Project update: the Petrolia & Erie

snipped-for-privacy@gannon.edu wrote in news:1174938792.150066.182460 @l75g2000hse.googlegroups.com:

Have you considered building triangles into your structure? They're the best geometric shape for keeping things in place.

Get good plywood if you're going as thin as 1/4". If you're thinking of moving the module (for shows or moving every couple years) stop no shorter than 1/2" cabinet grade. "I need your help to move this" is a lot easier than "I've got to fix this huge crack down the middle of the road."

I haven't used homasote, but one complaint I heard often about it is its responsiveness to humidity.

Build slow, and take the time to reevaluate your work if you're not sure about it. That way, you've only got a module or two to fix, rather than a whole layout.

I made the decision to finish (but not superdetail) each module of mine before I went on to the next module. As a result, I've always got something different to do and space to try something new.

Puckdropper

Use deeper but thinner sections of timber - even use plywood in place of timber.

snipped-for-privacy@gannon.edu wrote in news:1174938792.150066.182460 @l75g2000hse.googlegroups.com:

In the below, I suggest using baltic birch rather than regular wood or other plywood because it is much stronger, has twice or more number of plys, and its outer layer won't shred like soft plywood (bitter experience here with Home Depot plywood). You will need to find baltic birch at a hardwood supplier. 1/2" is stronger than 3/4" regular plywood or dimensional wood.

Next time consider using 1/2" baltic birch plywood for the frame, fastening it with Tite-bond yellow glue and airgun brads. Incredibly strong and true.

You do not need the plywood if you do below.

You could nest it only 1" deep if you wanted a stream to wander through. If the module is just flat, consider gluing and bradding 1/4" baltic birch to the top and adding a 1" brace every 18" or so to prevent any sagging.

You might try (if you have access to a table saw or radial saw) using I-beams made from 1x2s on their sides, with a 3/8 deep groove centered in one facing side of each, and a 3" piece of 3/8 MDO or plywood glued into the grooves as the web of the beam. Lighter and cheaper than the usual 1x2 plus 1x3 L-girder combination, but reputed to be quite stiff.

And triangulated bracing can help resist racking.

Racking or twisting resistance is a function of the depth of the framework. It pays to use the lightest possible beams, so the above is a good suggestion. The same method is used in so-called engineered floor joist systems.

Trevor Marshall (IIRC) published an article in RMC in which he described building 4" deep frames made of 1/4" or 3/8" plywood. He used hot glue, screws and 1x1 blocks in the corners, adding diagonals to triangulate the whole frame. He first cut large holes (ca. 2" diameter) in the beams. The holes lightened the framework, and also provided passages for the wiring. The frames were 4ft to 6ft in length an up to 2ft wide. IIRC the lumberyard ripped the plywood sheets for him. He wrote that the net cost about the same as for the usual frame made of 1" dimensional lumber, and a good deal lighter, despite the extra bracing.

A lot of work IMO, but probably justified for portable module sections, or in preparation for the moves that seem inevitable in one's career-building years.

A bricklayer friend has given me cutoffs of black extruded styrofoam insulation panels 15-5/8" wide by 3" or 3-1/2" thick. Very light, very rigid, won't rack, period. I will be gluing two of these side by side to make a "frame" 31-1/4" wide by about 48" long, as base for a portable N scale exhibition layout. Two pieces of 1/4" ply glued to the bottom will help hold the pieces together, reducing strain on the center joint. (Just an oval of track with passing siding and a couple of spurs, looping round a bay, tunneling through a headland, and crossing the harbour mouth on a bascule bridge. I want an excuse to build a lighthouse.)

HTH

GP (and others),

What I did was the following... I went to the lumber yard and bought some good one side 3/4" plywood. I had them cut it into strips that were three and four inches wide by the length of the material. I estimated how many of each I would need.

I had a pretty detailed plan that I worked off of for the frame. I carefully used thin long nails and wood glue to build the framework; I used the three inch strips on their edge. I tried to consider section joints and having some longer strips for added strength & rigidity. I made smaller sections in the garage then assembled them in my train room due to doorway considerations.

Once I had the entire frame completed on the floor in my train room, I added the four inch strips on the outside so that the bottoms were even with the framework. This made the framework recessed an inch inside of the outside framing. I also added some simple metal 90° angles in strategic corners for extra strength & rigidity. Now comes the hard part... I raised the entire grid up on some boxes that looked like milk crates to attach the legs. I was careful to keep the tops of the legs level with the tops of the framework. I attached the 2x4 legs with wood screws & bracing.

Next, I laid sheets of 1/4" luan plywood on the framework. Where necessary, I simply marked them from below to fit then cut them out. I used wood glue and an electric brad gun to secure the plywood to the framework. When the framework was completely covered, I did the same ting with 3/4" blue foam insulation board. I tried to stagger the joints for extra strength. After the parts were cut to fit, I glued them in place with Liquid Nails that was compatible with foam. The 3/4" foam and 1/4" plywood made up the extra inch so that when I was done, the deck of the layout was even with the boards I used on the outside of the layout.

My layout kind of looks like a big capital "E" and it is strong enough that a relatively light tap on the one end can be felt all the way around to the other end. The layout is in a climate-controlled area (heat & A/C) but I have not seen any issues with moisture causing warping or anything along those lines. The boards on edge give you plenty of space to run wiring in such a way that it doesn't hang down in the way. All in all, I'm pretty satisfied with the way it turned out.

What I would do differently would probably only be to use 1/2" plywood instead of the 3/4" There isn't a whole lot of difference in price, but it would be lighter and probably about as strong. But the 3/4" foam glued to the 1/4" plywood seems to be plenty strong.

By the way, cork roadbed is glued to the foam; track is glued to the cork roadbed. That makes it pretty quiet. If you use any kine of nails that run into the plywood, that will allow the sound to resonate from the bottom of the layout like one large speaker. The only problem with this track-laying technique is that you need to be pretty sure where you want your track to be laid; the glue isn't easy to remove from the track and nearly impossible to remove from the foam & cork roadbed.

If anyone wants a more detailed description, please contact me outside of the group & I'll try to explain in more detail what I did.

dlm

------------- Dan Merkel

I would go with the 1/2" plywood sides to the frame rather than 3/4" or even lighter. (we've been metric in NZ for the last 30 years) I've used

My reasoning is that the trackbed needs mass to dampen train noise. Where the track rises or falls within the baseboard I make sure the corners in particular are gussetted with the 9mm chipboard and also areas between tracks that aren't required to be open for access are filled. I think the depth of the sideframes is important for rigidity but the thickness needs only be sufficient to stop them buckling from weight (people leaning on layout) so possibly a single 1/4" thickness might do the job. I keep meaning to try making the backscene the rear frame structure, but baseboard construction always seems to be hurried as I always seem to be focussed on the layout to come. ;-)

The other two factors I now try to keep to are total weight (moveable by two people, one being my wife) and baseboard (module) size small enough to fit through a standard doorway.

One I built was so precise that it jammed going through the doorway because I hadn't taken account of the vinyl to carpet floor covering transition.

Regards, Greg.P.

Hadn't really noticed, but I guess we have more than one "GP" on the group.

dlm

DM:

This sounds like as detailed a description as one could want, and seems like it would make a very light, rigid structure...I like it. I especially like the notion of getting the strips cut on the lumberyard's panel saw -- I don't have a table saw myself, but if I did that this method would be completely practical. I'll probably stick with built-up L-girders for now, since I have piles of 1x3's and 1x2's to use up.

I would imagine that you could remove track pretty easily by slipping a hack saw blade under it...perhaps you could glue the cork only at intervals, making this easier.

My brother once built himself a 4 x 6 model railroad from plywood...he hand- ripped it into 3" strips, too. :-)

I'd think you could make Steve C's engineered-beam design by just gluing some

Liquid nails and Robertson screws are good stuff, I find. Whoever mentioned that Lowe's doesn't carry such screws in certain places is quite right, by the way. Ours only has Phillips and star drive, in the big cartons. I didn't look in the 89 cent bags.

Triangles are indeed being built into the design...I have 45 deg. braces at the corners. One grid uses 1 x 3, the other 1 x 2. The smaller wood seems fine.

Cordially yours: Gerard P. President, a box of track and some grids.

Wolf:

Hmm. I read Marshall's article a while back. It seemed like a good system for a solid top (I can't recall if such was his layout). I do wonder how well it would work out with open-grid framing. Probably the 3/8" ply would flex too much.

Seems like his holes should have been about 1-5/16". ISTR that a beam isn't greatly weakened by crosswise holes that take up no more than the central third. Of course any horizontal drilling would make it less rigid in the horizontal direction...a 2" hole through a 4" beam would cut strength in this direction in half (in the vertical direction the effect would be much less).

I've seen this thick styrofoam, and it is indeed rigid stuff. What's it used for, walk-in coolers?

Cordially yours: Gerard P. President, a box of track and some grids.

There can only be one!

Let the duel begin *8^}

I've missed something here - is Dan suggesting I've contradicted myself and are you suggesting I'm likely to face myself with pistols or swords at daybreak???

I merely posted my prefered method of building baseboards based on 43 years experience - everyone is free to build how they like IMHO.

Regards, Greg.P.

Not mine (I think I saw the design on a Brit site), but I wouldn't do it that way; the dado groove adds a lot of strength.

snipped-for-privacy@gannon.edu wrote: [...]

Well, no, it wouldn't actually. The resistance to flexing is in the geometry of the frame, not the size of the members. Marshall's frame is a full 4" deep. Every cell is a triangle, none a rectangle. That's what makes it rigid. Compared to a 1x3" beam, the 4" beam is about 2-1/2 times more resistant to vertical bending. The triangular braces increase resistance to sideways tipping, which would result in twisting of the whole frame. The result is a very rigid frame, much more rigid than a

However, you're right that a skin on the top and bottom would increase rigidity even more. It would prevent almost all sideways tipping of the beams. IIRC, Marshall did put a 1/8" or 1/4" skin on the bottom of his frames. As for open grid framing: the risers and roadbed of an open grid system would actually add to the stiffness of the frame.

You can remove a good deal more than 1/3rd of the material. The plywood spars used in WW2 fighters had holes about 2/3rds the depth of the spars. And consider a truss: it's a beam with triangular holes in it. Most of the beam has been removed. Or consider an I beam: that's a solid beam with most of its material removed, too.

Most of the resistance to bending/flexing is near the edges of a beam. The further apart those edges are, the stronger the beam is. I forget the formulas, but IIRC a beam that's twice as deep has four times the bending resistance. **

No, regular wall insulation, installed between the studs. Or glued to the concrete block walls. Easier and much more pleasant to install than fiber glass batts, and a higher R value, too. Up here, we believe in keeping the heat inside in winter and outside in summer. :-)

GP:

Actually, Greg, I think he just noticed that you and I happen to have the same initials, and pointed it out for general amusement.

Cordially yours: GP (The one with the box of track and some grids.)

Wolf gets a bit stroppy at times for no apparent reason. I thought he was at it again. I normally sign as follows:

Regards, Greg.P.

Hi Greg:

This is off topic, but

I was sitting in a medical lab with my 86 year old Aunt this week, waiting for our turn to get her tested, reading an article in last week's U. S. News and World Report on Iceland (one place I've fantasized emigrating to), and the article said that in a survey of 168 countries, Iceland, New Zealand, and I think Finland were tied for the three countries with the least corrupt governments.

On the other hand, does New Zealand still prohibit U.S. Navy ships carrying any atomics from making ports of call there?

Wayne

Well, we really don't understand why the rest of you accept corruption in politics!

Absolutely - why would we run the risk involved in allowing _any_ nation's nuclear powered or armed ships in our waters???

Regards, Greg.P.

Er, uh, just how does that fit with "on the other hand"? I would think instead that it would follow naturally from having clean government.

of course, that probably makes them not good Republicans, but then, that also follows naturally from them having clean government.