What is a GI back nut used for?

A GI back nut secures threaded pipe connections — often used to lock valves or couple fittings in domestic and industrial plumbing.

What sizes do GI back nuts come in?

Common sizes include ½″, ¾″, 1″ and larger (1¼″, 1½″, 2″). TapMaster stocks popular sizes; contact us for larger diameters.

Are GI back nuts suitable for potable water?

Yes — galvanized fittings are commonly used for potable water. Ensure the product certification and local water authority guidance before use.

How do I prevent leaks with a GI back nut?

Use the correct thread sealant (PTFE tape for tapered threads) and tighten to recommended torque — avoid over-tightening.

How long do galvanized back nuts last?

Life depends on environment and water chemistry; in typical domestic installations galvanized fittings provide many years of service — inspect periodically.

Does TapMaster deliver across Kenya and offer same-day delivery?

Yes — TapMaster offers countrywide delivery and same-day delivery options for many plumbing items. Contact TapMaster or check the product page for availability.

Galvanized Iron (GI) Back Nut — Strong, reliable plumbing for Kenya

Introduction — what is a GI back nut and why plumbers use it

A Galvanized Iron (GI) Back Nut is a threaded female fitting used in plumbing to secure and seal pipe connections — particularly where a nut locks onto a threaded male fitting or valve stem. Made from malleable or cast iron with a zinc (galvanized) coating, GI back nuts resist corrosion and are cost-effective for many domestic and light commercial plumbing jobs. TapMaster Kenya stocks common sizes used across local installations, from ½″ up to larger trade sizes. TapMaster Kenya+1

Key benefits of GI back nuts

Corrosion resistance: Zinc galvanizing prolongs service life in wet environments.
Cost-effective: Cheaper than brass or stainless for many non-critical applications. (Good for domestic and many industrial uses.)
Wide compatibility: Available to match standard BSP/ISO threaded pipe fittings — works with commonly used GI fittings and valves. malleableiron-pipefitting.com
Easy to source in Kenya: Widely available sizes and competitive pricing — TapMaster Kenya carries popular variants and delivers nationwide. TapMaster Kenya+1

Specifications & common sizes

Typical GI back nut specs you’ll find at TapMaster Kenya and similar suppliers:

Material: Galvanized malleable iron / galvanized cast iron. valvestubesfittings.com+1
Thread standard: BSP (BSPP/BSPT) or ISO7-1 types (market standard for pipe threads). malleableiron-pipefitting.com
Sizes in stock (common): ½″, ¾″, 1″, 1¼″, 1½″, 2″ (and larger on request). TapMaster lists ½″–1″ variants on the product page. Price range seen across Kenyan retailers typically KSh 40–KSh 130 depending on size and seller. TapMaster Kenya+1
Working pressure: Many GI back nuts are rated up to PN25 / ~25 bar for malleable iron fittings (varies by manufacturer). Always verify with the product spec sheet for high-pressure systems. malleableiron-pipefitting.com+1

How to choose the right GI back nut

Match the thread type and size to your pipe/valve (BSPP vs BSPT matters). Use calipers or a thread gauge if unsure. malleableiron-pipefitting.com
Check the working pressure — for domestic water this is usually fine; for high-pressure or specialised systems choose rated fittings. malleableiron-pipefitting.com
Consider corrosion environment — galvanized is good for many uses, but marine/coastal or aggressive chemical environments may require brass or stainless steel.
Buy from reputable suppliers — ask for product conformity (standard references like BS EN 10242 where applicable). Hacketts Pipeline

Installation tips (quick practical guide)

Use a clean, correctly sized wrench — avoid over-tightening which can damage threads.
Use appropriate thread sealant (PTFE tape or liquid sealant) on tapered threads (BSPT/ISO 7-1) as recommended.
For assemblies that will be subject to vibration, consider a backing washer or locking method as per pipework practice.
Inspect galvanizing for damage; recoat or replace fittings showing severe corrosion before use.

GI back nut vs alternatives — quick comparison

Brass: Better corrosion resistance and appearance, more expensive — choose for visible fixtures or where galvanic concerns exist.
Stainless steel: Best corrosion resistance and strength — higher cost; used in highly aggressive or sanitary applications.
Galvanized (GI): Best balance of cost and performance for general plumbing and many industrial systems. malleableiron-pipefitting.com+1

Pricing & availability in Kenya

TapMaster Kenya lists GI Back Nut variants (price examples: KSh 40–KSh 60 for common sizes on the TapMaster product page). Other Kenyan vendors show a broad market price range depending on size and stock. TapMaster offers competitive pricing, product authenticity, and stock visibility on the product page. TapMaster Kenya+1

Why buy GI back nuts from TapMaster Kenya?

Wide local stock: Common sizes available on the TapMaster shop. TapMaster Kenya
Countrywide delivery & same-day options: TapMaster advertises countrywide delivery and same-day service on recent product pages and posts — ideal for urgent site needs. (Contact info & ordering on the contact page.) TapMaster Kenya+1
Local support: Phone and WhatsApp ordering makes last-minute procurement simple. TapMaster Kenya

Maintenance & longevity

Inspect annually in typical water systems.
Replace any fitting where the galvanizing is heavily pitted or the threads show wear.
Avoid dissimilar metal contact (e.g., direct contact of galvanized iron with copper in wet environments) without appropriate isolation — to reduce galvanic corrosion risk.

TapMaster Kenya