New engineered wood could have railroad applications

[CandOforprogress2]

Like going back to wooden boxcars and wood bridges see-

http://bgr.com/2018/02/08/super-wood-densification-building-material/

[Murphy Siding]

     Wood guy here. The problem is that the new wood product won't come anywhere near the price of what is is replacing. Note from the article that they've only made a small batch. Scaling up to make big batches will likely make it too expensive. About 15 years ago a company named Aztra made closed cell, foam panel mouldings. Their sales rep told us the stuff was so good that they could make 2x4 studs out of it- once someone was willing to pay $15-$20 for a $3 stud.

     Being wood, it will still have some of the characteristics of wood. It can split, warp, twist, crack, drip sap, delaminate, burn, swell with moisture, break down in sunlight and provide dinner for termites, fire ants and other bugs. Also, you've added some chemicals that need to be allowed for.

[Overmod]

Hey Murph -- there is a ringer here.  Read the account again (or find the linked Nature article) and tell me the key word amusingly missing from this account... the LIGHT will come on when you do.

This is not 'engineered wood' in the sense of glulam or flake board or Aztra Pringles.  They run the wood through the first steps of pulp making and then just compress it to densify the strands; the stuff is now dimensionally stronger but just as heavy as the pre-compressed piece.  

I do expect the result to have interesting applications, and I do expect it to be relatively cheap -- as described the process requires no injected resins or adhesives, and it should be comparatively easy to put a fungicide/insecticide or even something like borate for fire retardants at relatively low mass increase, diffused in during the pickling.  But 2x4s out of this stuff?  Unless you formed it into beam shape in the pressing, actual steel studs will be lighter, cheaper, and fully strong enough to do the job...

Now, it does have to be said that the OP's mention of this would include use as ties, and here a cheap process of densification might be interesting, especially in a world where subcontractors sometimes try to fake or 'short' preservative content in normal ties.  Assuming someone gets around the paper mill stink and waste issues -- not particularly difficult to solve -- this cheap heavy densification might have a place.  (But it will be interesting to hear comments from some of the actual people who do track work when they find out what each one's going to weigh...)

[GraniteRailroader]

We were discussing this at work last week. My current employment is for a saw blade manufacturer.

We want to get a sample of this, so that we can get ahead of the market if it comes to the table as a finished product. Have the first offering of saws designed to cut, plane, and trim-mold this product.

[Overmod]

I expect this will cut like any similarly dense wood, with the 'reflowed' lignin probably acting like any similar phenolic resin.  Suspect that there may be some tendency to chip the resin-rich regions if the feed is too great and to cause frictional heating and the usual problems with thermoset copolymers if the kerf is too narrow.

I'd be tempted to design a rotary saw blade almost like a serpentine dado head, with each successive tooth raked inward so it progressively shaves side to side of the kerf while not overheating the same area of resin and allowing the cut fibers and resin to clear the face of the cut easily.

[Murphy Siding]

GraniteRailroader

We were discussing this at work last week. My current employment is for a saw blade manufacturer.

We want to get a sample of this, so that we can get ahead of the market if it comes to the table as a finished product. Have the first offering of saws designed to cut, plane, and trim-mold this product.

 

I'd say start with whatever blade you have that will succesfully cut Ipe decking and you're halfway there.

[Murphy Siding]

Overmod

Hey Murph -- there is a ringer here.  Read the account again (or find the linked Nature article) and tell me the key word amusingly missing from this account... the LIGHT will come on when you do.

This is not 'engineered wood' in the sense of glulam or flake board or Aztra Pringles.  They run the wood through the first steps of pulp making and then just compress it to densify the strands; the stuff is now dimensionally stronger but just as heavy as the pre-compressed piece.  

I do expect the result to have interesting applications, and I do expect it to be relatively cheap -- as described the process requires no injected resins or adhesives, and it should be comparatively easy to put a fungicide/insecticide or even something like borate for fire retardants at relatively low mass increase, diffused in during the pickling.  But 2x4s out of this stuff?  Unless you formed it into beam shape in the pressing, actual steel studs will be lighter, cheaper, and fully strong enough to do the job...

Now, it does have to be said that the OP's mention of this would include use as ties, and here a cheap process of densification might be interesting, especially in a world where subcontractors sometimes try to fake or 'short' preservative content in normal ties.  Assuming someone gets around the paper mill stink and waste issues -- not particularly difficult to solve -- this cheap heavy densification might have a place.  (But it will be interesting to hear comments from some of the actual people who do track work when they find out what each one's going to weigh...)

 

Yes weight is one issue. Ten cubic feet of wood fiber smooshed down to one cubic foot must weigh about the same before and after. I seriously doubt that the dense wood will be as strong as a same size piece of steel. A 4x6 timber 12 feet long in IPE hardwood weighs in the neighborhood of 75# A railroad tie made out of something similar in density must weigh around 325#?

The bigger issue I think is still going to be cost. That's why I mentioned the Aztra example. Ten cubic feet of wood smooshed down to one cubic foot of dense wood will have to cost more than ten times what un-smooshed wood cost.

     So far it seems like they're doing this in a lab and just need to figure out how to do it on a production scale. The devil is in the details. I can see where this might have some sort of use perhaps in some sort of sandwich panel for building exteriors for example. On a train? Probably not.

[erikem]

The article that I ran across stated that the pressed wood density was on the order of three times the orginal wood - though no mention was made of the moisture content of the original wood.

The article also mentioned that samples had been exposed to high humidity environments for prolonged periods and the "wood" picked up 10% moisture content and supposedly unchanged mechnical properties. I would wonder about very extended exposure to moisture. I aso would (wood?) wonder about resistance to fungi, insects and other rot.

I'm also guessing that it will more than double the price of the equivalent weight of wood.

Add-on: For those into late 19th century wheel technology, the "paper" wheels used by Pullman and others used pressboard as part of the wheel. From what the article mentioned the preesed wood is of even higher density than the pressboard (made of paper pressed together).