Lab storage shelf collapse: postmortem - Page 1
Forum section: electronics / general

author: dfnr2
author_rank: Regular Contributor
timestamp: March 03, 2019, 11:24:51 pm
content: Hi all,I recently experienced a bit of a disaster in the lab. When I moved in, I had a carpenter place 24-inch deep shelving about 8.5 feet high around the circumference of the (small) lab, a converted 1-car garage. They were supposed to hold 100 lbs/ft.About a week ago, one section gave out. My wife heard some noise, and came into the lab to find a pile of heavy vintage computer wreckage on the floor. Some of it hit the workbench on the way down. Luckily, it looks like the equipment slid forward off a sagging shelf, rather than drop straight down, and nothing seems to have hit the RF test equipment on the bench below, although some accessories were knocked around.In retrospect, the design was flawed. Thesagulatorsag calculator indicates that for a 24 inch depth, 1 inch thick plywood material with a 1x2 inch edge should be able to support up to 100 lb/ft with a floating configuration (not fixed edges), and center loading (more sag than uniform loading), as long as the supports are no more than 36 inches apart. This design used 3/4-inch MDF, with some of the supports spaced 48 inches apart, and no edge strip. Thesagulatorpredicts a sag of 1.56 inches, which is dangerous.I’ve attached a photo (below) of the design. This is the section of shelf adjacent to the collapsed section. You can see some space where the shelf is separated from the wall, no longer supported by the MDF strip on the wall. The shelf was only held to that MDF strip by some thin nails. I would think some glue, but I don't see signs that the edge of the MDF ripped off, so I am thinking no glue. The separation is new, and I suspect it’s due to recent extreme variations in humidity (and to some extent temperature, but the lab is climate controlled.)So now, I have to take down all the equipment from the shelves around the room, and place them in storage. Then I have to replace all the shelving. This time, I’ll make sure that proper brackets are used. I was thinking something like this, or something standard like the unistrut system. The shelves will be 1 inch plywood with 1x2 edge strip, and supports at least every 36 inches.I've also attached a couple of photos of the bench below the failed shelf. I apologize for the state of the lab here. Normally it's reasonably tidy and clean. All the debris is from the fall. Also, I was recently given couple of computers, including an Apple II+, which I had on the bench for repair, adding to the clutter.Here’s how the equipment fared:- IMSAI 8080: several broken front panel switch handles. The case otherwise looks fine. The boards were not installed, and were bubble wrapped, so they are all still in good shape. Will have to power it up and make sure it is still OK, but I'm optimistic.- SOL 20: right wood panel sheared off the bolts and scratched. The left wood panel is still attached to the base, but dented (flattened) at the front upper corner. The panels had been pristine before the fall. I will see if I can find a way to restore them. Otherwise, I will try to make some replacements. The metal case itself is in great shape, as are the internals look great, but there’s no video, so this will be a project. I’m optimistic.- HP 9830A computer: heavy as a tank. The keyboard bezel is plastic and the front part is smashed, along with the spacebar. Several key caps have popped off, and some are broken, but the key switches still work. A couple of key stems are broken. I plugged it in and powered up, and it gave me a prompt, and I could type. So, just keyboard repairs and cosmetic fixes.- Infotek FD-30 disk drive. This went with the HP9830A. The front bezel is a bit cracked. I don’t have the cable for this, and so have not previously verified this was working, so if it doesn't work, I can't necessarily blame the drop, but I think I will have to check the mechanism and realign. I was able to find the biggest piece of the broken-off plastic and superglue it back. Only a tiny defect remains. I powered up the drive and the light comes on and the drive whirs. I’ll have to make this a project to get it working with the 9830A.- HP 9866A - This one face planted, and it looks like this printer broke the fall of the FD30A drive and HP9830A computer. The front plastic part is smashed to tiny bits and the mechanism make a sick grinding sound when I apply power, so I think this will be a parts unit.- HP 9836C - Luckily, the monitor did not implode, but the monitor case is cracked. The monitor fan comes on when I power up the unit, but no display. Not sure which part is the problem.- Commodore PET 4032 - This one miraculously landed with minimal scuffing and no dents. The monitor is just fine. I powered it up and got the BASIC prompt. The display is nice and clear. Inside, everything is tight and locked down. Most of the keys don’t work well, but that’s because the keyboard needs cleaning, not because of the fall.- Apple II+ - This was on the bench, and the shelf contents hit the Apple, and the power supply which was out for repair, on the way down. Four keys broke off the keyboard. I found what looks like replacements for the ALPS switches on AliExpress and have ordered them. Also, the power supply case is badly dented to the point where it won’t go back together or fit in the Apple II case, so I’ll look for a donor power supply case somewhere.Anyway, I thought I’d share this as a cautionary tale, and also share a bit of misery, since my family and friends don’t share the hobby and can’t really commiserate. . .Cheers,Dave

author: cruff
author_rank: Regular Contributor
timestamp: March 03, 2019, 11:45:55 pm
content: Looks like the door rail was bent by the equipment on the way down. I'm really surprised that screws weren't used to anchor the shelves to the rail.

author: schmitt trigger
author_rank: Super Contributor
timestamp: March 03, 2019, 11:48:13 pm
content: We in this forums, as your brothers in Instruments, DO feel your pain.Specially since some of those are mostly irreplaceable.I also have suffered a similar shelf colapse, although the damage was far less. The only irreplaceable component which I still mourn was an Arcturus blue-glass vacuum tube.Hang in there, bro.

author: SilverSolder
author_rank: Super Contributor
timestamp: March 04, 2019, 12:41:00 am
content: Are those supports held with just one screw on the bottom?

author: aargee
author_rank: Frequent Contributor
timestamp: March 04, 2019, 02:27:59 am
content: So it let go at the back of the shelf proper, then pivoted on the brace where it attaches to the wall?The turning moment where the weight of your gear would then be putting excessive force at the back of the shelf a few nails or screws for that matter aren't going to take it over time. The supports should have been full triangles with the vertical sections firmly attached to noggins.A PITA with 20/20 hindsight, I've made a few shelf assumptions in the past too that have turned into educational sessions.

author: Shock
author_rank: Super Contributor
timestamp: March 04, 2019, 02:41:19 am
content: That is sad to see and I still feel nervous for the little HP voyager sitting there on the table. Perhaps attaching to beams or joists will give better additional support, personally though I'd avoid anything but steel racking from the ground up.

author: TerraHertz
author_rank: Super Contributor
timestamp: March 04, 2019, 03:38:27 am
content: Quote from: aargee on March 04, 2019, 02:27:59 amNoooo, not the noggins! Those can't be trusted either, since they may be only attached to the vertical studs with inadequate nails. They are _supposed_ to have at least two big nails each end, but builders are lazy. Even in my own owner-built (by me) workshop I don't trust them. Massive screws (see pic) into the studs, and nothing less. In some cases even bigger coach bolts where the bolt has to take sideways force as well. Even then with so much weight on some shelves I worry about the 2x4 studs breaking under the torsional load. Metal racks direct to the concrete floor, are the only structure I'm fully comfortable with.But in OP's situation he can't do that due to the garage door opening path.

author: rdl
author_rank: Super Contributor
timestamp: March 04, 2019, 04:15:59 am
content: I don't think MDF was a great choice for the shelving material. MDF is basically just sawdust held together with glue. Seems like 1/2" plywood would be both lighter and stronger.

author: basinstreetdesign
author_rank: Frequent Contributor
timestamp: March 04, 2019, 04:48:36 am
content: Wow, that's a serious collapse.And yes you have to take it all down and rebuild it.If it were me I would make sure that each and every one of the triangle supports is built with 2 x 4 material and screwed into a wall stud with 3 or 4 4" #8 wood screws. That means one support every 32 inches at most and some or all only 16 inches apart. And definitely 1" plywood not MDF for the shelf. I built my bench from 1/2" MDF and regret it even though there's been no trouble yetCan you imagine if it had come down on your head?

author: edy
author_rank: Super Contributor
timestamp: March 04, 2019, 05:00:40 am
content: The problem is those 45 degree wooden supports. I would rather use something like a metal angle bracket screwed into every stud along the way, deep into the stud with several screws. See attached image. It is not the MDF that is the issue. It is those large wooden 2x4 cut with 45 degree edges and held into the wall with single screws. They put too much strain on a single screw and rip it out of the wall. Having an L-bracket with a few screws along the stud will greatly reduce the ability to shear off the screws.You can see also attached an image of shelving up in a laundry room. Screwed into every stud, all along the entire length of the shelf. You need them to avoid having the shelf "sag". If you prefer you can use the ones that look like a triangle, also metal, instead of L-brackets. They are even stronger. If needed drill a 3rd hole along the vertical to screw it into the stud with 3 nice size screws. It won't move, every stud, you can hang your entire weight from it. I still think it was those wooden 45 degree "supports" for the shelf. I never use those, and if I do I will always brace it beneath at the stud with additional horizontal beam (like you have at the top under the edge of the shelf) to avoid it slipping down. Honestly the metal brackets are cheap and easy to install than cutting wooden 45-degree supports and will be stronger.

author: med6753
author_rank: Super Contributor
timestamp: March 04, 2019, 05:11:31 am
content: I'm no carpenter and I didn't stay at a Holiday Inn last night but IMHO that whole structure is flimsy and I wouldn't trust it to support 50 pounds, let alone 100 pounds. Either your carpenter was a total idiot or he didn't understand your requirements. Here is what I would do:The strip along the wall is inadequate. It only gives you .75 inch mounting surface. Plus I don't see any evidence that it's lag bolted to the studs behind the wall board which in typical structures is 16 inches on center. Maybe it is and I just can't see it. Anyway, the strip should upgraded to a 2 x 4 which will give you 1.5 inches top mounting surface.Shelving: 0.5 inch MDF is OK. 0.5 inch plywood better. But I would consider .75 inch plywood. Firmly bolted with wood screws, not nails, every 6 to 8 inches or so to the top of the strip WITH wood glue.Supports: Those supports are completely inadequate IMHO. It appears by the tear out that the carpenter simply used wall anchors in the wall board. There should be supports every 16 inches bolted INTO the wall studs.Additional safety: Consider using steel strapping at each corner from the ceiling to the shelf similar to what's used to support the garage door rail.As I said I'm no carpenter but I do have some experience wood working as shown by this entire bench arrangement built by me.

author: Berni
author_rank: Super Contributor
timestamp: March 04, 2019, 07:00:28 am
content: Dang that is quite the carnage.The design is not all bad tho. This sort of 45 degree support can be incredibly strong and does not need any massive screws to hold the support against the wall, just needs to be held from slipping along the wall.The problem is that the top surface becomes part of the structure with such 45 degree supports. Loading it up causes the back of the shelf to be pulled away from the wall with significant force. There is more forwards force that downwards force on the back side. This is where you need big ass screws holding it into the wall. So the carpenter used crappy weak nails in the most heavily loaded joint.Okay the top surface being MDF is not great too. It needs way more supports to get anywhere near 100lb/ft. But then again MDF does give a fair bit of warning beforehand. It would sag more and more if overloaded letting you clearly see its overloaded before it would actually break.Plywood is certainly a better choice, but you could still fix up your shelves by putting in a crap ton of screws in at the back end and adding a few more 45 degree supports. MDF can tear a corner out under a lot of tension so the screws really need to be pretty narrowly spaced along the back. And yes glue is always a good idea (Also why a solid wood strip along the front is a good idea).

author: Ian.M
author_rank: Super Contributor
timestamp: March 04, 2019, 07:26:31 am
content: I wouldn't trust screws in holes too near the edge in MDF. Even if it initially looks ok, add some condensation and temperature cycling and the expansion and contraction can 'fret' the MDF against the screw shank resulting in delamination, and a massive loss of strength, so it tears out between the hole and the edge under load. Also, gluing MDF in sheer isn't that reliable for similar reasons - the face layer can delaminate and tear off.I agree with med6753's comment about the depth (front to back) of the batten the rear shelf edge lodges on. There is *NO* way to fix that without replacing the batten, as screw holes will either be too close to the edge of the MDF or too close to the face of the batten. I'm with the 'Triangular metal brackets and plenty of them' crew on this, with looooong screws into the stud at the top back corner of each bracket, so the MDF doesn't carry the cantilever forces pulling the shelf back edge away from the wall.

author: GreyWoolfe
author_rank: Unknown
timestamp: March 04, 2019, 12:51:11 pm
content: I would rebuild with something like these.These 8" by 10" brackets will support 320 lbs per pair. I used the bigger brothers to build my 'L' shaped desk and they support 600 lbs per pair. They are available at Home Depot.

author: Berni
author_rank: Super Contributor
timestamp: March 04, 2019, 01:30:24 pm
content: Yeah when i build shelves i just get metal brackets for the job and put a good strong piece of wood on top.I use this design a lot. Comes very usefully when you want multiple shelves on one wall since the height can be adjusted on the fly to the requirements. And they come in pretty beefy versions that can carry a lot of load. I mount the rails onto solid brick walls with plenty large screws into inserts and its rock solid.

author: Gyro
author_rank: Super Contributor
timestamp: March 04, 2019, 02:02:16 pm
content: No tear-out at all visible to me at the top of the back rail. Looking at the shelf to the left, it just looks like a glue line, and one that didn't 'take' very well!

author: Dielectric
author_rank: Regular Contributor
timestamp: March 04, 2019, 03:45:14 pm
content: I put up storage shelving in my garage, and used 1/2" plywood ripped the long way, with 2x4 framing underneath. Lag bolts to the wall studs at the back through the 2x4, and steel strap to the ceiling along the front. It's strong enough to hold a full set of wheels and tires for winter changeouts, in fact if I get up there it doesn't even make a noise. I'd feel comfortable sleeping on it. The problem, if there is one, is that the 2x4 framing is probably overkill but I can also hang stuff from those rails with screw hooks, like bikes, without worries.I also made some 4' wide shelves in a rack to hold tools, paint cans, etc. There, I used 1/4" MDF sheet for the top surface, a torsion box frame of 1x2 furring strips glued and screwed, and a thin Masonite skin for the bottom surface. That's a 4' span loaded with gallons of paint for about 10 years with no visible sag. The only support is at the short ends, 1/4" steel dowels set into drilled holes in the 2x4 uprights. It was a complete PITA to build but I liked the engineering enough to persevere.

author: ebastler
author_rank: Super Contributor
timestamp: March 04, 2019, 04:17:39 pm
content: Quote from: Dielectric on March 04, 2019, 03:45:14 pmHmm... In plywood, I would expect to find n+1 layers grained one way, and n layers grained at 90 degrees. For 1/2" plywood, n+1 becomes about equal to n...So I don't think the cutting direction matters much at all, except for looks. But of course itlooks"right" if the outer layers' grain runs the long way!

author: jmelson
author_rank: Super Contributor
timestamp: March 04, 2019, 08:21:47 pm
content: Quote from: rdl on March 04, 2019, 04:15:59 amYES, ONLY ONLY ONLY use plywood. No MDF or OSB (oriented strand board) these have no great tensile strength, and also sag over time.The plywood is screwed into 2x2 lumber, and NEVER screw into the edge of the plywood, always drill through with screws at right angles to the sheet.I built a set of shelves that fit on top of a steel bench 30 years ago, it is showing no signs of sag or weakening.Jon

author: aargee
author_rank: Frequent Contributor
timestamp: March 05, 2019, 07:11:04 am
content: Quote from: TerraHertz on March 04, 2019, 03:38:27 amNot a builder am I, I meant those vertical ones - studs.

author: Shock
author_rank: Super Contributor
timestamp: March 05, 2019, 09:34:17 am
content: Quote from: aargee on March 05, 2019, 07:11:04 amI think we can all learn from that, don't nail into a noggin, screw into a stud.

author: Johnny10
author_rank: Frequent Contributor
timestamp: March 05, 2019, 12:15:18 pm
content: You've got some great equipment ! Tek 370 Cool.That was not built by a real carpenter.Those shelves wouldn't hold heavy clothing boxes let alone heavy Tech equipment.Any carpenter would know that.Whenever you get away from Post and Beam type construction careful attention must be paid to support spacing and proper fastener attachment.Been a carpenter for 35 years.Seen lots of hobbyist carpentry over that time.Sagulator?? Come on. Just imagine if your house floor was constructed the same as your shelving.Typical home floor construction is rated 40psf.You would be in the basement.You need to be using at least 2 x 4's with no more than 24" Centers. And angled supports that are properly fastened. MDF is fine as long as there is proper support spacing. If your trying to make design with no supports going to floor from front of shelving you might drop threaded rod from the ceiling.Save that great equipment.I want to know how you get the heavy equipment up there? Without hurting yourself?Looking for effective designs with no supports intruding on floor space, I found this pic.

author: joeqsmith
author_rank: Super Contributor
timestamp: March 05, 2019, 12:25:13 pm
content: That's too bad. Looks like the next shelf down didn't take much of a hit. I use that portable steel wire shelving. I think they rate it to 500lbs per shelf and it provides a lot of air flow. What model LeCroy?

author: soldar
author_rank: Super Contributor
timestamp: March 05, 2019, 01:24:00 pm
content: Use strong brackets fastened securely into studs.Space them closely.If you are using mdf or if the distance between supports is too great then you should reinforce the underside of the shelf with one or several strips parallel to the wall.I am always surprised by how badly people judge and how undersized they build things. I always overbuild and never have problems.

author: SilverSolder
author_rank: Super Contributor
timestamp: March 05, 2019, 01:47:23 pm
content: You can make strong shelves out of inexpensive 2x4 lumber, but the carpentry has to be taken a little more seriously if you need heavy duty capabilities.

author: soldar
author_rank: Super Contributor
timestamp: March 05, 2019, 04:56:52 pm
content: Better still.

author: coppercone2
author_rank: Super Contributor
timestamp: March 05, 2019, 05:12:44 pm
content: I screwed 2by4 to the studs with a huge amount of 3 inch wood screws in addition to using 4x4 legs. I also used plywood and not mdf shit.It has a full frame and 2x4 supports every 18 inches to make ribsYour setup still seems anemic

author: coppercone2
author_rank: Super Contributor
timestamp: March 05, 2019, 05:24:03 pm
content: Quote from: coppercone2 on March 05, 2019, 05:12:44 pmFor the shelves i also screw a 2x4 into two corners of the wall and lay lywood on top and screw it down. Then i have flat wooden boards that go from the shelf to the also screwed in table.You would need to load it hard enough to bucle the boards and rip the screw out of the walls on every studThe full back brace adds alot of strenight because there is nothing to twist with a point loadPut a 2x4 lattice under the shelves to stiffen them but i dont require that weight handling.

author: Ian.M
author_rank: Super Contributor
timestamp: March 05, 2019, 05:27:39 pm
content: Quote from: soldar on March 05, 2019, 04:56:52 pmIt rapidly reaches the point where for most of us, the complexity and accuracy of the joints required to make good wooden brackets costs more than buying high load metal brackets, if you figure in the cost of your time to make them. Some economy of scale can be achieved if you clamp all similar parts side by side and set up a router jig to let you cut the same joint in each part in bulk as a single operation (or at most two operations). Pre-drill all holes, then dowel and glue the joints in a jig to complete the brackets.The other issue with wooden brackets is the length of screws they require. Even if you countersink the screw holes in the brackets considerably you'll probably need at least 4" screws to get 2" of engagement with the stud vs 2 1/2" screws for most metal brackets.

author: SilverSolder
author_rank: Super Contributor
timestamp: March 05, 2019, 06:11:18 pm
content: Quote from: Ian.M on March 05, 2019, 05:27:39 pmBuying pre-made steel brackets is sound advice.It is a pretty quick job to make wooden ones if you have a table saw or a circular saw (and a sunny afternoon, bottle of beer, etc.) - and if you have those, you probably have some 2x4 material laying about as well - but it isn't worth buying a set of new tools or learning to use them just for this.You don't actually need to route anything here, you can just make multiple passes with the saw set to the right depth to make the notches.

author: IanJ
author_rank: Unknown
timestamp: March 05, 2019, 06:28:35 pm
content: Hi,I wouldn't use these for heavy loads.......what happens is that the thin metal diagonal support bows (bends) over time and eventually the shelf collapses (talking from experience!).Ian.Quote from: GreyWoolfe on March 04, 2019, 12:51:11 pm

author: GreyWoolfe
author_rank: Unknown
timestamp: March 05, 2019, 06:36:39 pm
content: Quote from: soldar on March 05, 2019, 01:24:00 pmI agree. If I was doing that for myself and knowing that the shelves were going to hold quite a bit of weight, I personally would do appropriately sized brackets like I showed in an earlier post on every stud and still use 3/4" plywood for the shelves. Bolt the shelves and brackets together and should be Bob's your uncle.For the adjustable shelves on my 8 foot workbench, I attached 2X4 studs every 2 feet and still used 3/4" plywood and there isn't a lot of weight on the shelves. I originally did 1/2" MDF but the stuff bowed-that was a shame on me trying to save a bit of money. I knew better but did it anyway.Quote from: SilverSolder on March 05, 2019, 06:11:18 pmI have a table saw, miter saw, circular saw and I always have some 2x4s laying around. I would rather buy the metal brackets I need than make them.Quote from: IanJ on March 05, 2019, 06:28:35 pmIan, these are actually the style of brackets I use, no tubes. These 12" by 8" will support 600 pounds per pair. I use the 18" brackets for my desktop space not the 12" that these are. Since the studwork should be 16" on center here in the US, that would be 3 brackets per 4" shelf. That should support some decent weight. I like the brackets you posted but I have never seen anything like that here in the US.

author: IanJ
author_rank: Unknown
timestamp: March 05, 2019, 06:38:27 pm
content: I use these wall brackets, which are surprisingly strong as they have a mitred, plated & welded joints.Screwed into the studwork behind my plasterboard (dry wall), and with extra holes drilled in them for extra support against the wall.The shelves are 2 layers of 15mm contiboard (coated chipboard) glued and screwed together.No sagging after 1 year....pic attached.

author: soldar
author_rank: Super Contributor
timestamp: March 05, 2019, 06:55:34 pm
content: Quote from: Ian.M on March 05, 2019, 05:27:39 pmTrue. It also depends on the value of your time. Mine at market value is almost worthless.The second option I showed takes away having to cut notches and is very simple to do.Another issue is aesthetics although my solution is to not care about that.

author: ebastler
author_rank: Super Contributor
timestamp: March 05, 2019, 07:04:33 pm
content: A nice feature of the various metal brackets is that they are easy to install: Mount the individual brackets to the wall, put your shelf boards on top (the brackets already providing solid support), comfortably screw the shelf to the brackets from below.The various wood support designs will typically involve balancing a half-supported shelf while you install the angled supports, and/or adding screws from above (while balancing a half-supported self. ;-)

author: ajb
author_rank: Super Contributor
timestamp: March 05, 2019, 07:15:22 pm
content: Quote from: edy on March 04, 2019, 05:00:40 amThose are crap for heavily loaded, highly cantilevered shelves. They can be okay if they're made of heavy enough sheet metal, but they are prone to buckling because the amount of material in the compressively loaded area of the bracket is minimal, and open sections like that of the bracket have shit for torsional strength. Even if they don't fail, the tend to not be very stiff.The brackets posted by GeyWoolfe and IanJ are far better for heavy shelves.QuoteThe problem is almost certainly the fastening at the rear of the shelf. The toe of the 2x4 brace is in compression against the wall, and as long as the screw is into a stud, isn't sunk all the way through the 2x4, and isn't made of cheese it won't fail in shear either. Contrast a screw 0.375" at best from the edge of a piece of MDF in shear towards the edge of the MDF and you have a recipe for failure.

author: SilverSolder
author_rank: Super Contributor
timestamp: March 05, 2019, 08:34:34 pm
content: Quote from: GreyWoolfe on March 05, 2019, 06:36:39 pmIf I had wanted metal brackets, I would have welded them up too!- It's all in what you like to do, there are many "right answers" to get a job done - just avoid the directly wrong answers, and avoid sitting on your hands, and you'll be OK!

author: SilverSolder
author_rank: Super Contributor
timestamp: March 05, 2019, 08:37:31 pm
content: Quote from: IanJ on March 05, 2019, 06:38:27 pmThat looks a very elegant bracket. - I like the layout of the whole work area, very clean!

author: SilverSolder
author_rank: Super Contributor
timestamp: March 05, 2019, 08:44:52 pm
content: Quote from: soldar on March 05, 2019, 06:55:34 pmThe notched design is very strong and not hard to make. If made with some nice straight wood, they could easily be nice enough to use inside the house.

author: Neomys Sapiens
author_rank: Super Contributor
timestamp: March 05, 2019, 09:40:37 pm
content: Quote from: Berni on March 04, 2019, 01:30:24 pmThat would have been my recommendation too. Most of my Storage is based on this, with a mixture of 1-slot and 2-slot (pictured) system. Including my clothing cabinet, which just has a tarpaulin around.Some of those racks are stacked with paper and metal floor-to-ceiling.

author: Red Squirrel
author_rank: Super Contributor
timestamp: March 05, 2019, 11:10:00 pm
content: Ouch that sucks! Those shelves did not look all that strong though, I would not have felt right putting lot of weight on those TBH.I like to overbuild stuff though... this is the shelves in my shed:Probably be a bit stronger if I used plywood instead of cedar planks though, but still strong enough I think. I used cedar for it's bug repelant properties, I figure I might get less spider webs in there. Not sure how well that will work out but I'll see.For stuff that will load a lot of weight I usually make sure to build in such a way that the fasteners are never bearing the load directly. This is my battery rack for my server room:Technically the nails do bear some of the load for each shelf cross member but each shelf is held by the lumber only.I might actually move all of this some day though to a battery box that sits on the ground so that maintenance of the batteries is easier.

author: rdl
author_rank: Super Contributor
timestamp: March 05, 2019, 11:49:26 pm
content: When I first set up my bench, when it was in the closet, I used this exact same type of brackets as GreyWoolfe (well, except white).Very strong, probably far more than I needed. Biggest problem is that once installed, no adjustment is possible, practically speaking.I later switched to this type (image is from when I moved out of the closet). They have the double row of slots on the standards and folded metal brackets.Not as sturdy as the previous, but has the advantage of being very adjustable. Bad thing about both is they're not really suitable for extra deep shelves, but if you attach the shelves firmly with screws, 18"-24" might be okay. Mine are just stuck in place with hot glue, with only 11" depth that works fine and leaves no holes, so when they sag I can flip them over. I like these so much I've been tempted to cover the entire wall with them.

author: BravoV
author_rank: Super Contributor
timestamp: March 06, 2019, 07:18:23 am
content: Quote from: Berni on March 04, 2019, 01:30:24 pmYep, I use these too, the top shelves with big boxes probably under stress with total weight more than 50Kg.Posted the details ->HERECeiling height is 3 meters.

author: SteveyG
author_rank: Unknown
timestamp: March 06, 2019, 07:32:09 am
content: Gallows brackets can be built to be incredibly strong. There's nothing inherently wrong with the original design other than it was poorly implemented and the fasteners were inadequate.The OP can rescue what's already there by sandwiching the shelf at the back with another batten sitting on top of the shelf and adding further supports at more regular intervals.MRMDF would be a better choice than the plain MDF used, but unless it's getting really damp in there there's no need to rip it all out.

author: KL27x
author_rank: Super Contributor
timestamp: March 07, 2019, 11:06:11 am
content: I'd probably glue in some strips of wood from the bottom to secure the shelves to the back strip/batten. Shoot a few nails to hold it while the glue dries. And make sure the batten is screwed to the studs. This way I wouldn't have to take it all down.For sag prevention, maybe add a strip to the front lip. Or screw in some sort of U channel steel a few inches back from the front edge.Add more supports if needed. But it doesn't look like you can properly fit 100 lbs of stuff per foot up there, unless you are hoarding something denser than electronic equipment.It doesn't surprise me that this is held together mostly by just nails. This is the modern way of building things. Pulling a trigger is a lot easier than gluing things. I recently replaced some broken plywood in the frame of a sofa. Most of the frame was held together with a buttload of 2 inch long staples. They seemed to be sufficient, anyway. The wood failure was completely unrelated. Around the high stress area there were staples on top of staples. I had no idea I would be using a sawzall and a grinder to fix a wood frame couch. Then there's the wicker table I repaired. Square tube steel frame, wrapped in synthetic wicker. The wicker was secured to the steel frame by... yep. Staples. Just shot right into maybe 30-40 thousandths thick steel.

author: 0culus
author_rank: Super Contributor
timestamp: March 07, 2019, 09:47:44 pm
content: Wow, that is sad. Hope you can repair everything. My plan for my new lab is to get a beefy industrial rack system to hold my heavy test equipment that's not in use. I plan to possibly rackmount the stuff that I am using to free bench space.On another note, I do like your lab bench. Where'd you get it?

author: dfnr2
author_rank: Regular Contributor
timestamp: March 08, 2019, 05:18:18 am
content: Quote from: Johnny10 on March 05, 2019, 12:15:18 pmI was skeptical at the time he built them, but he assured me it would hold the weight. I have recently been learning a bit about working with wood, and had not long ago realized how vulnerable these shelves were. I had been planning to either replace them, or add some more brackets and a 2x4 along the front to support the front from the joists. But I never seemed to have the free time, and it didn't seem to be an emergency. . .QuoteI stand on the bench (or a stepladder) and hoist it overhead. I try not to put any individual piece over 30 lbs up there.

author: dfnr2
author_rank: Regular Contributor
timestamp: March 08, 2019, 05:45:15 am
content: Quote from: 0culus on March 07, 2019, 09:47:44 pmIt's a Benchpro, kennedy series. It's best to see if you can snag a used / surplus one, as they are expensive to buy new. This one is 10 feet wide, 36 inches deep. Because of the weight of the equipment on the bench's shelf, I had to brace the shelf with a 2x4 on either end, and one in the center (as you can see in the photo). This bench is used for working on large assemblies, electromechanical work, and RF work (and for playing with the occasional vintage computer). There are two smaller (5 ft by 30 inch) benches on the other side for test/debug, and for soldering / rework.

author: 0culus
author_rank: Super Contributor
timestamp: March 08, 2019, 05:55:36 am
content: Quote from: dfnr2 on March 08, 2019, 05:45:15 amThanks! It might be worth it for me to save up for a custom order because I want certain features and I really like the look of their heavy duty line. I hate benches that move around on me.

author: KL27x
author_rank: Super Contributor
timestamp: March 08, 2019, 08:04:04 pm
content: QuoteFrom what everything I can see and what most other people have suggested, these 2 things are secondary. The main weakness of this shelf is that the back of the MDF if only secured into the back "batten" with nails. If you think of a bracket as a triangle, the top rear of that triangle where it goes into the wall is where the thing has to be secured the best. In this case your triangular bracket is made up of the shelf on top, the 45 degree support beam in front, and the stud in the wall at the back. That intersection between the back of the shelf and the rear batten that attaches to the studs, held only with nails, this is the weak point in this setup.Personally, I fix this part first, with something like 1.5" x 1.5" maybe two strips of 3/4" thick board glued together (maybe cheaper at the local store than trying to find 2x2", if you have a suitable way to rip) and glued in the corner between the back batten and the bottom of the shelf. If there's a gap developing anywhere, already (e.g., you can see all kinds of daylight in this seam in your first pic, on the back of the shelf to the left of the one that fell out; this is probably why the brackets failed, because the shelf was pulling away from the wall and bending/pulling the bottom bracket screw out of the stud with tremendous force), I think I might remove everything and get up there with a hammer and some more nails to snug it tight, first. But this depends on what my level and square says*. Again, make sure there's at least one screw through this back strip in a stud, every 16", before you glue this up. I would just leave a gap in this reinforcement where these screws are, in case someone wants to take this whole thing down, one day. So these reinforcement would be ~15" in length, with the 2" gaps centered over the studs. Glue up, stick the pieces in place, add a few nails to hold it while the glue sets.Second, for the lip, I would use a smaller maybe 3/4" x 2" lip to the front with glue and nails. Placed at a right angle, of course. If I want more support than that I'd add a second strip back from the front one. This one might be easier to put in with counter sunk screws from the bottom to keep it in place while the glue dries. A single 2x4 at the front lip is excessively heavy and also will look crude, IMO, unless you have a jointer to clean them up. They will also not glue too great, raw, unless you have a bazillion clamps. Also might want to look into channel iron with pre-drilled screw holes. Angle iron (or individual small, predrilled right angle brackets) might also be good to secure the rear of the shelf to the batten, but IMO it takes more work to drill and screw. And the screws should be very close the the inside corner where it goes into the batten, unless the steel is very thick and rigid (and that means heavy and expensive), so there's not necessarily room for a good angle for a drill.Last thing I would add is more triangular brackets/supports, because in my estimation that's the last thing it actually needs. Highly doubtful that this is how and why it failed. Plus your studs are every 16". So if you add more brackets you would end up with either 3x as many or an extra bracket 1/3 the distance between the existing ones. I'd have maybe built it same as this guy did, every 4 feet. I suppose you could play musical chairs and shift some of the existing brackets to make them every 32". I bet the pieces of MDF for your shelve are a multiple of 4 feet in length, each, though. I'd make sure there are actual screws, at least 2 or 3 small screws, through the MDF and into the top of each bracket. Spaced out so that the MDF doesn't tear out under high load. The one single screw at the bottom is probably fine, so long as the back of the shelf is rigidly affixed to the back batten.*this is where a slide hammer might come in handy. I've often wanted one but never got around to buying or making one, yet. I might jerry jig something up if this were needed. I think it might be easier than turning into spiderman. Screw into the bottom of the shelf and smack it back down, tight. Also smacking the front of the shelves with a 3 lb mallet towards the wall to get it to reseat, properly, where the nails pulled out and away. Another possible method is to drill some large holes through the bottom of the shelves at the back, big enough to slip a small clamp through, to clamp them down to the back batten while gluing in the reinforcements.