Museum Wax alternative for unglazed ceramics?

[arielz]

New here, but have been lurking around the listserv for awhile. My job title is registrar, but as with many small museums, I end up having to wear many hats, which results in me installing and packing some of our objects.

I've run into this problem a few times and hope that someone has a good solution. When using museum wax on unglazed ceramics (stoneware or terra cotta for example) the wax leaves a residue. Museum putty claims to be safe with ceramics (http://www.gaylord.com/Exhibit-%26-Display/Installation-Supplies/Museum-Putty/p/MPUTTY) but I wanted to run it by the experts before I invested.

Does Museum putty also leave a residue on porous materials? Are there any better alternatives?

Many thanks!

[Jamie Hascall]

Products such as Museum/dental wax and Museum Putty can be useful and expedient to stabilize objects during installation, but I feel they each have liabilities that need to be considered. I feel that wax should only be used on unglazed ceramics if they are fired at a high enough temperature for the clay body to be well fused. Stoneware can fall into this category, but not always. The vitrification of the clay allows it to resist the absorption of mobile fractions of the wax that can occur on porous surfaces. More importantly, this level of firing gives the ceramic the strength to stand up to the bond that the wax can develop. I have seen pieces detach from low fired ceramics (even when glazed), especially when the object was pulled upward to release it from the wax. For this reason, I always encourage people to deinstall all waxed objects with a twisting motion to allow the wax layer to shear. I also recommend people use very small amounts of wax for this purpose. Three little balls the size of rice grains is usually sufficient.

In my experience, Museum Putty tends to leave a greasy residue. As a result, I haven't used it in many years and don't have first hand knowledge of the current formula. Gaylord is a good supplier, but I imagine they are taking the word of the product vendor on this one. As a result, you might want to test it yourself before deciding whether to use it or not.

A good way to test any material like the wax or putty for residues is to apply it to the bottoms of a couple of new terra cotta garden saucers. It helps to freshly abrade the bottoms with some scotch-brite and then put them bottom to bottom with the stuff in between and wrap a couple of rubber bands around them. Take them apart after a few weeks and see what you find. The terra cotta will visibly stain if there is a residue.

As far as alternatives, I don't have any other products that work in the same fashion. It is possible to paint a layer of B-72 resin on the bottom and to use wax on those spots. This solves the penetration problem, but the strength issue is still one to beware of.

If retaining the object for seismic/vibration purposes, a simple mount of a padded rod (1/8"-1/4") drilled into the deck and a piece of monofilament tied around the object can be enough. For more valuable or complex objects, I would recommend a mount designed for the piece.

Please post any further thoughts or questions. There is a wealth of knowledge and experience in this group.

Good luck,
Jamie