Fixing uPVC trim?

paperclap

Hi all,

Wanting to stick some uPVC trim to the inside of my front door, to cover up the gap between door and wall.

Is it best to use a regular (solvent-based) grab adhesive? Or, solvent-free?

Apparently solvent-based can damage the uPVC?

Never worked with solvent-free adhesives before. Do they have the same grip strength? Bearing in mind that the trim will only be held in place with this adhesive, and won’t be supported, so ideally wants to be “grabbed” instantly.

Or a thought. Would a low-modulus silicone be better for this scenario? May flex better and wouldn’t damage the uPVC (as it’s designed for external use on windows and doors anyhow!).

Thanks!

FreeBear

Most (all ?) the uPVC trims that have been fitted round my windows & doors are just held in place on a bed of frame sealant. Seems to work, and has the advantage that the trims can be removed without damage should the need ever arise.

paperclap

Yeah, I think I'm going to do just that. Just realised I've got a tube of low-modulus silicone sitting in my cupboard, so that should do the trick nicely.

ThisIsWeird

WWWAAAAIIIITTT!

Phew.

Ok, yes, the sili will almost certainly work perfectly well, but, y'know', it's messy stuff.

As FreeBear says, many such trims are just held using frame sealant, and these should stick perfectly well to PVC. Ok, they aren't very 'grabby', so won't hold trims firmly in place whilst it sets if the trims want to move, but if the trims are nicely straight, or you can hold them gently in place until the stuff dries, you should be fine.

And excess is nicely wipeawayable using a damp cloth.

I used this stuff recently: https://www.screwfix.com/p/no-nonsense-acrylic-frame-sealant-white-310ml/57529

And, if you are painting that wall up to the trim, it won't reject the paint like dried sili would.

But, if you are after super-sticky reliable grab and fix, then StixAll is pretty mighty. But, messy if you need to wipe away excess.

To answer your general Qs re grab-adhesive, I use solvent-free whenever I can as it's (a) much nicer to use, (b) doesn't skin as quickly, (c) is damp-cloth wipeawayable, (d) and stuff like that. But, it ain't as 'sticky', as grabby. Solvent free also shrinks a bit as it sets - prob the other stuff does too. So, 'solvent' is usually a better adhesive 'product' for most tasks, but s-free is much nicer to use.

Stixall is great - super-powerful, not smelly, doesn't skin so gives you time to work, etc. but don't get yourself in a position where you have to wipe away excess. Especially the black stuff...

Albermarle

Apparently solvent-based can damage the uPVC?

It would depend on the solvent. In any case a bit of solvent glue is not going to destroy the PVC, but could affect the surface, so could leave a mark on the door if/when you removed the trim at a later date. 

paperclap

This is the stuff I’ve got laying about. Surely, should be suitable to use?

ThisIsWeird

That'll do fine, with the provisos mentioned before - it ain't an 'adhesive', so won't 'grab' firmly until set, and any excess will be messy to wipe away. And any excess won't be paintable.

Other than that it's perf.