Interesting timing ... I was

Interesting timing ... I was just lamenting the cracks in my masonite backdrop... 

Try Good-Bye Cracks

I used Masonite for my backdrops, with drywall along the straight sections.  The joints were taped and compounded in the usual way, except I used Durham’s Wayer Putty instead of drywall mud.  Once the Water Putty was completely dry, I sprayed two coats of Good-Bye Cracks on the joint, overlapping the outside edge of the putty on either side.  Once the GBC was dry, just paint as usual.  Some of my backdrop has been up for 15+ years with no cracking.  

GBC is a latex material which floats over the joint and keeps the paint from cracking (it doesn’t keep cracks from forming in the underlying joint).  I got my GBC from Home Depot; it’s probably available in other big-box or hardware stores.

How about disguising gaps?

Marc: What do you recommend, or have seen, to disguise gaps in the backdrop where it must part for access to the room or staging? Any ideas are appreciated. 

NeilEr

Marc: What do you recommend, or have seen, to disguise gaps in the backdrop where it must part for access to the room or staging? Any ideas are appreciated

This a good question.

The best answer I can give is a very old picture about the first GD line of John Allen where he painted a door with a full mountain, sky and a excellent feeling of depht and distance.

I my future new room for my layout I will be confront with such problem.

I think I will try to make the same as John, paint the door like the backdrop; trying to do the bakdrop ending just at the edge of the door, remove the door Framework and may be gluing some flat 3D details on the door to give more illusion of continuity.

Since a double track will run over the door, I think I will really scenicked the door panel in a small depht and paint a backdrop in the continuity of the one on the layout.

About staging I think a factory could hide the entrance or the exit of the staging; a tunnel could also do the job.

Or a train going in forest which hide it from the edge and the turnout which allow train going in or out staging.is in this forest but hide from the operators

Also a bridge glued against the backdrop and the trains going under to go in or out the staging, but in this case, you must light the entrance behind the backdrop to not kill the effect of the bridge.

Just suggestion

TOMA & Backdrops

Thanks Marc. This is really an issue for those building modular style as well. Maybe some 3d relief will help disguise the joint. I’ll give it a try. 

G & D backdrops

There weren't many backdrops other than sky on the last G&D.  John raised the scenery horizon up to eye level just as it is in real life.  No doors.windows to contend with, though.

vinyl roll

Marc, are you talking about something like a shower curtain stretched tight all around with a wood frame? 

I guess they make shower curtains in blue...

Vinyl flooring, I think

@ JeffShultz

Yes, thank you is vinyl flooring I mean.

Course, I know the use of aluminium roll; this seems to be the ultimate backdrop.

Unfortunately this kind of roll of aluminium don't seems to be available in Europe.

I have no references about it in USA  or Canada were I'm going to live.

And no info's about the price of a roll of Aluminium including measurations and tickness availability.

I will try to find some pictures of layout wich use vinyl flooring backdrop and some info's about how they hang it.

Of course vinyl flooring is asking for a structucture to support it and a like  "clamp" made of wood above it, to hang it securely and in a durable way knowing is quiet heavy too.

Anyway when I see all the complaints about cracks in backdrop made of massonite or tempered wood or MDF, and not talking about all the filling and dust produced by joint compound application and the extremely hard way necessary if a repair is needed  I will seriousely think about an another way to make my new backdrop.

I will probably forget the family masonite backdrop and go for vinyl flooring or may be aluminium backdrop.

I am fortunate enough to have a future  train room which is something like 45' x 24', my layout will be a walking around design point to point, going along the wall  with two peninsula  in the middle of the room; this is the basic design

Each peninsula will be  divided in two sides with a medium lenght of around 36'; they need backdrop for each side so it's 36'x2 by peninsula

Just an estimation, now we are speaking about backdrop, this made a backdrop of  around 300 feet long; I never had think about it until now !

Now I'm sure, I don't use masonite or similar to do such lenght of backdrop for sure; with a medium lenght of 7' for a piece of masonite this give around 43 pieces of masonite giving around 86 joints and yes 86 possibilty of future craks

No really no, thank you; I go to try to use something else for sure.

Just my opinion

Flex patch

A product I use on the Free-Mo modules, when finishing the foam/wood gap at the module edges, has yet to crack.  It's called "ElastoPatch", made by DAP, in Baltimore MD.  It is an elastomeric patching compound for interior wall finishing.  Upside, I've yet to see cracks in it where I've covered 'moving' defects in the attic walls, which are subject to a lot of thermal stress. 

The downside, is that you have to feather it out for the final finish as you apply it.  Once it dries, you're done.  The stuff is not sandable in any reasonable manner.  On backdrops, I'd suggest a light water mist and the biggest drywall knife that'll fit.

Vinyl Flooring

Marc:

I too, would be interested in what you're referring to, and hopefully find a US equavilent supplier.

In the past I've used 1/8" tempered hardboard, and used linoleum (vinyl?) flooring for corner coves and covering joints, with the shiny "decorative" side glued to the hardboard. I then used spackling to blend the edges. This resulted in really nice texture for the paint to adhere. I could be interested in covering the hardboard with continuous (or much longer) sheets of vinyl if your source is similar to linoleum and a US equivalent is available in the US.

In fact, the backdrop stage will be the next in construction phase on my layout.

Andre

@ Laming

Yes , probably linoleum work better than simple vinyl flooring.

Just to see the price for a big roll.

It's probably possible to have a roll cut in two which correspond more of our use.

A height of 5 feet is for sure enough for the most of us so a big roll offer two roll for layout use may be

The goal  is to have no joint, a continuous backdrop all along the layout in one piece, knowing each join is probably a future troublesome point somewhere.

All the thread about craks in backdrop or complaint about it, are the proof if necessary, compound and masonite and similar are troublesome here and there.

Any repairs of a crack is asking big job with lot of dust, painting.....

As I mentionned before, knowing how much masonite panels I need for my future backdrop, meaning as a minimum the double of number of joint; no thank you.

So il will try a vinyl flooring or linoleum backdrop.

And one more benefit is the total absence in a moment of a lot of  dust, because no need of filling of compound joint anymore.

Already a must to have especialy if you build the backdrop after some parts of the layout are already build and sceniked, like in my case with my like Toma construction and the move in a new room.

Aluminum, Linoleum

Jeff, what's the issue - sagging, weight, or???  There is good and bad in both camps, I think.

Aluminum pros - lightweight, easily curved, 50' rolls (standard here, not sure about other lengths)
                cons - dent it, and you'll struggle to get that crease out; only available in 24" wide rolls (here, anyway);                             minor risk of cuts and nicks on the edges; cutting can be a challenge, as knives require                                         repeated scoring actions, while snips usually leave crinkled edges.

Flooring pros - not sure about length, but at least 50'; 12' wide; easily curved; clean cuts are easy; easy to notch                           around structural supports, too.
              cons - heavy, sagging requires significant effort to support; weight for significant sections means you'll                             likely want a crew to help install.

For me, having done a lot of aluminum exterior work over the years, I'll take the flooring.  Since I have hundreds of feet of backdrop to hang, in two standard widths and a bunch of custom widths, I think the best bang for the buck for me will be to cut very long sections, maybe 50', in the two widths - 15" lower deck, 24" upper deck.  Not sure what that's going to cost me, so I'll be on the hunt for roll leftovers and unpopular styles; perhaps a local flooring shop will be able to provide off-cuts and remainders, we'll see.

Blair

Sheet rock

is ideal if one has a stud wall to secure it to, it's cheap ,easy to hang and tape ,and has a nice texture for painting on. I'd rather tape sheet rock than try to hang long sheets of aluminium or vinyl flooring.If one can get by with a 24 inch tall backdrop a 4 by 8 sheet will do 16 feet of backdrop length with only four 24 inch tall seams per 40 feet of length ....DaveB

interseting

How old are your backdrops?. I used a "masonite" type board filling the seams with drywall and drywall tape, It has been up a little over two years and just went though a 7.0 earthquake and has no cracks yet.

Bob

aluminum flashing

On the Home depot Canada site they have a lot of choices on this page.

https://www.homedepot.ca/en/home/categories/building-materials/roofing-and-gutters/roofing/flashing.html

Availibility and mesurations

I made a few quick research on Google for vinyl flooring mesurations

These measures are from Europe for vinyl flooring.

Don't know if this availability is possible in USA or in Canada.

They comes in different width, 3 feet, 4,5 feet, 9 feet and 15 feet in roll standard of 106 feet or respectively  from 1 meter, 1.5 meter 3 meter and 5 meter and the roll are 35m lenght.

The 106 feet lenght is the maximum, but you can buy the lenght you are asking for.

The quality "linoleum" which is just a different texture are available in the same mesurations except the 3 feet width or 1 meter.

Special order are possible for roll going to 227 feet or 75 meter lenght , but only in the 9 feet width or 3 meter

Knowing vinyl is soft you can  easily cut a 9 feet roll in a 4.5 feet width, which is sure enough for the most backdrop, with a saw, knowing you have two perfect square cut outside.

The square cut above and your cut beneath, so the easy to put the backdrop along and follow the edge of the ceiling and the wall.

In my case as I mentionned just before the 300 feet envisaged and estimated backdrop will have only one joint !

And for the lone model railroader, course vinyl is quiet heavy, but making a special vertical Rolling support where the roll is sleeved at the standard height of the backdrop is not impossible to do; this is the way I will go probably.

Vinyl, linoleum backdrops

Vinyl, linoleum backdrops looks wobbly, but I can understand the use in a modular layout. The best and low cost material for "permanent" backdrops is the drywall. The issues at the joints are solved and you can build any curved surface.

Scraps of linoleum

can be found and usually at a reasonable price.  Butting them on a stud and filling with joint compound then light sanding or sponging worked well for me.  No cracks or wise cracks either....

Nick

@ vggrek

This magnificient European layout of a good friend of mine is considered  of one of the better done in Belgium and probably in Europe and  use a linoleum backdrop.

http://www.ferbach.be/html_fr/frcadcf.htm

This backdrop is in place since more than 25 years as far as I know; It's not woobly but at the start it was put on a sturdy wood frame , glued on the frame and  clamped above and beneath.

The dry wall method is also expensive, ask a lo tof work, and heavy work, need some knowledge, ask a lot of sanding and make dust, a lot of dust, and curved drywall is not so easy to do and can crack in time like again some joints.

The purpose here is no cracks anymore knowing they are extremely difficult to repair when the layout and scenery is constructed; take a look at  all the complaints and remarks about these backdrops cracks on this forum; they are not seldom, really not; I can say this is a general trouble.

I often visit the site of the  http://www.aorailroad.com of Dave Stewart; all the bacdrops are for the most drywall mixed with masonite......and he speak about cracks here and there again; the layout is 5 years old......

Well know modeler Howard Zane, say in his book He like vertical scenery of course, but one of the reason why his scenery nearly cover his walls room is because He had craks which appears here and there on the walls. http://www.zanestrains.com

My house in belgium is a new construction  no more than 6 years old, with an heavy use of drywall like they use tomorrow to build the inside and.......numerous cracks here an there which appears.

The house were I go to live, has my future layout room with no finished walls, they are just painted.

They are just concrete block all around and  for sure I don't want to put drywall all around, knowing also my modules need to be put in this layout room anyway for storage, because of available space, this allow no dust work in  the area.

I'm a firm opponent of the making of any dust in the train room, even my scenery hardshell is not made of plaster but with red rosin paper

Slowly. I didn't find any

Slowly. I didn't find any details of the backdrop framing for the layout linked. The "sturdy" wood frame, the work and  the material, maybe is for free for you. I'd like to see your price comparison of the two applications. Please don't use prices for double sided drywalls complete structure.:> )
The cracks on the drywalls may caused by a lot of reasons and not by the material itself or the work quality. I saw cracks on concrete, bricks, etc. so what? As a structural - civil engineer I have a better knowledge about the materials and the failures, but I would cause a disaster as a car engineer though.
The linoleum and the vinyl roles are a floor covering materials, the drywall is a wall covering material. The modelers are free to use anything in any way as they like. Our failures can't be concidered as definitive proofs of nothing.
The dust is not so much as you present it and beside this the backdrop can be installed and prepeared as the bench structure is finished. Even if it is nstalled after the layout is finished you can cover the layout like when you paint the house. The seams of a layout backdrop are 0,5m long and let's say we have 2pcs at every meter of the backdrops length. This is 1m of seam per meter of the backdrop lenght. Search some videos in the youtube about the drywalls montage and finishing and you will see how they do it without dust and tears. Anyway, the rule "pick the right material for the job, use it as it have to be used, use the right tools and the right method" is still valid.
I'm sorry you have so bad experiences and I hope you see a drywall made the right way.

Photo backdrops are an answer

Especially printed on vinyl. You can get a big one -8 feet- fir $50. 

Sags and flexes

"The dry wall method is also

  Sheetrock can be finished with very little dust. The key is troweling the joints smooth as you tape them so heavy  sanding is necessary . Any small sanding required can be done with a damp sponge or scrubber so it doesn't make any dust. Sheetrock is quite stable so doesn't need a lot of fastenings which cuts down on the hole filling required. There's very good reason it's used as the common wall material in houses, and a layout backdrop is just a tiny portion of a wall set up behind the benchwork. The only reason I didn't use sheetrock on my latest layout is the weight, at the time my back was sore so  I didn't feel like carrying it home and hanging it up so went with a lighter masonite material instead.I certainly wouldn't have want to wrestle with a long piece of vinyl or aluminium at the time :> ) ....DaveB