Tape on double glazing

[600rob]

Temporarily removed a coupe of double glazed panels from a conservatory for some repair work.

The units have got tape running around the edge of the glass which is coming away in places so i guessing it will need replacing.

Does anyone know what type of tape this is and what its purpose is?

It looks like black gaffer tape but i wanted to know if its a glazing specific type of product.
Heres a pic of what it looks like

DSC_1694

• 600rob
• 5 Sep 2018

 

[seasickstevie]

Need a better pic of the tape

 

[ronniecabers]

You don't need the tape, if anything , normally when sealed units are going in wood it is advised to remove the tape as moisture can get caught in it. The tape is purely there to stop you cutting you hands and , during manufacture to prevent too much ' slump ' in the hotmelt in 24/28mm wide sealed units

 

[crank39]

Ronnie have you ever tried pulling the tape off once the hotmelt has fused itself to it, its nigh on impossible

 

[ronniecabers]

Lol, yep certainly have. We used to make sealed units, it's just as bad when it's first been put on to. It's a poly cloth tape and , as you say, fuses ( or rather melts ) to the hotmelt! I have noticed on mass produced sealed and units off automated lines That You can scrap it off with a single edge razor blade . To be honest most leave it on but it certainly isn't necessary for it to be there

 

[Gazman16]

I actually read a few years back about a manufacturer refusing to honor guarantees for fitters not having removed the handling tape! haha sod that

 

[600rob]

we use Hodgsons Flexistrip , a butyl flexible putty like strip, that expands and contracts, as it never sets rigid ( https://www.reddiseals.com/product/butyl-tape-sealant/ ) . It is perfectly safe to paint over too. In my honest opinion, the correct way to glaze a wooden frame with a sealed unit would be to put the ' Flexistrip ' flat on the back beads

Ronnie ive got another question....
My dgu's look like they were fitted as follows:

-Epdm around the rebate
- Dgu put in place
- Thick bead of silicone to seal any gaps between the frame and glass

The glazing bars look like they were fitted with pins and just a thin bead of sealant between the bead and glass...no trace of any sealant tape.

When refitting do you advise using tape on both sides ( between the glass and the rebate, and between the glass and the glazing bars) as well as an lmn silicon?

P.s
The dgu's were sat directly on the frame with no spacers so i beleive there not the self draining type of frames

 

[crank39]

Personally I would tape the rebate but silicone the glazing bead to the glass, glazing (EPDM) tape soaks water through, something you want to avoid as much as possible due to poor or no drainage at all

 

[ronniecabers]

As Crank says EDPM tape is porous so I wouldn't be using that externally. If using the Flexistrip though , it is perfectly ok to use externally , and saves any , potential, messy silicone accidents. We would use the tape on the rear of the rebate ( where the face of the sealed unit touches the frame ) , remove backing tape and presss sealed unit in place , leaving an even gap all the way round the sealed unit, we would then put the tape on the sealed unit on the outside facing pane, in approx same place ( this is for the beads ) , BUT don't remove the tape yet. Now wth LMN clear silicone fill the void oround the sealed unit, once done remove the flexistrip backing tape ...reason for this is so you don't get silicone over the sealed unit before the tape is put on , nor do you get silicone on the tape before putting the beads back, as the backing tape is removed after the silicone is applied. Now push beads on and pin them in. Any excess , visible flexistrip can be carefully cut back , any potential holes ( can happen... ) , you can push some flexistrip in the holes to fill it and then trim back . One point here , a sharp knife makes trimming much much easier!

Voila, no silicone on glass , or ' squished out' onto the bead

 

[600rob]

Thanks guys. Does it make much difference if the rebate is left as bare wood or painted before applying the glazing tape?

Its currently wood but was thinking of giving it a coat while im doing the rest of the frame.