How forgivable is unforgivable acrylic?

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Blobfish

Blobfish

Feeder Fish
MFK Member
Jan 28, 2016
18
2
8
Hi,

I am building a ~240 gallon acrylic tank and just "glued" the side piece to the back piece. I used the pin method with two 90 degree claps (see picture). The edge turned out perfect! but the alignment of the top and bottom, not so much :(. Looks like the 90 degree clamps do not align the bottom and top of the two pieces as I ASSUMED.

The side piece is less than 1/16" lower than the back piece (and obviously the top is higher by the same amount). I can see and feel that they dont align...maybe around 1/32"? Am I toast? When I "glue" the bottom and top of the aquarium onto these pieces will there be enough play in the softening of the material by the solvent?

any advice appreciated.

tank.JPG
 
best i can think of is to finish the sides, front and back, then use a router on all the edges to shave them to the same height. then put the bottom and top panels on. either way, if they don't sit flush, it will cause integrity issues

EDIT: if it's just 1/32, you MIGHT get away with letting the cement softening the acrylic enough to fill in the gap, but i have not worked with this size acrylic, so i can not help you there.
 
guess I should actually get a real measurement so I can quantify the problem....will get that tonight
 
Hello, I would like to ask so I understand. Are you saying that side panel is not flush with the rear/front panel? So in the picture the way it is now, that side panel is too far to the "right" or "left?"

Or are you saying that when you take a carpenters square that side panel isn't square to the back/front panel? Meaning in the picture it is leaning forward or backward?

Trying to make sure I understand. Did you prep the acrylic yourself? How did you prepare the edges? Did you use a router or jointer? Or scraping?

Also did you leave a lip or overage for the bottom panel to stick out past the size panel? Hard to tell if it is flush or if you left some extra. This is called flashing, you'll router that off later but that really helps get strong welds
 
its not leaning forward or back....theres a carpenters square taped in place on the back side where you cant see in the pic.

Acrylic was cut at the acrylic provider and then I sanded down the minor saw marks with four progressive grades of sandpaper with a block to prevent rounding the 3/4" thick acrylic.

so the "glued" edge you see in the pic is flush, but the ends of the side panel is not (hidden by the 90 degree clamps in the picture). Does that make sense? If I had just moved the upright panel (which will become the side of the aquarium) ever so slightly to the left all would be perfect.
 
Okay so looking at the picture, when you rub your finger of the seams the side panel is just a little too far to the right? And the left side you can feel it needs to slide over just a little bit to be flush?

put these two piece on the bottom panel and tell me how big the gap is underneath? One panel will be flush the other will sit higher because they aren't planar or flush. The size of this gap will determine a lot. The solvent will melt and help level things out. I'm hoping that gap is small as I've had minor imperfections correct themselves using pin method. Another reason the capillary method is outdated. You wouldn't have a chance right now if you were using the capillary method.

Try to get a picture of how uneven those edges are. Doing the above will help you get an idea how off centered you are.
 
thank you! ill measure the off set as best I can and set on bottom piece and see how that looks...will take pics and post late tonight

thank you!!
 
ok,

two photos that illustrate the gap. This is with the two welded pieces sitting on the bottom piece. The pin is size 24 and the gap is just a smidge larger than that as the pin is loose but you can't really rock it up and down. I don't have a micrometer or calipers to get a good measurement unfortunatly. Also, looks like I have a welding issue right at the end that I didn't notice before. There are no air bubbles anywhere else but it looks like there is no weld at the very end below the air bubble.
IMG_1014.JPGIMG_1017.JPG
 
Okay. This might be a little beyond me. I'm hesitant to recommend routing that down flush, because you'll need to do it to the other pieces and square the whole project again. Do you have a table router with a really good fence?

Weld on #40 comes to mind, with the 3061 added to thin it a bit so it flows better. You might be able to use pins everywhere else when fill the gaps with #40. I think regular 40 without the thinner added might be too thick to "inject" into that narrow gap.

We're gonna need some more help here, let me shout for my buddy wednesday13 wednesday13 . I know he's been really busy lately but hopefully he can stop by and give his opinion also. He knows his stuff.

If all else fails I'm tempted to send you over to reef2reef forum to find Floyd R. Turbo. He also owns Turbosaquatics. If anyone knows what to do here he does. Or Acrylics (named James) from Reefcentral forum, he's the one who first leaked and shared the pin method years ago.

In preparation for your next seam: When welding the side panels to front, try to put both pointer fingers (gloves on) on the opposite edges of the seams and you'll have a few seconds to flush the panel by touch before it sets. If you slide it too fast or too much it will allow air intrusion into the seam so be careful. But a minor offset like this can be corrected as the joint is very slick before it sets.
 
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