11 Awst 2021
Rhoddwyd caniatâd i adfer deuddeg ffenestr fawr dalle de verre gan Jonah Jones a symudwyd yn 2019 o eglwys gaeëdig ym Morfa Nefyn cyn i’w hail-leoli yn eglwys Gatholig Dewi Sant yn yr Wyddgrug, Sir y Fflint.
Mae dalle de verre (‘slabyn gwydr’ yn Ffrangeg) yn golygu darnau o wydr lliw, a osodir fel arfer mewn matrics cynhaliol o goncrid ac epocsi-resin.
Y Ganolfan Gwydr Pensaerniol (CGP) yng Ngholeg Celf Abertawe, sy’n rhan o Brifysgol Cymru Y Drindod Dewi Sant, sy’n gwneud y gwaith adfer. Mae pob ffenestr yn cynnwys dau banel ac yn mesuro rhyw 2.9 medr o ddyfnder a 0.78 medr ar draws, gyda phob panel yn pwyso oddeutu 100 kg. Uwchben pob ffenestr ceir panel bach plwm (‘light’ neu ffenestr fach) yn ychwanegol.
Seilir gweddill yr erthygl hwn ar adroddiad gwaith a ddarparwyd gan Owen Luetchford, technegydd yn y CGP. Gadawsom hwn yn y Saesneg wreiddiol oherwydd ei natur technegol – ymddiheurwn am hyn.
“At the time of writing, the general cleaning of the glass dalles has almost been completed. This process has involved the careful removal of a patina of dirt and dissolved solids from both faces of the dalles, resulting in a notable shine.
Work has started on rebonding dalles that have come completely free of the resin matrix supporting them. A greater challenge has been to replace missing dalles lost through gradual deterioration or petty vandalism over the years since the windows were first installed in Morfa Nefyn in the late 1960s. The AGC [y CGP] has developed and tested an innovative system of line-tracing the voids using vector-based software, enabling accurate waterjet-cutting of new replacement dalles. The method has proved successful and cost-effective, allowing the best possible fit without having to remove any material from the existing resin matrix. To fix the new dalles into the voids, several bonding agents have been tested, and the one selected has proven highly effective at sealing the glass to the resin.
Once the missing dalles have been replaced, the next stage will be to move on to stabilising other dalles that have fractured in situ but are otherwise intact.
The 12 leaded lights have been documented, with students assisting in taking accurate rubbings and in carefully dismantling the panels and cleaning the glass ready for releading. Where glasses are damaged beyond repair, replacement glasses have been obtained. The leading work will be done using a box of original 18mm Stillemans lead, arguably the best quality lead profile, which, although sadly out of production for several years now, has successfully been sourced by the AGC.”
Pedwar cam mewn atgyweiriad (o’r chwith): darn gwreiddiol o waith atgyweirio yn ei le, a oedd wedi’i wneud yn Morfa Nefyn, ac yn cynnwys tair haen o wydr nofiol; y gwydrau atgyweirio wedi’u tynnu o’u matrics yn y CGP; dalle newydd wedi’i dorri gyda jet dŵr; a dalle wedi ei ailosod yn ei fatrics.