Paraloid B-72 (en.wikipedia.org)
206 points by Ariarule 3 days ago
mooman219 2 hours ago
Oh 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.
CarVac 8 hours ago
Heh, 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.
Xmd5a 8 hours ago
Could 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 2 hours ago
PVA also exists, solves in pure water.
zdw 9 hours ago
This 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?
aejm 7 hours ago
This 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!
boppo1 9 hours ago
Oil 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 9 hours ago
I 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 3 hours ago
What's the application?
uxhacker 3 hours ago
nmstoker an hour ago
Yes, 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! :-)
glimshe 3 hours ago
Not 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!
kazin1870 9 hours ago
I use paraloid all the time, a bit surprised to see it posted here but I’ll support it.
boppo1 9 hours ago
I'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?
chromacity 9 hours ago
halestock 9 hours ago
greygood 2 hours ago
uxhacker 3 hours ago
The 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 3 hours ago
You can see the research here : https://www.woodresearch.sk/wr/201104/07.pdf?utm_source=chat... and here https://www.researchgate.net/publication/400226168_Aging_Mec...
greygood 3 hours ago
It does not turn yellow, Paraloid B66 does. B72 has a low Tg, 40°C, so it can soften and creep when warm
uxhacker 2 hours ago
lollapalooza 3 hours ago
lollapalooza 3 hours ago
Agreed. 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.
CarVac 8 hours ago
I'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 3 hours ago
Yes 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 34 minutes ago
colordrops 9 hours ago
They should make non-yellowing transparent phone cases out of this stuff.
0xbadcafebee 9 hours ago
Huh. So it's a stronger, harder, less brittle, clear wood glue you can dissolve with acetone. Neat!
aidenn0 9 hours ago
How does its strength compare to MMA structural adhesives? What materials is it compatible with?
shermantanktop 5 hours ago
My 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”?
clort 3 hours ago
methmethacrylate (ie acrylic)
FpUser 9 hours ago
Am I the only one that read it as Polaroid ;) ?
perilunar 4 hours ago
I thought it was going to be about a bomber with a parabolic-shaped wing, or something similar.
UncleOxidant 9 hours ago
No,you are not. I was expecting it to be a camera.
zephen 9 hours ago
I thought it was a cross between a camera and a bomber.
NDlurker 9 hours ago
tgrowazay 7 hours ago
Polaroid for B-72 bomber