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Anodes & Cathodic Protection (CP)

4 anode types — shipbuilding, ship repair, bridge, building & concrete structure repair

Start from your job— tap your environment or structure to jump to the products for it

Rebar in concreteConcrete anode — bridges · piers · coastal buildingsSee these products Marine · hulls · piersAluminium · zinc anode — seawater and brackishSee these products Fresh waterMagnesium anode — river craft · pontoonsSee these products Paint / coat against rustAnti-rust paint · underwater epoxy → Paint & Coatings pageSee these products Packing / exporting metal partsFilm · VCI bags · desiccant — rust protection in transitSee these products

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Sahawatthanakit (1988) supplies and sizes full-line Galvanic Cathodic Protection (CP) and sacrificial anodes — Concrete · Aluminium · Zinc · Magnesium Anode — anodes Thai-made to ISO 9001:2015 / TIS, with CP systems designed to DNV-RP-B401 and ISO 12696. Used in shipbuilding and ship repair (hulls, sea chests), structure and building repair (rebar in concrete), piers and river bridges — public and private projects nationwide. Anodes are sacrificial by design, so they are replaced on each maintenance / dry-docking cycle. Based in Nonthaburi, with nationwide delivery. We supply the parts only and do not take installation work — your own contractor fits them and we send the mounting details. Send your site conditions and sizes in chat for a quote right away.

Standards & Certifications

Cathodic protection systems designed per ISO 12696:2022 (concrete reinforcement) and NACE SP0169 (pipeline external corrosion) — the standards cited in EGAT / SRT / MEA / PEA TOR plus port and bridge projects in Thailand. The anodes we supply are for water immersion and concrete embedment only — buried/soil work is out of scope: zinc to MIL-A-18001K/GL-Zn1, aluminium to TIS 3359-2565 + DNV-RP-B401, magnesium (condenser anode) to ASTM G-97, concrete anode to TIS 3029-2563 + ISO 12696. Current capacities are on the product pages. ICCP MMO anodes run 20+ years at DC 1-50 A. Every installation includes a Cu/CuSO₄ reference electrode (per NACE TM0211) plus ON/OFF potential testing every 6 months per ISO 15589-1.

Anodes & Cathodic Protection (CP)

4 anode types — shipbuilding, ship repair, bridge, building & concrete structure repair

Concrete Anode (standard/high-output) — zinc in alkaline mortar pH ≥14 (lithium hydroxide), protection radius ≥60 cm, service life ≥10 years — TIS 3029-2563 / ASTM B418 Type II / ISO 12696
Aluminium Anode (Al-Zn-In) — ship hulls, piers, offshore platforms in seawater/brackish water — TIS 3359-2565 / DNV-GL (GL Section 7)
Zinc Anode Zn ≥99.314% (cast from 99.995% ingot) — ship hulls, sea chests, condenser seawater side — MIL-A-18001K / GL-Zn1
Magnesium Anode — barges, pontoons, river bridges (low-conductivity fresh water)
Polarization Decay ≥100 mV (NACE/AMPP industry KPI) · Complies with TIS, ASTM, ISO, DNV, GL, BS, AMPP
Reference clients: Freyssinet · AGC Chemicals Thailand · CPAC · SCG

Request a quote for this service 081-866-8368 (Khun Navin)

4 anode metals
for every water

Why buy anodes from us

• All four galvanic cathodic protection metals — concrete, aluminium, zinc and magnesium — selected by the water the structure sits in, not by what is in stock
• Inspect, protect, then verify: 3D LiDAR scanning locates the delamination and corroding rebar, the CP system is sized to those findings, and a repeat scan tracks it over time
• SAHA supplies and sizes CP systems to DNV-RP-B401 / ISO 12696 — anodes manufactured in Thailand under ISO 9001:2015 · supply only, we do not take installation work
• Full standards pack: TIS 3029-2563 / 3359-2565 · ISO 12696 · ASTM B418 · NACE · DNV · AMPP — accepted in Thai government tenders
• Delivered to State Railway of Thailand, Bangkok Metropolitan Administration, Department of Highways, Royal Thai Navy Supply Department and Royal Thai Air Force — 38 years in business

Corrosion protection 1 — cathodic protection (sacrificial anode)

Four sacrificial anode metals — chosen by the environment

Galvanic cathodic protection stops corrosion at the electrochemical level, extending structure life by 25–50 years against an epoxy repair that returns in 5–7 · our engineers size the system and write the specification for the tender.

The shapes we supply, and which metal suits which job

Everything below is taken from what the manufacturer publishes itself — shapes, standards and electrical figures. The size and weight table for each anode sits with that anode further down (Aluminium · Zinc); other sizes are cast to your drawing.

Concrete-embedded anode (rebar protection)

A solid alkaline-mortar puck around the zinc core, with a stainless wire leg leaving each side and bent upward as two separate free tails that are twisted onto the rebar before the pour

Round anode with a centre bore

Slides onto a shaft or pin through the bore, or bolts through it

Bolt-on anode block

Bolts pass through the two holes in the top into a steel insert cast inside, fixing the anode to the structure

Slab anode with weld straps

The flat strap core protrudes at both ends and is welded straight to the structure, the block sitting flush on the steel

Stand-off slab anode with a bent round-bar core

The two round-bar legs are welded straight to the structure; the block itself does not touch the steel · state the stand-off distance and leg direction on the drawing

Pick the metal from the water the steel sits in

Choosing the wrong metal is a leading reason anodes fail to protect even when fitted correctly — this table is the manufacturer's own answer.

Environment	Metal to use	Why
Seawater	Zinc or aluminium	Low resistivity, so both deliver current well — aluminium gives more capacity per kilogram
Brackish water	Aluminium	Zinc tends to grow a thick oxide film in brackish water and stops delivering current
Fresh water / very low salinity	Magnesium	High resistivity needs a high driving potential — aluminium passivates in these conditions
Embedded in concrete	Concrete anode (zinc core in alkaline mortar)	The alkaline mortar casing is required, or the zinc passivates inside the concrete
Standing in open air	No anode works at all	A cathodic system needs all four elements (cathode · anode · a metallic current path · an electrolyte) — air is far too resistive to act as an electrolyte, so this is a coating job instead

Before you fit them — the manufacturer's own guidance

Welding is better than bolting — a bolt that works loose degrades the electrical connection, and the steel starts rusting again
Bolted types should have a rubber backing pad, or insulating paint on the back face only, so the mating face does not corrode until the anode falls off
Never paint over the whole block — an anode fully covered in paint cannot deliver any protective current at all
Check the system is actually working in one of two ways: measure the potential against a reference electrode, or confirm there is no rust within the protected radius
Aluminium-hulled vessels are generally best served by zinc anodes — the wrong choice risks severe hull corrosion, so ask before ordering

Which size do you need? Type it here

Not in the size tables? We cast to your drawing

Advertising a size in advance and then shipping something different wastes more of everyone's time than asking first. Send the size, the drawing or a photo of the anode you removed, and tell us how it is fixed (welded, bolted, tie-wired or shaft-mounted) — our engineer will size it and quote. A minimum production quantity applies to special sizes.

Send a drawing for pricing

Concrete Sacrificial Anode

Rebar in concrete — bridges, piers, coastal buildings, piles

Strength

A zinc core cast into an alkaline mortar (pH ≥14) stops corrosion electrochemically rather than sealing the surface over it — throwing distance ≥60 cm, design life ≥10 years, manufactured in Thailand so there is no import lead time

Who it suits

Tenders and projects that need written specification and a standards pack — compare the lifecycle cost against an epoxy repair that returns in 5–7 years

Concrete sacrificial anodes in four sizes, smallest to largest — round mortar pucks around a zinc core with two free stainless tie-wire tails for the rebar — studio render of the shape

Concrete Anode (CR series) — manufactured in Thailand

A zinc core encased in a special mortar containing lithium hydroxide at pH ≥ 14, which keeps the zinc from passivating so it goes on delivering current

Reinforcement in concrete, both new build and repair

Bridges · dams · piers · concrete structures in or near seawater

Not a product for anything without concrete or water as the electrolyte — no anode of any metal works in air

Shape:: a small puck, easily tie-wired or strapped to the reinforcement
Encasing mortar:: alkali-activating mortar with lithium hydroxide · pH ≥ 14
Independent test result:: polarization decay not less than 100 mV
Throwing distance:: not less than 60 cm
Protection life:: not less than 10 years
Safety to reinforcement:: no acid, and no chloride or bromide that would attack the reinforcement

TIS 3029-2563ASTM B418 Type IIISO 12696

Figures as published by the manufacturer.

Standard line — Concrete Anode (CR series)

CR20 (small)THB 670
CR60 (standard)THB 2,000
CR100 (large)THB 2,500
CR160 (extra large)THB 3,000

Budget line — for projects on a cap

Budget line — NOVA GalvaTect (T series) · for projects on a cap

T20 (small)THB 300
T60 (standard)THB 730
T100 (large)THB 840
T160 (extra large)THB 1,000

Full Concrete Anode specification Request a quotation

* Price per unit, excluding 7% VAT · ask for a quotation on volume

Concrete anode — shape in 2D and 3D

Drawn to the proportions of the real part. The maker publishes no size table for this anode, so no millimetres are shown — size and weight are confirmed on the quotation.

2D drawing · shape and proportion, not a size

3D view · Alkaline-mortar puck, one stainless tie wire out of each side at mid-thickness, free endscomputer render of the shape, not a stock photo

Ask for a quotation:CR20 CR60 CR100 CR160

Marine — hulls · piers · offshore

อะลูมิเนียมอาโนด Al-Zn-In — ก้อนยาวแบบเชื่อม แกนเหล็กยื่นสองปลาย และก้อนแบบขันสลัก มีรูทะลุ 2 รูด้านบน — ภาพสตูดิโอแสดงรูปทรง

Aluminium Sacrificial Anode (Al-Zn-In)

Seawater/brackish — ship hulls, piers, offshore platforms

The highest current capacity of the group, so less metal protects the same area — which saves both cost and the weight the structure has to carry

Seawater

Brackish water

Hulls · piers · piles · offshore structures

Very low-salinity water · fresh water · buried service — the aluminium surface passivates and stops delivering current

Composition:: Zn 4.0–6.0% · In 0.015–0.020% · Fe ≤0.100% · Cu ≤0.003% · Si 0.08–0.20% · other elements each ≤0.020% · others total ≤0.100% · balance Al
Potential:: −1.00 to −1.10 V vs Ag/AgCl in seawater
Current capacity:: 2,600 Ah/kg
Consumption rate:: 3.37 kg/A·year
Test result on the DNV certificate:: 12-month free-running test: 2,481 Ah/kg · closed-circuit −1,073 mV vs Ag/AgCl in seawater
Certified design values:: ≤30°C: 2,000 · 60°C: 1,500 · 80°C: 720 Ah/kg
Acceptance:: Accepted on any DNV-classed vessel

TIS 3359-2565DNV Type Approval (GL-Guideline Section 7)DNV-RP-B401

Figures as published by the manufacturer.

Size and weight table (84 sizes) ↓Full Aluminium Anode specification

Aluminium Anode sizes and weights (84 standard sizes)

Standard sizes from the production line, grouped by shape and fixing method. Gross weight includes the steel insert; net weight is the anode metal itself. Other sizes are cast to your drawing. Size and price are confirmed on the quotation.

Aluminium anode, stand-off, curved pipe core (U-shape)

5 sizesOffshore platforms and jackets, large port structures

2D drawing SWK-AU-262 · 2,300 × 228 × 190 mm · 262 kgTap any row below to redraw at that size.

3D view SWK-AU-262 · computer render of the shape (not a stock photo), drawn to this size's proportions

Length (mm)	Width (mm)	Height (mm)	Gross (kg)	Net (kg)
2,260	175	160	165	140	Quote
2,300	228	190	255	203	Quote
2,300	228	190	262	203	Quote
2,438	221	203	297	245	Quote
2,440	252	240	410	330	Quote

Aluminium anode, stand-off, bent flat-bar legs

10 sizesJetty piles, submerged steel structures, offshore work

2D drawing SWK-AS-133 · 1,040 × 230 × 210 mm · 133 kgTap any row below to redraw at that size.

3D view SWK-AS-133 · computer render of the shape (not a stock photo), drawn to this size's proportions

Length (mm)	Width (mm)	Height (mm)	Gross (kg)	Net (kg)
660	130	120	28	25	Quote
720	160	150	44	41	Quote
530	225	205	61	57	Quote
530	225	205	61	58	Quote
1,040	230	210	133	122	Quote
1,810	200	165	160	144	Quote
1,416	226	205	168	142	Quote
1,810	220	170	182	163	Quote
1,810	230	200	219	200	Quote
2,046	248	242	333	279	Quote

Aluminium anode, stand-off, pipe core with bent legs

5 sizesOffshore structures, heavy anodes

2D drawing SWK-AP-432 · 2,300 × 293 × 268 mm · 432 kgTap any row below to redraw at that size.

3D view SWK-AP-432 · computer render of the shape (not a stock photo), drawn to this size's proportions

Length (mm)	Width (mm)	Height (mm)	Gross (kg)	Net (kg)
1,300	340	280	300	284	Quote
1,800	334	262	384	365	Quote
2,300	293	268	432	410	Quote
2,500	295	273	478	455	Quote
3,200	292	264	587	560	Quote

Aluminium anode, stand-off, bent legs with weld pads

3 sizesPiles and submerged steel structures

2D drawing SWK-AD-150 · 1,160 × 230 × 210 mm · 150 kgTap any row below to redraw at that size.

3D view SWK-AD-150 · computer render of the shape (not a stock photo), drawn to this size's proportions

Length (mm)	Width (mm)	Height (mm)	Gross (kg)	Net (kg)
800	230	210	104	92	Quote
1,160	230	210	150	136	Quote
1,810	200	165	162	144	Quote

Aluminium anode, weld-on, four steel straps (flat plate)

5 sizesShip hulls, sea chests, flat steel surfaces

2D drawing SWK-AW-4.2 · 300 × 150 × 30 mm · 4.2 kgTap any row below to redraw at that size.

3D view SWK-AW-4.2 · computer render of the shape (not a stock photo), drawn to this size's proportions

Length (mm)	Width (mm)	Height (mm)	Gross (kg)	Net (kg)
300	150	20	2.9	2.3	Quote
300	150	25	3.5	2.9	Quote
300	150	30	4.2	3.6	Quote
300	150	45	6	5.4	Quote
300	150	50	7	6.4	Quote

Aluminium anode, weld-on, steel core out both ends (rounded ends)

11 sizesShip hulls, piles, steel in seawater and brackish water

2D drawing SWK-AE-7.0 · 550 × 115 × 50 mm · 7 kgTap any row below to redraw at that size.

3D view SWK-AE-7.0 · computer render of the shape (not a stock photo), drawn to this size's proportions

Length (mm)	Width (mm)	Height (mm)	Gross (kg)	Net (kg)
300	70	35	2	1.5	Quote
270	150	30	3	2.5	Quote
300	150	30	4.6	3.8	Quote
430	95	50	5	4	Quote
450	100	50	5.5	4.5	Quote
550	115	50	7	5.8	Quote
550	120	65	9.5	8.3	Quote
550	125	75	11.6	10.4	Quote
530	140	95	16.6	15.6	Quote
880	130	95	26.6	24.9	Quote
880	150	100	31.6	29.9	Quote

Aluminium anode, weld-on, steel core out both ends (square block)

12 sizesShip hulls, sea chests, seawater tanks

2D drawing SWK-AB-2.8 · 205 × 110 × 40 mm · 2.8 kgTap any row below to redraw at that size.

3D view SWK-AB-2.8 · computer render of the shape (not a stock photo), drawn to this size's proportions

Length (mm)	Width (mm)	Height (mm)	Gross (kg)	Net (kg)
150	70	30	1	0.7	Quote
200	100	20	1.7	1.3	Quote
205	105	30	2	1.6	Quote
200	105	35	2.2	1.8	Quote
200	100	40	2.3	1.9	Quote
205	110	40	2.8	2.4	Quote
205	105	60	3.7	3.3	Quote
310	110	60	5.8	5	Quote
480	100	40	5.8	4.1	Quote
585	134	40	9	7.8	Quote
600	140	45	10.5	9	Quote
700	150	75	22	20.5	Quote

Aluminium anode, long slender bar, steel core out both ends

4 sizesWhere a long, narrow anode fits — tight hull spaces, long steel members

2D drawing SWK-AT-10.0 · 1,010 × 60 × 65 mm · 10 kgTap any row below to redraw at that size.

3D view SWK-AT-10.0 · computer render of the shape (not a stock photo), drawn to this size's proportions

Length (mm)	Width (mm)	Height (mm)	Gross (kg)	Net (kg)
380	60	65	3.5	2.9	Quote
1,010	60	65	10	8.2	Quote
1,000	60	68	11	9.2	Quote
1,800	120	110	66	57	Quote

Aluminium anode, bolt-on (two fixing holes)

14 sizesShip hulls, sea chests — replaceable without welding

2D drawing SWK-AC-4.2 · 300 × 150 × 40 mm · 4.2 kgTap any row below to redraw at that size.

3D view SWK-AC-4.2 · computer render of the shape (not a stock photo), drawn to this size's proportions

Length (mm)	Width (mm)	Height (mm)	Gross (kg)	Net (kg)
200	100	30	1.4	1.18	Quote
390	50	40	1.8	1.8	Quote
300	150	20	2.5	2.1	Quote
300	150	25	3.1	2.7	Quote
300	150	30	3.4	3	Quote
300	150	35	3.8	3.4	Quote
300	150	40	4.2	4.2	Quote
300	150	40	4.6	4.3	Quote
300	150	45	4.7	4.3	Quote
300	150	50	5.3	4.9	Quote
600	101	57.5	8.6	8.6	Quote
300	200	65	10.7	10.3	Quote
300	200	65	10.7	10.4	Quote
300	200	77	11.2	10.9	Quote

Aluminium anode, ring / disc (centre hole)

3 sizesCentre-bolted — flanges, seawater-side condenser covers

2D drawing SWK-AR-2.7 · Ø228.6 × hole Ø16 × 25 mm · 2.7 kgTap any row below to redraw at that size.

3D view SWK-AR-2.7 · computer render of the shape (not a stock photo), drawn to this size's proportions

Outside Ø (mm)	Hole Ø (mm)	Height (mm)	Gross (kg)	Net (kg)
100	16	50	1.2	1.2	Quote
228.6	16	25	2.7	2.7	Quote
230	16	30	3.2	3.2	Quote

Aluminium anode, round bar, 300 mm long

12 sizesCut or machined for special fits — inside pipework or small equipment

2D drawing SWK-AO-D38.1 · Ø38.1 × 300 mm · 1.2 kgTap any row below to redraw at that size.

3D view SWK-AO-D38.1 · computer render of the shape (not a stock photo), drawn to this size's proportions

Diameter (mm)	Length (mm)	Gross (kg)	Net (kg)
12.7	300	0.12	0.12	Quote
15.87	300	0.25	0.25	Quote
19.05	300	0.35	0.35	Quote
25.4	300	0.65	0.65	Quote
31.75	300	0.92	0.92	Quote
38.1	300	1.2	1.2	Quote
50.8	300	2.12	2.12	Quote
63.5	300	3.3	3.3	Quote
70	300	5.25	5.25	Quote
76.2	300	4.8	4.8	Quote
80	300	6.45	6.45	Quote
101.6	300	9.8	9.8	Quote

Not sure which size? Send the drawing or photos of the old anode — the team sizes it for you. Anode sizing calculator

ซิงค์อาโนด Zn 99.314% ขั้นต่ำ — ก้อนยาวแบบเชื่อม แกนเหล็กยื่นสองปลาย และก้อนแบบขันสลัก มีรูทะลุ 2 รูด้านบน — ภาพสตูดิโอแสดงรูปทรง

Zinc Sacrificial Anode (Zn 99.314% min)

Seawater — ship hulls, sea chest, condenser seawater side

The lowest driving potential of the group, so it rarely overprotects — overprotection is what disbonds coatings and embrittles high-strength steel with hydrogen

Seawater

Hulls · sea chests · anchor chain · the seawater side of condensers and heat exchangers

Brackish water — a thick oxide film tends to form over the surface and block the current

Feedstock purity:: special high-grade zinc ingot, 99.995% minimum
Anode composition:: Zn ≥99.314% · Al 0.1–0.5% · Cd 0.025–0.07% · Pb ≤0.006% · Fe ≤0.005% · Cu ≤0.005%
Potential:: −0.95 to −1.03 V vs Ag/AgCl in seawater
Consumption rate:: 11.23 kg/A·year
Current capacity:: 780 Ah/kg
Compared with aluminium:: at equal volume, aluminium delivers about 21.8% more current capacity

MIL-A-18001KGL-Zn1DNV-GL (works approval)

Figures as published by the manufacturer.

Size and weight table (52 sizes) ↓Full Zinc Anode specification

Zinc Anode sizes and weights (52 standard sizes)

Zinc anode, weld-on, four steel straps (flat plate)

5 sizesShip hulls, sea chests, flat steel surfaces

2D drawing SWK-ZW-10.1 · 300 × 150 × 30 mm · 10.1 kgTap any row below to redraw at that size.

3D view SWK-ZW-10.1 · computer render of the shape (not a stock photo), drawn to this size's proportions

Length (mm)	Width (mm)	Height (mm)	Gross (kg)	Net (kg)
300	150	20	6.3	5.7	Quote
300	150	25	8.3	7.7	Quote
300	150	30	10.1	9.5	Quote
300	150	45	14.9	14.3	Quote
300	150	50	17.5	16.9	Quote

Zinc anode, weld-on, steel core out both ends (rounded ends)

8 sizesShip hulls, piles, steel structures in seawater

2D drawing SWK-ZE-11.0 · 430 × 95 × 50 mm · 11 kgTap any row below to redraw at that size.

3D view SWK-ZE-11.0 · computer render of the shape (not a stock photo), drawn to this size's proportions

Length (mm)	Width (mm)	Height (mm)	Gross (kg)	Net (kg)
300	70	35	3.8	3.3	Quote
270	150	30	6.6	6.1	Quote
300	150	30	10.3	9.5	Quote
430	95	50	11	10	Quote
450	100	55	13	12	Quote
550	115	50	15.9	14.7	Quote
550	120	65	22	20.8	Quote
550	125	75	27	25.8	Quote

Zinc anode, weld-on, steel core out both ends (square block)

11 sizesShip hulls, sea chests, seawater tanks

2D drawing SWK-ZB-8.6 · 205 × 105 × 60 mm · 8.6 kgTap any row below to redraw at that size.

3D view SWK-ZB-8.6 · computer render of the shape (not a stock photo), drawn to this size's proportions

Length (mm)	Width (mm)	Height (mm)	Gross (kg)	Net (kg)
150	70	30	2	1.7	Quote
205	105	20	3	2.6	Quote
205	105	30	4.8	4.4	Quote
205	105	35	5.2	4.8	Quote
205	110	40	6.7	6.3	Quote
205	105	60	8.6	8.2	Quote
480	100	40	12	10.3	Quote
310	110	60	14	13.2	Quote
585	134	40	20.5	19.3	Quote
600	140	45	25.6	24.3	Quote
700	150	75	50	48.5	Quote

Zinc anode, long slender bar, steel core out both ends

2 sizesWhere a long, narrow anode fits — tight hull spaces, long steel members

2D drawing SWK-ZT-8.3 · 380 × 60 × 65 mm · 8.3 kgTap any row below to redraw at that size.

3D view SWK-ZT-8.3 · computer render of the shape (not a stock photo), drawn to this size's proportions

Code	Length (mm)	Width (mm)	Height (mm)	Gross (kg)	Net (kg)
	380	60	65	8.3	7.7	Quote
	1,010	60	65	22.1	20.3	Quote

Zinc anode, bolt-on (two fixing holes)

11 sizesShip hulls, sea chests — replaceable without welding

2D drawing SWK-ZC-8.9 · 300 × 150 × 35 mm · 8.9 kgTap any row below to redraw at that size.

3D view SWK-ZC-8.9 · computer render of the shape (not a stock photo), drawn to this size's proportions

Length (mm)	Width (mm)	Height (mm)	Gross (kg)	Net (kg)
200	100	30	3.2	2.98	Quote
390	50	40	4.5	4.5	Quote
300	150	20	5.9	5.5	Quote
300	150	25	7.5	7.1	Quote
300	150	30	7.7	7.3	Quote
300	150	35	8.9	8.5	Quote
300	150	40	10.6	10.2	Quote
300	150	45	11.2	10.8	Quote
300	150	50	12.5	12.1	Quote
300	200	77	27.5	27.2	Quote
300	200	65	27.6	27.2	Quote

Zinc anode, ring / disc (centre hole)

3 sizesCentre-bolted — flanges, seawater-side condenser covers

2D drawing SWK-ZR-7.0 · Ø228.6 × hole Ø16 × 25 mm · 7 kgTap any row below to redraw at that size.

3D view SWK-ZR-7.0 · computer render of the shape (not a stock photo), drawn to this size's proportions

Outside Ø (mm)	Hole Ø (mm)	Height (mm)	Gross (kg)	Net (kg)
100	16	50	3.2	3.2	Quote
228.6	16	25	7	7	Quote
230	16	30	8	8	Quote

Zinc anode, round bar, 300 mm long

12 sizesCut or machined for special fits — inside pipework or small equipment

2D drawing SWK-ZO-D38.1 · Ø38.1 × 300 mm · 2.67 kgTap any row below to redraw at that size.

3D view SWK-ZO-D38.1 · computer render of the shape (not a stock photo), drawn to this size's proportions

Diameter (mm)	Length (mm)	Gross (kg)	Net (kg)
12.7	300	0.3	0.3	Quote
15.87	300	0.47	0.47	Quote
19.05	300	0.67	0.67	Quote
25.4	300	1.2	1.2	Quote
31.75	300	1.86	1.86	Quote
38.1	300	2.67	2.67	Quote
50.8	300	4.75	4.75	Quote
63.5	300	7.43	7.43	Quote
70	300	9.02	9.02	Quote
76.2	300	10.67	10.67	Quote
80	300	11.79	11.79	Quote
101.6	300	19.01	19.01	Quote

Not sure which size? Send the drawing or photos of the old anode — the team sizes it for you. Anode sizing calculator

Fresh water

Magnesium Sacrificial Anode (Fresh Water)

Fresh water — barges, pontoons, river bridges, water heaters

The highest driving potential of the group, so it pushes current through a high-resistivity electrolyte; available bare or plastisol-coated

Fresh water

Very low-salinity water

Heat exchangers and condensers

Ordinary seawater — more driving potential than the duty needs, so it consumes faster and risks overprotection

Alloy grades:: High potential · AZ63B · AZ63C · AZ63D
High-potential type:: open circuit 1.70–1.75 V · closed circuit 1.57–1.62 V · capacity ≥1.100 A·h/g · efficiency ≥50%
Low-potential type (AZ63):: open circuit 1.50–1.55 V · closed circuit 1.45–1.50 V · capacity ≥1.105 A·h/g · efficiency ≥50%
Measurement note:: all potentials are referenced to a Saturated Calomel Electrode (SCE)

ASTM G-97

Figures as published by the manufacturer.

Sizes: Cast to your drawing (minimum production quantity applies) — tell us the water and the design life you need

Full Magnesium Anode specification Request a quotation

Magnesium anode — shape in 2D and 3D

Drawn to the proportions of the real part. The maker publishes no size table for this anode, so no millimetres are shown — size and weight are confirmed on the quotation.

2D drawing · shape and proportion, not a size

3D view · Bare — cast magnesium, thick round body, small centre bore (plastisol-coated also available)computer render of the shape, not a stock photo

Ask for a quotation:Bare Plastisol-coated

The other route to corrosion protection — protective coatings

Anti-corrosive coatings · underwater epoxy · wet-surface paint

Alongside cathodic protection we supply anti-corrosive coatings for steel and concrete — anti-rust primers, underwater-applied epoxy, wet-surface paint and PU anti-rust primer — several of which apply without abrasive blasting. Full specifications and prices for every formulation are on the Specialized Paint & Coatings page.

ช่างพ่นสีกันสนิมโครงสร้างเหล็กอุตสาหกรรม

See every coating — Specialized Paint & Coatings

Anti-rust · epoxy · specialist coatings, every formulation

Metal protected end to end — corrosion protection during packing and shipping (VCI)

Rust protection for shipped parts — film · VCI bags · desiccant

Beyond the anodes and coatings that protect a structure for decades, we also cover the short window that ruins finished parts: the voyage. Vapour-phase corrosion inhibitor (VCI) protects steel parts and spares in transit or long storage without oiling them, and without a wash-off step before use.

Choosing between VCI, silica gel and a rust inhibitor for an export shipment? Read the comparison table, then let us match it to your parts and packing method.

Compare export rust protection

* Priced by quantity and specification — ask for a quotation · size and grade matched to the part and the packing method

Brands we carry

Products sourced from OEM-approved manufacturers — quality and certification you can trust

Concrete Anode (CR series)

Made in Thailand · ISO 9001:2015 · supplied by SAHA

4-type Galvanic Cathodic Protection — Concrete, Aluminium, Zinc, Magnesium Anode — TIS 3029-2563, ASTM B418, ISO 12696, NACE, DNV, AMPP certified.

Genuine manufacturer products · all trademarks belong to their respective owners — authorised-dealer status varies by brand.

Often used together with

Customers on the same job usually add these — just say so if you want them on the quotation

Industrial paintTopcoat over the rust treatment for long-term protection 3D scanning / structural movement surveyFinds settlement and cracks before the rust repair

Still deciding?

Compare specs + price + recommendations

Free comparison tables — full specs, real prices, standards references, and use-case picks

Galvanic vs Impressed Current

Cathodic protection — sacrificial anode vs DC

Magnesium vs Zinc vs Aluminum Anode

Anodes — choose the metal by the water it sits in; water and concrete only

Rust Converter vs Sandblast vs Epoxy Primer

Rust treatment methods — choose by TOR + budget + service life

Read before you decide

Why the cheapest option today is often the most expensive over 20 years — Life-Cycle Cost

Sticker price ≠ true cost · repaint cycles + downtime · ISO 15686-5 / ISO 12944

Read guide

Product Specifications

6 product lines available

Deep dive into specs, working principle, standards, and benefits — click any item to expand.

Embedded Galvanic Anode for Reinforced Concrete

Cathodic Protection (CP) — for Reinforcing Steel

Purpose & best fit

Protects rebar in reinforced concrete from chloride-induced corrosion, carbonation, and saltwater ingress. Suitable for both new construction and repair of existing structures.

Working principle

Zinc anode encased in special alkaline mortar (pH ≥ 14 with lithium hydroxide) prevents zinc passivation. Galvanic current flows to the rebar, maintaining the passive film and preventing chloride-induced corrosion.

Specifications

Polarization Decay: ≥ 100 mV
Protection Radius: ≥ 60 cm
Service Life: ≥ 10 ปี / years
Mortar pH: ≥ 14
Installation: ผูกกับเหล็กเสริมด้วยลวดหรือเหล็กรัด / Tie-wired or strapped to rebar

Real-world applications

Reinforced concrete structures in coastal/marine environments
Piers, jetties, submerged concrete piles
Bridge decks exposed to chloride deicing
Dams, pumping stations, structures with saltwater ingress
Patch repair of corroding existing structures

Benefits & outcomes

Contains no chlorides or bromides that damage steel
Easy installation — tie-wired to rebar before concrete pour
No external power needed (vs. impressed current) — zero maintenance
Extends structure life ≥ 10 years, reducing long-term repair cost

Industry reference standards

ASTM B418 Type IIมอก. 3029-2563 (TIS 3029-2563)ISO 12696

Aluminium Sacrificial Anode

Marine CP — Seawater & Brackish Water

Purpose & best fit

Protects submerged or splash-zone steel structures in seawater/brackish water — ship hulls, piers, offshore pipelines. Chosen over zinc when high current capacity per unit weight is needed.

Working principle

Based on Galvanic Series — aluminium has lower electrochemical potential than steel and corrodes preferentially, releasing electrons through the electrolyte (seawater) to suppress anodic reaction on the steel surface.

Specifications

Base Metal: High-purity aluminium alloy
Environment: Seawater + brackish water
Current Capacity: สูงกว่าสังกะสีต่อหน่วยน้ำหนัก / Higher than zinc per unit weight
Forms: Slab, ribbon, bracelet — ตามแบบโครงการ

Real-world applications

Ship hulls
Steel piers & pilings
Offshore structures, oil platforms
Ballast tanks

Benefits & outcomes

Highest current capacity among sacrificial anodes
Lighter weight per unit of protection vs. zinc
More cost-effective than Impressed Current systems for medium scale
Works in both seawater and brackish water — single formulation

Industry reference standards

DNV-GL Section 7 (Corrosion Protection)ISO 9001มอก. (Thai industrial standards)

Zinc Sacrificial Anode

Marine CP — High-strength steel + overprotection-sensitive systems

Purpose & best fit

Protects ship hulls, sea chests, heat exchangers, and seawater-immersed steel where low driving voltage is needed to prevent over-protection (coating disbondment, hydrogen embrittlement).

Working principle

Zinc (anode Zn ≥ 99.314%, cast from 99.995% ingot) corrodes preferentially via galvanic action. Lower driving voltage than aluminium/magnesium — safer for high-strength steel that can suffer hydrogen embrittlement under over-protection.

Specifications

Zinc content: ≥ 99.314% Zn
Driving Voltage: ต่ำสุดในกลุ่ม sacrificial / Lowest of the three
Environment: Seawater (low resistivity)

Real-world applications

Cargo ship hulls
Sea chest, mooring chains
Seawater-cooled condensers/heat exchangers
Marine steel & aluminium equipment

Benefits & outcomes

Low driving voltage reduces over-protection risk
Prevents coating disbondment from hydrogen evolution
Minimises hydrogen embrittlement in high-strength steel
Compliant with MIL-A-18001K and DNV-GL

Industry reference standards

MIL-A-18001K (U.S. Military)DNV-GL (GL-Zn1)ISO 9001

Magnesium Sacrificial Anode

CP for high-resistivity environments

Purpose & best fit

Protects structures in high-resistivity fresh water — where aluminium/zinc cannot drive sufficient current. Used for barges, pontoons and freshwater heaters. Buried pipelines and underground tanks are outside what SAHA supplies.

Working principle

Magnesium has the lowest electrochemical potential (~−1.55 V) — the highest driving voltage in the sacrificial family. It can push current through high-resistivity electrolytes where Al/Zn cannot; we supply it for fresh water, not for buried work.

Specifications

Driving Voltage: สูงสุดในกลุ่ม / Highest of the three
Environment: น้ำจืด / fresh water, high-resistivity electrolyte
Forms: ทรงกระบอกหนามีรูกลาง (condenser anode) / Thick cast cylinder with centre bore

Real-world applications

Barges · pontoons · river craft
Condensers and heat exchangers on the fresh-water side
Hot-water heater steel tanks
Fresh-water structures (dams, lakes)

Benefits & outcomes

Highest driving voltage — works in high-resistivity media
For low-conductivity fresh water; buried work is outside what we supply
No external power source needed
Available bare or plastisol-coated

Industry reference standards

ASTM G-97

Single-Component Moisture-Curing Polyurethane Primer

Industrial Coating — Rust Prevention

Purpose & best fit

One-part moisture-curing polyurethane primer that cures via atmospheric humidity. Functions as primer, intermediate coat, topcoat, or single-layer finish. Contains aluminium flake for barrier protection.

Working principle

Isocyanate groups in the resin react with airborne moisture (H₂O) to form urea crosslinks, curing into a hard film. Aluminium flakes align in lamellar pattern, blocking water and oxygen ingress.

Specifications

System: 1K Moisture-Curing Polyurethane (MCP)
Recommended DFT: 150 ไมครอน / 150 µm
Salt Spray (ASTM B117): ผ่าน 2,000 ชม. ที่ 150 µm / Pass 2,000 hr at 150 µm
Application: แปรง / ลูกกลิ้ง / airless spray
Substrates: เหล็ก, เหล็กชุบกัลวาไนซ์, เหล็กสนิม, อลูมิเนียม, คอนกรีต, ไม้, พลาสติก

Real-world applications

Tanks, vessels, factory steel piping
Steel structures with existing rust (no need for SA 2½ blast)
Plant maintenance touch-ups without shutting down production
Tight-access steelwork — brush-applicable

Benefits & outcomes

Apply over existing rust — no full sand-blast to SA 2½ required
Single-component eliminates mixing error and pot-life concerns
Faster work cycle and curing time vs. 2K epoxy systems
Chemical- and UV-resistant

Industry reference standards

ASTM B117 (Salt Spray)

Solvent-Free Two-Component Epoxy (Underwater-Applicable)

Industrial Coating — Underwater Repair

Purpose & best fit

Two-component solvent-free epoxy applicable directly to wet, damp, or fully submerged surfaces. For structures that cannot be dry-docked or fully dried before repair.

Working principle

Solvent-free epoxy chemistry — does not need to displace moisture; it incorporates surface water into the polymer matrix. Provides simultaneous resistance to acids, alkalis, amines, salts, and solvents.

Specifications

System: 2-component solvent-free epoxy
Recommended DFT: 400 ไมครอน / 400 µm
Salt Spray (ASTM B117): ผ่าน 2,000 ชม. ที่ 400 µm / Pass 2,000 hr at 400 µm
Application Temp: 10 – 40 °C
VOC: Solvent-free, low odor
Substrates: เหล็ก, เหล็กที่มีสนิม, คอนกรีต — เปียก/ชื้น/ใต้น้ำได้

Real-world applications

Risers, pipes, splash-zone structures (oil & gas)
Underwater pier repair, submerged piling
Treatment ponds, acid/alkali process equipment
On-stream repair without shutting down machinery

Benefits & outcomes

Applies on wet, damp, or fully submerged surfaces — no dry-docking
Solvent-free, low VOC — safe in confined spaces
Broad chemical resistance (acid, alkali, amine, salt, solvent)
Brush/roller-applied — no separate primer required

Industry reference standards

ASTM B117 (Salt Spray)

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Common Questions

Before you send an RFQ

Q1.How does Cathodic Protection work?+

Uses anode (zinc/aluminum/magnesium) as sacrificial — corrodes before the protected steel. Bonding cable + structure-to-electrolyte potential monitoring per NACE SP0169.

Q2.Zinc vs Aluminum vs Magnesium anode — which?+

Zinc: seawater. Aluminum: seawater and brackish water, the highest capacity. Magnesium (condenser anode): fresh and very brackish water, the highest driving potential. Choose by the water the structure sits in. Sahawatthanakit supplies anodes for water immersion and concrete embedment only; buried/soil work is out of scope.

Q3.Anode replacement interval?+

Depends on design weight + corrosion rate — typically 5-15 years. Inspect residual annually, replace at <30% residual (NACE recommendation).

Q4.Is SP10 surface prep really required before coating?+

Yes for marine + structural steel — SSPC-SP 10 (near-white blast) gives best adhesion. General work SP 6 (commercial) suffices. Rushed jobs SP 3 (power tool).

Q5.CP-integrated coating vs standard epoxy — difference?+

A coating with integral cathodic protection extends steel life 2-3x. Standard epoxy is barrier-only. Worth it for hard-to-access structures (offshore towers).

Q6.Steel parts rust during sea-freight export — how to prevent it?+

Use VCI (vapor corrosion inhibitor) packaging — VCI film (wrap/cover steel plate, coil, structures; line container interiors) or VCI bag (machined/marine parts — protects bores, recesses and threads that oil can't reach). Nitrite-free: no oil to apply, no wash-off before use. Add a desiccant sachet for a second moisture layer. Sizing/type selection per part + export packing guidance included — quote-only, send the part and volume.

Rust Treatment & Coatings — delivery by province

Pick your province for delivery details and a quotation

Bangkok Nonthaburi Samut Prakan Phra Nakhon Si Ayutthaya Chonburi Rayong Chachoengsao Prachinburi Nakhon Pathom Ratchaburi Prachuap Khiri Khan Ang Thong

See all 28 provinces

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