Bonding lexan to glass

[EthanDouglas]

I'm looking to DIY my sump and I need something to bond the lexan baffles to my 20 gallon long. Is there some sort of epoxy that is definitely reef safe and will bond lexan to glass? Thanks for your help

 

[aKlevans]

You could go with aquarium-safe silicone. Just be sure that it is 100% waterproof.

 

[bblumberg]

For a sump, silicone should be good enough to hold the baffles in place. Most any 100% silicone labeled as having no anti-mold additives (such as GE Type 1 that you can buy at the local home store) works well. Other people like Momentive RTV which is said to be a bit stronger. You did leave some space between the sides of the baffles and the tank, right? Lexan does not expand much, but I'd leave 1/8" on each side just to be on the safe side.

Bruce

 

[EthanDouglas]

For a sump, silicone should be good enough to hold the baffles in place. Most any 100% silicone labeled as having no anti-mold additives (such as GE Type 1 that you can buy at the local home store) works well. Other people like Momentive RTV which is said to be a bit stronger. You did leave some space between the sides of the baffles and the tank, right? Lexan does not expand much, but I'd leave 1/8" on each side just to be on the safe side.

Bruce

I'm having a specialty place cut the baffles right now. The guy has experience with aquariums so we're on the same page and he knows what I need. From what he said, I need a special epoxy to bond the lexan to glass. He said normal silicone doesn't hold very well. I'm no expert, so I'm more or less following his lead.

So is silicone (I have a tube of the 100% GE from Home Depot) good enough to keep the sump baffles solid? Thanks

 

[bblumberg]

I am quite sure that silicone is adequate for baffles in a sump, even with dissimilar materials such as lexan and glass. I would not try to bond a lexan panel to glass panels for an aquarium due to the pressures involved. In the case of baffles in a sump, pressure is not a significant issue. GE Silicone is good enough as long as it does not have mold inhibitors added.

Bruce

 

[islandbreeze]

I'm looking to DIY my sump and I need something to bond the lexan baffles to my 20 gallon long. Is there some sort of epoxy that is definitely reef safe and will bond lexan to glass? Thanks for your help

In my nightmare tri-tank and sump I recently built, Ive got about 14 bulkheads (thruhulls )besides another 15 for drains and glass drilled holes. in addition probably 100 joints of acrylic with some glass in this crazy project ive been into. If ever a lesson has to be learned and this is not really pertain to post, but use flex tube for all bulkheads outside sumps if even for a couple inches cause rigid pipe in complex runs will ultimately be a headache w leaks. Fortunately my persistence has prevailed. back to the subject, I can say silicone is good, the plastiweld by jb weld works great for glass/ plastics ... Only down side is that it is yellow and runs. 5200 is better IMHO although white which isnt as bad, its thicker, more flexible, less tear able, It bonds the best w glass ive found but a little tape to trim your sump pieces like 1/2 or 1/4 inch to protect from oversanding and some fine grit emery cloth will make bond way stronger than silicone. silicone is safe and works good but go thick if you have HIGH flow sump or better yet i recommend a caulk tool, its a little rubber like 4 inch tool w multiple precut angles thats meant for perfect joints. that if you tape first blue tape and keep at 45 angle you get flat filled corners, not egged out like what happens when you run finger along joint. with silicone or 5200. i redid my hex tank also after my sump build w silicone and tool and it looks awesome like new again. it drags tight so theres no silicone or 5200 to trim before you peel the tape. I repeat 5200 works great but let cure for 5 days before wet. it trims nicely w razor if needed and sticks better than silicone. i liked it the best honestly w glass 5200 w nylon hardware (if needed) is as strong as it gets. for display obviously acrylic/ lexan to glass ids def. no bueno. The weld on products for acylic to acylic is best for sumps no doubt , get needles from cvs and clamp with stripped bread ties for gap . inject and wait, its awesome and works best for all acylic to acylic. Weld on 4 excellent and they also make a thick voc in tube that works great for touch ups clear as day. Remember to alcohol prep always. Anyway hope this helps. Long post lol, my cappachino must be kickin in.

 

[islandbreeze]

if you make L-brackets made from acrylic with thick lip to each side of glass downstream, you can simply bond your dividers to those also. did that make any sense lol

 

[cilyjr]

The easiest way is use a 100% silicone sealant. It doesn't bond as well to plastics (lexan or lucite) as it does to glass. That said a generous application will hold it in place. I've had the same baffles in place with 100% sealant (not adhesive ie. Momentive) for about 10 years.

Just be sure to allow plenty of time to cure. Most take a couple days to a week (the difference being neutral cure vs acetoxy the former taking longer) . The 24 hours they state is for an 1/8 th bead and nobody uses that small of an amount.

 

[Sleepydoc]

As cilyjr said, silicone will not bond long term to acrylic or polycarbonate. You can use silicone fillets to essentially wedge a baffle in place, which works fine for a sump, but it the silicone bond to the polycarbonate will loosen with time and it will not be water tight. The other thing to consider is that acrylic (and I believe polycarbonate) expand in water so you need to leave some expansion space so they don't put undue stress on the tank walls risking a rupture.

 

[lion king]

this stuff http://www.homedepot.com/p/GE-2-8-oz-Silicone-Sealant-GE-57/202038072
tried and true.

 

[EthanDouglas]

So what I'm getting as a general consensus is that the GE 100% silicone w/o mold whatever is good enough for a sump as long as I allow plenty of time before I add water. Thanks everybody

 

[cromag27 Verified Sponsor]

No. Momentive rtv 100 series only. save the GE stuff for your bathtub and windows.

 

[Sleepydoc]

No. Momentive rtv 100 series only. save the GE stuff for your bathtub and windows.

While I agree with you that the Momentive RTV 100 series is a better silicone, quite honestly, for something like sump baffles the GE silicone I will work fine.

I've seen the GE plastics silicone. It definitely has better adhesion to acrylic than plain silicone I, but I would still not trust it in a critical application.

 

[islandbreeze]

telling you 5200 works. everyones scared but ive used it and it blows silicone out of the water. silicone is fine however for most all applications just sharing my experience guess ill keep it to a min