Baffles

[caz2022]

Howdie all,
I have a question about baffles. I made a sump/refugium out of a 55 gal and used glass to make my baffles. I got the glass from Home Depot, I think it was picture frame replacement glass. Well the baffle that made up the end of the refugium going into the return compartment couldn't handle the strain and broke right down the middle. Now I just have a piece of plexi glass shoved in there to keep the sand and macro algea from getting to my pump.
I'm thinking about building another sump out of an old 75gal I have laying around. To make my long story short-Does anyoine have any thoughts as to how thick I should make the baffles for the 75 gal and what kind of glass I should look into?

 

[flower]

Quote:
Originally Posted by caz2022 http:///forum/thread/386095/baffles#post_3389147
Howdie all,
I have a question about baffles. I made a sump/refugium out of a 55 gal and used glass to make my baffles. I got the glass from Home Depot, I think it was picture frame replacement glass. Well the baffle that made up the end of the refugium going into the return compartment couldn't handle the strain and broke right down the middle. Now I just have a piece of plexi glass shoved in there to keep the sand and macro algea from getting to my pump.
I'm thinking about building another sump out of an old 75gal I have laying around. To make my long story short-Does anyoine have any thoughts as to how thick I should make the baffles for the 75 gal and what kind of glass I should look into?

You don't have to build another sump, you can fix the one you have. For the glass you need to go to a glass place and ask for glass the same thickness as your tank 3/4 or whatever it is. Then use silicone to seal it up real good.

 

[saxman]

There's no reason not to use 1/4" acrylic instead of glass. You can silicone it in place, or use EPDM weather stripping around the edges of the baffle (cut the baffle material slightly smaller to accommodate the thickness of the weather stripping) and make it a "pressure-fit" baffle that can be removed/changed.
I know somebody will likely jump in with the "you can't use silicone to attach acrylic to glass" thing, but I've been doing this for YEARS on several DIY sumps with no problems at all (we're not looking for true structural adhesion here). In fact, I have baffles that I've tried to remove and it was a real PITA to get them out.
I've also built sumps using the pressure-fit technique with good results, but these do take a little fooling with to get them "just tight enuff" till you get used to doing it. The nice thing about this method is it doesn't "burn" a tank and allows for adjustment of your compartment size.

 

[2quills]

Silicone bonds to acrylic, it just doesn't bond as well as it does with glass for a structural application like building a full fish tank out of, so I agree with Saxman. With that being said, 1/4" glass would be plenty for either tank and probably cheaper than acrylic. You could bump it up to 5/16" on the 75g for peace of mind if you want but probably not necissary. If you do go with glass, try and to get the edges sanded so that they're not as sharp as a razor blade.

 

[flower]

Quote:
Originally Posted by 2Quills http:///forum/thread/386095/baffles#post_3389208
Silicone bonds to acrylic, it just doesn't bond as well as it does with glass for a structural application like building a full fish tank out of, so I agree with Saxman. With that being said, 1/4" glass would be plenty for either tank and probably cheaper than acrylic. You could bump it up to 5/16" on the 75g for peace of mind if you want but probably not necissary. If you do go with glass, try and to get the edges sanded so that they're not as sharp as a razor blade.
2Quills...I'm confused..... I thought silicone won't hold plastic to glass very well...it is used for holding glass to glass on aquariums...I went out of my way to get glass for my baffles so the silicone would hold. Oh and I had the edges rounded on the top besides sanding the edges.

 

[2quills]

Quote:
Originally Posted by Flower http:///forum/thread/386095/baffles#post_3389263
2Quills...I'm confused..... I thought silicone won't hold plastic to glass very well...it is used for holding glass to glass on aquariums...I went out of my way to get glass for my baffles so the silicone would hold. Oh and I had the edges rounded on the top besides sanding the edges.
Don't feel bad Flower, I was confused about it as well. I remember putting the work in on making my 55g sump only to end up tearing it down because some folks had made me nervous telling me how their baffles failed because silicone doesn't bond with acrylic. Funny thing was is when I got the 55g tank from a friend of mine it was already being used as a sump for 2 years with acrylic baffles and even with a razor blade I still had to work to remove them. They weren't budging very easy.
Since then I've talked with Mark from Melev's reef and I've done a lot of reading about working with acrylic from some of the "real" experts in the hobby over on the big site. From what I've learned and seen in my own experience is that silicone does indeed make a bond with acrylic. It's not necessarily something you can trust to build a whole tank out of, but for the most part it's plenty strong enough to hold a baffle in a sump, provided you don't skimp on the silicone and use thick enough baffles that won't completely bow out.
That being said there are some variables to think about as far as quality and strength of the material being chosen. Acrylic isn't always cheap, and the cheap stuff isn't always recommended. So for all intensive purposes if I had it to do all over again, I would still choose to go with glass baffles in a glass tank. Also, acrylic swells when it's wet, and there have been quite a few reported cases of the baffles swelling and actually cracking glass tanks. So a couple things to think about when going with acrylic baffles is, get the right thickness of material (usually at least 1/4" to 3/8" in most cases), cut the baffles a little short (approximately 1/4" the total length across the width of the tank) to allow for expansion, and don't skimp on the silicone. In fact, one little trick is to actually rough of the edges of the acrylic with sandpaper to have a better surface for the silicone to bite and grip onto. So if you follow those simple rules you should never really have a problem with it.
But glass is cheap, even if you get it cut by a shop. There's no question about the bond between the glass and the silicone. And the material matches the tank. So unless someone is going to build themselves an acrylic tank I still recommend glass in a glass tank. Even though I still have my acrylic baffles tucked away in a safe place.

 

[flower]

Quote:
Originally Posted by 2Quills http:///forum/thread/386095/baffles#post_3389282
Don't feel bad Flower, I was confused about it as well. I remember putting the work in on making my 55g sump only to end up tearing it down because some folks had made me nervous telling me how their baffles failed because silicone doesn't bond with acrylic. Funny thing was is when I got the 55g tank from a friend of mine it was already being used as a sump for 2 years with acrylic baffles and even with a razor blade I still had to work to remove them. They weren't budging very easy.
Since then I've talked with Mark from Melev's reef and I've done a lot of reading about working with acrylic from some of the "real" experts in the hobby over on the big site. From what I've learned and seen in my own experience is that silicone does indeed make a bond with acrylic. It's not necessarily something you can trust to build a whole tank out of, but for the most part it's plenty strong enough to hold a baffle in a sump, provided you don't skimp on the silicone and use thick enough baffles that won't completely bow out.
That being said there are some variables to think about as far as quality and strength of the material being chosen. Acrylic isn't always cheap, and the cheap stuff isn't always recommended. So for all intensive purposes if I had it to do all over again, I would still choose to go with glass baffles in a glass tank. Also, acrylic swells when it's wet, and there have been quite a few reported cases of the baffles swelling and actually cracking glass tanks. So a couple things to think about when going with acrylic baffles is, get the right thickness of material (usually at least 1/4" to 3/8" in most cases), cut the baffles a little short (approximately 1/4" the total length across the width of the tank) to allow for expansion, and don't skimp on the silicone. In fact, one little trick is to actually rough of the edges of the acrylic with sandpaper to have a better surface for the silicone to bite and grip onto. So if you follow those simple rules you should never really have a problem with it.
But glass is cheap, even if you get it cut by a shop. There's no question about the bond between the glass and the silicone. And the material matches the tank. So unless someone is going to build themselves an acrylic tank I still recommend glass in a glass tank. Even though I still have my acrylic baffles tucked away in a safe place.

I learn something new everyday...this hobby makes me feel young again, just like when I was a kid...I would think I know something......then discover...... I don't ... LOL

 

[acrylic51]

Quote:
Originally Posted by 2Quills http:///forum/thread/386095/baffles#post_3389282
Don't feel bad Flower, I was confused about it as well. I remember putting the work in on making my 55g sump only to end up tearing it down because some folks had made me nervous telling me how their baffles failed because silicone doesn't bond with acrylic. Funny thing was is when I got the 55g tank from a friend of mine it was already being used as a sump for 2 years with acrylic baffles and even with a razor blade I still had to work to remove them. They weren't budging very easy.
Since then I've talked with Mark from Melev's reef and I've done a lot of reading about working with acrylic from some of the "real" experts in the hobby over on the big site. From what I've learned and seen in my own experience is that silicone does indeed make a bond with acrylic. It's not necessarily something you can trust to build a whole tank out of, but for the most part it's plenty strong enough to hold a baffle in a sump, provided you don't skimp on the silicone and use thick enough baffles that won't completely bow out.
That being said there are some variables to think about as far as quality and strength of the material being chosen. Acrylic isn't always cheap, and the cheap stuff isn't always recommended. So for all intensive purposes if I had it to do all over again, I would still choose to go with glass baffles in a glass tank. Also, acrylic swells when it's wet, and there have been quite a few reported cases of the baffles swelling and actually cracking glass tanks. So a couple things to think about when going with acrylic baffles is, get the right thickness of material (usually at least 1/4" to 3/8" in most cases), cut the baffles a little short (approximately 1/4" the total length across the width of the tank) to allow for expansion, and don't skimp on the silicone. In fact, one little trick is to actually rough of the edges of the acrylic with sandpaper to have a better surface for the silicone to bite and grip onto. So if you follow those simple rules you should never really have a problem with it.
But glass is cheap, even if you get it cut by a shop. There's no question about the bond between the glass and the silicone. And the material matches the tank. So unless someone is going to build themselves an acrylic tank I still recommend glass in a glass tank. Even though I still have my acrylic baffles tucked away in a safe place.

Agree with you and Saxman......I remember talking about this a long time ago with you Corey, when you had concerns......Hey Flower!!!!!

 

[reefkprz]

I definitely agree with 2 quills. the strength of the bond between silicone and glass versus silicone and acrylic has been discussed many times. if you want small neat silicone lines in your glass sump, I would recommend using glass baffles. if you don't care about how thin the silicone lines are you can use acrylic, like 2quills mentioned you just need to really whop the silicone to it so you are more building a silicone bracket for the acrylic to sit in than you are glueing the baffle in place. on a 1 to 10 scale the bond strength of silicone to glass is a 10 while the bond strength of silicone to acrylic is only a 5.
the thinner the acrylic baffle used the more silicone is going to be required to hold it in place simply because the extra flexing puts even more stress on the silicone's already dubious grip.
Personally I prefer glass baffles in a glass tank. I did build a sump long ago with acrylic baffles and of course after a couple years a one by one the baffles did let go. the first baffle let go when I first filled it so I had to drain and resecure it. I actually still have this sump out in my back room. it definitely was one of my favorite sumps because I angled the baffles so the front of the sump was all the fuge area and hid all the equipment in the rear corners. I think I used this sump for about 10 years