Some quick questions:
Read an anecdotal article (non-MR related) today on foam separation issues. The author states that two layers of foam are better than a single layer for preventing separation and that joints should be offset vertically and horizontally. Is this true for a MR layout and is it worth the effort?
My layout is a 5x9 tabletop with two foam seams (1 inch extruded foam over 1/2 inch plywood). It is in the basement, temperature does not vary greatly, never above 70 degrees with low humidity. After 20+ years there is a 1/16 inch wide crack at the seams. Foam separation from the fascia is now 1/16 to 1/8 inch. Double layering and offsetting may have prevented or maybe not...
The next layout will be wall-mounted with narrow shelves and will be built in sections. Would double layering prevent cracks at the seams or any tips to prevent cracking at sectional seams?
Finally, putting together an open grid box, should I use a Kreg pocket jig or an air nailer on the butt joints of the open grid? I will need to purchase the selection and it would most likely only be used with model railroad benchwork.
Thanks!
Honestly, I'd just go with my good old drill and screw bits if the only use of an expensive tool is going to be benchwork assembly. The hundred bucks I'd spend on the Kreg jig or a nail gun could go towards the layout instead.
I'll use a nailgun because I already own it. But, I bought it for home projects, so it gets more use than getting sidelined as soon as the benchwork is done.
IDRickThe author states that two layers of foam are better than a single layer for preventing separation and that joints should be offset vertically and horizontally.
Sounds like a lot of work to cut the foam and glue in that manner, and depending on the dimensions, wasteful of foam.
Ken Patterson (Youtube) claims his foam shrunk just as you describe. That's not what the foam manufactures say, but as he just lays it on the table, one can't blame the benchwork. I believe he thinks that painting the foam prevents that, but I can't swear to it.
David Popp uses glue and a nail gun for the MR projects.
Henry
COB Potomac & Northern
Shenandoah Valley
BigDaddyKen Patterson (Youtube) claims his foam shrunk just as you describe. That's not what the foam manufactures say, but as he just lays it on the table, one can't blame the benchwork.
How do we know that the frame isn't expanding?
maxmanHow do we know that the frame isn't expanding?
It's free floating on the frame, not glued down. The track should hold it together. In fact the track does hold itself together but there are gaps between the foam.
IDRick,
It took me a while to decipher the title to your thread.
Has the foam shrinkage affected your track?
Thanks,
Dave
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
hon30critter IDRick, It took me a while to decipher the title to your thread. Has the foam shrinkage affected your track? Thanks, Dave
Hi Dave, my title was a bit cryptic... Sorry about that! Love your Rotisserie thread! Cliff notes would be good!
Did not really impact the trackwork as the foam seams were not near track joints and I had not soldered rail joiners so was some available slack for slight movement. The foam separation along the fascia was more bothersome to me based on appearance.
Forty seven years house building and remodeling, foam eventually shrinks a little. There is no building material that is 100% stable. Everything deteriorates, just glance at the mirror next time you walk by. We would all be grateful to only expand or contract by 16ths and 32nds.
Seventeen years ago I did my bench with a drill and wood screws. I layered up foam to a total of 4", in steps, along a twelve foot span over plywood. Used no more nails for gluw, with weights.
No problems so far.
IDRick...Finally, putting together an open grid box, should I use a Kreg pocket jig or an air nailer on the butt joints of the open grid?....
I can't visualise where or why there'd be a butt joint anywhere. When I make a section of open grid, usually 8' or 10' long, and at a width suitable for the available space and in consideration of the necessary aisle width, it gets set upon the support framing and fastened in place with short 1"x2" verticals, screwed to the support framing and the grid. The next grid section, and all subsequent ones, are attached likewise, and also attached to the grid already in place, using screws through the end cross-members.This makes a solid support for the layout, but one which is also readily disassembled if the layout needs to be moved or altered.
If the aim is to save materials by eliminating the cross-members at the ends of each segment of open grid, then the simple (and economical) solution is to use a leftover piece of the grid-making lumber to make a lap joint at the points where the open ends of the grids abut one another.
This open grid was improvised to allow for a rounded-end on a peninsula...
While I've decided to use some extruded foam for some scenic effects, most of my track is on cut-out 3/4" plywood roadbed, mostly curves. A lot of the structures are on plywood platforms, too, with the adjoining terrain represented by Durabond patching plaster over aluminum screen.The only portion of the layout with an actual top on the open grid is on the partial upper level, where I used 5/8 t&g plywood.There will be some landforms done with extruded foam, too, but I personally wouldn't use it as a sheathing material atop open grid, as it won't provide much rigidity should a section of open grid need to be removed or altered.
Wayne
doctorwayne IDRick ...Finally, putting together an open grid box, should I use a Kreg pocket jig or an air nailer on the butt joints of the open grid?.... I can't visualise where or why there'd be a butt joint anywhere. When I make a section of open grid, usually 8' or 10' long, and at a width suitable for the available space and in consideration of the necessary aisle width, it gets set upon the support framing and fastened in place with short 1"x2" verticals, screwed to the support framing and the grid. The next grid section, and all subsequent ones, are attached likewise, and also attached to the grid already in place, using screws through the end cross-members. This open grid was improvised to allow for a rounded-end on a peninsula... Wayne
IDRick ...Finally, putting together an open grid box, should I use a Kreg pocket jig or an air nailer on the butt joints of the open grid?....
I can't visualise where or why there'd be a butt joint anywhere. When I make a section of open grid, usually 8' or 10' long, and at a width suitable for the available space and in consideration of the necessary aisle width, it gets set upon the support framing and fastened in place with short 1"x2" verticals, screwed to the support framing and the grid. The next grid section, and all subsequent ones, are attached likewise, and also attached to the grid already in place, using screws through the end cross-members.
Use a drill/driver and screws on your butt joints. Drill a pilot hole when needed, to prevent splitting.
If you feel you need the pocket jig, so no screw heads show, that's your call.
I, myself, wouldn't mess with it. For furniture and finish work? Maybe.
As far as the foam shrinkage, I haven't had any problems, but the foam on my layout is made from random pieces from job sites, so they it all kinda overlaps each other.
Mike.
My You Tube
IDRickRead an anecdotal article (non-MR related) today on foam separation issues. The author states that two layers of foam are better than a single layer for preventing separation and that joints should be offset vertically and horizontally. Is this true for a MR layout and is it worth the effort?
IDRick Respectfully, your picture above has 11 visible butt joints (screws through a flat surface board into the end grain of another board).
A butt joint occurs when the ends of two pieces are butted against one another. Unless the mating ends are modified to overlap one another, or a separate splice plate is used, overlapping both pieces, it's not the kind of joint most builders would use.
Using your definition of butt joints would mean that most of the framing I built for my house is butt joints, but (no pun intended) if it had butt joints as I know them, it would have fallen down even before I had time to apply the exterior sheathing.
doctorwayne IDRick Respectfully, your picture above has 11 visible butt joints (screws through a flat surface board into the end grain of another board). A butt joint occurs when the ends of two pieces are butted against one another. Unless the mating ends are modified to overlap one another, or a separate splice plate is used, overlapping both pieces, it's not the kind of joint most builders would use. Using your definition of butt joints would mean that most of the framing I built for my house is butt joints, but (no pun intended) if it had butt joints as I know them, it would have fallen down even before I had time to apply the exterior sheathing. Wayne
IDRick
Respectfully, your picture above has 11 visible butt joints (screws through a flat surface board into the end grain of another board).
doctorwayneA butt joint occurs when the ends of two pieces are butted against one another.
IDRick ...Shrug, was not trying to start an argument, was simply identifying my source and respectfully disagreeing with your statement that butt joints (per Westcott definition) are rarely used in benchwork....
I didn't reply in arguement, either, but rather referred to the term as used by an uncle, who both owned and ran a lumberyard and also built houses, and for him, a butt joint was butt-ends butting against one another, as Mike has mentioned. My father, a design engineer, had a similar opinion of the term.
While the main portion of my layout is open grid, most of the track and structures there are not directly atop the grid, but rather on risers, attached to the grid. Structures of any appreciable size are likewise on risers, with a platform suited to the structure's shape and size.The partial upper level, also open grid when built, is covered in 5/8" t&g plywood, so I guess, technically-speaking, it's no longer open grid.
IDRickCliff notes would be good!
I'm glad you are enjoying my build thread. I am really frustrated right now because my recent injuries have stopped me from working on either the layout proper or doing any workbench sort of stuff. My shoulder is still weak and hurting after more than two months.
What do you mean by "Cliff notes"? I don't recall hearing the phrase before.
Because I know nothing, I went to the "end all source of knowledge of the universe", Wikipedia! (Don't yell at me. It's an attempt at a joke.)
York1 John
Cliff Notes were a "Godsend" in the 70's. They summarized a long book in like 30 pages with a synopsis by chapter. For me, I had a hard time reading Shakespeare but found that I could better understand if I read the book and its associated Cliff notes.
When I jokingly asked for cliff notes, I was saying it would be great to have a short summary on the key points of your rotisserie layout. I have bad knees and would love to work on layout sections mounted on a rotisserie rather than man handling pieces on a workbench! It's an awesome idea, Kudos! Your long thread had lots of twists and turns, typical and awesome for a close knit group like this forum!
DrWayne, I have a world of respect for you and your fine modeling skills! I greatly appreciate all the ways you provide assistance and encouragement to those of us with lesser talent and learning/developing skills! You are one of the top, must read posters in the MR forums. We're good, just a difference in definitions.
IDRickliff Notes were a "Godsend" in the 70's. They summarized a long book in like 30 pages with a synopsis by chapter.
Hi IDRick,
Okay, now I understand. In Canada we used to call them 'Cole's Notes' after the bookstore that produced them. They helped a lot of people.
I will consider your very valid suggestion. In fact, I did that before with another thread about upgrading a Walthers 90' turntable that got a little long in the wind too.
Just so you are aware, I currently have a partially torn tendon in my left shoulder which is severely limiting my abilities. I can type but not for long periods. Doing the 'Cliff Notes' version of the thread might be pushing my luck right now, but I would really like to do something in the future.
Thanks for the suggestion.
IDRick DrWayne, I have a world of respect for you and your fine modeling skills! I greatly appreciate all the ways you provide assistance and encouragement to those of us with lesser talent and learning/developing skills! You are one of the top, must read posters in the MR forums. We're good, just a difference in definitions.
All I've got to say is bull pucky.
Foam don't shrink.
You could bury it underground like they do and it'll take 30 years before it starts to decompose.
I've kept tabs on foam. A seven foot length shrank 1/16 of an inch over three years
Building materials come to the lumber yard up to 60% moisture. Building materials are categorized as cellulose. All cellulose materials have a high content of moisture. That is a problem as wood and man-made materials out of wood shrinks as it dries.
I remember an article in Model Railroader magazine years ago. A modeler did a spline lamination of some sort of cellulose materials. It didn't take long and when the spline material dried out, the track buckled severely.
I don't think modelers started to put foam over wooden bench work years ago for the heck of it. The foam fluctuates to the shrinkage and then later expansion and contraction of wood.
Cellulose material has been known to drink and expel moisture since the beginning of time. Foam laughs at it.
I don't know who wants to reinvent the toothbrush in some magazine as an author but you can't always believe what you read.
Foams expansion and contraction rate is extremely minimal. Modelers have been using it over bench work to buffer out movement underlying it since the 80s.
At this point I wouldn't reinvent the wheel either. How you fasten foam to cellulose materials does matter as well
Respectfully speaking for what I know
TF
I have started the 'Cliff Notes' version of the thread:
http://cs.trains.com/mrr/f/11/t/287007.aspx
I use beaded foam, it dose not shrink one cured enough to even see.
rrebell I use beaded foam, it dose not shrink one cured enough to even see.
Track fiddler All I've got to say is bull pucky. Foam don't shrink. You could bury it underground like they do and it'll take 30 years before it starts to decompose. I've kept tabs on foam. A seven foot length shrank 1/16 of an inch over three years Building materials come to the lumber yard up to 60% moisture. Building materials are categorized as cellulose. All cellulose materials have a high content of moisture. That is a problem as wood and man-made materials out of wood shrinks as it dries. I remember an article in Model Railroader magazine years ago. A modeler did a spline lamination of some sort of cellulose materials. It didn't take long and when the spline material dried out, the track buckled severely. I don't think modelers started to put foam over wooden bench work years ago for the heck of it. The foam fluctuates to the shrinkage and then later expansion and contraction of wood. Cellulose material has been known to drink and expel moisture since the beginning of time. Foam laughs at it. I don't know who wants to reinvent the toothbrush in some magazine as an author but you can't always believe what you read. Foams expansion and contraction rate is extremely minimal. Modelers have been using it over bench work to buffer out movement underlying it since the 80s. At this point I wouldn't reinvent the wheel either. How you fasten foam to cellulose materials does matter as well Respectfully speaking for what I know TF
Respectfully speaking, I did have separation at seams between foam pieces and separation between fascia and foam. The 5x9 benchwork followed the specs for a tabletop layout in Wescott's Model Railroad Benchwork. The top was 1" extruded foam over 1/2' plywood. I followed a MR article on how to build benchwork with a foam top. I don't recall which adhesive was used, it was either Liquid Nails for projects or carpenter glue, probably the LN. The top was weighted with college textbooks and left that way for a week. As far as I can tell, I did everything correctly but still had the separation develop over time. The layout was in a basement with temperature varying only a few degrees throughout the year and low humidity.
My bottom line is I want to use foam in my next layout but want to do all I can do to prevent separation along the fascia. I will be building the benchwork in sections and the foam top will be a single piece, thus no separation between foam seams within a section. How do I prevent separation between the foam:fascia and foam:endplates?
The anecdotal article (mentioned in OP) suggested that using two foam layers with 90-degree difference in seam orientation would prevent/minimize movement of the foam with benchwork expansion/contraction. Seemed plausible to me but then I'm a dairy scientist not an engineer, carpenter, or experienced layout builder. That's why I asked here...
York1 Because I know nothing, I went to the "end all source of knowledge of the universe", Wikipedia! (Don't yell at me. It's an attempt at a joke.)
It is possible the wood moved but impossible to test, given the age of the layout! I didn't purchase the wood far in advance and let it acclimate for a significant time in my basement. Rather, it was only a few days from purchase to benchwork construction during the summer months. The foam had direct contact with MDF fascia and the 1/2" plywood. I would not expect much movement with either material in our moderate temperature, low humidity basement.
Is there a reasonable way to test when it is "safe" to cut and construct with 2x 2 and 1x3 stock? The material in my layout did not warp but I have experienced warpage in 2x2 and 1x3 in my garage, stored flat. The new layout will be in the basement but the shop is in the garage. PITA to haul downstairs to acclimate, carry up to the shop to cut, then haul back to the layout room... Mrs does not want construction dust in the house...