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Patching Holes in Dark Rock

Original Post
Camdon Kay · · Idaho · Joined Mar 2021 · Points: 2,798

My local basalt crag has a lot of chopped bolts and empty holes everywhere, and I would love to help clean it up. Does anyone have tips for camouflaging patch jobs on rock that isn’t grayish granite or limestone? 

The basalt doesn’t crumble much, so it would be tricky to find a lot of rock dust or sand that would be a good color match. Is there a dark epoxy that works? I’ve been using instacrete.

Climb On · · Everywhere · Joined Jan 2016 · Points: 0

Grout pigment?

Brad Young · · Twain Harte, CA · Joined Apr 2009 · Points: 485

I carry a sharpie marker for all darker rock. Depending on how much ink you use you can make patches fairly dark. I usually rub the patch right after using the sharpie; this smears it a little and makes it a little less stark/blends it in.

bmdhacks · · Bellingham, WA · Joined Jan 2012 · Points: 1,633

I like to knap a flat bolt-hole sized pebble and then stuff it into the hole so that it sticks out and breaks up the patch.  See here for a patched hole in basalt 4 in to the right of the bolt...

Logan Peterson · · Santa Fe, NM · Joined Jan 2015 · Points: 186

Baggie of coarse sand/fine gravel. You can match any rock type if you have a hammer or smack 2 rocks together. Fill hole, then smear the mix in with thumb.

If you just want a dark gray fill, get some JB Weld putty at the auto parts store--the stuff that you can hand-mix rather than the 2 tubes.

Camdon Kay · · Idaho · Joined Mar 2021 · Points: 2,798

I went ahead and ordered some QuickCopper upon recommendation from Greg Barnes in an older thread. I’ll try to find some small basalt chunks to crush up as well! I’ll post up results. 

Brian in SLC · · Sandy, Utah · Joined Oct 2003 · Points: 21,701

I've used JB Weld putty a few times.  Some of the plumbers epoxy putty is easy to use and carry and its pretty dark in color.  Cheers!

John Clark · · Reno, NV · Joined Mar 2016 · Points: 1,398

Drill into some choss/loose basalt chunks to create the appropriately colored dust. Mix into your putty

Tal M · · Denver, CO · Joined Dec 2018 · Points: 1,524

Will say that as long as the color is generally a match, it matters less than the texture. My process is to use the aforementioned JB Weld putty and work it into the hole to the surface, then to take some small rocks from the ground/ledges and place them on the epoxy and then crush it with the hammer. This provides color, dust, and external color (as many times the dust is way lighter than the actual facade of the rock). I keep one small rock for the end and just roll and knead the patch with it to replicate texture. Generally with this process it creates patches that you often can only see if you know where to look and are intentionally looking for it - and even then I've seen some that I couldn't find until someone was literally touching it and pointing it out. 

Greg Barnes · · Unknown Hometown · Joined Apr 2006 · Points: 2,060

The ASCA provides 3 colors of hand-mix putty patching epoxy: light grey, dark red/brown, and very dark grey. The particular items are InstaCrete, QuikCopper, and FastSteel. I'd recommend FastSteel for black basalt, but on the other hand some basalt is red tinged. Here's a photo of what they look like after sitting on a windowsill for 8 years - InstaCrete is on both ends since it's the most common one we send out (unfortunately, the middle tan color is no longer made - that was QuikTitanium). I should probably do a fresh stick to compare and see if there's been color fading or not (the original idea with keeping it on the garage windowsill). Didn't have a really black rock handy, but that dark red rock is very dark:

Camdon Kay · · Idaho · Joined Mar 2021 · Points: 2,798

That is fantastic info, Greg! It’s been too sweaty to find partners to get out there and try the QuickCopper, but the FastSteel also looks like it would work! Some of the rock out here is more red, while others is very black. I think I’ll have to keep a tube of both handy

Cory N · · Monticello, UT · Joined Sep 2018 · Points: 841

Here is an anchor with a hole patched in wingate with QuickCopper supplied by Greg at the ASCA

Guideline #1: Don't be a jerk.

Fixed Hardware: Bolts & Anchors
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