Glass Baffles Vs. Acrylic

AmaleeC · Mar 16, 2020

Hello everyone! I bought a 20g Aqueon tank to create a sump and was curious as to wether you guys prefer glass or acrylic baffles? I know acrylic expands under water so I’m a little nervous to go through with that.
Also, what kind of adhesive do you recommend when using glass to acrylic/glass to glass?

At the moment I have a Home Depot, a Lowe’s and an Ace’s Hardware nearby. I’m hoping to buy the items needed there. If not, Amazon and eBay are okay too ;)

P.S. What I’d really like to do is just buy a DIY kit for sumps. I had to renovate the stand and the tank so I’m a little over the DIY stage here lol But I haven’t found any for under $40.

Spare time · Mar 16, 2020

I prefer glass as it doesn't bend like acrylic but glass can be a pain to deal with.

homer1475 · Mar 16, 2020

Glass in a glass sump, acrylic in an acrylic sump.

Acrylic in glass is tough because of the expansion, and the fact silicone doesn't stick to acrylic.

User1 · Mar 16, 2020

So some more searches as I've read stories of people using acrylic baffles in glass tanks only to have them expand and shatter the glass sump. Something about not sized properly or too tight not allowing space to expanding.

Edit: @homer1475 touched upon it above. Thanks!

redfishbluefish · Mar 16, 2020

My preference is acrylic baffles in a glass tank. The only reason I prefer acrylic is that I'm considerably move comfortable cutting acrylic than glass. If a glass shop would cut the glass, I'd have no problem with glass.

Now some may tell you that silicone won't stick to acrylic, and it will fail. Well that's just a bunch of bunk. You just need to buy the right silicone caulk. The good news is that it's available at HD, but not where you find all the other caulks in the Paint department. You will need to go where they sell acrylic sheet goods, and you'll find a red colored 100% silicone caulk made specifically for plastics. This stuff is reef safe and sticks like grim dead to both glass and acrylic.

Spare time · Mar 16, 2020

redfishbluefish said:
My preference is acrylic baffles in a glass tank. The only reason I prefer acrylic is that I'm considerably move comfortable cutting acrylic than glass. If a glass shop would cut the glass, I'd have no problem with glass.

Now some may tell you that silicone won't stick to acrylic, and it will fail. Well that's just a bunch of bunk. You just need to buy the right silicone caulk. The good news is that it's available at HD, but not where you find all the other caulks in the Paint department. You will need to go where they sell acrylic sheet goods, and you'll find a red colored 100% silicone caulk made specifically for plastics. This stuff is reef safe and sticks like grim dead to both glass and acrylic.

I go to a glass shop for mine. I wouldn't cut glass myself.

Billdogg · Mar 16, 2020

homer1475 said:
Glass in a glass sump, acrylic in an acrylic sump.

Acrylic in glass is tough because of the expansion, and the fact silicone doesn't stick to acrylic.

^^^This^^^

I prefer glass for glass as well. I would suggest that you use no thinner than 1/4" because the more readily available "single strength" window glass will crack if you bump it even lightly. You can get them cut at any local glass repair shop. The one that I have used for years can have them same day if I call in the morning. Regardless of which you choose, have them cut ~ 1/8" less than the actual width. The remaining space will be easily filled with a little bit of silicone.

As to the silicone - for something like baffles, any 100% silicone caulk without mold inhibitors will work just fine.

hth!

AllSignsPointToFish · Mar 16, 2020

I have acrylic baffles in my glass sump for 4 1/2 years. I suppose I haven't had issues because I cut my baffles kind of small to allow the silicone to get between the glass and acrylic. I have not noticed any adhesion issues between the acrylic and silicone, so I don't know what's up with that.

AmaleeC · Mar 17, 2020

homer1475 said:
Glass in a glass sump, acrylic in an acrylic sump.

Acrylic in glass is tough because of the expansion, and the fact silicone doesn't stick to acrylic.

That’s probably what’s terrifies me the most about all of this - coming home to a broken sump because I used acrylic.

After hearing everyone’s input, I looked into different glass options and found a place nearby me that’ll cut it and sand the edges for me (so the glass isn’t too sharp) for $15!! That’s awesome! I know RTV Momentive is the best adhesive to use right know. But do you all have any suggestions on adhesives I can buy today and use for glass baffles on a glass tank?

homer1475 · Mar 17, 2020

Any 100% silicone caulk that does not have mold inhibitors will work.

o-townFLA · Mar 17, 2020

I used glass.

If you have a HobbyLobby near by they sell different colors of 12x12 glass sheets

Squidward · Mar 17, 2020

Get 1/4" glass baffles cut from a glass shop, not lowe's.

Sebastiancrab · Dec 13, 2020

redfishbluefish said:
My preference is acrylic baffles in a glass tank. The only reason I prefer acrylic is that I'm considerably move comfortable cutting acrylic than glass. If a glass shop would cut the glass, I'd have no problem with glass.

Now some may tell you that silicone won't stick to acrylic, and it will fail. Well that's just a bunch of bunk. You just need to buy the right silicone caulk. The good news is that it's available at HD, but not where you find all the other caulks in the Paint department. You will need to go where they sell acrylic sheet goods, and you'll find a red colored 100% silicone caulk made specifically for plastics. This stuff is reef safe and sticks like grim dead to both glass and acrylic.

Per Home Depot's website today, this product (#600504) is only recommended above the water line.

redfishbluefish · Dec 13, 2020

Elaine123 said:
Per Home Depot's website today, this product (#600504) is only recommended above the water line.

Sssssshhhhh, I won't tell if you don't tell!

And if you call GE, they will also tell you it's not aquarium safe.

The only thing I can tell you is that I've been using it for years on multiple sumps, and it works. Never had a failure. My only recommendation is to let it cure for as long as you can before getting it wet....I like at least a week. :cool: