Paraloid B-72

Please post all your topics related to cleaning your metal detector finds here.
Post Reply
staters quo
Posts: 17
Joined: Tue Sep 10, 2019 11:41 pm
Has thanked: 9 times
Been thanked: 14 times

Paraloid B-72

Post by staters quo » Thu Nov 07, 2019 9:21 pm

Does anybody have any experience or tips regarding the use of Paraloid B-72 as a stabilizing agent on ferrous objects? I have a landowner who is particularly interested in the horse shoes (to be fair, they are 13th century) and other obviously agricultural items. Of course these are all iron, so they start rusting badly once out of the ground. Now, after yesterday's dig, I'm here in my kitchen looking at a Roman horse shoe as well.

I have up until now used simple light oil to halt the oxidising process, or at least slow it down, but it evaporates quickly and the rusting begins again.

I can't say I'm convinced by the "boil it in wax" method as even this has time limitations as to its efficiency. The wax breaks down eventually and is specifically warned against by the PAS in any event.

Museums and institutions seem to use Paraloid B-72 as a stabilizer, so I'm going to give it a go. The only issue is that I want to be able to make a specific concentration (5-10%) which means I need to buy both the pellets and the acetone in which to dissolve them.

As far as I'm aware it's not possible to purchase acetone any more, at least not without MI6 bashing your door in at 4am.

So does anybody use Paraloid B-72 at all? If so can you share some insight?

Thanks all SQ



User avatar
dig-dog
Posts: 950
Joined: Sat Jan 26, 2013 2:24 pm
Location: Kent
Has thanked: 328 times
Been thanked: 340 times

Re: Paraloid B-72

Post by dig-dog » Thu Nov 07, 2019 10:02 pm

I’ve used it with pure acetone. I purchased it from a certain auction site without any problem.
I’ve also started preparing a steel sculpture for sealing. My mate bought a couple of gallons without any problem. If the rules have changed in the last few months, then you can also dissolve it in paraffin I believe and there are other things you can use but I can’t remember what.
It takes a bit of patience as it takes ages to dissolve properly, don’t expect to get it done in an afternoon.

DD ::g
E-trac 13" ultimate coil.
Full XP Deus 11" coil / hf elliptical coil
Sniper spade

WVAM
Posts: 551
Joined: Thu Nov 01, 2018 6:15 pm
Has thanked: 167 times
Been thanked: 280 times

Re: Paraloid B-72

Post by WVAM » Thu Nov 07, 2019 10:13 pm

I'm no expert in this and can ask a colleague for more advice if needed.
My two penneth would be to wash out as many 'salts' as possible otherwise they will continue to attract moisture below any preservation layer - have a read up on the Mary Rose cannonball problems.

I would also experiment with a rust converter although I think these make the surface much darker forming ferric tannate or phosphate. Baltimore in the US had a lot of cast iron lamp posts that didn't need painting as the surface had been converted to try and stop them rusting red. You might be able to use some of the car body rust products.

Then try and get all of the moisture out - the shoes, even when dry, will have the same moisture content as the air where they are kept. Several days in a warm oven might work. Then seal the surface. The data sheet on Paraloid says it will also dissolve in isopropanol or ethyl alcohol - both more readily available (your local non-chain pharmacy might help). Google shows plenty of acetone for sale from a variety of outlets.

I would pick a shoe you aren't too worried about and try some experiments. In the meantime, dry them out and pack in boxes with a moisture absorbent material (not in contact) until you are ready to treat the important ones.

As above - not an expert and just how I might approach it. And be careful with volatile liquids :D

User avatar
Wuntbedruv
Posts: 155
Joined: Fri Mar 01, 2019 3:00 pm
Location: West Sussex
Has thanked: 70 times
Been thanked: 205 times

Re: Paraloid B-72

Post by Wuntbedruv » Thu Nov 07, 2019 10:18 pm

You can use it, but if I'm honest I wouldn't bother.

Iron is NOTORIOUSLY difficult to stabilise out of museum conditions.

A conservator would neutralise the corrosion in a vacuum environment, remove every ounce of moisture and then seal the object with a lacquer.

If you apply it straight on, the object will continue to corrode because there will still be moisture present.
God gives all men all earth to love, but since man’s heart is small,
Ordains for each one spot shall prove beloved over all.
Each to his choice, and I rejoice, the lot has fallen to me
In a fair ground—in a fair ground—Yea, Sussex by the sea!

staters quo
Posts: 17
Joined: Tue Sep 10, 2019 11:41 pm
Has thanked: 9 times
Been thanked: 14 times

Re: Paraloid B-72

Post by staters quo » Thu Nov 07, 2019 11:47 pm

Thanks for the input folks. I didn't realise you could still buy acetone, I thought it had gone the way of all the other useful chemicals. Good point about the moisture staying inside the artefact under the coating - I think I'll bake whatever I'm going to treat, probably more than once. Reckon I'll give the rust converter a go as well.

One thing's for sure, I have enough iron here to experiment on for the next year or so!

It must be possible to achieve a certain level of stabilisation though, I quite often see things like Viking swords which have somehow stopped rusting, and it would be good to get a processing system sorted, if only for my own satisfaction.

WVAM
Posts: 551
Joined: Thu Nov 01, 2018 6:15 pm
Has thanked: 167 times
Been thanked: 280 times

Re: Paraloid B-72

Post by WVAM » Fri Nov 08, 2019 7:35 am

staters quo wrote:
Thu Nov 07, 2019 11:47 pm

It must be possible to achieve a certain level of stabilisation though, I quite often see things like Viking swords which have somehow stopped rusting, and it would be good to get a processing system sorted, if only for my own satisfaction.
Keep in mind you have very different objects. A horse shoe needs to last 6-8 weeks before it is either thrown away or the metal recycled for other shoes / implements. A sword would be a treasured possession for life made of much different and hardened steel, unlike soft iron shoes.
I believe the rusted swords you see are regularly inspected and conserved (Wuntbedruv will know more) but they continue to rust – just very, very slowly. Glass cases give some control over the atmosphere too.
You should be able to stop the surface rust that appears quite quickly so he has something nice to display.

Some before and after pictures would be good ::g

PinkFloyd
Posts: 185
Joined: Fri Sep 27, 2019 9:31 pm
Been thanked: 96 times

Re: Paraloid B-72

Post by PinkFloyd » Fri Nov 08, 2019 7:52 am

Flap wheel grinder, get it shiny and as near to original as possible then 2pack lacquer it ::g

Look far better than a big blob of rust in a u shape

staters quo
Posts: 17
Joined: Tue Sep 10, 2019 11:41 pm
Has thanked: 9 times
Been thanked: 14 times

Re: Paraloid B-72

Post by staters quo » Fri Nov 08, 2019 9:32 am

Good point about the different quality iron being used, I hadn't thought of that. I know the Romans had identified carbon steel as far back as the iron age because they were using the iron that was closest to the charcoal in the smelting process for their weapon edges.

The flap wheel idea has a strangely appealing ring to it although I'm not sure I'm ready for it quite yet.

Just did a quick search and there are a couple of other processes apparently - electrolysis being the main one, and also air abrasion. Not that I have the kit for the latter lying around in my garage.

Apparently using "city water" to clean iron is a no-no as it contains chlorides and basically gives you rust on steroids. I hate to think how much iron I've run under the tap. Distilled water from now on then.

This is a really good video I just found regarding conservation of iron artefacts, and I think this particular process will form the basis of my home-grown efforts:


jcmaloney
Posts: 2306
Joined: Tue Apr 12, 2011 9:17 am
Has thanked: 803 times
Been thanked: 422 times

Re: Paraloid B-72

Post by jcmaloney » Fri Nov 08, 2019 10:43 am

My favourite link...................... https://finds.org.uk/documents/file/PAS ... 18-all.pdf

::g ::g
Opinions expressed on MY posts are mine and NOT those of any democratic organisation I volunteer for. ::g

WVAM
Posts: 551
Joined: Thu Nov 01, 2018 6:15 pm
Has thanked: 167 times
Been thanked: 280 times

Re: Paraloid B-72

Post by WVAM » Fri Nov 08, 2019 11:24 am

staters quo wrote:
Fri Nov 08, 2019 9:32 am

This is a really good video I just found regarding conservation of iron artefacts, and I think this particular process will form the basis of my home-grown efforts:
I think if you had really important balls it would be a different matter!

https://www.bbc.co.uk/news/science-environment-43334700

For your horse shoes you've only got to conserve them until your land owner dies so no point in going overboard on treatments. ;)

As for PinkFloyd's 2 pack idea - just got me thinking what I could do with the shoes on my wife's horse - candy red perhaps :))

Bootneck45RM
Posts: 283
Joined: Fri Dec 08, 2017 3:37 pm
Location: East Devon
Has thanked: 292 times
Been thanked: 223 times

Re: Paraloid B-72

Post by Bootneck45RM » Fri Nov 08, 2019 4:24 pm

Hi s.quo,
Been using B72 for some time. Tend to buy the pellets from ebay and acetone from Sainsburys (other supermarkets are available). Easy to mix w/v and store. BUT don't inhale the fumes, wear gloves/mask and store carefully.
To do job properly have a look at this google link
Enjoy and take care.
20191108_161915.jpg
You do not have the required permissions to view the files attached to this post.
Go not quietly into the dark night - take a torch and a trumpet! - and cause a rucus!

staters quo
Posts: 17
Joined: Tue Sep 10, 2019 11:41 pm
Has thanked: 9 times
Been thanked: 14 times

Re: Paraloid B-72

Post by staters quo » Fri Nov 08, 2019 4:56 pm

Thanks for that Bootneck, I would never have mixed the B72 that way, it's a very helpful bit of info.

Hadn't thought of simply getting the acetone from the supermarket either... somehow I assumed the nail polish stuff was different or unsuitable in some way. I know what you mean about safety gear though, I once used neat acetone to clean some bike parts. It didn't end well, I thought my skin was turning inside out.

Bootneck45RM
Posts: 283
Joined: Fri Dec 08, 2017 3:37 pm
Location: East Devon
Has thanked: 292 times
Been thanked: 223 times

Re: Paraloid B-72

Post by Bootneck45RM » Fri Nov 08, 2019 5:22 pm

No worries,
Acetone is £1.69 for 50mls (I buy 2 little bottles)
Bought glass jar from Wilkinsons for £1.50.
Muslin cloth same shop for a pound.
Some little paint brushes.
20 gms of B72 in packets of 5mg for £2.
7.5% solution lasts ages.
Permission of the wife to store it in the kitchen - priceless.
Off ya go!
😀👍
p.s. - all products can be bought in other shops 😁
Go not quietly into the dark night - take a torch and a trumpet! - and cause a rucus!

User avatar
Buriedbytime&dust
Posts: 718
Joined: Tue Jun 20, 2017 6:03 pm
Location: Suffolk
Has thanked: 264 times
Been thanked: 360 times

Re: Paraloid B-72

Post by Buriedbytime&dust » Fri Nov 08, 2019 7:10 pm

staters quo wrote:
Fri Nov 08, 2019 4:56 pm
Thanks for that Bootneck, I would never have mixed the B72 that way, it's a very helpful bit of info.

Hadn't thought of simply getting the acetone from the supermarket either... somehow I assumed the nail polish stuff was different or unsuitable in some way. I know what you mean about safety gear though, I once used neat acetone to clean some bike parts. It didn't end well, I thought my skin was turning inside out.

Yep. Don't use the acetone based nail polish remover, it has all sorts of additives, including oils. You want the 99.5% stuff.

I get mine 5 litres at a time off eBay, which I use for dissolving propionate pellets as a wood sealer for making wooden fishing lures. I presume Paraloid B72 is a very similar product (I have some and it looks pretty much identical).

As mentioned, be careful with the fumes. It's potent stuff ::g

staters quo
Posts: 17
Joined: Tue Sep 10, 2019 11:41 pm
Has thanked: 9 times
Been thanked: 14 times

Re: Paraloid B-72

Post by staters quo » Fri Nov 08, 2019 7:27 pm

OK great, thanks for the info. I've just ordered some B72 so I'll have a look for some acetone now.

I have actually started looking at air abrasion kit now as well. This could all go horribly wrong, but it'll be fun trying.

Post Reply

Return to “Cleaning Finds Forum”