The Blue Window - 500 G in wall, never ending build

[Dennis Cartier]

I am using the walk platform to do double duty as both access for me and to support the rails that run along the top of the tank.

I built a jig to help measure the lengths of extrusion needed. They all ended up different sizes as it turns out, the tank is level, but the floor where the platform is installed rises a fair bit over its length which I had to account for to get the supports to match up.

Here is a close up of the measuring jig in use.

The supports and top frame are in place here.

You can also see the first attempt at a lifting mechanism for the light rail. The carriages on the uprights on each of the four corners work great, but the pulleys were not great. More updates on this front later.

Dennis

 

[328 reef]

I am using the walk platform to do double duty as both access for me and to support the rails that run along the top of the tank.

I built a jig to help measure the lengths of extrusion needed. They all ended up different sizes as it turns out, the tank is level, but the floor where the platform is installed rises a fair bit over its length which I had to account for to get the supports to match up.

Here is a close up of the measuring jig in use.

The supports and top frame are in place here.

You can also see the first attempt at a lifting mechanism for the light rail. The carriages on the uprights on each of the four corners work great, but the pulleys were not great. More updates on this front later.

Dennis

Love the build!!! Following..

 

[Dennis Cartier]

Ok, let's get into the light rack lifting system. My original plan, which you can see in the last photo above, was to have some pulleys mounted along the top rail that would lift the light rack from the centre braces at 4 points along the light rack. I was using some hardware store cord. With no lights on it, and being hand pulled, it was just OK. One thing that concerned me, was what would happen should the lifting cord(s) break. I got a first hand look at this scenario when the pull cord slipped out of my hand and the light rack came crashing down against the stops. One stop was knocked off the vertical rail, probably due to not being tight enough, but the force that was released gave me reason for concern. This was with an empty light rack with no lights. With a couple hundred pounds of lights, a similar event would have been even more serious.

My first re-think of the lifting system was to switch to kevlar kite cord. The kevlar based cord had a breaking strength over 2000 lbs, so a couple hundred should be fine. I also took this opportunity to "improve" the pulley arrangement. I removed the pull cord that operated on a sliding clip that slid along the 2 sides of the pulley system and went with a single line that ran the length of the light rack and was routed through pulleys and a central mounted winch to take up the cord from the center.

You can see the pulley system below.

The results were, fairly terrible. The new arrangement using a single cord made the motor driven linear actuator I had planned on using unusable due to the length of travel of the new pulley arrangement. The solution to the insufficient range of the actuator was to move to the manual winch. Lifting with the winch was less than confidence inspiring. When testing the previous pulley arrangement manually, all the actions happened at once and rather quickly. Any deficiencies were obscured by the speed of the action. Using the winch was like watching paint dry, thik, thik, thik, thik, all the while the light rack slowly creeping upward while shaking and shimmying this way and that, while the small pulleys whined and screeched. it was not the end result that I was looking for.

All this was with 1/3 of the lights I plan to use set into place temporarily. Once the light count tripled, the rickety operation would likely be more pronounced.

The first order of business is to re-think the lifting system, hopefully with more robust, quieter pulleys and with some safety against unplanned descents. I have some parts arriving today with DHL that will hopefully help in this regard.

Dennis

 

[328 reef]

I was thinking of using a round pully like what is on a car crank shaft, hooked to a motor in turn which would turn the long cable up. My mom used a small Whench to pull the top of her car off. I hope this helps.

 

[328 reef]

So looking at the picture above, I would install a small electric winch on the back wall close to the ceiling( the unpainted part) and install another pully on end off light rack, then cable up to winch on ceiling.

 

[Dennis Cartier]

So looking at the picture above, I would install a small electric winch on the back wall close to the ceiling( the unpainted part) and install another pully on end off light rack, then cable up to winch on ceiling.

Hmm, I never really thought of installing an actual electric winch. I went in a different direction, but if that does not work out, than I can always look into the electric winch idea. Thanks.

Probably overkill, but I want the light rack to glide up and down, especially the down part.

Here is what I have planned. I have 2 x 500mm pneumatic double acting cylinders, along with the supporting fittings and a 3 position 5 way valve, speed controllers, etc. All the pulleys are being upgraded to larger stainless, ball bearing pulleys. The rigging will also be greatly simplified, and I plan to use either aircraft cable (not sure about its corrosion resistance), or some other heavy duty rope. The way I am planning to arrange it, while the light rack is lowered in a resting position, the rod of each cylinder will be fully retracted to protect it from the salt air. The cylinders would only be under pressure when the light rack was lifted for tank access.

It would have been cool to use pneumatic cylinders to directly act on the light rack, no pulleys or rigging, but I was concerned about lateral forces being applied to the cylinders and hastening their wear.

Each cylinder is capable of lifting 251 lbs @ 130 psi, so I should be good even if I operate them at a lower pressure.

Dennis

 

[Dennis Cartier]

I was supposed to cut the grass today, but where is the fun in that? Far more fun to install and test the pneumatic light rack lifter. I started on this last night and got it far enough along for testing this afternoon.

I mounted the new pulleys on the four corners. These pulleys are much more suited to lifting the light rack than the cheap little Home Depot ones I tested before this.

The pneumatic cylinders are mounted along the ceiling, up and out of the way. Each cylinder lits one end of the rack.

The pneumatic lines are installed here, along with the 5 way valve.

Finally, a video of the unit being raised and lowered.




After testing it out, I found that it is very sensitive to differing weight, end to end. I had 1 row of 3 HD26 lights placed on one end of the rack without the matching set at the other end being present, and the ends lifted at different speeds causing some racking to occur. I am using a single speed controller for the up and another for the down. If I were to install 4 speed controllers, at the cylinder end instead of after the valve, I could probably adjust away the racking. However I have dealt with the same issue in the past for DIY CNC machines. In those cases, to keep a gantry parallel, a moving knot system was employed. I have 4 extra pulleys on hand, so I will see about setting up a moving knot system to keep the light rack level, even when the weight distribution is uneven.

Dennis

 

[User]

I was supposed to cut the grass today, but where is the fun in that? Far more fun to install and test the pneumatic light rack lifter. I started on this last night and got it far enough along for testing this afternoon.

I mounted the new pulleys on the four corners. These pulleys are much more suited to lifting the light rack than the cheap little Home Depot ones I tested before this.

The pneumatic cylinders are mounted along the ceiling, up and out of the way. Each cylinder lits one end of the rack.

The pneumatic lines are installed here, along with the 5 way valve.

Finally, a video of the unit being raised and lowered.




After testing it out, I found that it is very sensitive to differing weight, end to end. I had 1 row of 3 HD26 lights placed on one end of the rack without the matching set at the other end being present, and the ends lifted at different speeds causing some racking to occur. I am using a single speed controller for the up and another for the down. If I were to install 4 speed controllers, at the cylinder end instead of after the valve, I could probably adjust away the racking. However I have dealt with the same issue in the past for DIY CNC machines. In those cases, to keep a gantry parallel, a moving knot system was employed. I have 4 extra pulleys on hand, so I will see about setting up a moving knot system to keep the light rack level, even when the weight distribution is uneven.

Dennis

THats awesome! I’m doing the same with linear actuators. I didn’t one in my last house for a ceiling kayak lift in the garage and it worked awesome for like a 150lb load.

Once your lights are up for real- will there be any uneven weight distribution? If there’s is, couldn’t you just add ballast to the lighter points to even it out instead of more pulleys?

 

[Dennis Cartier]

THats awesome! I’m doing the same with linear actuators. I didn’t one in my last house for a ceiling kayak lift in the garage and it worked awesome for like a 150lb load.

Once your lights are up for real- will there be any uneven weight distribution? If there’s is, couldn’t you just add ballast to the lighter points to even it out instead of more pulleys?

Thanks. My original plan was to use a linear actuator. I have a 450mm that I purchased for this project, but then decided to try pneumatic instead.

The loading should be fairly even. I will have the same number of lights on each end of the rack, 11 x Ai 26HD per end. I am still going to test out the movable knot to see how well it addresses the off balance issue, should it be off balance.

Dennis

 

[Dennis Cartier]

Ok, the results are in. The movable knot system totally compensates for differences in balance. With the extra 3 lights placed on the rack to off balance it, the rack lifts very flat. Previously the lighter side would be 4-6" ahead of the heavier side. I am planning to keep it in the design.

The movable knot system is comprised of 4 pulleys, all attached to the rack. A line runs from the bottom of an upright, over the pulley above, over to and under the far end pulley, and then is attached to the top of the upright. A second line mirrors the first.

... and a video of it operating using the movable knot to prevent racking.




All in all, I am impressed that it works so well, and that I remembered how to set it up.

Dennis

 

[User]

Ok, the results are in. The movable knot system totally compensates for differences in balance. With the extra 3 lights placed on the rack to off balance it, the rack lifts very flat. Previously the lighter side would be 4-6" ahead of the heavier side. I am planning to keep it in the design.

The movable knot system is comprised of 4 pulleys, all attached to the rack. A line runs from the bottom of an upright, over the pulley above, over to and under the far end pulley, and then is attached to the top of the upright. A second line mirrors the first.

... and a video of it operating using the movable knot to prevent racking.




All in all, I am impressed that it works so well, and that I remembered how to set it up.

Dennis

That’s how i did it with my kayak rack on the garage ceiling. Works very well.

 

[JMM744]

That’s one impressive lift system. You are certainly a detail person. This build is awesome! Love it! Looking forward to seeing your fish selection.
Jim

 

[Dennis Cartier]

That’s how i did it with my kayak rack on the garage ceiling. Works very well.

Yes, it does certainly help a lot. Just to see how much it is helping, I loaded up all the lights on 1 half of the rack, and only had 2 mounted on the other half. It lifted fine, though the empty half did get ahead of the ladened half by about 2". I can live with that. I would never have it out of balance by anywhere near the 100 lbs+ , which the test involved.

Dennis

 

[Dennis Cartier]

That’s one impressive lift system. You are certainly a detail person. This build is awesome! Love it! Looking forward to seeing your fish selection.
Jim

Thanks. I am trying to be more detail oriented with this build. I tend to rush things and make do with "good enough", so I am taking my time with this one. I am hoping to have it wet and cycled before the end of the year. Mind you, I said the same thing last year .

As for fish, you are probably going to be disappointed, at least initially. I do plan to have a nice assortment of schooling fish and lots of tangs, but that will come much later as I need to build quarantine and acclimation systems first. So much to do still.

Dennis

 

[JMM744]

No disappointment here. It’s always exciting and even encouraging to see a new build, especially one of your scale! Wet by Christmas, eh!

 

[Dennis Cartier]

I put the rest of the lights up today to test it with a full set. I am going to have to make a couple of changes though. I did not have enough mounting plates but I have the proper ones on order. In the meantime I used some oversized ones. I also realized that I am going to need to swap out some T-nuts. The ones I used tend to bite in and are not easy to slide, and the cross members the lights are mounted to need to be able to be slid about to space the lights properly. So I will need to disassemble and swap nuts.

The other issue is sagging in the center.

I already had a centre cable support that prevents sag when the rack is down against the stops, but when lifted, the centre sags an inch or 2 in the middle of the 10 ft length. I had been thinking of using 1 of the cylinders to lift an end and the center, but at the time was worried about off balancing the ends. Not so much of an issue with the movable knot system in place, but today I think I have come up with a better idea.

I am going to add a looped cable that runs through the tang on both cylinders that traverses a horizontally mounted pulley on a cross member mounted inline with the end of the cylinder. The cable will then go through another pulley mounted vertically, again on a cross member mounted to be inline with the rack rails/ Then a pulley mounted on the outside rail of the rack in the dead center of the span. This would be followed by pulleys matching the first 2 and get us to the tang of the opposing cylinder. The opposite side of the rail uses matching pulleys as the first.

Let's see if I can do some bad ascii art to illustrate, lol.

Side view: =---o   o---=
                \ /
        _________o________
      
Top view:  O---=-=-=---O
           |           |
    XXXXX->|           |<-XXXXX
           |           |
           O---=-=-=---O

At first, I thought finding the right mounting spacing to get the same length of travel and progression rate between the center pull and end pulls would be hard, but then I realized it was simple trigonometry, just solving for the length of the side of a triangle. There is an App for that!

I have ordered the 10 pulleys needed for the center pull. I am starting to think about how to power the 22 lights. I really don't want 22 transformer bricks stuck to the ceiling! I am thinking a few Meanwell's are in my future.

Dennis

 

[Dennis Cartier]

I am waiting for more parts to arrive. In the meantime I am thinking about the next items that are on my list of things that need to be addressed still.

The sump is still an open question. I have been planning on using a stock tank rather than a professionally built sump, both for cost and flexibility. I have a 100G stock tank on hand that I had planned to use, but the height of the stock tank will leave only about 12" of clearance above the rim of the sump. That strikes me as lacking in the clearance for both installing and maintaining equipment within the sump. I can foresee many regrets of my choice if I go forward with the 100G. The challenge is that most stock tanks are just a bit too wide to fit under the stand. I have just a bit over 32" of clearance between the stand supports. Most stock tanks, are wider than this, and if they are not, they are either too tall, or of too small of a capacity. I calculate the amount of water that could potentially drain into the sump when the returns are off as 18G of water. So having too small of a sump will not provide enough margin of safety, while still providing a reasonable depth of water during normal operation. The 2 choices I have found so far are a 50G oval tank and a 75G rectangle tank. The 50G does not have a drain, yay, less for me to have to retrofit. The 75G has a drain already fitted, but it has a brass fitting. Obviously the brass has to go and I would want to use a holesaw to install a PVC bulkhead in its place. The only concern that I am not sure about, is if the preinstalled brass bulkhead has a moulded in brass flange within the layers of the stock tank. There seems to be a bit of a bulge around the brass bulkhead and it worries me that it is brass in there. If the hole for the PVC bulkhead is larger than the bulge of possibly embedded brass, than I should be able to remove it with the hole plug. Assuming I can cut the hole properly centred, never a certainty, lol.

The Meanwell power supply for the lights. I got a response from AI on my query about using a Meanwell. It was mostly a 'it will void your warranty and could damage the lights' response. However, when scanning the label on the Hydra 26 HD power supply, I found that the lights use a constant current power supply. This will be a problem. My goal was to concentrate multiple HD 26 units onto a larger Meanwell power supplies. However using a constant current power supply means the lights expect to be powered with 2.5A of current, in this case at 36V. A larger Meanwell provides much higher current (16.7A) and the HD 26 units would need to be wired in parallel to reduce the current to below 2.5A to prevent damage. This could be done, but, if a unit is disconnected (or fails), then the other units on that power supply would see a jump in the current they are being fed. So, ya, not worth the risk. The little pieces of plastic with velcro straps that AI sells for mounting their power supplies cost $28 (+tax) locally. That is just shy of $700 for the 22 power supply mounts. Let me see what I can come up with to hold these neatly in place that does not cost $700.

I also need to find out where the A.C.R. CalRx I ordered is. I keep forgetting to call them to find out when it is going to be shipped.

Dennis

 

[Dennis Cartier]

I must be cursed. I ordered 2 larger pneumatic cylinders for the next phase of the build several weeks ago. About 2 weeks after ordering them, I received a refund from Paypal. My order had been cancelled by the seller on eBay. I was a bit miffed, I could not even leave feedback as the order was cancelled. The seller re-listed the cylinders at a higher price. Hmmph, I made sure to find a different seller to re-place the order with. I did not want to reward the first seller.

It has been a few weeks since re-ordering the cylinders and I have been monitoring the shipment as it wound it's way through eBay's Global Shipping Program. For those who have never had the pleasure, it is run by Pitney Bowes and it takes forever for packages to make it to their destination. Nonetheless, today was the day they are going to be delivered. I made sure to go to Princess Auto to get the bits and pieces of pneumatic parts I would need to get to work once they arrived. I came home a little bit ago and found a single small box about the size of a shoebox on my door step. Doh, the cylinders had not arrived yet and this must be something else I ordered. I glanced at the tracking number and recognized it as one I had seen recently.

The package was very light, but I thought it must be some part or other. I proceeded to open it and this is what I found.

Lol, 1 pair of knock off women's shoes. Chanel nonetheless. Hmm, a bit perplexing. I started comparing the tracking number to my list of orders and ya, this number is listed as 1 of my pneumatic cylinders?!? Gah, all that waiting and I get a pair of fake women's shoes. For the record, I am not a woman, nor do I dress as one. Sigh.

Upon closer inspection of my pending orders, not the shoes, I see that there is another tracking number for 1 of the cylinders that is supposedly out for delivery as well. So that order may contain 1 cylinder, 2 cylinders, or another random item of women's clothing. I can hardly wait

Dennis

 

[JMM744]

Let’s hope the clothes match the shoes!

 

[JMM744]

Why don’t my emojis work? there was supposed to be a crying out loud after that comment.