For those who may not be familiar with Peshtigo, it's in Northern Wisconsin, not far from the border with Michigan's Upper Peninsula.

John R. Baker, P.E.
Product 'Evangelist'
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Siemens PLM Software Inc.
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To an Engineer, the glass is twice as big as it needs to be.

Yes, didn't Peshtigo burn down on the same day as the great Chicago fire?

Beautiful place. Here's some pics from my last Peshtigo River run.

• http://files.engineering.com/getfile.aspx?folder=77d4e85c-f446-4226-961c-25

In reality, on the same day as the 'Great Chicago Fire', four other cities in Michigan and Wisconsin were also destroyed, or nearly so, by fire, but the Peshtigo fire was the deadliest as it destroyed the entire city as well as several smaller nearby towns as a forest fire swept in from the West and burned everything in it's path, right down to the shoreline of Lake Michigan. There never was an accurate count of the dead but some estimates placed it as high as 2,500, making it the deadliest fire in the history of the country.

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:

To an Engineer, the glass is twice as big as it needs to be.

The Peshtigo Fire was on 08 October 1871 the same night as the Chicago Fire. The Peshtigo Fire destroyed 1.2 million acres and killed between 800 and 2,000 people. It destroyed much more than just the village of Peshtigo and adjacent areas.

At that time Peshtigo was home to the world's largest woodenware factory, making all sorts of wooden products for everyday use: shingles, pails and all sorts of buckets, much more and of course, lumber.

It is fitting that the town that arose from the ashes of the 1871 fire was ultimately become the birthplace of the structural glued laminated timber industry in North America in 1934. The laminating plant in Peshtigo is still in operation.

So what was the glue in the original beams? was it hide glue , Casein , or did they have access to the phenolic resin glues by then?
B.E.

You are judged not by what you know, but by what you can do.

Casein adhesive was utilized in the glued laminated timber industry by and large until the 1960s. It is a good adhesive, not waterproof of course, so can only be used for interior applications. Waterproof resorcinol and phenol resorcinol adhesives were used during World War II for marine applications. They were not universally adopted by the structural laminating industry until the 1960s.

The Peshtigo and Chicago fires deforested much of Wisconsin. First by fire, then by the enormous demand for timber that followed immediately after.

These events, as well as the other fires mentioned earlier, did a number on the standing timber in Michigan as well. The town I grew up in Northern Michigan was one of those that started out as a lumber camp which then grew to a substantial lumbering and saw-milling operation, but which died out after the turn of the century (1900) as the forests were cut-over and the big lumber operations started to move further west where there were still stands of virgin timber.

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:

To an Engineer, the glass is twice as big as it needs to be.

So, with this date of construction establishing the glued laminated beam use, when was "plywood" first used?

And, over time, how long will the tens of millions of plywood house widely built after the war begin loosing roofs and walls as the plywood delaminates from itself?

Ra cook pe,
I cannot answer the first part of the question, however I did get a practical answer to the second part of the question.
2 years ago I re- roofed my house which was built in 1962, over 85% of the plywood had to be replaced because it was de-laminating. It appeared to be a urea formaldehyde type glue ( clear) which was not holding up, other sheets that had resorcinol type glue appeared to be fine.
B.E.

You are judged not by what you know, but by what you can do.

Glued veneer plys were found in tombs of the Eqyptian mummies.

Sobering.

ThePioneer,

Glued veneer plys should work well in mummy tombs. It is moisture that attacks mummies and plywood adhesives, right?

--
JHG

How can one discuss "glued laminated timber" without mention of http://en.wikipedia.org/wiki/De_Havilland_Mosquito

The Mosquito wasn't the only WW II aircraft to use glued wood structures, but it's a great example.

The F4U Corsair had plywood elevators.

old field guy

Yeah, but the Mosquito used it for primary structure and was very high performing.

Many aircraft of that era used wood of one kind or another in some more or less significant way but Mosquito stands out in terms of amount used and relative performance.

How about the Spruce Goose?

My grandfather owned a plywood factory in Luebeck, Germany. That kept him from getting drafted in WW2. Then he ran afoul of the SS and hid from them by enlisting in the army.

This post has digressed from the original topic of structural glued laminated timber into glued veneers and plywood.

Structural glued laminated timber is made of dimension lumber with grain orientation parallel. It can be straight or curved. It is utilized for structural arches and beams and trusses and ship ribs and highway noise barriers and utility towers and many other applications.

Wow...very interesting Tick. Did your grandfather supply the Horten brothers by chance?

I'm not sure why the OP feels the topic is off course...we're all talking about laminated wood assemblies...some are more interesting than others perhaps. I always think these guys got it rolling in a big way:

Link

Reminds me of the Forest Products Labs. Their research into plywood manufacturing and applications goes back to 1910. You can download the test reports from their library, which is on-line now.

The aero types in the crowd may find it interesting to note that many techniques of structural analysis of "sandwich panels" were studied thoroughly by the Forest Products Labs. These days, the typical aircraft sandwich panel is faced with aluminum or fiberglass, and the core is usually a honeycomb of flame-retardant-soaked nylon (or more aluminum) but the original idea seemed to be plywood facings with corrugated paper core. You can always find the FPL in the references sections of books like Bruhn or ESDU, and in the airframe design manuals used by the OEM's, and, of course, the ANC-18 wood design manual that is still "acceptable data" to the FAA.

STF

Pioneer, I believe some of the Mosquito structure would still fall into your second category since they used a balsa core for some structure but if you don't want to talk about such things fair enough.