11th Feb 2007, 04:21 PM #1
What is the best glue for laminating beams ?
I still have a quantity left of the structural timber pack (bought 2 years ago is part of the Vic great hardwood purchase )and I want to make a laminated beam to support a bearer so I can remove a stump that is in the way.
The timber is 120*35mm and I would laminate 3 pieces to form a beam 120*105mm.
What is the best glue for that? Would pva be suitable as I will be using a few coachbolts to keep them together as well.
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11th Feb 2007, 04:34 PM #2
Recorcinol is the glue used commercially but you would not need a waterproof glue being under the house I guess so I would use PVA but the bolts as well ??? Dunno. Sounds as though you are spanning maybe 3 meters or so in which case more than 120mm would be the go .I've just become an optimist . Iv'e made a 25 year plan -oopps I've had a few birthdays - better make that a 20 year plan
11th Feb 2007, 05:03 PM #3
The span of the beam will only be about 1.1 metres and the span of the bearer resting on it is also about 1.1 metres.
But I like to over engineer where removal of stumps are concerned hence a few bolts.
11th Feb 2007, 05:14 PM #4
Glued beams use resorcinal as it won't deteroirate from humidity in the air.
But if its going to be on edge you could vertical laminate using bolts without using any glue. Put bolts through every 240mm with them alternating about 25 - 30mm in from the edges
like the asterisks are here
* .*. *. *.
. *. *. *. *
----------------Regards, Bob Thomas
11th Feb 2007, 06:10 PM #5
Thanks Bob, your diagram makes good sense.
As they will be on end it looks like some pva glue and bolts will be the way to go.
That will be nice and simple to do and the removal of that annoying stump will give me much easier access to the DC area for emptying the separator drum and beyond further under the house for additional storage areas.
11th Feb 2007, 06:17 PM #6
$15 will get you a bottle of polyurethane glue from Bunnings. I think its called vise grip and is an Australian made product.
It's waterproof and works very well. I would use it over PVA for a structural application. The other option is epoxy. Techniglue is ideal but more expensive again.
11th Feb 2007, 10:51 PM #7
Is this a permanent fixture or just something you are going to do as a temporary thing until the stump is going to be removed?
If this is a permanent fixture to be used in your house or some other building, you should engage a structural engineer (I am assuming that you are not one) to specify the beam. I suspect that said engineer would not be overly keen on certifying a beam made by you (or me if it came to that). I would certainly be seeking professional advice before proceeding.
I'm not doubting your ability or enthusiasm just that I would hate to see you unintentionally underestimate the complexity of what (it sounds like) you are doing.
If you know what you're doing, please forgive me and understand that I was offering this advice with only the best intentions.
12th Feb 2007, 07:29 AM #8
Good advice Mark as this kind of work should not be undertaken lightly by aspiring DIYers and a general warning regarding this kind of work is most appropriate in this kind of thread.
But I've had some experience in this as over the years I've already removed 10 stumps to create my workshop underneath the house and replaced a load bearing wall with a large beam.
The initial ones was with an engineering mate to help me and none of the stumps I've removed and replaced with beams have had any problems.
Thanks for your concern,
12th Feb 2007, 07:36 AM #9
Sturdee, whatever glue I chose it would certainly NOT be PVA or any similar thermoplastic glue. Any joint subject to load, even temporary load, is liable to creep and possibly let go. I don't think you'd like that.
Use a glue like resorcinol or epoxy - not for their water resistance, which is immaterial in this situation as already noted, but because they don't creep.
12th Feb 2007, 07:53 AM #10
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