Working with Weld-On 16 ?

[DiverDude]

I'm building a HOB sump and given this sucker will hold ~50lbs of water, I bought some Weld-On 16. I've only ever used the water-like stuff before and always clamp-up my pieces and then apply it when everything is as I like it.

With the '16' though, it appears that you have to apply a bead and then assemble which makes making a box quite challenging.

I know a number of people on here have used this stuff before -and more than likely built sumps and other 'boxes' with it.

Any pointers or should I just stick to the water-like Weld-On 3 ?

[whatcaneyedo]

I've been told Weld-On 16 is for filling gaps and fixing breaks so that is all I have used it for. If you're able to produce nice clean cuts Weld-On 3 will give you a much nicer finish.

[DiverDude]

I've had good results in the past with weldon-on 3 but I've never done a) anything this heavy b) anything that held water before so when I saw that weld-on 16 was 'high strength', I naturally grabbed some

[no_bs]

Instead of welding the piece that hangs off the tank, why dont you form it, then weld the box onto it. Just a thought, it will be stronger.

[DiverDude]

Actually, that's the plan. I'm making a box; there will be a cutout at one end which will be the spillway back into the tank and the whole box will hang on a piece that I will heat-bend into a U shape and then bond to the box part.

That will be plenty strong. In fact, I'm pretty sure that weld-on 3 will be fine for the box as well but I 'discovered' this thicker, and supposedly stronger weld-on 16 and bought a tube to try and thought it would be good for the box -until I found it was a gel and not a water-like substance.

[no_bs]

I have used the 16 to octopuss proff our acrylic tank, and it worked out fine. I found it to be a little more forgiving and just as strong, IMO.