DIY TT CLD advice

[webby]

Hi All,
Can you help?
I need advice on Glueing two materials together or maybe three...
I have a Nice piece of Walnut for the top layer of my plinth, i also have an Asda Granite chopping board to add mass and damping. But i am not sure how to bond them together?
I was thinking of using silicon sealant and put some heavy weight on the plinth to seal them together, or maybe No more nails / grip fill type gunk? Also i have a roll of Lead flashing i could use for a CLD sandwich , but i am not sure if its necessary?
Thanks for any advice you can offer
Ian

 

[despotic931]

I would try epoxy.

How thick are you planning on going with the walnut, and will it all be machined after the glue up?

I ask simply because I have been researching building a diy turntable, but dont know yet how I will go about making the platter.

-Justin

 

[webby]

Hi all, Justin.
I have bought a VPI platter and bearing, Also using the fantastic Mark Kelly / Sylvain motor controller. The plinth is 45mm thick walnut worktop. I was planning to drill the bearing hole, fit the bearing and then bond the granite chopping board to it. I was thinking of silicon sealant so i could separate them if I needed to get at the bearing nut. The plinth overlaps the granite, so i will screw the feet into the plinth and the granite would be off the shelf. The granite is polished, so i am not sure how well it will stick, its heavy and could do a lot of damage if it fell off.
Would epoxy be permanent, if so could you suggest another bonding material.
Many thanks
Ian

 

[graeme uk]

I think using silicone would defeat the object. You want to couple the materials together, silicone will isolate them from each other.

As mentioned, try and use an epoxy glue. Araldite will work out expensive but theres got to be other options.

 

[despotic931]

Hi all, Justin.
I have bought a VPI platter and bearing, Also using the fantastic Mark Kelly / Sylvain motor controller. The plinth is 45mm thick walnut worktop. I was planning to drill the bearing hole, fit the bearing and then bond the granite chopping board to it. I was thinking of silicon sealant so i could separate them if I needed to get at the bearing nut. The plinth overlaps the granite, so i will screw the feet into the plinth and the granite would be off the shelf. The granite is polished, so i am not sure how well it will stick, its heavy and could do a lot of damage if it fell off.
Would epoxy be permanent, if so could you suggest another bonding material.
Many thanks
Ian

You don't want it to be permanent? I would consider roughing up the granite prior to gluing. As far as non-permanent solutions go, maybe try Elmers ? It all depends on how permanent you want it to be, but I agree silicon isn't what you want to do.

-J

 

[webby]

Hi all,
Thanks for your input so far, Silicon is out.
epoxy glue, would this be permanent?
What about no more nails type stuff, that sets solid and could probably be prised apart with some force.
One last question, is there an easy way to rough the granite, sandpaper etc?

Thanks again
Ian

 

[graeme uk]

To get a bond good enough to work it will have to be permenatnt i think.

To roughen up the granite it would be best to get a diamond wheel for a hand held grinder and run a load of criss cross lines through it.

On the subject of cranite, yes, it will provide mass but it wont provinde any damping, granite is reasonably resonant i think. Its too hard to damp properly.

I'd use the granite for the bottom layer personaly.

 

[kevinkr]

A little more work, but why not get some masonry or rock drills and carefully drill a few holes in the granite block and use large nuts and bolts to hold the pieces together - this will allow you to get really good coupling between the pieces and is not permanent if you need to take things apart in the future for modifications.

Another option would be to install threaded brass inserts (hollow threaded sleeves) in the granite block - epoxy them into place. These inserts are commonly used in furniture and are available in quite large sizes. You can them bolt the granite block to the rest of the plinth.

Drilling the block requires some care, a little water for cooling and a good drill. Everything you need should be available at your local home center.

A local "monument" (grave marker) maker might be willing to do the work for a reasonable fee if you can't drill the granite yourself.

 

[nhuwar]

Non permanent, try double sided transfer tape.



You need diamound to cut granite.

 

[SaSi]

I agree that epoxy gives a good bonding together without isolation between the two materials and silicone or any elastomer material creates some isolation.

Why would the elastic isolation be dismissed? Isn't each density change acting as a dampener?

If a non permanent non-isolation bonding is required, I would also consider 4 screws. As I understand it, the granite is under the walnut. If the walnut has enough thickness to secure screws, 4 holes to house the screws on the granite would allow an underside coupling.

 

[YNWOAN]

I would (and have done) use either Epoxy for a non compliant fixing or Contact adhesive (like Thixofix) for a more compliant fixing. I wouldn't use silicone myself unless you want an extremely compliant mount - in which case i would use thin spacers between the materials whilst the silicone sets.

 

[webby]

Hi All,
Thanks for the suggestions. I am not sure if i want compliant bonding between the layers, some advice on this would be great.
I held the Walnut plinth (top layer) and did the knuckle wrap test, i then lay the walnut on top of the granite and did the same. With the granite made a massive difference, so i just want them together, but i don't know if i want compliant or non compliant bonding???
Has anyone tried hardwood and granite?
The reason i would like non permanent is, i may in the future upgrade the platter and bearing, but would like to keep the walnut plinth?
Please keep your ideas coming, i really appreciate it.
Ian