how much silicone is needed for lid flap?

[Sophia]

This is what I am trying to recreate or rather fix in my bugs tank:

We added some glass flaps to the internal edge of the bugs tank so the lids could sit inside, and rest along the long side of the tank, and essentially be a closed flat lid so the killifish couldn't jump out. The flaps don't go from edge to edge like the one in the photo below. They take up half of the inside edge, right in the middle.

One side is fine, but this week the other slowly started to drop. I got the blame for putting mozzie water pot on the top of the tank but I think it was also to do with there being a lot of silicone and it hadn't cured properly before I put the pots on top.

So I've taken the falling piece out, removed all the silicone from the edge it was stuck to and itself, and cleaned it off with acetone - it's clean and dry.

Can/Should I put a line of silicone around the edge of the flap or should the whole piece be coated like glue before sticking it to the under side of the tank edge again?

Does the piece that the lids rest on need to go right from edge to edge? Comparing mine to the one Greg made, his go edge to edge but there is no silicone gluing it at the ends.

The tank is 25cm wide and the glass is 5mm thick.

[GZ_Loach]

Rule of thumb is to put about a drinking straw thickness bead of silicon around the edge and smooth it off with your finger, if its load bearing you can add more but it won't necessarily make it any stronger as the silicon between the two sheets of glass is the structural part of it, not so much the outside edges.

Let it cure for atleast 3 days and make sure the surface is bone dry and clean before application (no dust etc)

*Just re read your post and I'm not 100% sure what you mean, if you want to join two pieces of glasss there should be silicon the whole way along the pieces that are to be joined

[Sophia]

Sorry, here are some better photos of what I'm up to

left side has flap that works (not the flap with the lamp attached, the one stuck to the inside of the tank for the lid to rest on

working flap closer

[the-obstacle]

Yeah, just make sure there's a layer (as thin as possible) between the 2 bits of glass and run a thin bead around the edge of the flap and it'll be all good. Chances are it didn't cure or wasn't kept with pressure on it for the first few hours / days of curing so slowly let go.

[Sophia]

didn't turn out exactly as I'd hoped, we didn't have a nozzle thingy for the end so it was a long blob. I had it clamped for a long time but it didn't really need it. If this one lets go I will do something different for the lid.

[GZ_Loach]

You can put masking tape along the edge where you don't want silicon and then asap scrape the silicon into a nice even shape with your finger or a bit ice cream container plastic (cut to shape).

Little trick is to wet your finger or spit on it so the silicon doesn't stick

[Sophia]

too late, it's blobbed now

next time (though there had better not be one)

[smidey]

if you want your lids to be a good fit don't run a bead of silicone in the corner of the intersection, just smear silicone in a thin layer all over the face of the lid support where it will be touching the panel above.

[Sophia]

thanks Smidey