UBUCIKO
UBUHLE NEMPILO
UBUCIKO BEZANDLA
AMASIKO NOMLANDO
EZOKUZIJABULISA
IMVELO
UKUDLA NEZIPHUZO
REVERSE ENGINEERING
IZAYENSI
EZEMIDLALO
UBUCHWEPHESHE
IZINTO EZIGQOKWAYO
Epoxy Resin
Woody

Yenziwe ngu-

Woody

22. uMandulo 2026NO
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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.
Oqalayo
2 hours plus 24 h cure

Imiyalelo

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.

Izinto zokwakha zalesi sinyathelo:

Ipulangwe lomphayiniIpulangwe lomphayini1 ucezu
Iphepha LokugayaIphepha Lokugaya1 ishidi
Itheyiphu lokumbozaItheyiphu lokumboza1 umqulu

Amathuluzi adingekayo:

Isaha SesandlaIsaha Sesandla
Irula LensimbiIrula Lensimbi
IpenselaIpensela
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.

Izinto zokwakha zalesi sinyathelo:

I-epoxy Yezingxenye EzimbiliI-epoxy Yezingxenye Ezimbili25 ml

Amathuluzi adingekayo:

Amagilavu E-nitrileAmagilavu E-nitrile
Isethi yamasirinjiIsethi yamasirinji
Izinkomishi zokuxuba ezinemigqa yokukalaIzinkomishi zokuxuba ezinemigqa yokukala
Izibuko Zokuphepha EzicwathileIzibuko Zokuphepha Ezicwathile
3

Mix thoroughly

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

Amathuluzi adingekayo:

Induku YokugovuzaInduku Yokugovuza
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.

Izinto zokwakha zalesi sinyathelo:

Iphepha elinengcinaIphepha elinengcina1 ishidi

Amathuluzi adingekayo:

Isibambo se-springIsibambo se-spring
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.

Amathuluzi adingekayo:

Iqoqo Lamapensela E-graphiteIqoqo Lamapensela E-graphite
I-Loupe YokukhulisaI-Loupe Yokukhulisa
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.

Amathuluzi adingekayo:

Isibambo SebhentshiIsibambo Sebhentshi
Isando serabhaIsando serabha
Izibuko Zokuphepha EzicwathileIzibuko Zokuphepha Ezicwathile
8

Ratio, leftovers, results

Ilayisha incwadi ye-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.

Izinto

5

Amathuluzi Adingekayo

13

Ama-blueprint ahlobene

Lama-blueprint abelana ngolwazi — amasu, izinto noma izimiso

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

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

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Kwezimboni

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Casting Clear Epoxy Resin Paperweights — Embedding Objects in Resin

Casting Clear Epoxy Resin Paperweights — Embedding Objects in Resin

ngu-MaryFI

Amakhemikhali

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Silicone (Rochow Direct Process)

Silicone (Rochow Direct Process)

ngu-ClayDK

Ukwenza Ipulasitiki

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CC0 Isizinda Somphakathi

Le blueprint ikhishwe ngaphansi kwe-CC0. Ukhululekile ukukopisha, ukuguqula, ukusabalalisa, nokusebenzisa ngaphandle kwemvume.

Sekela uMenzi ngokuthenga imikhiqizo nge-Blueprint yabo IKhomishane Yomenzi kumiswe ngabathengisi, noma dala inguqulo entsha yale Blueprint bese uyifaka njengoxhumaniso ku-Blueprint yakho ukuze wabelane ngemali engenayo.

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