Styrosplines

[kelticsylk]

Don't know if I should report a disaster or a break through. The laminate is as tough as I was hoping. I used a straight spline this time in lieu of a curve so there would be no optical illusions that look like deflection. Here's 35-40 pounds over a 2' span...

Encouraged, I went for broke piling all the bolt buckets inside a bigger bucket...

The rather heavy Bucket O' Buckets displaces 70 pounds on the scale...

I then struggled to lift the bucket onto the roadbed.  I used a piece of 2x4 to help balance the weight. This also concentrated all that pressure into a 4"x 4" space. Unfortunately this may have been a mistake. There was creaking and groaning and gnashing of teeth. Before I could take a closeup I had to quickly catch the bucket before it fell over, but not before the weight did this...

And some delamination...

It's the glue that failed this time. "D'lamination" reared its ugly head in a major way. The laminate strips were able to twist, obliviating any vertical strength they may have added. Had this not happened, I believe the spline would have stood up to the test. With the proper adhesive it may be able to support even more weight. I'll have to buy more bolts and buckets to test that 

I moved the surviving length of spline to a 1' span and tried again. I went straight to the 70 pound weight balanced on the 2x4...

Over 1' it works well, vertically and horizontally. You might be able to span 2 feet but you need stronger glue or mechanical reinforcement, like drywall screws I used earlier as disposable clamps. If I had used drywall screws instead of actual clamps, the results may have been slightly different, but the glue would still be an issue. I

While the lattice strips are easier to use, but the much lower cost of the laminate strips makes a little more experimentation worthwhile. I'm going to try yellow wood workers glue and see what happens.

[Scottl]

70 lbs and it failed.  LOL.  I think you are safe to use foam.

[kelticsylk]

70 lbs and it failed.  LOL.  I think you are safe to use foam.

I wonder how many pounds per square inch that works out to? Would it matter?

[LV LOU]

 I've done a little testing over the years..The two best adhesives for foam/cork are water soluble contact cement,and Weld Bond Glue.I noticed that roadbed could be pulled right up with regular white glue,if you lightly sanded it,and put on Weld Bond,it was there for good.Same with the contact cement,but no sanding needed.I don't use it like they recommend,apply,let dry,press together,I just brush it on,and screw it together..GOOD LUCK getting it apart..Probably cheaper than white glue,too,a quart is less than ten bucks..I use the Weld Bond mixed with Elmer's School Glue so it's water soluble for cork & trackwork,contact cement for foam.I might be a little hesitant to use the contact cement for the splines,since it's rubbery when dry,and doesn't cut or sand well...

[Lemosteam]

Frank did the glue fail on the finish surface of the laminate or the rough side?  I've had success belt sanding the finish side for glue prep.  I think I would use a polyurethane construction adhesive az long as it won't attack the foam...  Sticky and strong.

[GaryHinshaw]

It's the glue that failed this time. "D'lamination" reared its ugly head in a major way. The laminate strips were able to twist, obliviating any vertical strength they may have added. Had this not happened, I believe the spline would have stood up to the test. With the proper adhesive it may be able to support even more weight. I'll have to buy more bolts and buckets to test that  .

Once it delaminates, you are definitely prone to a lateral buckling mode if there is a small lateral displacement.  This is the main failure mode that affects pony truss bridges.



I think you should subtitle your blog: Adventures in Experimental Model Railroading. 

[LV LOU]

You know,let's not forget the scenery.When you put hardshell up to this,it will greatly increase the strength.Like putting up a house framework,and testing strength without and walls or roof...BIG difference..

[kelticsylk]

You know,let's not forget the scenery.When you put hardshell up to this,it will greatly increase the strength.Loki putting up a house framework,and testing strength without and walls or roof...BIG difference..

That is one of the things I was hoping. Thinking of the layout as a whole everything should be stronger if it's an integral mass (sort of).

Once it delaminates, you are definitely prone to a lateral buckling mode if there is a small lateral displacement.  This is the main failure mode that affects pony truss bridges.



I think you should subtitle your blog: Adventures in Experimental Model Railroading. 

I got more than lateral buckling this time See below...

I think I will do that. It needs a subtitle and yours is more positive that what I'm thinking right now 

Frank did the glue fail on the finish surface of the laminate or the rough side?  I've had success belt sanding the finish side for glue prep.  I think I would use a polyurethane construction adhesive az long as it won't attack the foam...  Sticky and strong.

The rough side is glued to the foam, the smooth side, being a lovely shade of light travertine, faces out 

I'll be direct...I got the spline to break. I had photos of the actual moment of failure, but then accidentally deleted the pictures when I went to download them to the computer (stupid buttons!) I took another set of pictures of the aftermath and this time I managed not to delete them. It helps if you actually look at the screen BEFORE you click the mouse! Anyway, I went into the garage tonight for some reason that I can no  longer recall. I noticed that A- The roadbed still had a undamaged section and B- The glue had dried completely. That should make every question the validity of the last experiment. The glue was still wet. Probably needs a full 24 hours when used to laminate structural components  Of course, I just had to try the fiasco again so I set everything up on supports spaced 2' apart. I set the 2x4 on the middle of the span and placed the bucket. At that point it was about 30-35 pounds. Everything looked great and I took some lovely snapshots. I went for 70 pounds and had my camera focused on the spline. It didn't instantly fail, it took several seconds, but it did break. I was so busy with the camera I didn't catch the bucket. Below are photos of the aftermath.

The scene of the disaster...

Shards of roadbed....

70 pounds of hardware at the bottom of the abyss...

[kelticsylk]

A final comment (yeah...right)...I'm sticking with the laminate despite the disaster. If it takes 70 pounds to break over a two foot span that'll work for me. I'm going to assume that it'll stand up to much more if the supports are spaced on 12" centers, which is the plan. Any gap wider that 12" will require a "spanner" so a support can be placed at the proper point.

I really can't pass up the "cost effectiveness" of this type construction. The mainline, minus the Llyswen Yards area, is about 50 feet long. That's 6 pieces of 8 foot spline, give or take. Multiply that by the eight soft splines required to support four tracks. I need about 50 8 foot long blue foam splines. The The blue foam costs me about $13-$14 for one sheet. I can make 24 two inch high splines from that single sheet. That's enough to build the entire right of way at two tracks. Since I'm going with 4 tracks I need two sheets (already purchased both). The soft roadbed costs $26-$28 for the entire layout. The sheet of laminate cost me $20, again 24 two inch high splines. I only need about 18 for the entire layout.  So all the the hard splines I need cost $20. The entire right of way can be built for a little less than $50. Foam lattice would cost me $3.46 per 8 foot length, or about $70. The total cost for the roadbed using foam lattice comes close to $100.