# Hard adhesive for broken marble piece



## Canarywood1 (May 5, 2012)

"If that's true, using epoxy to glue on the split off "chip" won't work. In fact, didn't - for what ever reason."


Thats what they use to patch cracks in marble


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## stadry (Jun 20, 2009)

when we had a monument company, akemi was the ' go to ' supplier for marble/granite repairs,,, here's our source:
https://www.granquartz.com/Pages/It...h_type=Product&class=&advanced=&productPage=3

just as w/good tools, good materials aren't cheap


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## tearitup (Jan 4, 2015)

@Canarywood1 - epoxy "used to patch cracks" in marble, vs. used to glue a large piece back on? Two diff things. There are different chemical formulations in "2 part epoxies" - assumed for different materials? My knowledge falls short here. Probably, "epoxy" is kin to terms "caulk" or "glue." 

The epoxy didn't adhere well to the bumpy surfaces of the split piece or the bumpy bored hole. Now I notice the borehole walls & broken chip are bumpy, but still have very visible sheen. Don't know how it's possible to have an even textured, bumpy surface on a bored hole that still has some sheen. 

But it stuck well to the countersink hole (for bolt head) on underside of the base. Countersink hole is smoother, but 100% dull. That part took chiseling to remove epoxy.

Seems likely I'll have to dull the glue surfaces, but they're moderately to very bumpy. Hard to sand or grind anything but the peaks. Maybe some muratic acid (already have) will etch it & dull the surface? 

JB Weld says,http://jbweldit.com.au/index.php?main_page=document_general_info&products_id=9


> "For the best weld, roughen surfaces to be welded with fine or coarse sandpaper."


Marble is listed as compatible material."
Again, the support agent said it has to be ~ 1/8" thick layer to reach rated strength. Full strength is overkill - just needs to stick. 

An unscientific test of tensile strength for several brands of 2 part epoxy (mainly for metal), in a shop on sandblasted surfaces. 



 To see which ones failed 1st.

Possible variable in the video - if the same epoxy thickness wasn't left under each bolt head - affecting strength. If only 1/32" less epoxy out of say, 1/8" was used, that's 25% less thickness. 

Many yrs ago, I believe some brands of general purpose 2 part epoxies struck better, were stronger (as were some cyanoacrylates).


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## stadry (Jun 20, 2009)

caulk, glue, & epoxies are entirely different materials employed for differing purposes,,, if 1 is willing to use ' $6 ' materials while anticipating $100 repairs, who's in error ? gave a good source but feel free to stick w/apron/vest store materials,,, using the correct epoxy, thickness would be measured in mils,,, today's materials are far superior to what we had 35yrs ago


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## tearitup (Jan 4, 2015)

@ stadry - thanks for the link, but this an inexpensive item.
The products on the linked site may be superior, but they cost several times more than my item.

I'm quite sure the shiny surface on the broken parts & borehole, what ever the cause, is why epoxy didn't stick. It stuck where the surface was dull. 

I'll have to dull & clean the irregular surfaces - probably w/ acid or abrasive powder & small brush. Maybe a Dremmel flexible abrasive wheel.


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