Ill be building a couple plywood tanks soon and I think Ill be going with sweetwater epoxy to waterproof. The rep I spoke to believed the epoxy would seal straight to the glass. Saying there isnt a need for silicone. What is your guys experience? If I do a sealant as well, I believe Ill order some 3M 5200 Marine Adhesive Sealant. Do you think It would bond with the sweetwater?
3M 5200 Marine Adhesive Sealant and epoxy
- Thread starter fishhooked
- Start date
I would advise against using 5200 anywhere that will be exposed to direct contact with tank water. Yes it will stick to almost anything and it will tear chunks out of the plywood before it does come off however I am pretty sure it contains mildewcides that will poison the fish.
I have used it on my boats for years and it never grows anything either above or below the waterline.
You also don't want to use it for anything you ever might want to remove. 4200 is almost as tough but can be removed without ripping wood but probably contains the same mildewcides.
I have used it on my boats for years and it never grows anything either above or below the waterline.
You also don't want to use it for anything you ever might want to remove. 4200 is almost as tough but can be removed without ripping wood but probably contains the same mildewcides.
fishhooked;4873867; said:
Was this the rep for Sweetwater or for 3M? I find that advice a bit surprising.
Sweetwater sticks to glass very well but you still need a thick layer of flexible caulking to deal with any flexing or expansion/contraction of the plywood tank. Sweetwater is somewhat flexible once cured but not as flexible as 5200 and it would be very difficult to get a thick enough layer.
I don't recall using 5200 but have used other polyurethane based caulks in tanks. I would research very carefully which are fish safe once cured. The formulations have changed a lot and I am not up to date on their specifications.
Regardless, if 5200 is anything like other polyurethane caulks it will bond very well to cured Sweetwater.
Sorry for the confusion. The rep was for sweetwater. What caulking did you use? Or what would you recommend?
Also, could I seal the interior edges of the tank with this caulking and then apply a couple coats of sweetwater over the caulking. Caulk the glass to the frame. Caulk the glass edges on the interior of the tank and then paint the sweetwater over the caulking on the interior of the tank? Id like to have a little overlap.
Also, could I seal the interior edges of the tank with this caulking and then apply a couple coats of sweetwater over the caulking. Caulk the glass to the frame. Caulk the glass edges on the interior of the tank and then paint the sweetwater over the caulking on the interior of the tank? Id like to have a little overlap.
Make sure you test whatever you are going to do before you apply it to your build. When I was testing liquid rubber we all thought it would stick to glass and would almost be self sealing. Well, it stuck to glass great and when dried was difficult to get off the glass...until it got wet! Then it came off with the wipe of your hand leaving no trace behind. Sweetwater might react the same way. Don't accept it will stick to glass until you try it yourself.
Thats good advice BadOleRoss. Once I make some decisions on the sealant or caulking. I will definately be testing it out before it goes on the tank
fishhooked;4874482; said:
I would rather not recommend specific products that I have used unless I know that the formulation hasn't changed since I last used them. In the case of polyurethane caulks the formulations have changed.
As far as painting over caulking, I have done this with epoxy paint (not epoxy resin) over polyurethane caulk before. It wasn't by design but instead due to a last minute change in plans. I overlapped epoxy paint from bare plywood, over polyurethane caulk and onto glass.
In general one should not seal over a material unless the topcoat is at least as flexible as the substrate. I got away with it but it was in shallow paludaria and not deep tanks.
In general I would recommend using the epoxy paint over the bare wood and then using whatever caulk you choose to adhere the glass to the sealed frame.
If you use some of the elastomeric emulsions like Liquid Rubber then I would do things differently.
so the 3M 5200 may not be fish safe. hmm.. there has to be something that would work. so I went looking for an "adhesive" silicone that is for aquariums and I found one. only problem is that it's located in the UK. anyone use this stuff before? I think it's well worth looking into.
HA6 Marine Grade adhesive silicone sealant
http://www.decoratingdirect.co.uk/viewprod/b/BITHA6/
HA6 Marine Grade adhesive silicone sealant
http://www.decoratingdirect.co.uk/viewprod/b/BITHA6/
Thanks for the ideas. I guess I'm looking for an aquarium caulk- (ing)? lol. I dont believe Id be able to get the stuff from the uk as its a VAT or whatever, and I think everything registered VAT has to be shipped by ground to wichita, Kansas ( where I'm located). So an ideas on some aquarium caulking??