Sandstone bolting with power drill

I just bolted a short sandstone route with a small 20 volt rotary hammer drill. I used the 1/2” wave bolt glue ins that needed about a 5” hole. Everything has gone well, but before I start on some longer routes nearbyI have a question for experienced sandstone bolters? Holes drilled in 6-10 seconds...I got the right depth, blew them out clean, filled with Red Head 2 part epoxy 2/3’s full, taped in all the way with rubber mallet.

Everything seems great, but is 5-10 seconds normal, or is this rock too soft?

If the drill is a dewalt 20 volt the rock may be fine. That drill is a beast.

If the holds are solid the bolts will be good. Propably.

Do you do a vibration tap test on the rock before you drill your hole? Place your hand next to where youre about to drill and tap lightly with your hammer to see if the section of rock youre about to drill into feels solid without marking up the rock.

While not sandstone, i develop a lot on volcanic tuff and have seen some pretty bad rock to this point. I think 5-10 secs to drill a hole is really fast. Thinking about it, i like that 30-60 sec mark to drill a hole into good tuff.. might not be that long for sandstone but 5-10 secs seems like a really short time.. Did you hit any really soft patches while drilling? Like the drill bit is sinking in slowly then drops into the hole suddenly like you hit bad patches while drilling.

And you know the only respectable thing to do after bolting a route is going up and testing the falls... get er done!

Edit: Also listening closely to the sound of how the bit sounds when it hits the rock. Drilling into good rock almost sounds like its chiming or clanging when it makes contact. Bad rock sounds when you hit it sounds like youre hitting wet cardboard. Has a very dull sound as well when drilling.

I have a little bigger drill, Bosch 36v. Unless we're talking about Dakota or Nutall, that's all it would take.

I think if you're a little worried, it was wise of you to use glue ins.

Less then 10 seconds is fast for any rock.  Our sandstone takes 15-20 seconds., and is widely considered choss.  Sandstone that is weathered and no longer strong should be cleaned off the wall.  Testing a bolt location for good rock is the most important part of drilling holes.  The hammer tap test will give you an idea if your rock is ok, if the hammer rings and bounces back when tapped the rock is good,  if the hammer doesn't bounce back and the tone is flat and vibrating, the rock is bad. Are you drilling stuff at Peshastin? Its easily some of the worst I've ever touched. Might be the problem, its like 100 PSI concrete.

Thanks guys. Great info. I tap tested the first one kinda without knowing and it was fine. I’ll check the others  and proceed carefully. Looks exactly like Peshastin. Not near any cracks or fissures or layering. Feels even going in. It is a brand new Dewalt. It’s hard to imagine how such a long glue in could fail unless...Famous last words...

Zach Harrison wrote: Are you drilling stuff at Peshastin? Its easily some of the worst I've ever touched. Might be the problem, its like 100 PSI concrete.

Only place I've ever actually pulled an anchor completely out of the rock with my fingers and made my peace with god before rappelling. 

Also the only place I've ripped the wall apart trying to place a nut.

Also the only time I've felt smears weren't secure, brushed my shoe on my calf, then realized I was actually just removing grains from the "solid" rock because my rubber was that sticky.

I think you could hand drill there in 60 seconds or less. 

As a granite developer, 6 seconds to drill a 1/2 inch hole sounds like you're drilling through a loaf of bread. My gut says you may want to spend some time learning how to analyze rock quality before putting any more bolts in, but i'm not a sandstone developer, so maybe i don't know what i'm talking about. Either way, take your time learning and be safe out there.

Sounds like it may be closer to siltstone...I would be highly suspicious of the anchors quality

How about attaching a picture of the bolt in the sandstone?  I’ve drilled SS before and used 1/2’ dia x 4” expansion bolts.  Definitely check the area around the proposed bolting location.  I prefer the size of a basketball for solid sounding rock for the location.  It sounds like the sandstone you are drilling some sugar sandstone.  “Highly granular.”  If this is the case then I would heed caution to your route effort.  As mentioned previously, you do want your hammer test to have a solid “pinging” sound.
I also use a bore brush and blow tube to clean out the hole. FYI.
Send some pics or a short video if you are in doubt.  Best luck!

-Jeremy Nelson wrote: How about attaching a picture of the bolt in the sandstone?  I’ve drilled SS before and used 1/2’ dia x 4” expansion bolts.  Definitely check the area around the proposed bolting location.  I prefer the size of a basketball for solid sounding rock for the location.  It sounds like the sandstone you are drilling some sugar sandstone.  “Highly granular.”  If this is the case then I would heed caution to your route effort.  As mentioned previously, you do want your hammer test to have a solid “pinging” sound.
I also use a bore brush and blow tube to clean out the hole. FYI.
Send some pics or a short video if you are in doubt.  Best luck!

You can tell how strong a bolt is from a picture? I´m impressed! Save me a lot of laborious testing in the future.

I'd be surprised the stone is climbable. Wouldn't trust anything but glue ins or 12" of snow picket pounded in at an upwards angle.
Mechanical anchors don't set in soft unconsolidated rock. You can keep wrenching forever. If that happens, you need to find if there is any different matrix nearby by tapping your hammer. Be prepared to yank the failed bolt and patch the hole and abandon it. 

Don’t be so sure about glue ins in soft rock.  I’ve seen botched glue ins come out by hand once the glue dried.   The surrounding rock was so bad the glue had no good surface to bond to and it pulled out along with a layer of sand attached to the glue.

Google “glue in bolt failure” and look at the images. 

i honestly don't know why anybody would waste their time and money bolting anything on peshastin-like sandstone.  it sounds like you weren't banging the rock and listening before installing the bolts - this is a sign of serious inexperience.  even on good rock you always want to verify that the rock you are drilling into is good.  i honestly wouldn't want to climb something you have bolted on this type of rock.  i know this sounds harsh, but i am just being straight with you.

bheller wrote: Sounds like it may be closer to shitstone...I would be highly suspicious of the anchors quality

fixed it for you :)

Jim Titt wrote:

You can tell how strong a bolt is from a picture? I´m impressed! Save me a lot of laborious testing in the future.

For those of you that aren't familiar - Jim tests gear!  In a lab!

slim wrote: i honestly wouldn't want to climb something on this type of rock. 

Fixed that, seriously WA sandstone all seems to be closer to a sand dune than stone. Never found sandstone in WA that I would want to trust any type of bolt in. Granted I haven't check out the new boulders in Bellingham, but I don't need to trust bolts there. 

6 seconds? Probably take that long to drill through a bag of sugar along its width.

I don't know why you would bolt that Peshastin choss? You should go to these areas where they have bomber bolts in bomber rock.   

I can drill a 5 inch  1/2 hole into our local Navajo Sandstone with my 20V Brushless Dewalt in 10 seconds.  I prefer wedge or sleeve bolts because if they tighten up they are good.  If they spin and wobble then I know the guts of the bolt hole are hollowed out sugar rock and that I need to reconnoiter.  I always shied away from glue ins for the reason Kevin gave above thread.  

Well now, all I got to say as a choss to good (not great) bolting guy, is, it ALL depends on the rock and the "hammer hollow test"  You, as in life, can be fooled by appearances.

A long angle piton driven into a drilled hole may yet be the most secure for softer rock. The hole should be tapered, narrower in deep and wider nearer the surface. The channels of the piton dig into the rock. If you decide to remove the pin, the mangled hole may be more difficult to patch, although no worse than removing a glue-in.