Saturday, May 29, 2010

Sika™ AnchorFix-2 anchoring adhesive

Whilst exploring the masonry area of my local big-box homeowner's warehouse store, I discovered the most wonderful adhesive / fill material. It is intended for fixing anchor bolts, rebar, threaded rod, and the like in holes in masonry. It sets very fast and may be fully loaded typically within an hour (depending on temperature).

For the maker / mad scientist / hobbyist / engineer, I would say this material fills in a notional gap between say, JB Weld and a bag of Quickrete™.

It's called Sika AnchorFix-2. It is a quartz(silica) filled, two-part acrylated epoxy packaged in a standard (10oz) caulking tube. The two components of the epoxy are separated by long skinny bags inside the cartridge. These bags are closed with a crimped wire at the nozzle end. To open and use, one simply removes the replaceable cap from the nozzle, pulls the crimped plastic out a bit, cuts it off with a knife, inserts the cartridge into a caulking gun, connects one of the included mixing nozzles and get busy.

The stuff is stronger than concrete. Pot life is strongly dependent on temperature, but this stuff cures fast! At 20ºC it has a working time of only 5 minutes, and in 40 minutes it has reached its full strength for rated loads. Work quickly or in small batches.

It's a bit tough to find detailed technical properties. There are bulletins with its ratings for specific anchoring applications for which it is intended (such as threaded rod or rebar into undercut holes in concrete) but not much else that I've found so far:

And it's expensive. I paid $19 for a 10.1 oz tube at Home Depot. It comes with two mixing nozzles and a cap. I used up both nozzles (clogged both with cured epoxy) in quick succession. But I soon discovered that where the stuff comes out of the nozzle on the cartridge, the two ingredients don't really come into contact - much. The tube come with a cap so you can recap it. Turns out you can simply squirt it out onto a handy piece of cardboard and mix it up with a putty knife. Clean it off your putty knife before it cures or you'll be sorry.

I bought it to anchor the floor end of a piece of reinforcing steel which beefs up the entry door to my garage and workshop. But it appears I'll be able to save the rest for a future job, which is good, given the price tag.

The cured product is quite tough and abuse resistant, and sticks to anything normally epoxy-able. It is FAR less brittle than portland cement-concrete. Within an hour, you need a masonry bit to get through the stuff. Hammer blows don't faze it once cured. It sure doesn't like being heated to the melting point of steel though, heh-heh. (I had to weld on some steel that had this stuff under it). Makes an awful stink, which is no doubt toxic.

And DON'T try to drill it with HSS tools - it's got sand in it, remember?

I've never seen anything quite like this before. It goes way beyond the garden-variety, sand-loaded, butyl rubber masonry repair compound I've been using for decades. Now I'm going to be watching out for applications for this stuff all over my property...

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