BiscuitSlayer's 75 Gallon Stand and Canopy Build Journal... 56K Beware!

[BiscuitSlayer]

Originally Posted by intermediate_noob

So wow that is confusing without a picture. I will try to post one tonight. Basically all I was saying is that with a single GFCI, if it trips, everything goes down. I added a secondary precaution to keep my pump and heater going. Thoughts on this?

My thoughts are that you thought it out better than I did. By making two different circuits as you did, you are less likely to have a complete outage. Nothing wrong with overdoing electrical at all with regards to splitting things up and minimizing your points of failure.

I might add another GFI now and tie it into the switch I am going to use for the filters and heaters.

Actually, it would probably be OPTIMAL to have two seperate circuits for each filter and heater. That way if there was a ground fault on one circuit, the other would remain up and running.

Very good points.

[Sandman333]

Originally Posted by BiscuitSlayer

Essentially it is not an afterthought. The whole point is that you don't want the load of the tank, water, substrate, etc. to be transfered through the floater to the floor. You would effectively be taking all of that weight and transfering it to your floor rather than evenly transfering it to the lower frame (which covers more area).

If it doesn't make sense to you now, read the original link to Intermediate_Noobs thread at the top of mine. From there it will take you to the reef central threads where this design was originally thought of.

It is definately not an afterthought. I originally thought like you do, but now I am a believer.

In addition to this, if the 2x4 was only touching on the top OR the bottom, the screws securing the 2x4 to the rest of the frame will be taking the entire load of the tank. Screws are very weak in this direction (shear force) and they are very likely to break. The way the stand is built, the only shear force that the screws have to withstand is the weight of the 2x4 itself.

[rolloffhill]

Originally Posted by Sandman333

In addition to this, if the 2x4 was only touching on the top OR the bottom, the screws securing the 2x4 to the rest of the frame will be taking the entire load of the tank. Screws are very weak in this direction (shear force) and they are very likely to break. The way the stand is built, the only shear force that the screws have to withstand is the weight of the 2x4 itself.

So you're saying that the 2x4's inbetween the top and bottom frames aren't transfering the load of the tank from the top frame to the bottom frame to the floor?

I don't see any flaws in the design at all, the top frame is supported by the bottom frame to the floor via the corner 2x4's. But I still don't see why the floater cannot make contact with the floor at all. Regardless of whether they touch the floor or not, the brunt of the load is distributed through the corners.

I don't disagree that the design is a good one, I just don't understand/agree that the "floaters" cannot touch the floor. I do agree that the "floaters" are there to keep the corners secure. In the original design the OP didn't state the use of ply on the top of the stand.

So back to my original statement, since you skinned the top with ply, that will distribute the weight as well as the "floaters" had they made it the full length and made it to the floor.

Additionally, if you were to skin the sides of this stand with 3/4 wood it would essentially be doing the same thing as the "floater" had it gone to the floor.

Majority of stands that are sold are nothing but 3/4" ply slapped together and they hold the weight of the tanks just fine. I personally don't like those stands as I tend to overbuild things myself.

I basically built mine the same way but didn't have the priveledge of finding a thread to give me cut sizes but it looks like a well built stand. I did the corners similarlly but my floater goes to the ground and there is also 3/4" pine that wraps the 2x4 frame. I also put on 3/4" ply on top over all of the main structure, and then put trim around all of that. I also added an additional 1/2" foam on top for extra piece of mind. This was for a 215g Oceanic with 3/4 glass, 3-400#'s sand, 100+#'s holey rock and water.

So that said, I think you did a nice job BS!!!

[eds]

Originally Posted by BiscuitSlayer

You would effectively be taking all of that weight and transfering it to your floor rather than evenly transfering it to the lower frame (which covers more area).

Okay - that makes sense to me. So instead of the weight being primarily on the 4 corners, this sort of spreads it out more to the entire bottom frame. Would it have distributed the weight better/worse/same if you had placed the floaters nearer the center of the horizontal span?

Apologies - I'm just a dumb lawyer, and know nothing about forces and such.

[eds]

Wow! That other thread is something! Made it thru the first 3 pages and then read the last. Bookmarked it for when I intend to build a stand next year or so. Will go back to finish it when I wish to avoid more work...

In the first 3 pages they mainly call the "floaters" screw strips, and describe them primarily as providing ease of construction.

Like I said, I know nothing about physics or engineering. My main concern is not simply overbuilding and ending up with something that is tremendously heavy but not correspondingly strong. Not sure how big a tank I'll go with - 90, 120, or bigger.

[BiscuitSlayer]

Originally Posted by rolloffhill

So back to my original statement, since you skinned the top with ply, that will distribute the weight as well as the "floaters" had they made it the full length and made it to the floor.

Additionally, if you were to skin the sides of this stand with 3/4 wood it would essentially be doing the same thing as the "floater" had it gone to the floor.

Majority of stands that are sold are nothing but 3/4" ply slapped together and they hold the weight of the tanks just fine. I personally don't like those stands as I tend to overbuild things myself.

I basically built mine the same way but didn't have the priveledge of finding a thread to give me cut sizes but it looks like a well built stand. I did the corners similarlly but my floater goes to the ground and there is also 3/4" pine that wraps the 2x4 frame. I also put on 3/4" ply on top over all of the main structure, and then put trim around all of that. I also added an additional 1/2" foam on top for extra piece of mind. This was for a 215g Oceanic with 3/4 glass, 3-400#'s sand, 100+#'s holey rock and water.

So that said, I think you did a nice job BS!!!

rolloffhill -

I didn't have to use the 1/2" ply on top of the stand. I did that more or less to secure the upper frame from any kind of a shift. It will distribute the load exactly the same way as if I hadn't used it. I too plan to use a foam bed for the tank. I just wanted something for the foam to rest on without sagging in the middle below where it doesn't make contact with the lower frame of the tank or glass.

I would imagine that skinning the stand with 3/4" ply would support weight as you have suggested. I can't really comment on how it would work as I have never tried it.

If you to run the 3/4" ply to the lower frame similar to the floater, I would imagine that it would distribute the weight very evenly to the entire lower frame. You are right about the stock stands sold in retail stores. They are exactly as you described. They do handle the load very well, or they wouldn't use/sell them. I personally did not want to go that route because I believe in a strong frame design with the ply as more of a decorative look rather than for load bearing purposes.

Thanks for your comments and praise!

Originally Posted by eds

Okay - that makes sense to me. So instead of the weight being primarily on the 4 corners, this sort of spreads it out more to the entire bottom frame. Would it have distributed the weight better/worse/same if you had placed the floaters nearer the center of the horizontal span?

Apologies - I'm just a dumb lawyer, and know nothing about forces and such.

Eds -

No apologies necessary. You can use center braces, but it isn't necessary based on the frame design. A four foot stand design suggests you can use 2 X 4s without a center support between the upper and lower frames. It is suggested that stands up to 6 feet merely require a shift to an upper frame using 2 X 6s. Stands up to 8 feet would require a shift to 2 x 10s on the upper frame. All of the frames are designed not to use supports as center braces. I on the other hand would use a center brace on the larger stands (More than 4 feet) just as a precautionary measure. I would probably also change the legs to use 2 X 6s rather than stock 2 X 4s, although it is suggested that the lateral strength of a 2 X 4 is something like 17,000 lbs before it will buckle.

If I were to build a larger stand for a larger tank, I would do things a bit differently as I have suggested above. I would also include a center support brace. I did not think that the 75 would require this type of support.


Good questions guys. There is nothing wrong with questioning a design. Occasionally someone will find a flaw or a better way of doing things, and there is absolutely nothing wrong with that.

If anyone else thinks I have left anything out with regards to explaining things, feel free to chime in.

We could take these types of questions to intermediate_noobs thread too. That is where the main discussion about the frame design is taking place.

[BiscuitSlayer]

Originally Posted by jinx©

The wide prong side of your plug would get wired to the silver terminals/white wired/neutral side if that makes sense.

Look at the face of your outlet. If you were to plug it in the outlet, the wide pronged side of the outlet has the silver terminals/neutral (white) wires correct?.

Jinx -

You were dead on brother. I wired it up with the prong side on the netrual side of the switch and the other side (which also had writing on it) on the hot (black) side. The switch now controls the cabinet lights perfectly.

[plaakapong]

Don't want to beat a dead horse but, for the sake of clarity(I hope), the "floaters" don't need to "float". In the design they are acting as connectors and not structural members. If the"floaters", or a plywood skin, were applied to the structural frame to the same horizontal plane as the frame(top and bottom) they would all become part of the structure without problem. There would be no shear on the screws.The problem would occur if any of these were proud of the structure, higher or lower, then they would bear the weight.

[eds]

Like I said, I intend to build a stand for a decent-sized tank within a couple of years. My main worry is I'll basically say - let's add another support here, and let's substitute 2x6s for the 2x4s just to be safe - and end up with some monster that requires that I rent a forklift and knock out a couple of walls to get it from wherever I build it into it's final location!

[plaakapong]

^^ In the first set of kitchen cabinets that I built, about 25 yrs ago, I built a string of the uppers together as one. Maybe 8 ft. long! Don't remember why? Didn't know any better I guess. Anyway when I got them to the house they wouldn't go in the door! Had to take out the picture window in the front of the house to get it in!! Fortunately the people were my friends and they wanted to replace the old window anyway.

[rolloffhill]

Originally Posted by plaakapong

Don't want to beat a dead horse but, for the sake of clarity(I hope), the "floaters" don't need to "float". In the design they are acting as connectors and not structural members. If the"floaters", or a plywood skin, were applied to the structural frame to the same horizontal plane as the frame(top and bottom) they would all become part of the structure without problem. There would be no shear on the screws.The problem would occur if any of these were proud of the structure, higher or lower, then they would bear the weight.

Yes, that was the point I was trying to make too. At least I'm not crazy...

[BiscuitSlayer]

Originally Posted by plaakapong

Don't want to beat a dead horse but, for the sake of clarity(I hope), the "floaters" don't need to "float". In the design they are acting as connectors and not structural members. If the “floaters", or a plywood skin, were applied to the structural frame to the same horizontal plane as the frame (top and bottom) they would all become part of the structure without problem. There would be no shear on the screws. The problem would occur if any of these were proud of the structure, higher or lower, then they would bear the weight.

Originally Posted by rolloffhill

Yes, that was the point I was trying to make too. At least I'm not crazy...

The light bulb went off in my head! I think...

I believe what you are saying is that the floater remains a floater regardless of what length it is as long as it is level with the top of the upper frame and bottom of the lower frame. Since you are still using outer legs that support the full weight of the tank, it doesn't matter with regards to the fear of the screws shearing or weight being transferred through the inner legs because the inner legs still don't really support any of the actual weight as long as they are exactly equal and don't extend past the upper or lower frames. Am I correct with what you guys are saying? If so, I am leaning towards agreement.

One of the things that might have been a factor for the design is to insure that the floaters don't extend past upper plane or lower plane. This concept might have been to take added length out of the picture. If someone were building the stand and they happened to make one of the inner legs (or two, or three) slightly too long, then it could lead to the stand not being level or a single point of contact with the floor that carries the load rather than properly distributing to the lower frame. I don't know what the cause was for the frame design. I am merely speculating at this point.

Using the floater as a shorter cut 2 x 4 did make putting the whole thing together easier though. All 8 of the outer legs were cut exactly to 18 inches (for my stand), and the inner floaters were all cut to a length that I can't remember. My goal was to join them to the upper frame first since it was more true than the lower frame. Since I used 2 x 6s (that are actually more like 5 1/2 inches wide), I measured the floater at 5" and struck a line on 4 of them. I then used this line to line up my edge of 4 of the outer legs and screwed them into place. Then I joined the floater with one outer leg attached to the upper frame, and there was a 1/2" gap between the top of the upper frame and the top of the floater. Attaching the lower frame was also very easy. Since there was only way it could fit, I put it in place and screwed it down. Then I attached the other 4 outer parts of the legs, and it was done.

One possible reason for the design might have been for ease of assembly. You don't have to be nearly as precise when the floater length is shorter than one that would be the full height. As long as the cuts for your 8 outer lengths are exactly precise, you really only have to figure out how much space you want to float. As long as you are close, it doesn't really matter.
Are we on the same page now?

[rolloffhill]

I think so!!

[intermediate_noob]

Going back to the original post on Reef Central (can be found here) the author states the following with regard to the "floaters":

*The green pieces are screw strips. These provide limited load strength but serve to make assembly easier and help keep the stand square.

The author goes on to say this:

The reason the screw strips are shorter is that it prevents them from being part of the load bearing structure. Because they sit above the bottom frame you are assured its the frame sitting on the floor, not the screw strips. They are below the top surface to ensure that plywood or the tank frame sits directly on the upper box, rather then on the screw strips.

<Another user> So by making them shorter, you ensure the screws aren't load bearing. Otherwise, you run the risk that the actual load bearing posts are too short and aren't actually supporting the weight. I understand the principle. I found it easier to build the stands with the fastening posts the same height. I won't have the need to build another stand until probably February. I'll play with it then.

Yep, you just don't want them (the screw strips/green pieces) touching the floor when the tank weight is on them. A small piece of 3/4" plywood or 1xwhatever will shim/hold them up while screwing into them and fall off once the stand is picked up. I might suggest cutting the screw strips an inch longer if you're only able to shim them 1/2" off the floor instead of a full inch so there is plenty of material to screw the top frame into place.

So once again, the "floaters" as we are calling them only serve the purpose of squaring the stand and making sure that it is easier to put together. Anything can be used, I think 2x4s happened to be what the author had. Also, I believe they are shorter to remove the "fudge factor" where the floaters extend too far past the bottom or top of the stand and end up bearing all or most of the weight. This could lead to catastrophe. My apologies, but I think someone might have said this before. Bottom line, you shim them up to make 100% sure they do not extend past the top or bottom.

Since some of us are going to use a pocket hole jig for attaching the members together, I wonder if these screw strips even become necessary at this point. Especially if the stand will be skinned with plywood. It will be something I will check out when I build my stand this weekend.

Just on another note Biscuit, with regard to the plywood top you used on your stand. From what I read (and I am not an expert), most people use the plywood top only when using flat bottom tanks such as rimless or acrylic tanks to spread the load. With the All Glass or other tanks that have a rim or trim piece, the full top is not necessary because the bottom glass never sits on the stand, only on the trim which sits on the edges.

Anyway, once again my two or twelve cents worth. Great work. Any new pictures so far?

[BiscuitSlayer]

Originally Posted by intermediate_noob

Just on another note Biscuit, with regard to the plywood top you used on your stand. From what I read (and I am not an expert), most people use the plywood top only when using flat bottom tanks such as rimless or acrylic tanks to spread the load. With the All Glass or other tanks that have a rim or trim piece, the full top is not necessary because the bottom glass never sits on the stand, only on the trim which sits on the edges.

Anyway, once again my two or twelve cents worth. Great work. Any new pictures so far?

Thanks for the input IN. With regards to the ply, I agree with you. The main reason why I added it was to keep as much dripping out of the stand as possible. I also wanted to keep the foam bed going under the tank from saging into the cabinet space.