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UBUKORIKORI
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IBYAMBARWA
Epoxy Resin
Woody

Yaremwe na

Woody

22. Nzeli 2026NO
1
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Epoxy Resin

Pierre Castan, a Swiss chemist at the dental firm De Trey Frères, was looking for a resin for dentures. He reacted a phenol carrying two hydroxy groups with epichlorohydrin, then hardened the product with an acid anhydride, and got a hard, clear, unusually adherent solid. Ciba licensed it and sold it as Araldite; in the US Sylvan Greenlee developed epoxies independently. **US 2,324,483**, "Process of preparing synthetic resins", Castan, granted 20. July 1943, claims condensing "a polybasic carboxylic acid anhydride" with the product of "a phenol having at least two phenolic hydroxy groups and of an epichlorhydrine". It does not single out bisphenol A, the phenol most epoxies use today. **Epichlorohydrin is a carcinogen; you start from a two-part kit.** You glue pine lap joints at the right ratio and four wrong ones, then test hardness and break the joints.
Utangiye
2 hours plus 24 h cure

Amabwiriza

1

Cut the joint pieces

Saw ten pine strips 100 x 25 mm. Sand one face of each end with 120 grit and dust off. Label five pairs 1:1, 1.25:1, 1:1.25, 1.5:1 and 1:1.5.

Ibikoresho by'iyi ntambwe:

Ikibaho cy'igiti cya pinusiIkibaho cy'igiti cya pinusi1 igice
Urupapuro rwo GusyaUrupapuro rwo Gusya1 urupapuro
Isheme yo gupfundikiraIsheme yo gupfundikira1 umuzingo

Ibikoresho bikenewe:

Umucumita w'IntokiUmucumita w'Intoki
Umurongo w'IcyumaUmurongo w'Icyuma
Ikaramu ya penisileIkaramu ya penisile
2

Measure by syringe

Gloves on. For each ratio draw resin and hardener in separate syringes (1:1 = 2 ml + 2 ml; 1.25:1 = 2.5 + 2; and so on) into its own cup. This assumes a 1:1-by-volume kit - scale to your label.

Ibikoresho by'iyi ntambwe:

Epoksi y'Ibice BibiriEpoksi y'Ibice Bibiri25 ml

Ibikoresho bikenewe:

Uturindantoki twa NitirileUturindantoki twa Nitirile
Ibikoresho by'urushinge rw'inshingeIbikoresho by'urushinge rw'inshinge
Ibikombe byo kuvangamo bifite ibipimoIbikombe byo kuvangamo bifite ibipimo
Amadarubindi Asobanutse yo KwirindaAmadarubindi Asobanutse yo Kwirinda
3

Mix thoroughly

Stir each cup 2 minutes, scraping the walls and bottom. Unmixed streaks behave like a wrong ratio.

Ibikoresho bikenewe:

Akati ko KuvangaAkati ko Kuvanga
4

Glue and pour

Spread each mix on the sanded ends of its pair, overlap them 25 mm and spring-clamp over wax paper. Pour the rest as a coin-sized puddle on wax paper beside it.

Ibikoresho by'iyi ntambwe:

Urupapuro rwasizwe ibushishiUrupapuro rwasizwe ibushishi1 urupapuro

Ibikoresho bikenewe:

Igifashi cya resoriIgifashi cya resori
5

Cure 24 hours

Leave everything at room temperature, 20 °C or warmer, for 24 hours. Cold slows the cure.
6

Pencil hardness

Sharpen pencils 6B to 6H and flatten the tips on 400 grit. Push each at 45° across a puddle, from hard down, until one no longer scratches. Record that grade.

Ibikoresho bikenewe:

Amakaramu Menshi ya GirafiteAmakaramu Menshi ya Girafite
Lupu YaguraLupu Yagura
7

Break the joints

Clamp one strip of a joint in the vise and tap the free end sideways with the mallet until it breaks. Estimate how much of the bond face is torn wood.

Ibikoresho bikenewe:

Ifatiro ry'AmezaIfatiro ry'Ameza
Inyundo ya kawushuInyundo ya kawushu
Amadarubindi Asobanutse yo KwirindaAmadarubindi Asobanutse yo Kwirinda
8

Ratio, leftovers, results

Gupakira ikaye ya Jupyter…
9

History & Context

**What the patent specifies:** a resin from a two-hydroxy phenol and epichlorohydrin, hardened by a polybasic acid anhydride. **Modern build (derived):** a two-part kit, most with an amine hardener that cures at room temperature. Epoxy became the glue that holds metal, the matrix of fibreglass and carbon-fibre parts, and the boat-builder's resin. Its limits: it yellows in sunlight, softens with heat, and uncured resin and hardener sensitise skin - which is why the gloves stay on every time.

Ibikoresho

5

Ibikoresho bikenewe

13

Blueprint zijyanye

Izi blueprint zisangira ubumenyi — uburyo, ibikoresho cyangwa amahame

Making Bakelite — The First Fully Synthetic Plastic That Launched the Age of Polymers
Akaga

Making Bakelite — The First Fully Synthetic Plastic That Launched the Age of Polymers

na CharlieDE

By'Inganda

49
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0
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1
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Casting Clear Epoxy Resin Paperweights — Embedding Objects in Resin

Casting Clear Epoxy Resin Paperweights — Embedding Objects in Resin

na MaryFI

Ubutabire

70
0
0
0
0
0
Silicone (Rochow Direct Process)

Silicone (Rochow Direct Process)

na ClayDK

Gukora Plastiki

1
0
0
0
0
0

CC0 Umurenge rusange

Iyi blueprint yasohowe munsi ya CC0. Ushobora gukoporora, guhindura, gukwirakwiza no gukoresha nta kwemererwa.

Shyigikira Umuremyi ugura ibicuruzwa binyuze muri Blueprint ye Komisiyo y'Umuremyi byashyizweho n'Abacuruzi, cyangwa kora verisiyo nshya y'iyi Blueprint ukayinjiza nk'isano muri Blueprint yawe kugira ngo musangire inyungu.

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