Self tappers for uPVC conservatory

[Tim Watts]

Any one with experience of screwing...

into conservatory :)

I want to mount some LED strips:

onto the plastic "cove" that runs under the roof.

2 options, having pulled one off: It's very heavy gauge uPVC that "plugs" into a moulding in the ali frame.

1) Coarse self tapper into the plastic (about 1/2" clearance behind)

2) Or straight through into the ali. I think it's a big hollow section, about 2" thick. Certainly clear of the glass by miles. Should be safe to screw into.

So what screws?

is what I actually have to fix. So we cannot go too massive with the screw. Roughly the equivalent of a 5mm "goldscrew" would be OK.

Would stainless self tappers cope with aluminium? I'd like them not to rust in place over time.

Or is there are particularly coarse threaded screw that would work will in uPVC? The weight supported is very low.

Or indeed, option 3 that I just thought of: is it hard to hand-tap a machine thread into 2-3mm thick ali?

Asking, because I'd like to not make a mess of this!

Cheers, Tim

[Andy Burns]

That's what I'd go with.

[Bob Minchin]

Drill clearance holes in the aluminium first, then fit with very low torque setting on your screw driver to avoid stripping the plastic.

[dennis]

Double sided tape and forget the brackets.

Use a short wood screw into the plastic it isn't exactly a heavy load. Our blinds are held up without screwing into the metal.

[Tim Watts]

Thanks for that.

Not so keen on tape as it get's bloody hot in summer - have a suspicion tape will fail.

[Jeff Layman]

I wondered about the possibility of using a strip of mild steel (painted or rust-protected) behind the PVC and neodymium magnets glued or screwed to the light fitting. No drilling needed. Those magnets will grip through several mm of plastic, but they aren't cheap.

[PeterC]

When some uPVC-specific screws came undone with most of the plastic thread attached I used the suitable screws from Toolstation. They're a tad bigger, so just screwed in and held. For many years I've used A2 st. st. fastners on bikes and trikes that get covered in salt and have never had a rusted one, including ally-steel.

[Tim Watts]

That's a rather smart idea!

I used a couple of those monster magnets for holding a plinth on in the kitchen in front of a part of machines (so it has to be removable).

The LED ali profiles are quite light so it could work.

[Tim Watts]

Any idea what they are called - I can't find any other than generic self tappers?

[Andy Burns]

Don't think TS/TF stock them, but "uPVC repair screws" seem to generally have a wider thread

e.g.

[PeterC]

Yes - and there are thicker ones available for stripped-out holes. It's just that I was replacing hinges and the profile isn't very thick at that point, so having more threads and less 'machining' of the hole has worked well.

I need 2 or 3 screws and everywhere I looked there were boxes of more than the number in the entire house! Trouble is, apart from abou a tenner wasted on screws I didn't want, I'd have no use for those 'spares'; the standard self-tappers are always useful.