Acrylic fabrication questions? I can help!

alllllllrighty folks. I've made a mistake and would like some comments on fixing.

I'm pretty sure the last baffle was assembled just a little proud of the bottom seam. In gluing the bottom on (last) I'm getting horrible seam. I haven't water tested it - don't see the point, really.

My thought is to put some square stock on the inside, what I'm worried about is the seam as it runs across the baffle.

I still have 1/4" along the outside edge of the sump, so I'm thinking a 1/2" - 3/4" high band along the outside bottom would OK.

I've already tried some more weldon 3 to take the bottom off - no dice. The baffles are in there pretty good as well. I'd be OK with cutting off the bottom with edge guide and router as last resort but the baffles would be problematic I think.

Thoughts? Comments? Thinkin right or just wastin time?

Sorry the pics aren't clear, but I think you get the idea. This is for a 22" by 16" sump that will run @10" of water so I just don't want leaks - aesthetics are secondary.

036_zps3998f7f2.jpg
 
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Lou Young said:
What is a good place for newb to go read/learn about making acrylic tanks?
Click to expand...

Go to Acrylite's website - they have technical documents on how to cut, handle, weld etc along with aqarium calculators to determine thickness of material based on size. Or you can go through 10 years of posts in RC.

Either way it isn't terribly hard for smaller projects like sumps and other odds and ends especially if you do a bit of wood working (you'll already have 90% of what you need). Don't recommend starting with a large display tank.
 
I do see where that method is much, much simpler than the pin method. All other things being equal.

There are so many way to skin these cats it's great. Sometimes it's just freakin' frustrating to find the "right" way on your own.

==============

BONDING RECOMMENDATIONS
WELD-ON 40 is recommended for bonding of acrylic plastics especially where good clarity retention is required.
It is versatile having many applications in the sign industry and in the manufacturing and repair of aquariums,
museum quality cases and other plastics fabrication industries.
 
Floyd R Turbo said:
Yes, that is a very bad idea IMO. Silicone does not bond structurally to acrylic. One could argue that the water pressure keeps it in place and the silicone just keeps it sealed, but it will, IMO eventually fail. Think about it, if the overflow box is 1/2 empty, that is a lot of buoyant pressure pushing up on the box. If it breaks loose, you're looking at a significant downtime since the minimum cure time is 72 hours and you really *should* wait 2 weeks before exposing fresh silicone to water. You're better, for many reasons, to use a 5-sides box on the inside and outside and hold it on place with bulkheads -kind of like how Reef Savvy does their overflow boxes, or Glass-Holes.
Click to expand...

Floyd, you mentioned attaching the overflow box I'm going to fabricate via bulkheads. I want to go that route but am having a tough time figuring it out with the eurobrace. Unless make the overflow box 10" deep or so I'm not sure how I'll access the nuts to tighten the bulkheads and the street 90s for the Bean Animals. I'm open to any adjustments or ideas. The foam in the pic is 48". I'm thinking I may jump the box up to 60" or 72" though. Thanks.
 
Well update on sump. Did the inside fillet method. Passes initial water test with inch of water. Will let cure a bit longer before full test.

037_zpsc1480eee.jpg


As for the overflow. You could do a weir all the way across the tank. Then assemble an external overflow with the BA plumbing. Sheets are 8 feet on long side so you could do one piece. Personally such a long span I'd consider a thicker glue. It will not be arrow straight anyway and I'd think 4 wouldn't be thick enough to ensure a nice seam. I guess if you are patient with a scraper you could get it perfect.

My initial thought for attaching the outside box would either entail bulkheads and plumbing to external box (you'd need to consider how to affix) or line up holes-slots to drian the water and glue the external box directly to back of tank. Gussets under neath if you are unsure of weight methinks. I'd use opaque (not clear) acrylic to help with hiding the plumbing behind it.

Or if you are going with limited overflows you might cut some access holes in euro.

Or make overflow stick out past euro enough for access. It's already 5-6" out there - you'd have to eyeball if you'd be good with perhaps an 8" weir.
 
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jonwright said:
alllllllrighty folks. I've made a mistake and would like some comments on fixing.

I'm pretty sure the last baffle was assembled just a little proud of the bottom seam. In gluing the bottom on (last) I'm getting horrible seam. I haven't water tested it - don't see the point, really.

036_zps3998f7f2.jpg
Click to expand...

jonwright said:
Well update on sump. Did the inside fillet method. Passes initial water test with inch of water. Will let cure a bit longer before full test.

037_zpsc1480eee.jpg
Click to expand...

That fix should do the trick. To me it looks like you did not have a tight fit on the bottom sheet. This could be due to the baffles or ends not being square, or at least the same relative to one another. What this means is that if you square each piece manually, you then have to stack them all together and place them on a common edge to see how they line up relative to each other. So you might line up the left side (that is bonding to the back panel) of each pieces, the stand them up on a table and look at how the bottom edge lines up. If the left and right edges are parallel to each other (they should be) then you might see that the right edges all line up, but the bottoms are off over a distance. Like if you line up the bottom left corner while they are stacked on the table on the left edge, you can see that they don't line up on the bottom right.

The result is that you have to "force" all the joints as you bond them, or you make it work as best as possible and then shave off the peaks with a razor blade after it's cured, before you bond the bottom on. I've done my share of this and it's not fun. It's difficult to get it perfect, I've even had to do this with CNC cut pieces on occasion (due to inconsistencies in thickness, bonding parts don't always go together perfectly square)

The solution is to double-stick tape all of your pieces (end pieces and all interior baffles) to one another and run them through your router to parallel the side edges, and square the bottom edge, then make sure that you bond them all on the same relative edge. Flipping one baffle around can introduce the gap, and when you get this gap and fill with solvent, it looks good, you pull the pins, it looks good, but that 1/1000 of an inch shows it's ugly head when on baffle protrudes down a bit further and lifts that whole edge, and air intrudes. That's what you're seeing there.

jc03 said:
Floyd, you mentioned attaching the overflow box I'm going to fabricate via bulkheads. I want to go that route but am having a tough time figuring it out with the eurobrace. Unless make the overflow box 10" deep or so I'm not sure how I'll access the nuts to tighten the bulkheads and the street 90s for the Bean Animals. I'm open to any adjustments or ideas. The foam in the pic is 48". I'm thinking I may jump the box up to 60" or 72" though. Thanks.
Click to expand...

That's a tough one, but really the only way you are going to get around that euro even with a bonded-in-place box is to extend it out past the brace a few inches so you can reach in there. I would consider making your overflow box more square rather then long and narrow, and center it on the tank. You won't get the effect of the coast-to-coast, but the only way to get that is to make it long AND deep, which will act as a light blocker.
 
Floyd R Turbo said:
That fix should do the trick. To me it looks like you did not have a tight fit on the bottom sheet. This could be due to the baffles or ends not being square, or at least the same relative to one another. What this means is that if you square each piece manually, you then have to stack them all together and place them on a common edge to see how they line up relative to each other. So you might line up the left side (that is bonding to the back panel) of each pieces, the stand them up on a table and look at how the bottom edge lines up. If the left and right edges are parallel to each other (they should be) then you might see that the right edges all line up, but the bottoms are off over a distance. Like if you line up the bottom left corner while they are stacked on the table on the left edge, you can see that they don't line up on the bottom right.

The result is that you have to "force" all the joints as you bond them, or you make it work as best as possible and then shave off the peaks with a razor blade after it's cured, before you bond the bottom on. I've done my share of this and it's not fun. It's difficult to get it perfect, I've even had to do this with CNC cut pieces on occasion (due to inconsistencies in thickness, bonding parts don't always go together perfectly square)

The solution is to double-stick tape all of your pieces (end pieces and all interior baffles) to one another and run them through your router to parallel the side edges, and square the bottom edge, then make sure that you bond them all on the same relative edge. Flipping one baffle around can introduce the gap, and when you get this gap and fill with solvent, it looks good, you pull the pins, it looks good, but that 1/1000 of an inch shows it's ugly head when on baffle protrudes down a bit further and lifts that whole edge, and air intrudes. That's what you're seeing there.



That's a tough one, but really the only way you are going to get around that euro even with a bonded-in-place box is to extend it out past the brace a few inches so you can reach in there. I would consider making your overflow box more square rather then long and narrow, and center it on the tank. You won't get the effect of the coast-to-coast, but the only way to get that is to make it long AND deep, which will act as a light blocker.
Click to expand...

Thanks Jon and Floyd. Based on what you're saying I may try and do something in the 36"-48"x8"-12" range. I'm mock it up and see how it looks. Would it be suicide to notch the Euro around where the holes are drilled in the pic above? If I could get 2"-3" of it out where the bulkheads would attach I think I could easily get away with an 8" box. If the answer's yes, what would you cut it with? It's 1" thick.
 
Don't notch the euro, the answer is yes, you are asking for trouble. That's a good size euro, so don't mess with it. The radius on the cutout is really small, meaning any notch you make will cause the stress to focus there instead.
 
Thanks, Floyd. I did route on my table with a really good fence and all my pieces lined up perfectly. What I messed up is assembling the baffle. I let it stand out a little proud from the bottom edge. I thought it would be an issue and was going to get out the cabinet scraper and got distracted. When I revisited I just put on the bottom thinking I was ready for assembly. Then I put 2 n 2 together when that baffle had an awesome seam and the rest of the bottom did not.

If I had just remembered or put a piece of tape on that baffle to remind me to scrape it and check with straight edge I'm sure I'd not have to spend 1/2 the day cutting the little pieces and then figuring out how to glue them in between the baffles.
 
JC: Don't mess with the euro brace. Make accommodations around it. It's there to support the front and back pieces, in essence. You MIGHT get away with cutting access holes, but I'd err on the side of caution, really. And *IF* I were to do that I'd do holes and not notches or anything with a square edge. I mean, you could also cut holes or access panels if needed then glue pieces back over it - but that weakens the material and will look like a$$ when you are done (it will look like what it is - drilling and patching due to lack of thought).

Might as well go Coast to coast on the overflow - or if you put it in 2 pieces have them match up to where the cutouts are for the euro. You could make the top of the weir attach to the euro with a nice long U shape in the middle - catch what I'm saying?

Lemme tell ya sumpin about cutting stuff. I bought a Festool jig saw and I'm continuously impressed by what I can do with it. It really is making me rethink what is possible with a jig saw. I'd have no issues siccing my jig saw on 1" acrylic with no splinters with a square (90 from the top/bottom) cut that's smooth with the correct blade.

I've free handed stuff with a pencil line that unless you pull out the straight edge you'd never know I was cutting with a jig saw (*I* think). It is not the HD $30 Black and Decker model that jumps around so much that you know you won't get a straight line. In the middle of a cut I can let up my hand to re-position to continue the cut - the saw won't go jumping around and stays perfectly still.

I'd feel very comfortable with a GOOD jig saw on a finished product with the CORRECT blades. I've done it on cabs with confidence.
 
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Thanks for all the advice guys. I've gone back and forth on this overflow box about a million times. I have cheap access to a 48"x48" sheet of black 1/4" cast acrylic. Is it feasible to join pieces of that material to get an 80" or so piece. If so would you just butt them together and use Weldon 4? I attached a couple terrible drawings to help explain. If I drill the left side of the tank for the bulkheads can I use them to attach the overflow? My concern is he 60" or so to the right of the last bulkhead. I'm thinking it won't be centered based on the location of the sump and the fact j have to cover the hideous pieces of acrylic that formerly held the old overflow boxes on. Sorry for all the questions and thanks in advance.

By the way, Jon your sump looks really nice!


 
I think the biggest concern would be the torque on the box. The inside will not be completely full due to the nature of an overflow, so you're going to have a buoyancy issue. The far side of the box will exert vertical buoyancy and this will be magnified like a lever on the bulkheads. You don't generally want this kind of uneven pressure, eventually something is going to fail, whether that's a weak joint/bond or the bulkhead seal.

I would try to re-imagine this with a centrally located overflow, or maybe one that's not quite so long.

I like your idea about the larger section of the box for access to the bulkheads, that's what I was envisioning for one that was centrally located and just square - using the sides and front for the weir.

Something you might consider also is making the internal box out of clear on the bottom, this would reduce the amount of light blockage when you place it under a light fixture, and it won't detract from the aesthetics, meaning, a clear overflow box look ugly because you can see all the plumbing, black walls and clear bottom would still hide the innards.
 
Im not sure if this is a proper thread to post this here but, i am about to silicone an acrylic overflow box into my new 45 rimless cube. Do i use the same technique as i would with baffles? Large seam between the box edges and glass, then a seem that covers the outside perimeter?
 
You got me, did it come with instructions? If it's like the BRS overflow boxes you might ask them what they recommend for installing theirs. Silicone doesn't structurally bond to acrylic but I'm sure people still do it with these types of overflow boxes all the time. I don't have any experience doing so personally thought, so I'm no help here :(
 
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