I have just installed my 1/8" Masonite backdrops on the lower level of my layout. I did not use any bracing on the curved corners and they seem to be very rigid and self supporting. I did use DAP vinyl spackling compound on one of the joints (with no tape) and experienced hairline cracking right away when the backdrop was flexed a bit. My backdrop is fastened to 1x3" wall brackets and "floats" over the wall between the brackets (see photo below). Pushing or pulling on the Masonite between the brackets causes a tiny bit of flex at a seam that causes the hairline crack. As hardshell scenery goes in and gets attached to the backdrop, this should nearly eliminate any flexing of the Masonite. Regardless, I am now in the process of finishing the joints with extra screws, fiberglass tape, then drywall mud and paper tape like a typical drywall joint. Jamie
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I would definitely not use nails to hold up the 1/8" hardboard. This is asking for them to work loose as the wood they're in starts to dry and shrink. Just look at what happens to some of the drywall nails in a new house after a few years. You start to see nail heads which have to be reset.
I've had some preliminary success making countersink holes in 1/8" hardboard using countersink bits available at Lowes, Home Depot, etc. These are the bits that allow you to set the depth/length of the drill bite using a set screw to hold the drill bit in place after its position has been set. The drill bit makes the initial hole in the material and the countersink portion makes the depression around the hole to make the space for the head of the screw so it's below the surface of the board. You can usually buy these countersink bits in sets having sizes to accomodate different screw sizes. If you pre-drill the holes, put a scrap piece of lumber under the hardboard so you drill into it. I would suggest practicing on some scrape hardboard to get the feel for how much pressure you need to apply to get the proper depth of the countersink without going all the way through the hardboard.
Bob
Raised on the Erie Lackawanna Mainline- Supt. of the Black River Transfer & Terminal R.R.
I'm about to start installing my backdrop and am using the method described in Jeff Wilson's book on benchwork construction. I'll be attaching 1/8" hardboard 24" wide x 8' long (smooth both sides) to a framework made of 1x2 furring strips attached to the wall studs . Each of the joints will have a backer 1x4 behind it to which the adjacent two edges of the hardboard will be glued and screwed. I primed both side of the hardboard (1 coat on the back and 2 coats on the front) in order to reduce expansion and contraction due to moisture absorption and to prepare the front to receive my sky color. My inside coved corners will be at a 24" radius and I do not plan to use any type of bracing behind these corners. In Joe Fugate's DVD on scenery (Vol.4 Part 1) he uses DAP brand vinyl spackle to cover the joints between the sections of his backdrop. He finds that this works better than drywall compound to prevent cracks forming at the joints. However, in the video he is using strips of vinyl flooring for the backdrop rather than hardboard.
I would be interested in knowing what type of joint tape (paper or plastic) people are using when they do their backdrop joints with drywall joint compund. Also what type of joint compound is being used. I understand it comes in different types depending on the application.
loathar wrote: lvanhen wrote:Cracks in the joints are best filled with a material that stays somewhat flexible. I'm not familar with Goodbye Cracks - might be a regional product. If the cracks are not large, and don't run the entire length of the joint, siliconized latex caulk may work - just don't get silicon caulk unless it says "paintable" clearly on the tube!!I have to agree with using something flexible. Masonite WILL expand and contract. I've used some stuff called vinyl joint/patching compound that held up well in non train related patches.I got it at Loews or Home Despot...(sp?)
lvanhen wrote:Cracks in the joints are best filled with a material that stays somewhat flexible. I'm not familar with Goodbye Cracks - might be a regional product. If the cracks are not large, and don't run the entire length of the joint, siliconized latex caulk may work - just don't get silicon caulk unless it says "paintable" clearly on the tube!!
I have to agree with using something flexible. Masonite WILL expand and contract. I've used some stuff called vinyl joint/patching compound that held up well in non train related patches.I got it at Loews or Home Despot...(sp?)
The corner itself is the flexible part of the equation: as long as the edges at the ends of the curve are fastened securely, the curve will adjust itself as the Masonite expands or contracts. Because the ends cannot move, expansion will cause the centre of an inside corner to move closer to the corner (decreasing the radius of the curve) while contraction will have the opposite effect. The curve itself provides its own rigidity, so extra bracing or support behind it is not necessary, and, indeed, not wanted, as that would prevent the the curve from adjusting as described above. That may lead to cracking at the ends of the curve, where it meets the straight wall and has been taped/mudded, etc.
Wayne
Capt. Grimek wrote:Hi Don,Well I know yours looks great. How long has it been up again?Has it been several years? I was paranoid that the masonite wouldeither try to spring back pulling hard at screws (1 1/2"ers) into studs.I may have to use some toggle bolts too in the dry wall. Any problems there?Wondering if 4' vs. 2' width would make any difference. I'd be willing to try without but wondered if I could add something after the fact if there were issues, but don't see how practical that would be...I was thinking that the curvature should stay nice and even in the corners if the screws alongside were plentiful/strong enough... It had been my impression from reading that everyone (or most) used corner braces.Maybe not with tempered masonite and modern techniques?I'd be very interested to see a "poll" as to how many folks have used no corner/curvature form bracing for years and have had no issues. It certainly would be much easier and faster to do without.Batman, if you're reading this, did you use any corner brace pieces on yours? > Oh yeah, almost forgot. Did you use smaller pieces for the corners or just curve the large/full sized panels around the radius/corner? Thanks.
I'm pretty sure that I've replied to at least one of your other threads and, as I showed there, the coved areas are completely self-supporting, due to the curve, when the edges (at the ends of the curve) are securely fastened. Don't waste money on tempered Masonite - regular Masonite works just as well. The "tempering" has nothing to do with flexibility. I taped and mudded all joints, as mentioned, and have experienced no cracks or buckling in over 15 years. My layout is in a well-insulated but unheated basement, which is reasonably dry.
Capt.,
My backdrop has been up for over a year with no problems in the coves. The only problem I've had is due to me not using tape over the joints; I simply floated them with joint compound. After suffering through an extremely dry summer, the seams are showing as small cracks. Nothing really obvious, though the cracks occasionally catch my eye as I walk by.
Don Z.
Research; it's not just for geeks.
Captain, my Captain,
My Masonite backdrop is 24" tall and I didn't use any braces in the inside corners. I simply coved the backdrop into position and had someone hold it in place while I started fastening it to the walls. On my sheetrock walls, I used a small bead of adhesive latex caulk along the top edge of the backdrop and used 1/4" crown staples in my air gun to shoot the staples into the studs.