Our armchair, affectionately known as the “lollipop” chair, was made circa 1880. George Jakob Hunzinger (born 1835 in Tuttingen, Germany), was a progressive designer out of New York who was often influenced in his designs by machinery; their geometry and patterns of repetition in their elements. This is a Hunzinger original, a family piece, which has weathered more than a century of continuous use.
Note: Mitchell muses about the process in several areas; these parts are italicized.
To begin, go to Hunzinger “Lollipop” Chair, 1 Excavation.
This is part 2, Reparation, of 4 parts.
SECOND ASSESSMENT
After excavation, we began a second thorough assessment, focusing on the frame and stuffing which we can now see.
The chair was damaged from many poor repairs, apparent in the bare frame shown right. The barrel shape was originally created to have its tenons compress into the seat mortise without the aid of glues, screws or lag bolts, all of which were installed over the years. Because of those ineffective and destructive repairs the tenons split and now required major reparation.
To restore the historic chair to viability while remaining true to the
original decorative design intent required developing and applying
extraordinary woodworking strategies relative to structural repairs outside the upholstering effort, some of which will be described in text, or shown through
step-by-step photographs of structural work performed below. ~Mitchell
DESIGN
The chair was originally designed with a modest seat apron height; in spite of this, it was fitted with tall medium gauge coil seat springs. The interior structural base and outer decorative seat frame and legs were created from Birch, a softer hardwood.
All leg mortise’ and tenon connections were badly bruised from compression wear, preventing the joinery from having tight connections. All this caused stability issues within the seat to leg structure and formed loose connecting points between the decorative rungs and seat.
I surmise an early 20th century upholsterer set lag bolts through the front corner blocks penetrating the front arm mortise and inside arm tenons in an attempt to mitigate the problem. This may have saved the front legs from breaking away from it’s original joinery, however, the repair person who introduced the lag screws failed to make repairs to the multiple abandoned leg stump mortises. Because of these issues lag repair and leg stump connections ultimately failed and damaged the front mortise and leg tenons.
This changed the order in which we upholstered and reassembled the chair. The back assembly (spindles and turnings) had to be properly affixed to the seat prior to upholstering, requiring us to carefully tack upholstery to the side rail tops. This made the process far more difficult, as we had to take care not to mar the back turnings.
Also, Huntzinger designed the barrel shaped chair seat with double continuous mortise’ which bored deeply into the side/rear seat apron, companion rear leg stump and adjoining rear barrel shaped seat apron. The long oak dowel tenons were softened inside a steam chamber then slipped into the continuous mortise’ while still pliable until all connecting points tightly aligned. The seat was then placed into a band style clamp and allowed to remain in stasis until the joints cured and stabilized. Once the moisture evaporated from the mortise and tenons the wood substrate shrank tightly, requiring no glue to maintain a tight connection.
Huntzinger’s modest seat design resulted in a flaw in the seat joinery engineering. The upper dowel to mortise connections are placed at one-eighth of an inch below the tacking surface, causing upholstery tacks to continuously penetrate through the mortise wall and into the dowel tenon, splintering the tacking surface and undermining the tenon to mortise connection. Decades and multiple upholsterings simply eroded the tacking surface, exposing the structural tenon to environmental issues and subsequent damage from poor repairs.
As these connecting point issues evolved, small losses turned into significant damage causing other major issues to develop. Most of the damage to the chair began within the seat and extended into other elements (legs, spindle connections, etc.) as the chair endured multiple damaging upholsterings and poor subsequent repairs. Over time the chair began to list while in use, causing the birch wood legs to move under stress whose forces then extended along unintended grain lines, eventually causing the rear legs to split at stress points. Over time both structure and upholstery became untenable making the chair nearly unusable without risking either the chair or one’s limbs during use. ~Mitchell
OVERVIEW OF DISASSEMBLY
Corner blocks
Disassembly of the frame began with the removal of the original corner block hardware. In general, after lag bolts and corner blocks are removed, above, warm water is introduced into mortise and tenons to allow the various glues to soften. When the glue softens, the frame top is gently wiggled until loose; the tenons can be pulled upward, removing them from seat frame.
Note regarding glues used throughout: Many eroded joints were amended with additional same species woods in order to mitigate gaps, but bruising was so severe that not all gaps could be dealt with through amending. I mixed a 50/50 slurry of hide glue from Patrick Edwards’ “Old Brown Glue” combined with Garret Wade’s PVA gap filling glue. This specialized glue amalgam was created and applied at room temperature, rather than warmed, in order to slow the curing process and assure the glue did not contract pulling away from coated joinery elements during cure. This insured good adhesion of the repaired parts, a reliably bulky and compression resistant consolidate filling minute gaps, while also maintaining the possibility of future reversibility.
THE LEFT-FACING FRONT LEG
An example of the damaged and carelessly placed nails which were carefully extracted from both the decorative left-facing front leg face and the historic blocks. Note the nail, previously carelessly driven through a finished leg in a haphazard repair, which we removed, image two.
Note: Each damaged part was filled or otherwise repaired in all cases prior to reassembly.
LEFT-FACING BACK LEG
The left facing rear leg shattered in the early 20th century and was poorly repaired with screws which penetrated the leg. The screws are still in the leg, countersunk beneath wood plugs. I removed the upper plug in order to remove the screw penetrating the seat joinery and inside back tenon, allowing us to remove the back from the seat frame! ~Mitchell
The screws and badly placed reparation nails which secured the large rear corner block to the internal seat apron were removed and freed the rear apron joinery for disassembly. Once the corner block was removed and set aside, the extent of the seat tacking margin disintegration became apparent, along with the recognition of the necessity to amend portions of the element.
Above, the old reparation of the split left-facing leg with the exposed screws.
Two brass wood screws bisected the break on both the exterior and interior leg. These repair screws, though originally unsightly and poor substitutes for a traditional contextual repair, were successful in acting as structural tenons holding the leg together for several decades without concern.
Ultimately it was decided to leave the screws in place after treating the break for losses within the crack. It was determined the only other solution for repair was to re-create the historic leg and in so doing lose the authenticity of the aged finish patina.
RIGHT-FACING BACK LEG
As with the left facing rear leg’s blocking system the right-facing corner block was removed then set aside, thus freeing the entire rear joinery to slide open and separate for disassembly and restoration of joinery surfaces.
RIGHT-FACING FRONT LEG
The right-facing front leg was the last section of the chair seat to require disassembly and in many ways the most revealing relative to the structural dynamics because of the close intersecting points between the seat front, seat side and upper turning mortise proximity.
Note the split front apron requiring reparation.
As the front leg and apron connection was revealed inspection of the joinery made clear the extent of damage from abuse from poor repairs and the extent to which we must go relative to developing strategies for repairs which would not either compromise the elements for future use and repairs, nor impact the original design and aesthetic intent.
BACK REMOVED AND TENDONS REPAIRED
Unfortunately some images were lost in a file transfer of the removal of the wooden flush cut plugs and the countersunk screws holding the back onto the seat frame.
The decorative back/arm unit was removed from the seat mortise connections and unit set out for assessment of the tenons/rungs.
The individual rungs with their decorative turnings were strung together like a necklace by the threading of two multi-strand copper cables at the crest and lumbar which terminated with countersunk brass screws which acted as decorative elements on the front of the arm-fronts, shown left.
The left-facing rear tenon and right-facing front tenon showed extreme damage from a century worth of losses in girth from compression within its seat mortise connection. As the tenons wore, the back unit became increasingly loose.
Unwise and damaging repair attempts exacerbated the loss in joint connection. At least two of the tenons had been shattered by the inclusion of the lag bolts which were installed to stabilized the seat, shown below.
The lags penetrated the tenons, fragmenting the left facing rear tenon into two sections, thereby reducing the ability of that tenon to function as a reliable anchoring point.
I replaced this entire section of the left facing rear tenon, above, because it was not only fragmented by the lag bolt penetration, but also completely eroded from repeated upholstery tackings from above. As mentioned in the seat reparation section the original joinery design left little margin between the mortise and tenons relative to the decorative surfaces. Repeated expansion and contractions of wood substrate of the connecting joinery elements were prone to damage from not only repeated flex from load, but also from disturbances (tackings and repairs) which were attempted from the decorative surfaces.
The right-facing front leg tendon was also repaired, above.
The back/arms after reparation, above, and ready to be reattached to the seat frame.
LEG MORTISE AND APRON REPARATION
Once the accretions of numerous applications of various glues (original hide glue, injections of carpenters glue, etc.) within the joinery and poorly repaired breaks was removed from surfaces, we could begin repairs. The breaks within the legs were opened, glue was installed and the legs were placed in clamps to cure.
Irregular mortise bores were fitted with fresh doweling then re-bored to precise diameters. Areas of losses between the upper leg mortise and tacking surfaces were excised then fresh wood crafted to fit within the void. Once the glue within the fresh repairs cured we shaped the joinery to conform with the historic dimensions.
The left-facing rear leg which had been broken during the early 20th century then repaired using screws, was deemed supportable using the original screws. A decision was made to retain the historic leg rather than re-crafting the leg with fresh material since the repair was now considered historically contextual to the piece and the aged finish/patina of the leg to the surround was identical. Therefore, we removed the screws, opened the break, cleaned the wood substrate of old glue, set fresh pins into the screw bores, re-drilled the bores, then re-glued the leg break and re-installed the historic screws.
Huntzinger designed this barrel shaped seat with long dowel tenons which slid through the rear leg mortise, bending slightly to conform to the shape of the barrel which anchored well into the rear and side seat aprons. When the joinery components were seated the boring trajectory formed one long tunnel-like tenon to mortise connection. The slightly wider diameter (relative to the mortise diameter) dowels were cut to conform to the mortise length then placed in a steam box in order to make the wood bendable during assembly. Once the steamed dowels were thoroughly pliable the dowels were set into the leg stump and convex shaped seat mortises and the entire seat slipped together tightly as one unit.
Huntzinger chose a soft hardwood, Birch, as the primary lumber, not uncommon in the Depression era when designers were looking to find less costly woods with which to work. As seen in photos above, this became problematic because of the stresses upon the frame and the demand of multiple reupholsterings. This resulted in stress fractures, warping, twisting, and poor repairs by individuals without woodworking training. These repairs caused additional problems.
The eroded leg stumps were excised of debris, then dados were mortised into the leg stumps which bisected the original upper dowel mortises. Fresh wood was crafted to fit into the new crafted faceted voids and glued into place, then pinned. Once the glue cured the leg stumps were re-bored to configure to the original dowel mortise. The leg was once again viable at its connecting points.
“Modern upholsterers used inappropriately large tacks, a common mistake.
The entire frame was peppered with too many holes.
If not properly repaired, they will in time make upholstering impossible
without causing catastrophic damage to the frame.” ~Mitchell
The frame’s tack holes were repaired by inserting hardwood picks into the large tack holes after injecting warmed Old Brown Glue hide glue, shown above. The picks were allowed to set undisturbed for 48 hours in order to cure, then the picks were trimmed level with a chisel, and sanded smooth.
Corner blocks were installed, glued and clamped to cure for 24 hours, above. Reinstallation of screws were installed, and finally the internal seat frame retrofit was created and installed, above and right, then set to cure for 48 hours.
The internal seat frame retrofit created an internal structural dynamic which would allow add surface space where upholstery foundational materials (webbing, spring lashing, burlap, & stuffings) could be tacked.
This saved the historic tacking surfaces for the leather show-cover instalation only, and created a multi-faceted fulcrum which would prevent the frame and legs from future flexing thereby saving the elements from more damage during use.
The internal tacking rail would assure that the historic tacking rail could endure future upholsterings without invasive woodworking treatments. ~Mitchell
The restored joinery was coated with glue, and clamped to cure. The back of the frame was carefully reassembled.
The frame is ready for Finish Restoration, next post.
Written by Mitchell and Kate Powell ©MPF Conservation.
May be printed for your own use ONLY, not for use on blogs without permission.
