Consolidant Duel - PVA Versus PVB - Drama Aplenty!

[tracer]

ok, so i've developed opinions and decided to share them with you. i consolidate a lot of stuff. why? um, dunno, it'll all outlast me anyway, but let's say i'm doing it for the legacy value. some bones i find are literally pseudomorphed completely into chert, but others, not so much. let's face it, some stuff is fragile, and we want it anyway. i've gotten kinda decent, i think, at drying stuff out. even though i have little patience (you're shocked, i can feel it), i have learned that what has to happen has to happen. i also resist the urge to be too cheap. no, i don't like spending money on cans of acetone, ethanol, etc., but whatever. if they're needed they're needed. so lately, the wet and fragile stuff seems to find it's way into a container with some ethanol in it for a while. what i'm trying to do is prevent shrinkage, cracking, delamination, and other forms of falling into pieces before my widdle eyes. after i figure out quite a bit of the water has miscibled with the ethanolaciousness, i let a tad of evaporiticality occur, and then perhaps even plunk the darn stuff into some acetone for another go round at miscibility and evaporativamoosing of dihydrogen monoxide in a manner that won't cause crying. i control all this through a highly technical and orchestrated series of putting covers on things, and draping stuff partially over things, etc. used to use some mojo too until that was diverted to other uses.

at any rate, at some point one just has to reach the conclusion that the stuff is dry and life goes on, so it's time for consolidation. hey, caveat time here - kids, don't do ANY of this stuff EVER! you WILL shoot your eye out if you try it! it's intensely foolish to engage in such endeavors. anyway, so i get a relatively wide-mouthed (no smart remarks here, you know who you are) glass jar (yet another hazard), and carry it past the blow torches (foreshadowing some future drama) and get out my bags of polyvinyl acetate and polyvinyl butyral, and go "eeny meeny miney mo". actually, i don't. i put both bags on the floor and flip a coin and see which bag it lands on. the pva i have acquired is in the form of little tiny beads. the pvb is basically a powder. ya'll realize i'm just avoiding brand names here, right? ok, anyway, i get some acetone, put it in the jar, put some of the copolymer of choice for the day into the jar, put the lid on the jar, and go away. oh, i forgot the part about the careful measuring of the copolymer. i put this much in <holding up fingers the appropriate distance apart>. anyway, i give the consolidant time to decide if it's going to cooperate, and when i return, i invariably find the same situation. if it's pva, it's behaved relatively well and dissolved quite a bit. if it's pvb, i can see it hunkered down in a sullen viscousness silently asserting that i can't make it play well with others. but some's dissolved, i know it has. so i get a stick and stir it. but what i tend to do with both, and ya'll are gonna really be mad with me for this admission of imprecision, i use the stuff off the top and then just put in more acetone and stir it again. i kinda keep doing that until i can see there's not really any gooey goodness left in the bottom of the jar, then i dump some more copolymer of choice in. it's not unlike having to readjust the sweetness of your tea when the waitress messes with you by refilling your glass when it was perfectly sweetened and only a third empty. ok, so anyway, both the pva and pvb will leave a pretty shiny finish on your fossil if you use too thick a solution or you put too many coats on. but you can dull the finish by just wiping the fossil with acetone later. both pva and pvb each have one characteristic which annoys me. with pva, it's its low glass transition temperature (T_g). it tends to have a slightly tacky feel to it even after it's dry, and i guess it would tend to melt and flow if you stored your fossils in too warm a place, although i'm not sure why you'd do that. but pva is much more forgiving than pvb in the area of moisture. pvb creates a white haze on your fossil in any areas that are not really dry. this isn't a huge deal, if the material is fairly smooth, as a quick wipe with acetone seems to clear up the problem, but i sort of hate having to be careful regarding humidity and wondering if i've let a bone dry out long enough to avoid the problem. i don't really like letting bones get bone dry anyway cuz all they seem to know after they're dead is how to crack and make me mad. but pvb has a nice finish and feel to it after applied, and it seems to penetrate well in thin solutions. i think i may just keep using them both, sometimes. i still haven't figured out exactly what i want to do regarding using cyanoacrylate glue and consolidant together. i'm not sure how well cyanoacrylate glue sticks to pre-consolidated material, but i know i don't like putting the consolidant on after using the glue because the acetone in the consolidant will rapidly loosen the glue, and makes it go whitish also.

your mileage may vary!!!! kids, go study and stay away from 'splosive hazmaticious chemicals! haven't you ever see all the stuff that happens to that darned coyote on those cartoons!?

[beck man]

tracer only read a bit of that lot your like my daughter would be a millionaire if u got paid for talking. PS i only use water soap and a cloth to prep my bones and fossils honest.! tara for now beck man.

[tracer]

tracer only read a bit of that lot your like my daughter would be a millionaire if u got paid for talking. PS i only use water soap and a cloth to prep my bones and fossils honest.! tara for now beck man.

what makes you think i'm not a millionaire, and that i don't get paid for talking?

[barefootgirl]

All I can say to that is................

Even when your trying to pass knowledge on you still make me laugh!

[Auspex]

I rather like the Tao of letting the copolymer achieve its own oneness with the solvent. I'd be all wrapped around the axle about getting it ALL TO DISSOLVE! (I'm kinda' A.R. that way...). Do I presume that brushing is your preferred method of application?

[tracer]

I rather like the Tao of letting the copolymer achieve its own oneness with the solvent. I'd be all wrapped around the axle about getting it ALL TO DISSOLVE! (I'm kinda' A.R. that way...). Do I presume that brushing is your preferred method of application?

no my preferred method is submerging the fossil in the consolidant until no tiny bubbles come from it any more. but that's not always possible for me with the large stuff, in that i'm just not up for having big vats of it around. so i tend to brush/drench the big stuff.

as for getting it all to dissolve, one tip i saw in a florida paleo club newsletter was to take the jar of stuff and put a couple of rubber bands around it and put it on the rollers of a rock tumbler for an hour or so. you can get it all to dissolve, assuming you haven't gone too far overboard with the proportions. some people make a very thick "glue" of the solution and then just keep that stored and use it for sticking broken pieces together and also then dilute some of it with acetone when they need a consolidant. i probably just ought to get a much bigger container and more precisely make a much larger amount of consolidant to start with, which would allow me to dunk much larger stuff. the goal really is to get the stuff into the middle of the fossil too and not just have a hardened "crust" on the outside while the inside continues to be unprotected and deteriorate. and all this also has the goal of being reversible. art conservationists have a "code of ethics" that they follow, and i wish fossil conservators would adopt something similar. too much of what people are doing to fossils lately is trending toward fabrication, the euphemism for which has become "restoration". at least glue some little pegs on its neck so people will know they're buying a frankenfossil.

wait, where was i?

[bear-dog]

Nice thread.Really happy you added the part about wiping with acetone if you have whitish areas.Not too many people tell the new guy or girl that hint.

[tracer]

Nice thread.Really happy you added the part about wiping with acetone if you have whitish areas.Not too many people tell the new guy or girl that hint.

a quick wipe with acetone will remove a mild whitish haze. wiping a lot in one area will start removing and gumming up the consolidant and dulling the look of it. it readily redissolves with acetone.

oh, another point. after you use the stuff awhile you sort of develop a sixth sense regarding how to tell how thick or thin the solution is. if you dip a stick into it and lift it up, you can see how "watery" or "syrupy" the runoff is. and pure acetone evaporates fast, so you can actually see the wetted surface of a fossil's drying speed. the faster it's evaporating and the lower the sheen, the less copolymer is involved. it's all very scientific the way i do it - i even have a little chant i chant to control the process. it works very well, as illustrated below:

here is a picture of a fossil that i found that needed a little work -

and here is a picture of it after using my consolidant solution with chant -

please note that it's longest angle is now also well over 7 inches, so don't be pm'ing me offers for this puppy unless it involves big wire transfers from somewhere in switzerdelphia.

[jpc]

One of the coolest toys I have managed to inherit is a magnetic stirrer. Got it from a friend who was retiring from a University Bio lab job. Everything in the lab was up for grabs. I can mix up a quart of vinac (pva in tracer's rant) in 20 minutes. I rarely use pvb, although I should because in the hot WY sunshine, the vinac often just doesn't harden. And tracer, yes cyanoacrylate will glue things together that have been vinaced.

I like to apply vinac by pouring it out of the bottle... I use an old shampoo bottle... must be a #2 plastic or the acetone will eat it. For samller stuff I use a small paintbrush or an eyedropper. One thing you gotta watch out for when using acetone based preservatives is that the second time you treat the fossil, the first thing it will do is dissolve the first dose and thing just might fall apart.

Nice hunerus, what manner of beast is it form?

[wRick]

a quick wipe with acetone will remove a mild whitish haze. wiping a lot in one area will start removing and gumming up the consolidant and dulling the look of it. it readily redissolves with acetone.

oh, another point. after you use the stuff awhile you sort of develop a sixth sense regarding how to tell how thick or thin the solution is. if you dip a stick into it and lift it up, you can see how "watery" or "syrupy" the runoff is. and pure acetone evaporates fast, so you can actually see the wetted surface of a fossil's drying speed. the faster it's evaporating and the lower the sheen, the less copolymer is involved. it's all very scientific the way i do it - i even have a little chant i chant to control the process. it works very well, as illustrated below:

here is a picture of a fossil that i found that needed a little work -

and here is a picture of it after using my consolidant solution with chant -

please note that it's longest angle is now also well over 7 inches, so don't be pm'ing me offers for this puppy unless it involves big wire transfers from somewhere in switzerdelphia.

Uuuummmmm....

yeah, so you told us the secret formula for the consolidant,... and that's great 'n' all, but... What's the chant?

[tracer]

Nice hunerus, what manner of beast is it form?

i have perused it most carefully with my book of morphological comparinosities, and i pronounce it indubitably a <drumroll please>

bison

<runs away>

[tracer]

Uuuummmmm....

yeah, so you told us the secret formula for the consolidant,... and that's great 'n' all, but... What's the chant?

ooga booga ooga?

<lather, rinse, repeat>

[Scylla]

ooga booga ooga?

<lather, rinse, repeat>

isn't that "lather, rinse, lather"?

[tracer]

isn't that "lather, rinse, lather"?

not unless you want to go around with a head full of soap.

[bear-dog]

:lol: He got you. :Thumbs Up:

[frozen_turkey]

i found a jaw once and at the time (2 years ago) i did have any of that pva, pvb, pvz, abc or what ever its called. So i just sprayed it down with a thin coat of hair spray and its been holding together ever since and the best part is its removeable. AND its protects great against moister and trust me i know.......i live in iowa. We have some of the most humide summers and driest winters and that hasnt affected the jaw one bit.

So why go through all of this trouble with this fancy stuff when you could just give it a little sprits with some fancy goooooooood smellen hair spary.

I dont know if this is the right thing to do.............i have vary limited experience in this area.......heck bet ya tracer's cat has more experience in this area then i do.

-Frozen

[Darwin Ahoy]

I would think that hairspray doesn't really penetrate very well

And the ability of a fossil to hold up a couple years, and the ability to hold up for decades or more are a bit different...

I've actually never had the need to use a consolidant yet. Not enough real bone out here to warrant it.

[bear-dog]

Hairspray dosent penetrate.Over the years you will end up with a fragile shell of the fossil at best.If you really like your fossils you should look into consolidants.Just a thought.