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Router bit size for Intumescent strips

Discussion in 'Wood / Woodwork / Carpentry' started by opps, 16 Sep 2020.

  1. opps

    opps

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    Hi all

    A mate wants me to fit intumescent strips to his doors. The builders were supposed to but left the UK during the early days of the lock down.

    The doors are new and hanging. I haven't seen them yet. Can I assume that I need a 15mm router bit?

    I have never fitted them before. Do I only do top, left and right, removing the hinges and tubular latch as I go and ignoring the underside. Do I need to mitre the meeting joins or can I butt them?

    Should I glue or pin them? what is the maximum door/frame gap that they can deal with?

    Any pointers will be gratefully accepted.

    The house is going to be rented out to the council, he has moved into his parents to care for them and I don't want to fit them if they aren't going to function properly.

    Thanks in advance
     
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  3. danechip

    danechip

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    Is it possible they cut the grooves already before hanging the doors ?? That's what I would have done before fitting the hinges and lock.

    10, 15 or 20mm cutter (10 and 15 are the most common) Remove door and secure tightly removing all fixings in the way. Cut groove top and both sides down the centre of the edge to the depth of the seal with the fluffy part protruding, 4 or 5 mm, I forget. Most strips are self adhesive (make sure cut is cleaned out of any dust or grease OR pin in place. Mitre isn't really an option as you will be butting to the hinges anyway. You would fit a brushed strip to the bottom. These will be of no use if the door is badly fitted as in no more that say 4 - 5 mm gap around !!

    Dan.
     
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  4. opps

    opps

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    Thanks Danechip.

    Yeah, cutting the channels first would have made sense...

    I take it that the plastic part of the strip should be flush with the surface of the door?
     
  5. JobAndKnock

    JobAndKnock

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    Current fire regs staye that the gap around the three sides should be 2 to 4mm only, no more. A 5mm or larger gap would be regarded as a fail. Hinges must be fire rated and by definition a fire door should be fitted with an appropriately rated door closer. The gap at the bottom should not exceed 4mm when the door is closed. A better seal can be achieved by adding a drop seal to the bottom of the door, either routed in to the bottom of the door or surface fixed on the inside face of the door. Drop seals are required if the floor gap, when the door is closed, exceeds 4mm at any point across the width of the door. For 1 hour rated doors there are additional requirements in terms of intumescent hinge pads, wrapping of locks with intumescent paper, etc

    The "fluffy" strips (generally combined cold smoke seal/intumescent strips) are the most common type and come in brown or white from most suppliers. Whilst they are self adhesive, in high usage or aggressive environments (e.g. hospitals, universities, pubs, etc) it is quite common to pin with 16g or 18g pins every 200 to 300mm to prevent the strips working loose. In addition to the brush type cold smoke seals there is a second type, generally found in places like labs, hospitals, schools, etc, with a pair of parallel rubber wiper blades in place of the brush. This type is easier to disinfect/decontaminate but can wear more quickly

    Rather than try to run a router on the narrow edge if a door it is easier, faster, less risky and safer to use a bearing guided intumescent groove cutter (see Wealden Tool or Trend). These automatically cut to the correct depth
     
    Last edited: 19 Sep 2020
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  6. opps

    opps

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    Based on your advice I spent £30 on the Trend cutter from Toolstation. Thank you. It was money well spent. At five doors it worked out to £6 per door. With the first 2 doors I made the mistake of routiing doors that had been taken off. I then discovered that the A hole that fitted them had only left a 2mm gap. I then had to pack the hinges out and plane the lock side, which means I now to reset all of the mortice locks...

    The door hanging was shocking. Some of the hinges were so bad that I had to back fill them with 2K filler, a bit of polythene and then let the hinge in before the filler set.

    The door stops are retro fitted half inch by 2 inch, the stops are 10mm proud of the frames. It is an effin mess.

    And he told me that they, the "builders" had done a good job. So good that I have had to pack out every effing hinge and plane the leading edge and the reset the locks deeper.

    I get really pee'd of when I tell someone that I know need to charge them to re-do work that they have paid for, but I am not a charity.

    Here is an example of a hinge.

    20200919_142920.jpg

    And that wasn't the worst..
     
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  8. JobAndKnock

    JobAndKnock

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    That is truly awful. It is also an example of why chisel swingers like me tend to use a router to hog out the majority of the hinge recess to a consistent depth then just finish off with a chisel (that, and it's faster). Sorry, Woody, but I've seen far too many horror stories like that over the years where installation had been done by a "builder"
     
    Last edited: 21 Sep 2020
  9. opps

    opps

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    Yeah, when hanging a significant amount of doors I make a jig and use a tiny makita "laminate" trimmer to set the depth of the hinges. My only other router is an old Dewalt DW625. It does what I need it to, but the dust extraction is pants and I wouldn't feel confident using it on the edge of a door, additionally with the dust extraction "shroud" you cannot see the cutter when using it . I would upgrade but it is a tool that I might only use once a year or less.

    Anywho, all of the doors are now sorted, thanks to you and danechip.
     
  10. JobAndKnock

    JobAndKnock

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    With you on the DW625 - way too big, heavy and unwieldy for hinge recessing, even for Desperate Dan
     
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  11. opps

    opps

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    Agreed. It is an ancient machine but given how infrequently I use it I will continue to use it.

    out of interest do any routers have the rapid breaking feature?
     
  12. JobAndKnock

    JobAndKnock

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    Yes. The newest big Makita 1/2in routers (RP2301, etc) have it although TBH their dust extraction is pants. The only big routers I know of which have good dust extraction that I am aware if are the Festool OF2200e, the same company's OF1400e and the now sadly defunct (in the UK) deWalt DW622 - all 1/2in routers. I own both an OF2200 and a DW622 as well as both a 20 year old MOF177e (basically the Elu version of the DW625) and a 30 year old model and I can attest to the effectiveness of the dust extraction on the OF2200 and DW622 (and the longevity of the MOF177/DW625 router family).
     
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