Mountains of sawdust (360g plywood, LED, Arduino build)

[der_wille_zur_macht]

I chose white because it's something different. It's reflective, and I'm hoping it helps "open up" the space.

I don't intend to try too hard to keep it clean. It'll be mostly hidden anyways - the bottom will be covered with sand, and the sides will be shaded thanks to the eurobrace. I suppose over time it'll all be covered in coraline anyways.

 

[der_wille_zur_macht]

Poured the first coat in one "end" this morning. The tank had to be stood up on the ground to facilitate this:

That's a standard 48' x 18" drywall T square for reference.

 

[der_wille_zur_macht]

Oh and you can also see my really sloppy fill jobs around some of the joints in the bracing. I'll sand it all down later.

I'm proud to say that so far my joinery has passed the test of being tight. On some other plywood build threads, you read about the epoxy seeping out all over the place when it's first poured, since the joints aren't tight enough. So far, I've had one spot where it barely bled through a joint.

I also poured one end in the sump, though I didn't take a photo. I used packing tape to make a dam since there's no perimeter bracing on the sump. It looked like it worked fine. We'll see how easy it is to take off.

 

[MMERITT28]

Sorry for the newb question but how do you keep from having a seem where epoxy meets epoxy? Do you have to prep the bottom where the side pour meets it in order to get adhesion so that it does not leak there later on? Thanks

 

[johno4]

looks really nice. Im courious to see how the white will look once its done. It has the potential to look really different and nice as long as your able to keep it clean.

 

[der_wille_zur_macht]

Sorry for the newb question but how do you keep from having a seem where epoxy meets epoxy? Do you have to prep the bottom where the side pour meets it in order to get adhesion so that it does not leak there later on? Thanks

The epoxy basically cures in three stages:

1) Pot life: The epoxy is totally liquid. For this epoxy, it's around 45 minutes.
2) Setting: The epoxy starts the stage like really thick molasses. Near the end, it's more or less set, but still soft enough that you can easily dent it with a fingernail. It remains tacky. Around 12 - 24 hours for this epoxy.
3) Curing: 48 hours for this epoxy. At this point, it's solid, no longer tacky, and more or less completely done.

If you pour a new layer during the setting stage, they'll bond chemically and be as if they were one solid layer. If a prior layer sets up, you need to sand it to create some roughness, which lets the new layer form a mechanical bond.

Also, some epoxies blush (get powdery) as they set. For blushing epoxies, you need to clean the blush off and/or sand to create a good bond. This epoxy does not blush, so you can just pour before the old epoxy is totally set, and it forms a perfect bond.

So, if I time the layers correctly - between about 12 and 24 hours apart - the bond is good with no prep work. This is one of the reasons I chose this epoxy. No blush to clean up, and since it sets sooooo sloooooooowly, I have a big window to hit between layers. Also, the long pot life means I can take my time when mixing and pouring the layers.

So, I started out by pouring the bottom. I poured the last layer of the bottom last night. Then, today, I poured the first layer on the end panel. The "seam" where these two panels meet was fine with no prep work, since the top layer of the bottom was less than 24 hours old. However, when I pour additional sides, the bottom will be totally set, so I'll need to sand lightly to create a good bond. Once all the panels are poured, I'll go back and sand all the corners out pretty thoroughly, and make some nice thick fillets. This will ensure there's absolutely no chance of a leak on a seam.

Also, I used waterproof glue, and coated exterior screws. So really, the entire joint is waterproof.

looks really nice. Im courious to see how the white will look once its done. It has the potential to look really different and nice as long as your able to keep it clean.

Yeah, we'll see. I don't think I'll need too much effort to keep it clean, and I'm kind of hoping it grows in with coraline after a while, but we'll see. To give credit where it's due, I got the idea for a white interior from one of the builds on the fingerlakesreef forum. Once I saw it on that tank, I knew instantly that I would do it, too.

 

[MMERITT28]

I appreciate you taking the time to explain that to me. I am really impressed with your build skills and am looking forward to seeing this project progress. Happy New Year!

 

[kcress]

I appreciate you taking the time to explain

Ditto.

 

[der_wille_zur_macht]

No prob. I like talking about this stuff almost as much as doing it. :lol:

 

[A Reef Scene]

Do you think this process would work for a tank that is 120x48x36 with olny one viewing window?

 

[der_wille_zur_macht]

Absolutely. It would work for any size tank. You'd just have to scale the technique accordingly to be sure you have a sound structure. If you price out the materials, it's vastly cheaper than getting a custom tank built in larger sizes.

Check out fingerlakesreef.com - there's a whole subforum there dedicated to wood tanks, with several great build threads in the size range you're talking about. Or look around here - Mattshack has a ~1000g build thread you might want to check out.

 

[dahenley]

Absolutely. It would work for any size tank. You'd just have to scale the technique accordingly to be sure you have a sound structure. If you price out the materials, it's vastly cheaper than getting a custom tank built in larger sizes.

Check out fingerlakesreef.com - there's a whole subforum there dedicated to wood tanks, with several great build threads in the size range you're talking about. Or look around here - Mattshack has a ~1000g build thread you might want to check out.

Fingerlakes has a ton of wood info.

 

[der_wille_zur_macht]

Definitely. I couldn't do this project without those guys. None of the stuff I've done so far (at least in terms of construction methods) is new or groundbreaking, it's all just copying their methods.

I poured a bunch more epoxy, but no photos. My cellphone picked up the unfortunate habit of crashing and rebooting every time I use the camera. I'm tempted to "drop" it in a bucket of epoxy. I hate this freaking phone.

 

[der_wille_zur_macht]

Some more pics. This is a pretty "boring" part of the build - pouring epoxy every 12-24 hours or so - so I'll try to make it interesting. Some people have asked about the process of using the epoxy, so here are some photos.

My "mixing station:"

The epoxy vendor I used sells these handy dispensing pumps that do 1 ounce each, allowing for precise mixing. On very large batches, I'm using measuring cups and pouring, but anything under 30 or 40 ounces or so (a majority of the build) I'm using the pumps.

Once the resin and hardener are in the cup, I mix for several minutes:

I'm using cheap disposable plastic mixing pots and spatulas, but I re-use them. The plastic is handy because it's flexible and the epoxy doesn't stick to it. So, I have three sets of the mixing pots and spatulas. When I use a set, I scrape out as much resin as I can, then put it aside. When the resin on that set has cured, it kind of "peels" out:

The end result is a bunch of thin disks of epoxy, and clean tools I can re-use!

Once it's mixed, I pour it on the panel:

Then spread it with a wider spatula:

In those pics, you can sorta see two other details. First, around the openings or raw edges, I'm using clear packing tape to form a "dam" so the epoxy doesn't just pour out. This is very quick and easy, but not 100% effective. In one or two spots, I've had leaks past the tape. This isn't a big deal, it might waste 3 or 4 ounces (out of nearly 1,000 ounces of epoxy I'm using on this project!)

Here's the worst leak yet:

You can also see that the resin I was using in those batches is clear, un-tinted. I'm just tinting the final layer on each panel. No need to tint the lower layers, as they are buried.

Speaking of layers and being buried, Here's a clean edge, showing the tinted layer on top of the untinted layers. This also sort of shows the thickness. This was an edge that was taped up, so the epoxy has formed a little ridge, making it look a little thinner than it really is. It appears to be nearly 1/4" thick in this photo (the plywood is 3/4") but it's probably more like 3/16":

Anyways, another week or so of pouring and the epoxy will be DONE! Woo hoo!

 

[der_wille_zur_macht]

And one more shot of two completed sides and one bare side. Shows the final surface pretty well - smooth and glossy white, but pocked with bubbles. This was probably the bubbliest part of the tank so far:

As I mentioned earlier, once all sides are poured, I'll do fillets in each corner to make sure the seal is good.

 

[dogstar74]

Can't bubbles be "popped" using a butane lighter? If you lightly pass a flame over the bubbles, then they will pop before they solidify.

I hope someone can confirm this before you burn your whole project up.

Aaron

 

[AcroSteve]

I did that with my tank, but I used a different epoxy than willie. I used MAS and it worked fine. Just be aware that the epoxy WILL catch fire if you don't keep the flame moving.

 

[der_wille_zur_macht]

I've heard that, but haven't tried. You can also pop them by tapping them with the corner of the spatula. It's just a matter of getting them all - the bottom was especially hard because it's just so big. Some of the panels I've done since are virtually bubble-free. In the end, with three layers and more than 1/8" of epoxy, I'm not worried.

 

[der_wille_zur_macht]

I should note that I'm having the most trouble with bubbles in the pigmented layers - mostly because in the clear layers, you can see the sub-surface bubbles and do something to pop them. In the pigmented layers, you can only see the bubbles right at the surface. So, what I'm doing now is vibrating the tank much longer on the pigmented layers to get the bubbles to the surface.

 

[AcroSteve]

When I used the torch, many tiny bubbles that I had not noticed also burst.

I did not take much care when mixing my epoxy. i just stirred it fairly fast rather than very slowly.