This paper will discus the treatment of the two original “Stelman Chairs” (1963) designed by the Dutch architect Gerrit Rietveld (1888-1964, De Stijl icon) from the Kröller-Müller Museum collection (Otterlo, NL). The Steltman jewellery house in The Hague (NL) commissioned the set of Steltman Chairs, as seating for engaged couples looking at wedding rings. The two asymmetrical chairs are mirror images of each other and made of three right-angled elements that seemingly stand on top of or against each other. The chairs have a wooden inner structure, foam cushion and artificial leather upholstery.
Prior to treatment both chairs were soiled and discoloured. Furthermore there were areas of damage and loss to the leather on the corners of the covering. But more significantly, the seams of the leather covering had failed in certain areas. The open seams varied in length from 1 cm up to 30 cm, exposing the underlying foam, causing it to harden and discolour. In addition, the artificially leather shrank over time, making it more difficult to close the open seams. Lastly, one of the chairs had structural damage; the arm and back support were disconnected.
The immediate cause for restoration was the wish to exhibit the chairs during an exhibition at the Kröller-Müller Museum in 2010 devoted the Dutch architect and co-founder of De Stijl, Robert van ‘t Hoff. The closing of the seams should be guarantied till the end of this six-month exhibition. The main challenge was to find a way to close the seams without taking off the leather covering. Dummies were made and tests were done in order to investigate a suitable treatment method for the open seams. Five different glues were tested on new artificial leather, as well as different options for support (‘glue bridge’) to glue the seams.
The tests resulted in the decision to use the water-based BEVA D-8-S dispersion glue thickened with Al(OH)3 and a triple layered ‘glue bridge’ (i.e. a thin layer of glass fibre, non woven polypropylene fabric and a very thin polyester foil) that would be placed at the backside of the failing seams in two steps. The second step, and closing of the seams, was the most complicated part. Eventually the seams could be closed progressively using several glue clamps and a considerable amount of cable ties. The losses in the artificial leather were filled with a fill made from BEVA 371 with Al(OH)3 and retouched.
Now, five years and almost five exhibitions later (including the latest request for loan from the Rijksmuseum Amsterdam), the treatment of the Steltman Chairs has proven over time to be effective. Not only is the chosen method reversible, but –arguably more important- it is a retreatable one. The retreatability lies in the fact that if the seams would open again, you could relatively easily reglue and close them following the same procedure.