Construction Technique Pointers Request
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I just doodled this out to explain the countersinking I was trying to describe in case anyone missed it.
So, Duncan. Have you built this thing yet?
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LOL I'm gettin' there! I work a little slower than you guys do. Plus I got sidetracked by research into fasteners, so your "doodle" is quite timely, and quite demonstrative, too. I understood what you meant, but that confirms my assumptions. Thanks.
I'm wondering if you can help clear up a question I have, speaking of fasteners; I have read conflicting opinions about what type of fastener to use with MDF - there seems to be two (or more) schools of thought, with one camp saying "don't use wood screws, use Confirmat screws," and others saying "use drywall screws."
I know that drywall screws don't have the 'shear' strength, but would be the cheaper route to go, and I've read all over that guys say they are plenty strong for smaller projects. I have also read that the only proper way to secure MDF is to use the Confirmat bit and screws. What would you recommend for a 'cabinet' of this size? Also, won't I be screwing into the bracing? I thought I was trying to avoid screwing into the end grain like that. Or am I confused (It's possible
)?I know you guys will chastise me, but for my own personal build of this booth, I'm going to use 3/4" ply, as I have a bunch on hand, and can't justify (to myself, or the 'finance dept.' [read 'old lady']) the cost, no matter how small, of getting a sheet of MDF just for this.
I will however be producing the plans with the recommendation of MDF, so I'm not discounting what you guys are telling me, it's just that I wanted to use up the ply, and settled on this in order to do so. So I'll proceed as if I were building with MDF, in order to be accurate, but just be aware that I, personally, will be subbing plywood.
Regarding the overall design, there were just a couple of more things that I needed to work out, like adding some bracing below the booth bottom, as the blower motor will be hanging from it, and those motors aren't exactly light. So I wanted to make sure the bottom is secured strongly enough.
I'm also struggling with how to fasten the blower to the bottom of the booth. As it stands, the blower motor has two small sheet metal screws holding on the little circular screen, and I thought at first of just using longer screws to go through the booth bottom, through the spacer block, and into the housing.
But that seems a bit too flimsy to me, so I was thinking of some small diameter bolts instead, recess drilling the seat for the bolt head. I'd like to put the bolts in with the head side in the housing (and the nut in the recess in the booth bottom, but I don't think I can get them in that way, as the squirrel fan is in the way. Did I explain that clearly enough?
And also perhaps adding two more bolts for added stability. When the blower starts, it wants to twist, so I think I may need to strengthen it. Thoughts?
I put in the pole sockets and dowel as well - perfect. What a great idea! Thanks for that.
Ok, that's it for now. But I'll be plugging away at this tonight, so progress soon. And be patient with me - I'm a slowpoke.
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@dave r said:
Sorry to be vague on the rise/run bit...
Sorry? Don't be. I can be pretty slow sometimes. I totally understand what you are talking about now, I had just never heard it called "rise and run" - I must have missed that name while watching "This Old House." (I never miss an episode)
re: screws; Flat head wood screws with pre-drilled and countersunk holes. Check. I know the hazards of using things like drywall screws for something like this. Don't ask me how I know.
Also, regarding the plexi pieces; I'm thinking of just replacing the top piece with wood, and only using the plexi for the front, so the end user can better see into the booth.
Just FYI, for anyone who cares: that front piece actually serves an important purpose in the design: it helps to channel the air flow more efficiently down into the bottom of the booth. Without it, the air may eddy at the top of the booth, disrupting airflow and making the blower fan less efficient.
Thanks for sharing the updated model, that'll save me a lot of time. Right now I've got to crash, but I will pick up work on this tomorrow. I'll post my progress as I get it.
See you then.
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Duncan,
I sent you a PM to see if I can help you with your questions personally.
Dave
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@unknownuser said:
Fastening MDF, particle board, or Melamine board presents a special challenge: each of these man-made materials is basically composed of wood dust in a resin matrix — there is no traditional grain structure to resist withdrawal forces. The material is all end-grain, and basically fastening into end-grain can be problematic. Fortunately, there are solutions: Confirmat (also known as Cabinet Connecting screws), RTA connecting screws in combination with barrel nuts, or very long deep threaded cabinet screws.
Confirmat screws are unique fasteners developed specifically for edge-to-face joining of particle-based products like melamine board. They feature deep threads on an oversize shank, a clearance-hole diameter shoulder beneath the head, and a head that is just slightly larger than the shoulder. Installation requires a special 3-step drill bit, but the result is a tight, strong joint. Learn more about Confirmat Screws.
RTA screws provide superior joint strength compared to Cabinet Connecting screws, but the joint construction is more “fussy.” The screws themselves have large, wafer heads, blunt tips, and machine screw threads. The screws mate with small cylindrical “barrel nuts” that have a machine threaded hole in them formed perpendicular to the barrel axis. Installation requires precise drilling of two blind holes, but the system is readily adaptable to a wide variety of materials and joint conditions.
If assembly speed is a primary consideration, simply using an extra-long cabinet screw (such as our FSL’s or ProMax
series screws) provides a low-cost alternative. When working close to the panel edge, predrilling is extremely important (even when using auger point screws), since these man-made materials are prone to crumbling. Generally, these screws are best used as permanent clamps while an adhesive is curing, rather than as a primary fastener in this application. -
Cool, thanks for that dedmin.
Progress pics soon.
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@dave r said:
Sorry, Dave, one more question that I forgot to ask the other day; Am I to assemble the corner joints as you have described here, screwing the face to edge, and then (I'm assuming) glue the corner bracing into the inner corner?
Or should I be screwing into the bracing as shown here:
Sorry for the noob question, but this is unknown territory to me. Also, I've worked out a rudimentary construction/assembly procedure, if you have some spare time, would you care to critique? -
No need to apologize. It's a perfectly valid question. Especially considering what I wrote and drew. What you've shown would be right with the corner blocking except you would want to stagger the screws vertically so they don't collide. As to gluing, glue all of the surfaces that touch each other.
Probably the easiest way to assemble the corner is to glue and screw the corner blocks to the front and back pieces so they are flush with the ends of the boards. Then glue and screw the front and back to the end panels. These things would apply to both MDF and plywood.
I'd be happy to take a look at your construction/assembly procedure.
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Hi Dave,
Check your PM for the assembly list and a link to the latest iteration of the booth model - it was slightly too big to attach to a PM.
Heh, yeah. I thought about the staggering of the fasteners just as I was posting. I'll fix that in edit.
Thanks for the clarification on the bracing. I figured that was the way to do it, but I just wanted to be sure. By the way, do you foresee any problems with screwing so close to the edge of the MDF?
It took me so long to get back here because I had a bear of a time trying to figure out the best way to mount the blower, but still make it accessible for repair in case the blower needs to be replaced or something.
I ended up going with a sort of slide out panel in the bottom of the booth. Lay the booth on it's back, slide out the blower mount, replace the blower, slide the mount back in, stand the unit back up, and you're all set - no disassembly required.
I had to rack my brain for that one. Hopefully it works the way I envision it.
Thanks again for the help.
-Duncan -
Duncan,
I like the way you mounted the blower to that slide out piece. That makes a lot of sense.
I've read through your list and looked at your latest version of the model. I think I have some ideas for you for the list and I'll write them down as soon as I can.
Since you've removed the materials from most of the model, you could delete at least the MDF texture to reduce the file size. Then you could post it here if you wish.
What format do you intend to use for the plans for this thing?
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Yeah, that MDF texture file is pretty large. I think it was being used on that section cut face which is on a hidden layer. It could be deleted as well as the hidden dimensions which aren't very useful without the section cut.
Yes, I was thinking in terms of PDF file. I would think you could do the entire thing with SketchUp and LayOut with no problems.
Well, I'm off to fix an oxygen outlet.
Cheers,
Dave
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Have you talked to John Wilkes about this?
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I'm afraid I don't know who Mr. Wilkes is, so no, I have not.
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So you were the guy in history class who looked like he was taking notes but was really doing architectural and construction doodles.
John Wilkes' Booth (The guy that shot President Lincoln).
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Doh!
Sic semper fatuus.
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@dave r said:
I've read through your list and looked at your latest version of the model. I think I have some ideas for you for the list and I'll write them down as soon as I can.
Cool. Take your time.
@dave r said:
Since you've removed the materials from most of the model, you could delete at least the MDF texture to reduce the file size. Then you could post it here if you wish.
SketchUp told me it was still in use, but I couldn't see where. No matter. I deleted it anyway - huge difference! That's a pretty big texture file, no wonder my puny little laptop was chugging! LOL!
@dave r said:
What format do you intend to use for the plans for this thing?
How do you mean? Like PDF file format, or do you mean like A3, or ArchD, etc.? I was going to output to PDF in a hybrid magazine article/shop drawing kinda thing, if that makes sense.
Basically a letter size portrait layout for the "Article" portion (the assembly procedure), with an "Appendix" of shop drawings, also letter sized but landscape oriented, if they are needed. Just so the average Joe can print the plans out on a regular desktop printer.
If you've got other ideas, I'm all ears - this is my first time, so I'm just wingin' it!
Workflow:
SketchUp->LayOut->PDF->(maybe)InDesign, if it needs a polish.Thanks for looking
-Duncan
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