Can Perfect Fit blind fixings damage window glass?

[NoIdeasForWittyNickname]

I’m considering Perfect Fit blinds for a couple of windows and a glazed side door. Read and watched lots of installation manuals / videos and it looks like a great solution for what I need. The issue is that the ‘rubber seals’ in my window frames feel more like almost solid ‘plastic’ seals. Not sure if it’s by design or maybe they’ve just lost elasticity over time (the windows were installed by the previous owners quite a while ago).

So I’m concerned that the seals don't have enough give, and pushing metal brackets behind them will put too much stress on the glass which may crack or get dislodged somehow.

Has anybody had any issues with installing Perfect Fit blinds? Am I being silly and paranoid?

I've had them for a out 9y and no damage.

Thank you @AIstolemylunch. Do you remember if it was hard to push the brackets in when you installed them? It just seems like such a tight fit between the seal and the glass i my windows, the seal is not that squishy at all.

I have also wondered this!!

I have had them for a couple of years with no problems. There is a thing on the website to check you have the right type of windows. My seals were quite tight, so I used a bit of washing up liquid to ease the brackets in. I really love the blinds.

Thank you, @Pigeon66 Yes, what I'm worried about is that they have brand new double glazed units in mind. If you have older ones, they may not be truly (at all) compatible.

Could you ask if they will send you a bracket so you can test it before you place an order? Mine were new windows, and I know they won't fit some of the windows I have as they are aluminium.

I found with the lubrication they slipped in pretty easily, despite feeling tight, so I expect you would realise quickly if it really won't fit / could damage them.

Ooh, that's a good idea to trial the brackets. I'll try getting in touch with the company. Thanks, @Pigeon66

@NoIdeasForWittyNickname

Don't think they are likely to damage the glass. Far more likely to damage the seal.

I tried these on UPVC window that were about 20 years old but in very good shape. The problem was the black seal was very stiff - maybe the mechanical properties change over time, and also seemed stuck to the glass. The clips are quite thick so every time I tried to insert it just pushed the seal in rather than slipped under it.

What I did was get a piece of something called shim steel. This is very thin metal, thicker than tin foil but much thinner than the clip, maybe 0.1-0.05 mm. The edge of it is quite sharp, so I used a corner to gently separate the seal from the glass and then worked it in until there was a width of shim steel in there greater than the clip width. I then inserted the clip between the glass and the shim steel. The shim steel supports the seal as the clip is pushed in. Once the clip is in you hold the clip in place whilst pulling gently on the shim steel to remove it. Once you have the clip under the seal it is relatively easy to move the clip up and down to position it. But if you can't you can use the shim steel again to separate the seal from the glass above and below the clip. It sounds like a faff but a bit of practice and you can stick them in no issues. You might be able to do it with a knife, but there is a chance you could cut the seal and it doesn't work because the handle stops you holding the knife blade flat to the glass. A razor blade might work but would be difficult to handle without cutting yourself.

As said by a pp a lot of manufacturers will send you a free frame piece and clips to test, I used blinds2go and they did. If you can't do than then you can buy spare clips from ebay or amazon to practice on for a couple of quid.

@GasPanic, my window seals are exactly as you describe! Thank you for such a detailed tip!