“Repairing the Unrepairable” – Watch Webinar Recording

On 13 April 2021 we broadcasted a very informative webinar titled “Repairing the Unrepairable”.

In this webinar, Johannes Roberts from QuantiServ Sweden introduced QuantiServ’s in-situ machining solutions while Jeff Reeds from Lock-N-Stitch USA focused on metal stitching and thread repairs. Petter Bodman acted as moderator.

If you missed this session, or would like to watch it again, here is the recording:

Metal Stitching on Historic Bridge in Washington DC, United States

Our American colleagues have just completed metal stitching repairs on a historic bridge crossing the Chesapeake and Ohio Canal.

The Canal

The Chesapeake and Ohio Canal stretches over a distance of 297 km (184.5 miles) from Cumberland, Maryland, to Georgetown, DC on the US East Coast. It was constructed between 1828 and 1850 by approximately 35’000 labourers, mostly immigrants from Europe. Its purpose was to enable the shipment of coal from the rural but coal rich Allegheny Mountains to the much more densely populated regions and sea ports along the Atlantic coast.

The canal was operated from 1831 until 1924. While originally built for the transportation of coal, it quickly became an important lifeline for communities along its way.

The bridge we assisted restoring. Visible in the foreground is one of the canal's 74 lifting locks
The bridge we assisted restoring. Visible in the foreground is one of the canal's 74 lifting locks

Boats were used to ship agricultural produce and lumber to markets downstreams. They then returned loaded with manufactured goods. These boats typically did not have their own means of propulsion, but were pulled along by mules walking on towpaths located at either side of the canal.

One end of the canal, Cumberland, lies at an altitude 184 m (605 feet) higher than the other end, Georgetown.  This meant that lift locks were needed – in total 74 of them were constructed. One of them is visible in the picture above, in front of the bridge.

In addition to the 74 locks, the canal also featured many other feats of early engineering. There were seven dams, about 240 culverts, a few aqueducts, a tunnel 950 meters (3’120 feet) long and, of course, bridges. A few of these bridges still exist today, such as the one that our metal stitching specialists proudly helped to restore.

Metal Stitching Work Performed

Exposure to the elements for over 150 years took its toll on the bridge structure. Cracks had developed in many of the vertical cast iron columns carrying the bridge deck. In all likelyhood, the cracks that were found were freeze cracks. Freezing temperatures are common in Georgetown from the middle of December until early March. If water enters one of the exposed, hollow columns and gets trapped there, then it very likely freezes during a cold winter night. Over time, the freeze/thaw cycles led to cracks.

All of the cracks ran in vertical direction. They had a cumulative lenght of 7’400 mm (25 feet). Our specialists sealed them with stitching pins and added perpendicular locks for extra strength. They then ground the locks and pins flush and made them blend in well with the weathered surface texture of the antique columns.

For the work to be carried out, a section of the canal had to be drained
For the work to be carried out, a section of the canal had to be drained
The width of the cracks required pins with a large diameter to length ratio
The width of the cracks required pins with a large diameter to length ratio
Installation of stitching pins
Installation of stitching pins: Close to 1'000 were used for this project
In many locations, the cracks were wide open
On some of the columns, the cracks had caused a gap of up to 12 mm
Our specialists stitched over 7 meters of cracks
On this restoration project, our specialists stitched over 7.4 meters (25 feet) of cracks
Once completed, the repair blends in very well
The completed repair blends in very well
Stitching in progress
Metal stitching in progress: Stitching pins installed in an overlapping pattern
Locks were added for extra strength
Metal stitching in progress: Adding of locks, perpendicularly to the crack, for extra strength

Metal Stitching of an Engine Block in Tehran, Iran

 

Metal stitching on an auxiliary engine block

Our metal stitching expert traveled to Tehran, Iran, last week to repair a four-stroke main engine block on board a tug boat. It had a crack between the charge air space duct and the cooling water space around one of the cylinder liners, as well as some dents. Cooling water was leaking into the charge air space.

To repair the damage took our expert just one full day of work. The customer was very pleased with the result and was impressed by how fast the repair was being carried out.

Once again it was proved that metal stitching is a quick and reliable solution for cast iron repairs – for jobs big and small!

 

 

Enjoying a cup of tea in the engine room after a job well done

Enjoying a cup of tea in the engine room after a job well done

Metal stitching

A very happy customer

Metal stitching test piece resists water pressure of 12 bars

Metal stitching test piece resists water pressure of 12 bars

Metal stitching, as long as it is carefully and properly carried out by trained technicians, is tight against gases and liquids. To demonstrate this, QuantiServ has manufactured two cast iron half-shells and has joined them together by metal stitching. The resulting container was successfully pressurized to 12 bars (175 psi) and no leak was observed.

This proves that there is no issue to repair cooling water spaces in for example engine blocks, where the cooling water pressure typically lies around 3 – 4 bars (44 – 58 psi), by metal stitching. In fact we knew this well, because we have done it successfully many times. But that the stitching could easily withstand 12 bars impressed even us.