Cold Feet Building 180g Acrylic Tank... How Are Acrylic Tanks Made Professionally?

[shneerf]

So I'm in the process of building a 180g 6x2x2 tank and I bought enough acrylic to make the tank, sump, and overflow with some to spare. I planned on making the sump and using that as practice for the main tank. The first side seams were great, but once I attached the top to the bottom is where I got a lot of bubbles in various spots.

I have the sides made of 1/2 inch acrylic and a 1/4 bottom. I know it's overkill but I had 1/2 left over and it's the best thing I could make from it.

I used the pin method with Weld-on 4 which I wasn't comfortable with at first but after I did all the sides with no internal bubbles I thought it was easy. Now here's what I think went wrong with the bottom...

First I was rushing, I was timing myself to see how long it would take me to go around and I checked my timer and already spent 2 minutes only getting half way through. I told my helper to start pulling pins in order, waiting 5 seconds before pulling the next so she doesn't catch up to me quickly and reach seams I just used solvent on. I think my main issue was not using enough solvent and pulling pins too early. When I did the 4 side seams I made sure to run the needle with solvent on both sides. This caused me to use a good amount of solvent and as the seam dried and didn't "suck in" on the edges. I've noticed that the seam looked good with only a few bubbles when I first laid it down, but when I came back the bubbles were much bigger and other bubbles formed in different spots that wasn't there at first.

Now I'm getting cold feet on doing the main tank. The sides I'm not too worried about other than the fact that I made a huge mistake and made the shorter sides the ones that overlap... meaning I need to weld a long 6x2 3/4'' acrylic vertically onto a 2x2... no big deal right...

I've been looking into how they make tanks professionally. They obviously can't sell a product with bubbles so what method do they use? There's a thread on monsterfishkeepers.com that says Weld-on 40 is the way to go and it is the secret that they use in the industry. Is there any truth to that? An acrylic bond made from solvent fusing together separate pieces once the solvent dries seems way stronger than a catalyzed monomer acrylic that doesn't dissolve the acrylic it's placed on. Or maybe the strength is overkill anyway so it's not an issue. Does the catalyst also fuse the already existing acrylic pieces so it's also fused on a molecular level? Also there's a rumor of people that claimed Weld-on 40 yellowed over time. I don't believe it but I've been wrong before.

Anyway, I would appreciate any advice on this matter. I've followed along Turbo's Aquatics thread on Acrylic Q&A thread and see a lot of advice which I've used. Am I overthinking it? How much time do I really have to fuse the top to bottom?

 

[GillMeister]

A guy I know that built large scale, high end acrylic tanks said he just kept the panels in place and allowed the solvent to wick into the seams. I never got to see the process myself.

 

[AlexG]

I can't comment on the methods for acrylic seems but I do have some general advice for the cold feet. I have encountered many issues over the years with DIY where time limited processes must be completed due to glues, sealers, or adhesives pot life. The best thing to do is get some scrap material and practice a few times to gain some confidence. Act out some dry runs and throw some problems at yourself to think about how you will resolve them before the actual process is completed. I have worked with weldon 4 and since its like water maybe try a few dry runs with water instead of glue in the applicator bottle to get your dry runs as close to the real process as possible. This should help you learn if there are any time efficiencies that can be gained. Its always best to take your time and prepare rather than rushing a project. There are a few acrylic tank builders on the forum so I am sure someone will chime in on the acrylic glues.

 

[shneerf]

I can't comment on the methods for acrylic seems but I do have some general advice for the cold feet. I have encountered many issues over the years with DIY where time limited processes must be completed due to glues, sealers, or adhesives pot life. The best thing to do is get some scrap material and practice a few times to gain some confidence. Act out some dry runs and throw some problems at yourself to think about how you will resolve them before the actual process is completed. I have worked with weldon 4 and since its like water maybe try a few dry runs with water instead of glue in the applicator bottle to get your dry runs as close to the real process as possible. This should help you learn if there are any time efficiencies that can be gained. Its always best to take your time and prepare rather than rushing a project. There are a few acrylic tank builders on the forum so I am sure someone will chime in on the acrylic glues.

Dry run... with water... that makes perfect sense actually...

I didn't think of that. That will help out a lot and since there's a lot of gluing to be done it'll help us prepare how many refills we're going to have to make too.

 

[shneerf]

So on the other note about Weld-on 40. Anyone build a tank with this stuff? Is it weak or strong? There seems to be almost no info about this stuff for aquariums but it says on the description that it is used in the manufacturing and repair of aquariums.

 

[JPG@CFI]

I use Weldon 40 almost daily. It’s great stuff, but not easy to work with for the first timer. I build tanks professionally for the last 29 years, and 98% of the time, I use a solvent. I mix my own as Weldon 3&4 are not strong enough. One rule I have is never use 16! Horrible stuff that diy guys use all the time, and is garbage. Also look for a mix date on your solvent. 6 months old, and it has degraded. I mix my own every other week. If you have any q, hit me up on Instagram under Clear Fabrications.

 

[Shirak]

I use Weldon 40 almost daily. It’s great stuff, but not easy to work with for the first timer. I build tanks professionally for the last 29 years, and 98% of the time, I use a solvent. I mix my own as Weldon 3&4 are not strong enough. One rule I have is never use 16! Horrible stuff that diy guys use all the time, and is garbage. Also look for a mix date on your solvent. 6 months old, and it has degraded. I mix my own every other week. If you have any q, hit me up on Instagram under Clear Fabrications.

Does Weldon make something a tad thicker than 4 that is a solvent for diy? What would you recommend instead of 4? I have been using 4 for some 1/4" acrylic frag tanks etc and it's a difficult to not get bubbles. I have found a little pressure for about 30 seconds seems to help since the pieces are small and don't have much weight to them.

I have a 3/4" thick 150g tank I will be building in the near future. The frag tank practices have been helpful but I don't want to mess up the new DT!

 

[Lowell Lemon]

If you followed the Acrylic Q&A you will encounter the correct method and solvent for professional results. Forget the Weld On products all together and use the formula Turbo recommends. Also we use foam tape used to seal truck canopies on pick up trucks as a support under the pieces to be joined to prevent uneven pressure along the weld area. Most hardware stores carry the foam. Cell cast acrylic is not dimensional stable (thickness varies along the sheet due to the manufacturing process). The foam helps to compensate for the difference in thickness. Capillary action with removable pins and the correct solvent will go a long way in gaining success. Sequence of assembly is important as well. Join the face, back, end panels, and overflows first. Then make sure the top and bottom surfaces are dead flat before joining to the top with the routed out access holes already done. Flip the tank onto its bottom and bond the bottom in place. This sequence will prevent the tank from floating off the bottom due to the air pressure insides a sealed box. I always over size the face, and back lenght to allow for trimming the acrylic back after assembly. I do the same thing for the top and bottom dimensions. This prevents solvent from running off the edge of the each of the parts and creating a blemish. So for a face panel I would cut the parts 1/8" longer (in your case 72 1/8" x 22.50" if your tank is made out of 3/4"). Top and bottom dimensions of 72 1/8" × 24 1/8".

You may need to use a small amount of weight at each step to prevent the seam from drawing in air bubbles as the weld sets up. Hope that helps.

 

[Shirak]

If you followed the Acrylic Q&A you will encounter the correct method and solvent for professional results. Forget the Weld On products all together and use the formula Turbo recommends. Also we use foam tape used to seal truck canopies on pick up trucks as a support under the pieces to be joined to prevent uneven pressure along the weld area. Most hardware stores carry the foam. Cell cast acrylic is not dimensional stable (thickness varies along the sheet due to the manufacturing process). The foam helps to compensate for the difference in thickness. Capillary action with removable pins and the correct solvent will go a long way in gaining success. Sequence of assembly is important as well. Join the face, back, end panels, and overflows first. Then make sure the top and bottom surfaces are dead flat before joining to the top with the routed out access holes already done. Flip the tank onto its bottom and bond the bottom in place. This sequence will prevent the tank from floating off the bottom due to the air pressure insides a sealed box.

You may need to use a small amount of weight at each step to prevent the seam from drawing in air bubbles as the weld sets up.

Thanks for the suggestions! I will look up the solvent recommendation. I had much better results on the 2nd frag tank and noticed as you say the edge was not flush on the face of the bottom piece I was attaching too. I was using the surface of a machined cast iron table saw bed so I am fairly certain it's flat. I used pins under and along the edge the 2nd time to make sure there was no gap along the seam before bonding. That helped a lot I think along with slight pressure after removing the pins in the joint. I will look into the foam tape you mention for another run as I have more frag/grow out tanks to build.