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Building A Desk: What to do with the bottom of the cabinets and how to cover a hole

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Forum topic by lilmanmgf posted 08-07-2016 03:53 PM 508 views 0 times favorited 7 replies Add to Favorites Watch
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lilmanmgf

9 posts in 126 days


08-07-2016 03:53 PM

I’m getting ready to begin my first large woodworking project, which will be a computer desk. I am making the bulk of the cabinets out of maple plywood, with the face being made of hardwood. One thing I’m unsure of, is if there is anything special I need to do with the bottom. The majority of it will be an unfinished plywood edge. When finished it will be in a carpeted room, I was concerned that the edge may damage the veneer. One thought I had was to hammer furniture slides into the edge so the wood itself isn’t actually resting on the floor. The desk will only be 26” tall (I’m short), so I don’t want to use decorative legs and lose cabinet space. Does anyone have any suggestions on how to handle this?

One of the cabinets I’m building is going to contain components to a computer. In order to facilitate airflow I need to have holes for fans on both side panels as seen below. Does anyone have any suggestions on how to cover it. One thought I had was to use vintage speaker cloth and try to frame it somehow.



7 replies so far

View BurlyBob's profile

BurlyBob

3695 posts in 1732 days


#1 posted 08-07-2016 04:26 PM

I built a couple of bookcases using oak plywood. I glued a 1/8” strip of oak on the bottom edge of the plywood on the first bookcase and didn’t on the second. I could hear it catching on the carpet fibers as I moved it into position. In hindsight, ( it’s always 20/20, right?), I wish I hadn’t got lazy. I should have done the same on the second bookcase. Based on my experience, I’d recommend you do the same. I really wasn’t that big of a deal. Like I said I was in a hurry and got lazy. That thin strip is barely noticeable down in that carpet. It won’t detract from your project.

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JBrow

819 posts in 387 days


#2 posted 08-07-2016 05:28 PM

lilmanmgf,

The floor on which the desk will set may have slight peaks and valleys. Long straight bottom edges on the desk may rock or otherwise not set just right on such a floor. Adding feet at the corners of the plywood box would elevate the long lower straight plywood edges. Alternatively routing way the center of the long lower edges of the plywood could leave corner plywood load bearing points.

The feet could be simple ¾” x ¾” maple blocks glued to the corners of the lower plywood edges of the desk at the corners. If the edges of the maple blocks are chamfered or rounded over, the maple blocks would be less likely to catch on carpet.

If the lower center sections of the plywood are cut away leaving plywood bearing points at the corners, the edges of the plywood could be sanded smooth and finish applied. I personally sand exposed edges of plywood so that the brush applying finish to the edges does not catch and drag.

Whatever direction you choose for the lower edges of the plywood, I would personally sand the edges smooth, including breaking the plywood edges. Then I would apply finish, the same number of coats as applied to the entire project, maybe even a few more. Breaking the edges would help prevent a stray plywood splinter catching the carpet and tearing at the veneer. The finish would reduce friction and provide a little protect to the veneer while at the same time adding a little protection to the plywood should a drink be spilled near the plywood edges.

I would think the speaker fabric would block a lot of air. If speaker fabric is used to cover the holes created for air flow, larger holes would probably be needed to preserve air flow. I am sure there are covers that can be purchased to cover ventilating holes, but since these are pretty ugly, making your own covers, perhaps with narrow strips of maple half-lapped together could be built and would, in my view, look nicer. Alternatively, an open louvered design, could hide the holes but would be more difficult to build.

A completely different approach to solve the ventilation problem would to be to alter the design for the back. The back could be reduced in height. The back could then be installed while holding the lower edge up from bottom shelf by ¼” – 3/8” while also holding the upper edge of the back down from the top by the same amount. This would produce an air slot at the top and bottom and promote circulation. Since it is at the back, it would go unnoticed. Even with the back exposed to view, the top would conceal the upper channel while the lower channel would be seen as a black line. No covering would be required.

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bondogaposis

4036 posts in 1818 days


#3 posted 08-07-2016 05:50 PM

Build a plinth for the base. Think about it, that plywood veneer is going to take a beating right at the carpet line from the vacuum cleaner. If you ever try to slide the desk, the veneer will catch on the carpet and could easily tear.

-- Bondo Gaposis

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clin

514 posts in 463 days


#4 posted 08-07-2016 06:35 PM

No matter what, I would finish the bottom edge. Very slight rounding over the edge and applying finsign would help a lot. Iron on edge banding would go a long way to.

I would however, put feet on it. You could put adjustable feet up inside the face frame and sides. So the feet are attached to the bottom. Make sure the bottom is well attached to the sides (dado for example). You could adjust the height of the feet to just hold the sides off the floor. You’d never see the gap in carpeting, and even on a wood or tile floor, you could keep the gap so small you’d never notice.

As for venting, if you are NOT using a fan to force air into the space, you need to rely on convention. In that case, you want to have an opening down low on one side, and up high on the other side. As the air warms it will flow out the top.

I would not let the warm air flow into the leg compartment (must be a name for that). It might make it uncomfortable in the summer. Though would be a plus in the winter.

You could easily put a vent down low, inside the leg compartment, it would be hardly noticeable. That would require the top vent to be on the side or probably better the back since computer usually exhaust air towards the back.

Up to you what that vent would look like. That’s a design choice. Obviously the more open the better.

Now, I would seriously consider forced air venting (putting a fan on the cabinet). Computers can draw a few hundred watts. This can really heat up a small enclosed space like this. Heat is bad, bad, bad for electronics.

I used some fans from these guys to cool the cabinet I have all my TV, XBOX, Blu-Ray player etc in. Very quiet and on a thermostat, only runs when needed.

Obliviously you can make whatever grill you want, even the fabric idea (very open weave fabric).

They have a LOT of options. I’m just showing one that they sell with a wood grill. I use ones powered by small AC-DC power supplies that have a temperature sensor input for thermostat control.

https://www.coolerguys.com

If you use a fan, you want to get cross ventilation, but if the door on the cabinet doesn’t fit tight. For example, has little bumper on the door (common on cab doors), a 1/16” gap all around the door, would be enough for the fan to draw air in. No need to add a specific intake vent. These fans don’t move a lot of air, but still way, way more than passive venting would do.

-- Clin

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lilmanmgf

9 posts in 126 days


#5 posted 08-07-2016 07:14 PM

I was planning on using forced air. The green piece on either side is something I am having 3D printed which can hold 4 120mm fans. I like the idea of louvers but was concerned making them may be too difficult. I’ll look into them again.

In terms of leveling feet, I was looking at these as a possiblity:
http://www.rockler.com/adjustable-corner-support

I was planning on using pocket screws and glue to attach the bottom of the cabinet.

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clin

514 posts in 463 days


#6 posted 08-07-2016 10:05 PM



I was planning on using forced air. The green piece on either side is something I am having 3D printed which can hold 4 120mm fans. I like the idea of louvers but was concerned making them may be too difficult. I ll look into them again.

In terms of leveling feet, I was looking at these as a possiblity:
http://www.rockler.com/adjustable-corner-support

I was planning on using pocket screws and glue to attach the bottom of the cabinet.

- lilmanmgf

Those type of leveling feet would seem to work well.

I’m a fan of pocket screws, but here are some things to consider. Some won’t apply if you use those Rockler feet, but I’ll mention it in case you go a different route.

The feet you show put the weight onto the side/back or side/face-frame. Face frame would rely on support from the bottom. I think it would be fine, but is probably the weak point in these (though, not necessarily too weak).

If you chose feet that attached to the bottom panel, then the weight of the desk is carried by the bottom panel to side/back joint. This is where pocket screws alone, would NOT be a good choice. Again, I get that those Rockler feet attached to the sides, not the bottom.

Of course, even if the bottom doesn’t carry the desk weight, it will carry the weight of anything you put on it. Therefore a cleat under the bottom and attached to the side/back would help to support the bottom and any weight put on it. This of course is not an issue for feet that attach to the bottom.

On the other hand, if you do have the feet attach to the bottom, then the weight of the desk is on the bottom to side/back joint and in this case pocket screws would be iffy. In this case I would put cleats on top of the bottom panel. Desk weight goes on to cleat, then on to the bottom and finally the feet.

Bottom line, is pocket screw joints remove a lot of meat from the panel. For example, if it were 3/4” plywood, you would have about 5/16” of plywood to either side of the screw and depending on plywood quality, the screw could tear through. of course this all depends on how many screws, total weight. Does your overweight brother-in-law sit all his weight on the corner of the desk, so on and so forth.

All this may be things you are well aware of, but I mention it for the sake of completeness.

As to 4 fans, I think this overkill. But it does depend on how much power you figure is dissipated in that compartment.

If blowing warm air into the leg compartment doesn’t matter, and of course this air would only be slightly warm, then you could put the fans on the leg side, and as I mentioned, if the door doesn’t fit tight, you could avoid having a dedicated intake. The desk would then not have any obvious air ventilation openings. Of course if you run 4 fans, than this may not be enough area to not overly restrict the fans or maybe even cause audible air noise.

-- Clin

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skatefriday

380 posts in 949 days


#7 posted 08-08-2016 01:48 AM

I recognize that autodesk appearance pattern on that model.

Why do you have the spreaders on the back?

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