**ORIGINAL POST 8/31**
I've had a chance to work on the tank over the past few days. I've made a little progress but also had a setback.
On Tuesday I started working on the top eurobrace flange. The top is a 3" eurobrace out of 3/8" acrylic. I probably could have used 1/4" for the top but liked the thought of the thicker material. Plus I think it looks nicer when all the pieces are the same thickness. I knew that I had to make a jig of some sort so that I could route out the solid piece to create my 3" flange. I looked at hundreds of pics online and settled on using some of those ideas along with ideas from Melevsreef. I found some 3.5" wide MDF at Lowes and figured that I could make a "window frame" and set the outside dimensions of the frame to the dimensions of my acrylic sheet. If I routed out the center of the frame that would give me a 3.5" flange. Since the tank is only 28 X 24 a 3.5" flange all the way around wouldn't have provided a very big opening to the tank. So I then found some 1/4" thick window trim and figured I could nail that to the MDF at 1/2" and then I could get my 3" flange. So I placed a scrap piece of MDF on the saw horses to make a work service. Then I used 1" brad nails and attached the white 3.5" MDF to the table. Then used 3/4" brad nails and affixed the 1/4" window frame to the white MDF to create my 3" flange. The acrylic sits on top of the white MDF and the 1/4" window frame holds the acrylic in place.
Here is the router bit that I used. It's a 1/2" Bosch Laminate bit. It has a bearing on the tip which is used to trace along the jig while the cutting head routes out the acrylic.
It took about 90 seconds to route each side of the top. I found that if I went too fast the bit would skip and i'd get a bump in the edge. If I went to slow the acrylic shavings got caught between the edge and the bit and then as they cooled they melted back onto the edge.
After the center was routed out, I vacuumed all the shaving up and then made another pass to smooth out those bumps and to clean up any little areas that needed. Since the brand of acrylic that I have has brown masking paper on both sides, I needed to remove the paper so that I could see my jig. Unfortunately, dragging the router along the acrylic scratched the heck out of it. I used a buffing wheel and some Novus 2 and did my best to polish out the scratches. This tank isn't meant to be a TOTM show tank so I didn't worry about it too much. This is a learning experience and as I get more proficient I'm sure I'll figure out how to keep things looking pretty. Perhaps a router table if I'm going to keep doing this. It was time to glue (solvent weld) the top to the tank. I'd like to add that since this was my first build I wanted to keep it simple. I had watched several videos of acrylic tank fabrication and one of those videos showed the tank being built from the base up. Taking the bottom of the tank, gluing the front, sides, and back. Then finally gluing the top. I figured this would be the easiest way. This is not the way professional tank builders do it and now I see why. Professionals will glue the 4 sides, then the top, and then attach the base last. More in a second on why this is important.
Here is the attached top. While it's not perfect, I think it looks pretty good and I was pretty proud of my self. BTW, all the sides are 3". In the photo, the back seams looks thin. I'm a terrible photographer.
So according to the folks that do a lot of acrylic tank fabrication - the proper sequence for assembling the aquarium is (and I should have listened):
1.) Attach a side panel to the font panel - let cure for several hours if possible, minimum 1 hour
2.) Attach the opposite side panel to the front panel - let cure for several hours, min 1 hour
3.) Attach back panel to side panels - let cure 24 hours
4.) Attach top or bracing - let cure for 24 hours
Attach all above to bottom - let cure for 24 -48 hours
The theory is to make sure all seams are glued in a horizontal fashion. I took this lightly and took the easier route by starting with the bottom attaching the front, then sides, then back, and then top. I glued vertical seams and after seeing how the solvent didn't wick into the seam via capillary action that well - I was a little nervous. I ran a bead of Weld- on #16 along the vertical joints after the tank had cured for 24 hours. I did turn the tank so that the 16 was applied horizontal. Weld-on #16 is thicker than #4 and is used to fill small gaps where the acrylic panels might not be making perfect contact. It still works the same way as it melts the acrylic so that the molecules in the two pieces bond and then the liquid part of the solvent evaporates. Weld-On #4 is water like in consistency so while trying to glue the vertical joints, you can image how I managed to drip on the viewing panels. Because it's a solvent, you can't wipe it. While attaching the top, I wasn't able to get as much solvent into the seams as I'd like and naturally, while doing the seam on the front panel, I managed to get several drips. I'm going to attempt to sand these out later... maybe. Since the top doesn't need to be water-tight, just a strong bond, I think I'll be OK.
Water test time...
he tank was about 1/3rd full and going well. Then... I noticed a single drop of water at the left front vertical seam.
NOOOOOOOOO..... I put another gallon of water in to see if the leak would get worse. It stayed constant with one drop every few seconds. So I siphoned the water and dried the panels. I should have continued to fill the tank to see if I had any leaks further up the seam. After the tank was dry, I started running a thicker bead of #16 across all the seams. Letting each seam dry for at least an hour before rotating the tank and running the solvent on the next set of seams. I'm going to let those cure for the next day and attempt to re-test on Saturday. If this test fails then I'll have to start again.
I have a fair bit of 3/8" material left as I purchased a full sheet (4' X 8') of acrylic. I don't think I have enough left for the whole tank so I might just have to buy a few pieces to make up for what I don't have. If that's the case, and I start over, I'm OK with that. I've learned a lot so far from this build and I think by fully understanding the proper way to assemble an acrylic tank now, my next go will be much more successful. I'm also going to be starting my sump this weekend. The sump will be 1/4" material and I'll have some new challenges such as cutting teeth into my baffles and getting my bubble trap baffles correct. If my water test on Saturday is successful, I will leave the tank full for 1 week to make sure it holds solid.