Granite Attachment

[L Harding]

Hi all

Im making a dinning table, oak underframe (legs and rails - standard set-up)

The granites 30mm and has a 30mm overhang all round. Problem is i dont know how to attach it to the rails. I'd normally pocket screw or button a wooden top on, but i cant see the granite taking a screw!

Has anyone got any experience of this?

Luke

 

[Chems]

Isnt there a glue for granite tops?

 

[big soft moose]

normally you'd set it in as frame to protect the edges but thats not an option here.

based on my meagre experience (two slate topped tables) I'd say that you either get a specialist with a rock cutting saw to do a dado to fit on frame top , or you glue four battewns in a square to the rock then screw the frame to them

 

[Max Power]

Luke , a granite tabletop 30mm thick isnt going anywhere. Once the base is in position bed the top on a bead of clear silicone, job done :wink:

 

[big soft moose]

Luke , a granite tabletop 30mm thick isnt going anywhere. Once the base is in position bed the top on a bead of clear silicone, job done :wink:

problem with that come when some numpty (or more likely two numpties given the weight) picks it up by the top to move it and the weight of the oak pulls the frame off the silicon sealant.

 

[Woody Alan]

The people who install fireplaces have an epoxy specifically for granite and marble to glue to itself. I would have a chat with them see if it works on wood too.

Alan

 

[CNC Paul]

For permanent fixing of granite you need Akemi, I would go with the silicone.

 

[Max Power]

I wouldn't attempt to move the frame and granite as one item regardless of whats used to secure it ,at least with silicone they could be separated for transport

 

[Mr Ed]

When I use stone in that format in construction work I use Keil undercut anchors to fix it. Looking at the Keil website they appear to have a product intended for countertops, rather than buildings.

http://www.tile-eze.com/CountertopAnchoring.html

The issue may be the cost of the kit to drill the undercut holes, but I bet you could find a stone supplier with an undercut setup

Ed

 

[dickm]

SDS drill into the underside of the granite, Rawlplugs and then screw on standard buttons to engage with slots in frame? As with timber top, but with care?
(Daughter made a HUGE granite dining table, but she welded up a steel frame for the undercarriage, with the granite sitting in a shallow well)

 

[Mike-W]

I made a 35" x 35" workstation for our new kitchen about 18 months ago, the frame is 4" x 4" legs with rails under the Granite top and a base shelf all made from Ash and Tulipwood which was painted with Milk paint. I was advised by the Granite supplier to fix the top to the frame with a thin bead of low modulus Silicone, well after 18 months there is no sign of movement whatsoever- Job Done!

Mike

 

[L Harding]

thanks guys the silicon sounds like a good solution. The things going to weigh a ton so i can see it moving much anyway, so silicon beading round the inner side of the rails should be a perfect solution. I can tell them about future movement etc anyway.

Cheers

 

[awkwood]

I would use either evo-stick sticks like s**t adesive or sikaflex, both have worked well on similar projects, but moving it by the top may be a problem.
There is also the option of sticking 2 battens or even on all 4 sides, to the underside of the granite and then screwing to this. These would have a much larger gluing area depending on the width

 

[Doug B]

Having watched a granite firm remove their work surface from a kitchen i`d installed 7 days after they`d fitted it even though there was a large fault in it, i can`t see you`ll have any problem with silicone.

They certainly did.

 

[eoinsgaff]

Would it not be possible to epoxy some form of nut into a small core/hole in the base of the granite. A bolt could then be fastened from the legs, through a slot rather than a hole, up into this nut.

One of those threaded gismos for break down (MDF) furniture would probably be a better option than the nut but I'm sure you get the idea.

Eoin

 

[ondablade]

Epoxies and i think polyurethanes usually work very well on stone and concrete. Hilti have for many years offered a heavy duty anchoring stud that's bonded into a drilled hole using epoxy contained in a glass capsule.

Araldite is now owned by Huntsman, the TDS for their stone bonder is below.

That said whatever i was thinking of using i'd want to call their UK operation's tech support to verify the selection, as the potentially large differential in rates of expansion between stone and wood could cause joint failure fairly quickly. Thickness of the bond line (layer of adhesive between the surfaces) is probably important too for a product to be able to handle movement. Strength if you have a large bond area may not require to be all that high.

Chances are that the likes of Dow Corning (structural silicones used to bond tiles etc to buildings, or ship's decks, and Sika (mostly polyuethanes, but i think for similar applications) would be able to offer high flexibility options.

I've very successfully bonded lacquered birch to tiles using a high quality bathroom silicone - it's still perfect a year later.

ian

November 2007 Araldite® Stone 1800 A/100 B 1/3
Advanced Materials
Araldite® Stone 1800 A/100 B
Epoxy System
Araldite® Stone 1800 A/100 B
Medium-viscosity, fast curing liquid epoxy system for natural stone
processing applications
Applications Araldite® Stone 1800 A/100 B epoxy system is designed to meet todays demands for
innovative stone processing. It is especially suitable for:
slab reinforcement with mesh
Characteristics Araldite® Stone 1800 A/100 B epoxy system presents the following features:

high adhesion even to damp natural stone surfaces

stronger than stone

excellent breakage resistance

high moisture and chemical resistance

very low shrinkage

curing at room temperature as well as for accelerated oven cure

no solvent or styrene emissions
Technical Data If not mentioned otherwise, the following technical data describe the typical properties of
ready mixed Araldite® Stone 1800 A/100B epoxy system.

Aspect: transparent yellowish liquid

Color (gardener): <3> 95% of final strength) 2 hours at 40°C
1 hour at 60°C

TECHNICAL DATA SHEET

November 2007 Araldite® Stone 1800 A/100 B 2/3
Instructions for use

The stone slabs must be clean and dry before the ready mixed
Araldite® Stone 1800 A/100 B epoxy system is applied.

By weight 100 parts of the A-component must be homogeneously mixed with
25 parts of the B-component. (eg. 1 kg of A-component with 250 grams of
B-component). Alternatively by volume, the mix-ratio is 100 parts of the A-component
to 25 parts of the B-component. (eg. 1 litre of A-component with
250 ml of B-component) which must be homogeneously mixed.
Araldite® Stone 1800 A/100 B epoxy system can be applied manually, for example
with a fine toothed spreader or roller as well as by machine, for example by spraying.
Specialist firms have developed resin application equipment from meter-mix-
machinery to fully automated resin application lines. Huntsman will be pleased to
advise customers on the best choice of equipment on their particular needs.
All tools should be cleaned with hot water and soap before
Araldite® Stone 1800 A/100 B epoxy system residues have had time to cure.
The removal of cured residues is a difficult and time-consuming operation.
If solvents such as acetone are used for cleaning, operatives should take the
appropriate precautions and, in addition, avoid skin and eye contact.
The potlife of 250 grams of readily mixed Araldite® Stone 1800 A/100B epoxy system
at 23°C is 15 minutes counting from start of mixing. This time will be shorter for higher
temperatures and longer for lower temperatures. Similarily the potlife will be shorter at
larger mixed quantities and longer at smaller mixed quantities.

The open time of freshly mixed Araldite® Stone 1800 A/100B epoxy system applied in
200 g/m2 layer is 45 minutes at 23°C. Within the open time the mixture remains liquid.
The open time will be shorter for higher temperatures and longer for lower
temperatures. Also this time may be influenced by the ambient level of relative
humidity. Bonding of the mesh to the coated marble slab should take place within the
open time.

The minimum curing temperature of Araldite® Stone 1800 A/100 B epoxy system is
10°C. Below this temperature Araldite® Stone 1800 A/100 B epoxy system will not
cure sufficiently.

Stone surfaces coated with Araldite® Stone 1800 A/100 B epoxy system will be tack-
free and allow for further handling after 4 hours cure at 23°C. Higher temperatures of
oven cure will accelerate this process, for example at 60°C cure Araldite® Stone 1800
A/100 B will have tack-free surfaces which allow for further handling after 30 minutes.

Araldite® Stone 1800 A/100 B will reach practically full strength (>95%) after 6 hours
cure at 23°C. Oven cure at elevated temperatures accelerates this process, for
example strength > 95% of final strength of Araldite® Stone 1800 A/100 B will be
reached after 1 hour cure at 60°C and subsequent cooling.
Packaging Araldite® Stone 1800 A/100 B epoxy system is available in hobocks (27 litre for A-
component, 30 litre for B-component), 215 litre drums and 1000 litre containers.
Storage Araldite® Stone 1800 A/100 B epoxy system may be be stored in the sealed original
container in a dry place at temperatures between 2 and 40 °C for at least 1 year. The
product should not be stored exposed to direct sunlight. The expiry date is indicated on
the label.


Araldite is a registered trademark of Huntsman Corporation or an affiliate thereof in one or more, but not all, countries.
© 2007 Huntsman Corporation. All rights reserved.

 

[jasonB]

I would just put a couple of small beads of silicon against the inner edges of the rails just to stop the granit from getting nudged out of place if its a small table, large one I would not even bother. My granite fitters seldon stick the worktops down, just a bead of silicon along the front edge to stop water running back under them is enough to stop them moving.

If the table needs to be moved into another room its likely to have to be moved on its side, trying to do this with a fitted top is not going to be easy. Having removed more than one granite worktop thats been stuck down you will either damage the granite or the table trying to get it off.

Jason

 

[Benchwayze]

http://www.365drills.com/adverts/drilli ... rktops.htm

This site reckons the best way to drill granite is with a diamond core cutting bit.

Depending on thickness of the granite, you could counter-bore for a nut fixed with epoxy and then use angle plates to secure from beneath.

Mind you, I don't know how much a diamond-core bit will cost, or if there's any resale value if you aren't likely to want it again.

Best of Luck

Regards
John

 

[jasonB]

356 are a bit of a rip off, once court re selling lidl diamond discs ar 3 times the price

I get through quite a few of teh diamond coated hole saws and yes they will cut granite, I tend to buy from the following. These diamond coated holesaws are disposable so no resale value.

http://richontools.com/index.php?main_p ... &cPath=1_5

Jason

 

[dickm]

Well, like I said earlier, ordinary SDS bits up to 1/2" in my old Bosch electropneumatic drill have no problems in the sort of structural granite you find round Aberdeen....... So unless worktop granite is very different, that would still be my choice.