Aloha e Mountmaker Hui,
We are currently in the midst of a major renovation of our main hall at the Bernice Pauahi Bishop Museum and are looking for alternatives in material for pedestal tops.
Our conservator has said that Medex may not be safe anymore because of a change in the formula, and heard that Sintra was tested and proven safe to use. If this is true, has anyone worked with Vycom, and is it safe? Our local supplier here said that this is their "Sintra" product that they carry in stock. Any information that anyone has on the safety of this product would be greatly appreciated.
Malama pono a me Mahalo,
We use Sintra on our art storage shelves and in our shipping crates. It makes it much easier to slide heavy objects in and out. We also use it for our text panels which get painted gallery wall color. So we know that it holds paint. But we haven't used it for cases yet. We still use Medex covered with Marvelseal.
Philip Brutz Mountmaker Cleveland Museum of Art 11150 East Blvd. Cleveland, OH 44106-1797 216-707-2617
RE: [mountmaking-forum] Re: Vycom-Sintra I am curious. I always avoided Sintra because it is Polyvinyl Chloride. Is Sintra somehow bonded or sealed? Or do they carry a product not made from PVC?
Philip Brutz 5/29/08
RE: [mountmaking-forum] Re: Vycom-Sintra We use pvc cement to glue it together so it must be similar.
Our conservation dept Oddy tested it a couple of times and it passed, but I have heard that it didn't pass at other places. I'd be curious to hear about others' results.
We experimented with it as a case material in an exhibit a few years ago and it did have some limitations in terms of case construction and mountmaking - although it is a rigid material, in larger decks it slumped enough to require ribs every few feet. It was also relatively "soft" to install mounts into, meaning you still need to drill into it, but for mounts designed for a pressure-fit installation, I had to drill 2-3 drill sizes under instead of 1 or 2. But if you use a mechanical attachment, it should work fine.
The exhibit will be deinstalled in July, so we'll see if there was any adverse affect on the objects then!
I would recommend aluminum laminate over your medex pedestal. You should be able to roughen the surface and paint (while letting it cure of course) without any problems. Another option would be either back- painted acrylic or fabric wrapped acrylic as a topper.
PVC is considered unstable and I'd suggest staying away from it. The chlorinated solvents used in it's production will leach out over time and cause the remaining plasticizers to migrate and pool together. All vinyl, from house siding, to records, to wire coatings, is also chemically photoreactive and will degrade, becoming more brittle, when exposed to light.
Philip Brutz 5/30/08
RE: [mountmaking-forum] Re: Vycom-Sintra How do you apply the aluminum laminate?
RE: [mountmaking-forum] Re: Vycom-Sintra I inquired of a Conservator friend regarding the Sintra, and following is her reply, plus some previous discussion from other sources.
Good Morning Bradley,
Yes, I too am skeptical regarding Sintra due to its PVC constitution. PVC should normally be avoided when creating display cases. For some reason though, it has passed all of the Oddy testing and has been often used in permanent display cases. Perhaps it does not have as large a quantity of plasticizer in it which would cause deterioration over time? Most PVC materials can have up to 50% by weight plasticizers in its composition (Hatchfield, p.57). I queried my colleague in the Getty conservation department regarding this very topic awhile back and will attach the response below:
"As best I know, we are using Sintra http://www.alcancompositesusa.com/product_detail.html?uid=gd40c8c3818a3bf&gc lid=CP_NqKKHy4wCFRcQYQodBwt2Tg
for almost all case decks now and paint them with acrylic emulsion paints. It seems to pass all of the tests we've thrown at it, so I guess not all PVC is equal. I didn't' do the tests myself, but we use it an awful lot, so I trust it has been pretty thoroughly vetted. We use it unpainted too."
Bradley, if you do choose to use it instead of DiBond or Alucobond, I would just be judicious about its use and since it is still a PVC, I would take all safety precautions for you and your staff in handling it. Do not breathe in dust or vapor (if melting/bending/whatever). PVC is still a horrible substance and usually is one of the ingredients that kills people who die in fires. Much of that smoke inhalation is burning vinyl chloride. (as an aside: a documentary to rent is BLUE VINYL, it shows the seedier side of PVC)
Here is an older posting I found on a conservation distlist archive:
From: Jed Bark <jbark> Date: Saturday, July 31, 2004 Fine art photographers and the studios that do their mounting continue to use closed cell polyvinyl chloride sheets as mounting panels. The most commonly used brand in the US is Sintra; other brands of PVC sheet are: Komacel, Celtec, Trovicel, and InteFoam. Recently there appears to be a shift away from Sintra to the use of aluminum sheets and aluminum clad panels such as Dibond for the mounting of photographs, but PVC is still often used.
These PVC products successfully replace wood based panels in many signage applications, in large part because of their light weight, and their use as a mounting material for works of art has naturally evolved with the increased scale of contemporary fine art photographs. Apparently some of the first studios with whom photographic artists worked to print and mount their photographs already used PVC sheets to cold mount photographs for advertising display.
Over ten years ago we wrote the manufacturer of Sintra to find out if any independent testing had been done to predict the aging characteristics of the product. The threat of the formation of hydrochloric acid was our primary concern. We received the results of a test the company had commissioned in which (if I recall correctly) pieces of Sintra were immersed in water and the pH of the water compared before and after lengthy immersion. Though the experiment demonstrated to their satisfaction that no HCl would be formed in the presence of water, we were not convinced, and we have continued to respond with caution when asked about its use.
Periodically I search Conservation OnLine to see if there has been a study published addressing the question: Is closed cell expanded PVC safe to use as a mounting material for photographs and for other works of art? I still haven't found more than passing reference to the topic.
I would like to hear if any such work is being done or is contemplated. Resolving the PVC question one way or the other would be a great service.
Jared Bark Bark Frameworks New York City
A n t j e N e u m a n n Conservation Department National Park Service Harpers Ferry Center P.O. Box 50 Harpers Ferry, WV 25425
We've used a low VOC contact cement. But keep in mind in the outer edges of the deck have to extend beyond your vitrine, which ends up giving you a slightly ziggurat-style case. We've done tests building wall case interiors with a single view window with this method. The substrate is medex and the laminate was pre-applied. Where the corners met at the mitered joint, our cabinet builders have cut in a perpendicular groove about 3/16" much like where you would place a spline, except the kerf is placed just below the laminated side. This intentionally exposes the edge line in all corners where the laminate is applied to the medex. The inset kerf allows us to apply a food-safe paintable caulk that seals the laminate edge lines.
We're in the process of building a cabinet with this method that we'll hook up to one of our microclimate generators for re-conditioning Artsorb and rhapid gel packs. I'll post a drawing that will illustrate the corners.