) under the background fabric. If this is done, there should be no need for a thicker backing or for the second layer of acrylic behind.
 
farmgirl

I forgot that he did indeed use polyester batting under the black cotton velvet. He follows the suggestions of a flag dealer who has conservators on staff and the suggestion is to use acrylic on the front and back. The acrylic is 1/8 and the coroplast is 1/8" and is not really rigid. The pressure of the points on the edge of the frame will provide adequate pressue in the center of this large flag?
 
Several progressively-smaller layers of needle-punched polyester batting, which is more dense than ordinary 'polyfill' quilt batting, would provide a mound in the center of the prepared mounting board. Thus, pressure would be greater in the center, if the backing board is properly rigid.

An acrylic overlay mount of those dimensions should be constructed with thicker-than-usual acrylic, in order to minimize deflection in the center. I suggest 6 mm Museum Optium Acrylic, which is treated for abrasion-resistance, but also filters 98% of UV and provides optical coatings.

Check the Grumble archives for "overlay" mounting references. The June 2009 PFM article on page 36, "Acrylic Overlay Mounting", may also be useful.

Since you and your knowledgeable collector/customer are unfamiliar with the issues, please consult with an experienced conservator, or urge the customer to do so. The future of that fragile silk flag is at stake.
 
For what it is worth, there are a few things I have found that help prevent central bowing based on those that have gone before and my own experience:

One is to have a very rigid backboard (coroplast comes in 3/8") backed with a cross braced strainer.

The other is to set the textile into a sink mount, as deep or shallow as required, (ranging from 4-ply, to 8-ply to 1-2 inches made from Ethafoam) that helps keep the edges on plane and rigid.

The third is, as Jim and Dave suggest, to have layers of batting (needle punched polyester, one brand of which is Insulate), and maybe extra layers with staggered edges in the center (like a topographical map) to keep everything level. I tend to stitch the central layers with a curved needle ; I think Jim has an adhesive based system.

It may require some trial and error.

Let us know how it goes.
 
Rebecca said:
... I think Jim has an adhesive based system.
Click to expand...

I guess you are referring to a suggestion I mentioned some time ago. I've used this tactic only a couple of times, and not yet on a customer's property. I'm just not sure about the long term effects of having the dried adhesive in direct contact with a textile item.

If you want to try this yet-unproven technique, place small (say, 1/8" diameter) dots of acrylic gel or Lascaux 360 on the padded-fabric backer where they would contact the corners of the mounted item. Allow the adhesive dots to dry thoroughly before assemblying the mount.

The purpose of the small dots is not to actually glue the item, but to provide slightly non-slip spots in the corners, in order to prevent it slipping. I call this the "bath-mat principle".

I first used this tactic in an acrylic sandwich mount, where the item would be prone to slide around between the sheets. It worked well for that purpose, but only time will tell whether there are any drawbacks.

Especially for such a fragile silk item, maybe this tactic could cause trouble. If the textile were forced to move in the mount due to some sort of impact, and the corners were held fast by the small corner-dots, then it is conceivable that shredding could result. In that case, I think it would be better for the entire textile to move unimpeded.
 
Jim, re the adhesive I thought you used it also to attach top layers of polyester to underlying layers of polyester padding. It would certainly be quicker than sewing. I think the Lascaux dot method would also be good for lightly tacking the textile in place, though maybe not for fragile silk, for reasons you describe.

Thanks for the explanation of this technique.
 
Oh, yes. A little smear of Lascaux or arylic gel on the batting is all it takes to keep the layers from sliding around.
 
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