Last hearth build question, I swear!

[brider]

I've already bought the screws to fasten together my plywood/Micore/cement board/tile hearth pad, but I can't help but wonder if there isn't a structural adhesive I could use between the plywood and Micore to REALLY make the resultant pad flex-free. I figure any flexing will be the result of shear between the layers, and a buttload of screws should distribute the load, but if the lower layers were BONDED together, that would be the best.

Is there a structural adhesive that resists high temps?

 

[fossil]

I've never worked with Micore, but I've certainly worked with plywood, Durock, and tile. A layer of thinset is commonly used between Durock and plywood, then the screws are installed. I don't know why a layer of thinset between the plywood and the Micore, then another between the Micore and the Durock wouldn't work. It's not going to increase the stiffness of the structure, though...just make for more complete bonding of the layers. Rick

 

[begreen]

brider, are you an engineer? Methinks you obsess too much over this. It will be fine.

 

[fossil]

Engineers rarely talk about quantities of threaded fasteners in terms of "buttloads". :lol: Rick

 

[brider]

Well, I thought of mentioning my 10 x Diameter pitch idea, but figured I'd be pegged for an engineer, which I was anyway.

I'll stop obsessing and just build it.

Picked up the Micore just today.

 

[Jags]

Huh, and I always thought "buttloads" was a technical term. ;-P

 

[jay3000]

Liquid nails..

 

[Jags]

Liquid nails..

Nope! Its considered a combustible and can actually give off fumes when heated.

 

[fossil]

Huh, and I always thought "buttloads" was a technical term. ;-P

Only when we're trying to get a point across to the guys who work on the flight deck. %-P Rick

 

[PeteD]

Engineers rarely talk about quantities of threaded fasteners in terms of "buttloads". :lol: Rick

True, we usually say "@#$^loads"

 

[Jags]

Huh, and I always thought "buttloads" was a technical term. ;-P

Only when we're trying to get a point across to the guys who work on the flight deck. %-P Rick

That comes from buttloads of JP5 fumes. :lol:

 

[badger1968]

Hey Brider--I just completed a similar hearth extension to yours. It's a Durock/Micore double decker sandwich on top of plywood and bricks. I recommend Thinset as your adhesive backed up with a fair amount of Durock screws. Good luck!

 

[brider]

Thinset, it is!

 

[jakep]

you can use a high temp mortar im a fire brick layer my company sells 3000 degree mortar that we use in furnaces.

 

[gerry100]

These days we use metric #$% loads, or metric butt loads.

 

[fossil]

Yes, one of the standard units of measurement commonly in use today around the world is the Bart, which is equal to exactly 1/1000 of a metric butt load, making a metric butt load equal to 1 kilobart. :coolsmile: Rick

 

[brider]

Finished screwing together the 3 first layers of my pad this weekend (4th layer is tile), a MAJOR accomplishment for me, a working stiff with 3 little kids and a wife that likes to say "I've had them all week, YOU watch them now so I can get something done...".

In this case, a "buttload" equates to about 175 1 5/8" coated Durock screws.

What I couldn't find was a suitable edge trim at Home Depot. Gonna have to look at a real lumber yard.

 

[fossil]

Sounds more like about two kilobarts. I bet if you had a great big electromagnet it'd pick that sucker up. Rick