rollingstone
starting to spend too much on rocks
Member since July 2009
Posts: 236
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Post by rollingstone on Aug 6, 2007 18:29:43 GMT -5
Hi folks, I found this piece of petwood today, and it's a special specimen for me as almost all petwood around here is brown, and the only pieces with red in them I've ever found have been tiny and usually crumbly. I put in some pics below, and you can see in the third pic that there is some kind of coating on the top and right-hand side of the piece. I'd like to get remove it so show the petwood below. Not entirely sure what it is, might be a rind of calcium carbonate, as the river is very alkaline. Just wondering if anyone has cleaned up this kind of thing before, and how? If it is calcium carbonate, then an acid soak would seem the route to go, but how strong and how long and what kind of acid? I don't want to damage the silicified wood beneath. Or should I use something mechanical like a dremel brush (seems tedious and might mark the petwood). Suggestions? -Don [glow=red,2,300]ADDED AUG.7 :[/glow] Here's the same view as the last picture, but after treating with muriatic acid (HCl) for just a few minutes, until the bubbling stopped. What a difference, thanks for the tips!!!
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Post by texaswoodie on Aug 6, 2007 18:41:21 GMT -5
Very nice chunk of wood Don. i would try oxalic acid. You can buy it at the hardware store as wood bleach. It's not going to hurt the silicafied parts at all.
Curt
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,472
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Post by Sabre52 on Aug 6, 2007 18:42:43 GMT -5
Don: That encrustation appears to be caliche which is simply calcium carbonate. Marine calcified algae leave that sort of calcium carbonate deposit too if that's a beach find. Should come off in an acid dip or maybe even with one of the acidic over the counter toilet bowl cleaners. I've used swimming pool acid ( muriatic acid which I think is hydrochloric acid) and it works great but does release chlorine gas and is a bit dangerous so be careful if you choose that option....mel
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fossilman
spending too much on rocks
Member since April 2007
Posts: 256
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Post by fossilman on Aug 6, 2007 19:26:55 GMT -5
muriatic acid may be the best way to go. It is hydrochloric, and should be treated with great care. Once it's stopped fizzing, it's cleaned. You can neutralize it with baking soda, just don't dump a whole bunch in, it makes a LOT of bubbles and can go over the bucket edge easily.
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Post by texaswoodie on Aug 6, 2007 20:14:17 GMT -5
Hey Dan I use muratic 50/50 and have never found anything that will hold it except glass. I even tried a steel porcelain coated pan. Went out there in the heat of the day and porcelain was popping every where. I tried to neutrilize it one time with fireplace ashes. The aluminum bucket I had it in got so hot I couldn't hold it and there was a toxic cloud hanging over our house.
So Don, be very careful with muratic.
Curt
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rollingstone
starting to spend too much on rocks
Member since July 2009
Posts: 236
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Post by rollingstone on Aug 6, 2007 20:39:55 GMT -5
Thanks for the quick replies of suggestions and warnings. I have a big glass container that would hold the entire chunk of petwood, so I'll have to give it a try. -Don
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Post by parfive on Aug 6, 2007 21:51:31 GMT -5
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WyckedWyre
fully equipped rock polisher
Member since April 2007
Posts: 1,391
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Post by WyckedWyre on Aug 6, 2007 22:50:00 GMT -5
I've dissolved that stuff by soaking wood in a strong vinegar solution, as well...might be safer.
:PS
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rollingstone
starting to spend too much on rocks
Member since July 2009
Posts: 236
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Post by rollingstone on Aug 7, 2007 2:12:31 GMT -5
Rich, that's an excellent link with detailed instructions, thanks.
Susan, I'll probably try the "good stuff" first, being impatient by nature, but I am also curious about the vinegar (acetic acid). I've tried the 5% stuff before (standard vinegar), but didn't see much happening, do you use the standard vinegar or the more potent pickling vinegar (7% acetic acid), or something different? How long do you leave them?
Thanks again folks, -Don
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hoganflagle
having dreams about rocks
Member since April 2007
Posts: 62
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Post by hoganflagle on Aug 7, 2007 4:33:44 GMT -5
Not sure why the effort to acid bath in glass or metal containers? I used to clean a lot of antique bottles with straight muriatic acid and I did it in 5 gallon plastic buckets without any problem. Figured out using the plastic buckets would be safe since the acid came in plastic jugs.
I did have to take a lot of precautions with the acid such as storing the buckets in open ventilation where the acid fumes would not harm anything, and where kids or animals could not get near it. I always kept a couple of buckets of baking soda solution nearby for any type of emergency. Neutralizing and disposing of the leftover acid was tedious and time consuming though.
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stefan
Cave Dweller
Member since January 2005
Posts: 14,095
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Post by stefan on Aug 7, 2007 10:30:22 GMT -5
I've tried vinegar before on some iron stains- left it soaking for weeks- to no avail- might work ok on calcium based stuff
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rollingstone
starting to spend too much on rocks
Member since July 2009
Posts: 236
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Post by rollingstone on Aug 7, 2007 22:33:11 GMT -5
Wow, a few minutes in muriatic acid, and the lime disappeared completely! Great stuff, thanks everyone for your help. -Don
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Post by larrywyland3 on Aug 7, 2007 22:43:04 GMT -5
nice chunk of pet wood
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Post by parfive on Aug 7, 2007 23:09:42 GMT -5
Ya gotta show a after pic, Don.
Rich
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rollingstone
starting to spend too much on rocks
Member since July 2009
Posts: 236
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Post by rollingstone on Aug 7, 2007 23:40:20 GMT -5
I know Rich, I just wanted to soak the petwood in clean water for a bit to get rid of any residual acid. Pic added up top with the others. I went for the good stuff (hydrochloric acid), works like a charm, thanks for the link! -Don
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Post by flintfish on Aug 8, 2007 5:08:13 GMT -5
Beautifuly done mate - that cleaned it up nicely.
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