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Howdy,
I've got some planter boxes made of colourbond that I need to seal off the front and sides.
Can I just use something like https://www.bunnings.com.au/selleys-475g-no-more-gaps-interior-multipurpose-gap-filler-3-pack_p12323... , or does anyone else have any better ideas?
Thanks
Hello @NamedUser
Welcome to the Bunnings Workshop community. It's sensational to have you join us, and thanks for sharing your question about your planter box gap.
I propose looking at using Selleys 290ml Grey Storm Waterproof Gutter And Roof Sealant. It's a robust sealer that goes on almost any substrate and provides an instant waterproof seal. It provides excellent weather and UV resistance plus its rated for indoor or outdoor use.
If you need further assistance, please let us know.
Eric
Hi @NamedUser,
Foam backer rod or some sort of backing would certainly be a good idea, as it helps the silicone sit properly in the joint rather than just sinking into the void. The tricky part here is that you’re working with a really thin edge between the corrugated steel and the pebblecrete, so I think you’d find it hard to keep a backing rod in position. The only way I can picture it working is if you could wedge the rod underneath that thin edge, but even then it might not stay put.
Another option could be to run a strip of something like gaffer tape along the back edge against the pebblecrete. That would give you a semi-solid face to fill against with the silicone, and you could peel the tape away afterwards. The main goal is just to have something behind the gap so the silicone has a surface to form against.
If the gap isn’t too large, you might also get away with simply cutting the nozzle of the silicone tube quite wide and laying down a thick bead to bridge the space in one pass. In that case, I’d recommend applying it from the inside of the planter box so you don’t end up with a messy finish showing on the outside.
Please let me know if you have any questions.
Mitchell
That depends on which side you want to run the bead of silicone @NamedUser, but in this case I’d suggest applying the silicone from the inside of the planter box. If you go that route, you’d put the gaffer tape on the outside so it gives you a backing to fill against. That way, you get a neater finish on the visible side and all the sealing work happens out of sight inside the box.
As for the bead itself, the “thickness” just refers to how much silicone comes out of the tube, and that’s controlled by how far you cut back the nozzle. If you cut the nozzle quite fine, you’ll get something like a 5mm bead, which is great for small gaps. If you cut the nozzle further down, you’ll get a wider opening that can lay down something closer to 10mm, which is much better for covering larger gaps in one pass. So when I mention a “thick bead,” I’m talking about cutting the nozzle back further so you can lay down a good, solid line of silicone that bridges the whole gap cleanly.
Mitchell
Yes, that's it @NamedUser. However, now I'm second-guessing how tenaciously the silicone will adhere to the tape. I believe the tape will pull away once the silicone is cured. It might be worth doing a test section just to be sure, though.
Mitchell
Hello @NamedUser
Although the Parfix 340g Expanding Foam Filler is capable of sealing the gap its not as durable as the silicone sealer. The expanding foam filler when fully cured can be chipped off when hit or bumped with a sharp object. Whereas a silicone sealer will absorb the hit and bounce back.
Eric
