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Paraloid B-72
- 0xbadcafebee 6mo agoHuh. So it's a stronger, harder, less brittle, clear wood glue you can dissolve with acetone. Neat!
- zdw 6mo agoThis is the most esoteric post I've seen on HN in a while. How many museum curators who need non-yellowing flexible thermoplastic are there on here?
- kazin1870 6mo agoI use paraloid all the time, a bit surprised to see it posted here but I’ll support it.
- boppo1 6mo agoI'm new to it and having trouble finding guides: - how do I apply it as a coating? I want it to be ~ 1/6" to 1/8" thick and as hard as possible - will turpentine dissolve or soften it?
- halestock 6mo agoI found a couple: https://resources.culturalheritage.org/osg-postprints/wp-content/uploads/sites/8/2021/11/osg025-001.pdf https://resources.culturalheritage.org/osg-postprints/wp-con... https://www.zoicpaleotech.com/pages/paraloid-b72-in-fossil-preparation https://www.zoicpaleotech.com/pages/paraloid-b72-in-fossil-p... acetone will dissolve it, dunno about turpentine.
- boppo1 6mo agoI'm reading that turp does not dissolve it, which is ideal so I can mix paint on top of it.
- chromacity 6mo agoIt's a relatively soft plastic and I don't think you can realistically build a uniform, good-looking layer that's 1/8" thick, if that's what you mean. If you need that thickness, high hardness, and nice appearance, I think your best bet is just a sheet of glass or acrylic on top. It can be used as protective varnish, but that would be a very thin layer, probably 0.1 mm or something like that.
- boppo1 6mo agoDoes it not level from gravity like other resins?
- chromacity 6mo agoIt's solvent-based, so it won't set well in thick layers and it will shrink significantly as the solvent evaporates. You can do thick layers with solvent-free thermoset resins such as epoxy, but epoxy will yellow over time.
- greygood 6mo agoPurchase as crystals and dissolve in acetone or ethanol to desired concentration. It will self level based concentration, allow to evaporate before applying next layer
- deleted 6mo ago[deleted]
- boppo1 6mo agoOil painter here, this is news to me and if it doesn't dissolve in gamsol this is EXACTLY what I've been looking for for about 2 years.
- card_zero 6mo agoI followed the link to flexographic ink, and now I'm wondering whether boutique fine art flexography could or should exist. Like lithography, but more plastic.
- bfivyvysj 6mo agoWhat's the application?
- uxhacker 6mo agoIt is used to strengthen materials. For example if plaster has crumbled, or the paint on a canvas has become flakey, or wood rotten, Paraloid B-72 can be used to hold everything together. The issue is that generally it is not reversible. Therefore one should always look at varnishes that can easily be removed and reapplied, but sometimes only Paraloid can hold everything toghther.
- bfivyvysj 6mo agoI meant in regards to use with gamsol but thanks for the insight
- colordrops 6mo agoThey should make non-yellowing transparent phone cases out of this stuff.
- CarVac 6mo agoI've done some DIY piano maintenance and I saw what was presumably this available to firm up the hammers. My piano needs them softened, though.
- clort 6mo agoYes it mentioned firming piano hammers in the article. From what I remember, a piano hammer is a shaped piece of wood (or several?) with a leather strip around the striker part? What is the difference for you between hardening and softening the hammer, and how would it be done with this .. is it penetrating? (acetone base would enable that, it is used for carrying chemicals through a surface). Could you soften the hammers by replacing the leather strips, or soaking them to loosen & expand the presumably compacted fibres? In my wider life in the UK, speaking to people associated with pianos (from a piano tuner, to school premises teams), it is often not worth the commercial expense to repair old pianos unless they are of particularly good quality or have some sentimental value.
- CarVac 6mo agoThe hammer is felt around wood. You don't replace the felt, you'd replace the entire hammer, but then you'd likely want to replace all the hammers to get matching sound anyway. There's a solution you can add to soften the hammers, but I don't know what chemical it is or how well it works since I haven't tried it yet; you can also needle the felt to fluff it up.
- aejm 6mo agoThis post has exactly zero relevance to my professional career or personal projects, and this is exactly the type of esoteric content I love about HN!
- uxhacker 6mo agoThe issue is that it does yellow but after 25 to 50 years. The challange is that it is very difficult to reverse. On the restoration of my house I allow its use on very specific cases. It very useful for example in strengthening wood that has rotten. Sometimes Paraloid is the only thing that can be used, but it needs to be used with care.
- uxhacker 6mo agoYou can see the research here : https://www.woodresearch.sk/wr/201104/07.pdf?utm_source=chatgpt.com https://www.woodresearch.sk/wr/201104/07.pdf?utm_source=chat... and here https://www.researchgate.net/publication/400226168_Aging_Mechanism_and_Performance_of_Paraloid_B72_under_Simulated_UV-Condensation_Environment_Insights_for_Cultural_Heritage_Conservation https://www.researchgate.net/publication/400226168_Aging_Mec...
- greygood 6mo agoIt does not turn yellow, Paraloid B66 does. B72 has a low Tg, 40°C, so it can soften and creep when warm
- lollapalooza 6mo agoDidn't really know of the different 9(!) versions of it. Thanks for pointing it out.
- uxhacker 6mo agoIt does discolor over time. The point is that one should be thinking about the impact over centuries and not years. It needs to be used with care and other alternatives need to always be considered. For a painting or building that has survived for half a millennium we need use methods that will preserve the object for another 500 years. Too many times I hear people say we will just use Paraloid.
- lollapalooza 6mo agoAgreed. My gf uses it regularly as she's a furniture restorer, finding the definition here it's a bit of a surprise, though. Great, unique material.
- glimshe 6mo agoNot many, but there are a few amateur and professional musicians here benefitting from better piano hammers made possible by Paraloid B-72! Note: I thought this was about Polaroid, not Paraloid, at first!
- nmstoker 6mo agoYes, but that esoteric nature is the charm of HN at its best. This is unusual as posts go, but it's not totally unreasonable and even though I wouldn't have an immediate use, it's fascinating, leads to further exploration (like another commenter mentioning the inks) and knowledge gets filed away. I try to remember posts like this when people are less positive about HN! :-)
- Eduard 6mo agoI'm especially curious about the high upvote count, considering the Wikipedia article as well as the substance in general is not that interesting IMHO.
- idiotsecant 6mo agoThe high number of upvotes is the same phenomenon as the comment chain full of people patting themselves on the back for enjoying estoteric content on HN. They didn't read it, they just like to imagine themselves as the sort of person who would read it. They probably have an apartment with a shelf full of curated tastefully selected novels that were purchased used for the proper patina and arranged just so, and then forgotten until it's time to subtly attract their guests attention to how clever they are. They probably have a couple Hemingway references they have memorized and bring out when the time is right.
- dekhn 6mo agoYou must be fun at parties.
- Avshalom 6mo agoPaleontologist and probably going to be doing pre-museum prep for some stuff here in the fall. Although we're cheap so we usually use butvar (polyvinyl butyral).
- rbanffy 6mo agoAs someone who repairs and collects old computers, it might be one more tool.
- FpUser 6mo agoAm I the only one that read it as Polaroid ;) ?
- UncleOxidant 6mo agoNo,you are not. I was expecting it to be a camera.
- zephen 6mo agoI thought it was a cross between a camera and a bomber.
- NDlurker 6mo agoEdwin Land, the inventor of the Polaroid, worked on the U2's camera. https://otislibrarynorwich.org/2024/04/08/edwin-land-and-the-u-2-spy-plane/ https://otislibrarynorwich.org/2024/04/08/edwin-land-and-the... https://www.smithsonianmag.com/innovation/polaroid-inventor-edwin-land-gave-us-more-than-just-instant-photos-180969119/ https://www.smithsonianmag.com/innovation/polaroid-inventor-...
- tgrowazay 6mo agoPolaroid for B-72 bomber
- mesonwarrior 6mo ago[dead]
- perilunar 6mo agoI thought it was going to be about a bomber with a parabolic-shaped wing, or something similar.
- adrianmonk 6mo agoI read it as "paraboloid" and expected it to be about some very specific geometrical shape with a niche practical application.
- aidenn0 6mo agoHow does its strength compare to MMA structural adhesives? What materials is it compatible with?
- shermantanktop 6mo agoMy only expansion for MMA is “mixed martial arts” and I’m not particularly familiar with it. Maybe there’s a wrestling move called the “structural adhesive”?
- CarVac 6mo agoHeh, I upvoted this a few days ago and it must've gotten on the second-chance queue. Links to obsure but interesting Wikipedia articles are some of my favorite HN posts.
- robotnikman 6mo agoThis is one of my favorite ones, just because of how crazy of an idea it was, as well as the fact it was deemed possible to build https://en.wikipedia.org/wiki/Lockheed_CL-1201 https://en.wikipedia.org/wiki/Lockheed_CL-1201
- EdwardDiego 6mo agoLooking at that just screamed "coolest GI Joe vehicle that one rich kid at your school had and never let you play with".
- Xmd5a 6mo agoCould this be used to 3D print supports ? For now, the only thermoplastic I know of that can be used to this effect is HIPS in conjunction with d-limonene.
- a3w 6mo agoPVA also exists, solves in pure water.
- deleted 6mo ago[deleted]
- Joel11 6mo ago[flagged]
- mooman219 6mo agoOh I've used this personally! I had various surgeries that removed various amounts of bone from me and I asked to keep the bones, which they allowed! I wanted to preserve them in case I wanted to make some esoteric jewelry and it lead to paraloid B-72. It's quite wonderful. I dissolve the paraloid B-72 in acetone (1 part B-72, 8 parts acetone), then soak the bone in the acetone for about an hour, let the bones dry, and then suddenly they're solid and strong. You can adjust how much acetone you use for how thin/thick you want the fluid. Bones are porus so I opted for a thinner solution and it worked great. It was also really cheap.
- stavros 6mo agoHmm, what, the acetone evaporates and leaves just the plastic? Is that how it works?
- 0xbadcafebee 6mo agoAnd typically penetrates into the material (https://rhadhesives.com/why-chose-solvent-based-adhesives/ https://rhadhesives.com/why-chose-solvent-based-adhesives/). Adhesives are a deep and interesting subject if you're looking for a wikipedia hole. For example, if you want the best general-purpose consumer structural adhesive, it's Loctite PL Premium MAX. For the best general-purpose consumer structural adhesive applied in wide temperature ranges, it's Liquid Nails Fuze-It MAX. If you want the best flexible general-purpose consumer structural adhesive, it's Gorilla Heavy Duty Construction Adhesive. For the best all-purpose consumer structural adhesive when properly prepared, applied and cured, it's epoxy resin. For the strongest general-purpose adhesive when tightly fitted and clamped between two porous materials, it's cross-linked PVA (wood glue). There are dozens of variables that change which adhesive is better per application.
- jdietrich 6mo ago>Adhesives are a deep and interesting subject. It's notable that adhesives are something that Chinese manufacturers still really struggle with. Companies like Henkel and 3M have a deep reservoir of trade secrets.
- webprofusion 6mo agoWhat we really need is a wipe on self leveling version. Finishing guitars is hard!
- Isamu 6mo agoMore posts please relating to conservator tech or websites. Thanks.
- cmpalmer52 6mo agoWould this work for fragile shells and things like sand dollar “skeletons”? I usually use thinned white glue, but it’s less than ideal.
- Avshalom 6mo agoYes this is exactly what we use it for.