Questions on wood thermal properties


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Hey everyone,

I just found this forum and I have high hopes about the information that I can pick from everyone's brain. So, a little about me. I am relatively new to woodworking proper, but I am not new to modding and creating various widgets, gizmos, and thingamajigs. Most recently some friends and I built a 3D printer, but I have only recently started my own woodworking projects. I am a student studying mechanical engineering and an avid PC gamer. A super nerd that loves to work with my hands and create things. I have been tossing around the idea of creating a beautiful hardwood case for a water cooled computer that has been germinating inside my head for over a year, and it is about time it break free form my skull into a physical manifestation, but I need your help. Why? Because I will be combining wood, heat, electricity, and water into a rather small box.  What could go wrong?

I have a firm grasp of the electricity and water when it comes to computers (something like this), but it's the wood and heat that I could use some input on as I know wood likes to expand and contract with varying humidity and temperature. Another consideration is vibration dampening from the fans so the case does not turn into a resonance chamber. I really like my computer silent. I guess the easiest way to lay this out would be to outline the design goals and constraints pertinent to the thermal properties

  • Design Goals
    • Elegant design with soft, rounded edges and smooth transitions (Thinking about kerf bending some of the corners)
    • Windowed side panel to see internal components
  • Design Constraints
    • Thin walled construction ≤ 3.4" Ideally ≤1/2"
    • Withstand frequent temperature fluctuation between 20 - 52 C (68 - 125 F)
    • Vibration dampened interface with computer components

So what types of wood should I use and what should I avoid? Is there a particular sealant I should use that is best suited for temperature extremes? Are there specific geometries that do not take kindly to temperature extremes to avoid? Etc. I have some ideas of my own, but I would like some outside input to make sure I am not overseeing anything.  As for tools at my disposal, I have a 10" Miter saw, router, circular saw, scroll saw, jig saw, drill, various hand tools and access to a table saw, jointer and planar as well as other tools at my friend's garage shop.

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No expert here, but based on your design goals and constraints I'd say your best bet is to veneer an exterior grade plywood, or fire rated plywood. I would do a small sample and subject it to the enviroment it will live in for a few months to see how it holds up. Assuming this will be vented, you can line the inside of the plywood with a heat reflective material such as teflon. I would look into construction adhesives for assembling the plywood. 

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I agree that some sort of plywood is best for this application.  It's not that wood doesn't like heat (to a point) but rather wood expands and contracts based on it's moisture content. Warmer air can carry more moisture and you are moving a lot of air to cool the electronics. This could dry (and shrink) your wood pretty significantly. Also, the advantage of metal cases is that they help to conduct heat and wood is a fairly good insulator so you may need to move more air - kind of in opposition to your silent PC desire.

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I don't think heat will be an issue, but humidity might be. Also, I would coat the interior with a conductive material and ground it to shield against EMI / RFI. Stewart Macdonald sells a conductive paint for shielding the control cavities of electric guitars, or you can glue in ordinary aluminum foil. As for noise, the wood itself will help to some degree, and you can use rubber or neoprene washers and spacers where the PC components attach to the wood. Personally, I would build the PC in a standard tower case, then make a wooden box to replace the exterior shell. Maybe even one that simply covers or adheres to the shell.

One tip for a tough, clear adhesive - Shoe Goo ™ is awesome stuff. Great for joining different materials, and remains a bit flexible after curing. Use regular wood glue for the wood to wood joints.

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Lexcel caulk works well with dissimilar materials as well.

My only concern is water in a cooling system usually finds a way to leak sooner or later and no matter how,well you seal wood moisture will find a way in. Maybe a plastic tray instead of a wooden bottom ?

1/2" Baltic birch may be a good case material then use a waterproof glue like Titebond 3 to veneer it.

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Having built several liquid-cooled towers, I'm familiar with the genre... Maintaining wooden boats gives me some experience with waterproofing wood... So, my 2c:

I'd use marine plywood and veneer something nice on the show surface for aesthetics... You can kerf-bend 1/2" marine ply fairly easily... Heat is no problem... Humidity will be fine... If you want a really sexy case, you can go aviation bending plywood (the stuff used for the interiors of custom private jets), but it's really expensive...

I'd use 3M's marine sealant (5200 series) for calk

I'd use West Systems laminating epoxy (105/207) on the interior for when you spring a leak -- or forget to connect a hose (like I did once) and wondered why it was taking soooooooo much coolant to fill the loop.... And of course, I was using Koolance's HP coolant (in blue), so it was both messy and expensive... Note: it took several years for the blue tint to wear off my assembly table, but that's another story...:)  And you guys wonder why I don't do shop tours... :)

 

 

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57 minutes ago, hhh said:

And of course, I was using Koolance's HP coolant (in blue), so it was both messy and expensive... Note: it took several years for the blue tint to wear off my assembly table, but that's another story...:)  And you guys wonder why I don't do shop tours... :)

Make sure you use green next time you leak it.

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==>Make sure you use green next time you leak it

Only if I get a paid sponsorship... :)

After a couple of years, the bright blue worn dull to ghostly blue haze --- I couldn't take it anymore, disassembled the table and ran the top through the sander...

Unfortunately, this sort of thing is an all too common occurrence in my shop... There is usually some sort of large stain somewhere... It just seems to happen... The worst was a gallon of #2ct super blonde hitting the floor, splashing several stationary tools and leaving an enormous puddle -- now that was a cleanup nightmare... :)

Scratch that, I once dropped a spray gun into a large pail of bright yellow two-part marine epoxy paint, then in my haste, managed to kick the pail... I hope never to top that.. :)

 

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3 hours ago, hhh said:

==>Make sure you use green next time you leak it

Only if I get a paid sponsorship... :)

After a couple of years, the bright blue worn dull to ghostly blue haze --- I couldn't take it anymore, disassembled the table and ran the top through the sander...

Unfortunately, this sort of thing is an all too common occurrence in my shop... There is usually some sort of large stain somewhere... It just seems to happen... The worst was a gallon of #2ct super blonde hitting the floor, splashing several stationary tools and leaving an enormous puddle -- now that was a cleanup nightmare... :)

Scratch that, I once dropped a spray gun into a large pail of bright yellow two-part marine epoxy paint, then in my haste, managed to kick the pail... I hope never to top that.. :)

 

Can we crowdfund a live stream of trip in his shop?

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==>Make sure you use green next time you leak it

Only if I get a paid sponsorship... [emoji4]

After a couple of years, the bright blue worn dull to ghostly blue haze --- I couldn't take it anymore, disassembled the table and ran the top through the sander...

Unfortunately, this sort of thing is an all too common occurrence in my shop... There is usually some sort of large stain somewhere... It just seems to happen... The worst was a gallon of #2ct super blonde hitting the floor, splashing several stationary tools and leaving an enormous puddle -- now that was a cleanup nightmare... [emoji4]

Scratch that, I once dropped a spray gun into a large pail of bright yellow two-part marine epoxy paint, then in my haste, managed to kick the pail... I hope never to top that.. [emoji4]

 

Can we crowdfund a live stream of trip in his shop?

Sounds entertaining enough to justify a Youtube Red subscription!

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I was also thinking of using plywood or MDF with a relatively thicker veneer (approx. 1/16" to 3/32" ) and using a quarter round to supply a nice corner, but would that bee too tight of a corner?  Is there a way I can make something similar to a quarter round with a more gentle curve?

What do you all think about using a quarter round as the backing for the corners to bend the veneer around?  It would provide a solid backing, and I could build the case and test everything before applying a veneer.  More food for thought: What about form bending to make my own "plywood"?

As for the computer stuff, I was thinking of using a thin rubber sheet  all along the inside to dampen vibrations so they don't resonate through the wood and to provide a water barrier with black caulk around the seams. This would give the inside a nice blacked out look for the internal components to shine when illuminated with a LED strip. I also realized something unique to water cooling that may remove the heat almost entirely from the equation: I am mounting radiators at the exhaust so the heat exits the case immediately and doesn't stir around inside. Regarding grounding am not too concerned as everything will be connected via the power supply which is grounded. 

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