01 · BONDED COMPONENTS
Rubber Bonded to Metal
in One Cure, Not Glued On After.
Mounts, bushes, rollers, plungers and sealing elements with rubber vulcanised directly onto steel, stainless, aluminium or brass — prepared, primed and cured as one part at our ISO 9001:2015 plant in Nashik. There is no adhesive joint to fail, because there is no joint: the bond forms while the rubber cures.
- ISO 9001:2015
- BONDED IN-HOUSE
- STEEL · STAINLESS · ALUMINIUM · BRASS
How is rubber bonded to metal?
Rubber is bonded to metal during vulcanisation and tested to ASTM D429: the insert is degreased, grit-blasted, chemically treated and primed, then the rubber cures onto it in the mould. There is no glued joint to fail. Margo bonds to steel, stainless steel, aluminium and brass. A sound bond fails in the rubber, recorded as 100% R.
02 · APPLICATIONS
Six Places the Bond Is the Part
Most of what we already supply is bonded. These six are the families where the metal and the rubber have to work as one component, and where a bond that separates is a failure of the whole assembly rather than a cosmetic defect.
Anti-vibration mounts
Sandwich, bobbin and conical mounts with rubber vulcanised between two metal faces. The bond carries every load the mount carries, in shear and in compression, for the life of the machine.
Bonded bushes and sleeves
Inner sleeve, rubber, outer sleeve, bonded in one cure. Torsional stiffness comes from the rubber section and the interference; the bond is what stops the sleeve spinning inside the housing.
Rollers and wheels
A rubber covering bonded to a steel or aluminium core, ground to your outside diameter and concentricity after cure. Bonded rather than sleeved, so it cannot creep under torque.
Plungers, pistons and stems
A rubber sealing element moulded onto a metal stem. The rubber does the sealing and the metal takes the drive load, and nothing between them is an adhesive joint added later.
Diaphragms with moulded-in plates
Where a diaphragm drives a stem or seats against a plate, the metal is bonded in during cure — no assembly stack, no adhesive line, no tolerance chain between two parts.
Vessel and pipework lining
Sheet rubber bonded to a steel vessel, sump or chute to protect it from abrasion or chemical attack. Same process, larger scale, and bonded rather than mechanically fixed.
03 · PROCESS
Three Steps, and the Third Is the Cure
Metal preparation
Two-coat bonding system
Bonded during vulcanisation
Tooling is cut in-house, so the insert location, the flash line and the bond area are designed together rather than negotiated between a toolroom and a moulder. First samples come back 48 to 72 hours from an approved drawing.
04 · SUBSTRATES
Not Every Metal Bonds the Same Way
| Substrate | Preparation | Bonds | What to tell us |
|---|---|---|---|
| Mild and carbon steel | Degrease, grit blast, phosphate | Readily | Grade and whether the part is plated. Plating and bonding do not mix — bond first, or specify unplated |
| Stainless steel (304, 316) | Degrease, grit blast, chemical treatment | Well, with the right primer | The grade. Passivated surfaces need a different primer from mild steel and the bonding system changes with it |
| Aluminium and alloys | Degrease, grit blast, etch or conversion coat | Well, with preparation | The alloy and any anodising. Anodised surfaces are the most common cause of a failed aluminium bond — tell us before tooling, not after |
| Brass and bronze | Degrease, grit blast, chemical treatment | Well | Whether the part is machined or cast. Cast surfaces hold more contamination |
| Zinc, cadmium and chrome plating | — | Not recommended | Bond to the bare substrate and plate the exposed metal afterwards, or supply the insert unplated |
05 · COMPOUND
The Duty Picks the Compound. The Compound Picks the Primer.
Every compound we mix can be bonded, and the bonding system changes with each one. These are ranked for bonded parts — tell us the load, the medium and the temperature and we will confirm the pairing.
| If the duty is | Compound | Service temperature | Note |
|---|---|---|---|
| Vibration isolation, dynamic load, high deflection | Natural rubber | −20 to +90 °C | The default for bonded mounts and bushes. Best flex-fatigue resistance and best damping of the eight, and it bonds more readily than anything else here. No oil contact |
| Oil, fuel or grease contact | NBR | −30 to +120 °C | The default where natural rubber would swell. Bonds well |
| Weather, ozone, outdoor, water and steam | EPDM | −40 to +140 °C | For lining and outdoor mounts. Never in oil or fuel |
| General purpose, marine, moderate oil, flame-retardant | Neoprene | −40 to +120 °C | The compromise compound, and it bonds readily |
| Abrasion, slurry, lining, low cost | SBR | −30 to +100 °C | Abrasion resistance at commodity cost. No oil contact |
| Hot oil and oil mist above nitrile’s ceiling | AEM | −40 to +175 °C continuous to +160 °C | The middle answer between NBR and FKM, at well under FKM cost |
| Aggressive chemistry, solvents, hot hydrocarbons | FKM | −20 to +250 °C continuous to +200 °C | Bondable, and it needs its own bonding system. Poor in the cold |
| Clean, high-temperature, low-load duty | Silicone | −60 to +220 °C | The hardest of the eight to bond to metal and the weakest in tear. It needs a dedicated primer system and it is the wrong answer for a load-bearing bonded part. Specify it only where temperature forces it |
06 · VERIFICATION
A Good Bond Fails in the Rubber
Bond quality is judged by where the part breaks, not by how hard it was to break. Pull a sound bonded component apart and the tear runs through the rubber, leaving a rubber-covered metal face; a poor bond separates cleanly at the interface and the metal comes back bare. ASTM D429 puts a notation on that — R for failure in the rubber, RC at the rubber-to-cover-coat line, CP between cover coat and primer, M at the metal. The target is 100% R, and anything else is a rejected process, not a weaker part.
| Check | Method | When |
|---|---|---|
| Visual bond line and flash | — | Every part |
| Adhesion, destructive | ASTM D429 · failure mode to 100% R | Sample per batch, NABL partner laboratory |
| Hardness | ASTM D2240 | In-house |
| Tensile and elongation | ASTM D412 | In-house |
| Compression set | ASTM D395 Method B | In-house |
| Tear strength | ASTM D624 | NABL partner laboratory |
| Dimensional conformity | ISO 3302-1 class M1 | In-house |
| Dynamic fatigue / cycles to failure | ISO 132 · ASTM D430 | not held |
Material test reports, dimensional inspection sheets and a certificate of conformance ship with every consignment. Batch records are retained per shipment and are available on request under NDA. Bonded parts are packed so the bond line is not loaded in transit.
07 · SPECIFICATION
What We Need to Quote
| Input | Range | Why we ask |
|---|---|---|
| Insert material | steel · stainless · aluminium · brass | Decides the preparation and the primer. See section 04 |
| Insert finish | bare · plated · anodised | The single most important line on this table. Plated and anodised surfaces change the answer or rule it out |
| Insert drawing | PDF · DWG · DXF · STEP | We need the bond face, not just the outline |
| Rubber section | to drawing | Bond area follows from it, and so does stiffness |
| Load and direction | static · shear · compression · torsion | A mount loaded in shear and one loaded in compression are different parts at the same size |
| Medium | named fluid | Decides the compound, and the compound decides the bonding system |
| Service temperature | −60 to +250 °C across the eight compounds | Narrows the compound with the medium |
| Hardness | 40 – 80 Shore A | Our output, not your input — recommended against the duty unless your drawing fixes it |
| Post-cure machining | ground OD · concentricity | Rollers and wheels are ground after cure; tell us the finished dimension and the runout |
| Dimensional tolerance | ISO 3302-1 class M1 | Tolerance follows the section, as on every moulded part in this catalogue |
Or send the failed part. A bond that separated cleanly and left bare metal is a preparation or primer problem; rubber left on the metal with a tear through the section means the bond held and the compound or the geometry did not. The two failures have different fixes, and we can usually tell which you have from the part.
ISO 9001:2015 · Certificate 09111526A
Integral Certification Ltd · Valid to 21 February 2027
Scope: rubber moulded components — quality management, not a product approval
IATF 16949 — upgrade in progress, certification targeted by end 2026
ISO 14001 and ISO 45001 — targeted 2027
FREQUENTLY ASKED QUESTIONS
Technical & commercial questions
Can you bond rubber to aluminium and stainless steel?
Yes to both, with the right preparation and primer. Aluminium needs an etch or conversion coat and stainless needs a different primer from mild steel, so tell us the alloy or the grade with the drawing. The two things that will stop us are anodising and plating — bond to the bare substrate and finish the exposed metal afterwards, or supply the insert unplated.
How strong is the bond?
We do not publish a peel or tensile figure, because a number from a test specimen tells you nothing about your part — bond strength scales with area, geometry and compound, and a headline figure is read as a guarantee for parts it was never measured on. The criterion we work to is the failure mode. A sound bond tears through the rubber and leaves the metal covered; a poor one separates clean and leaves it bare. ASTM D429 calls the first 100% R, and that is what we qualify to on your part, on your insert, with the report in your name.
Do you bond during moulding or glue the parts afterwards?
During moulding, always. The prepared and primed insert goes into the tool and the rubber is moulded onto it, so heat and pressure cure the compound and complete the bond in the same cycle. The part leaves the tool as one component. Nothing is glued, clamped or pressed together afterwards — there is no assembly joint, because there is no assembly.
Can you supply the metal inserts, or do we send them?
Either. Send your inserts and we bond to them, or send the drawing and we source and prepare them here. Sourcing them here is usually the better route on a new part, because insert design, tool design and bond area are one decision rather than three, and our toolroom is in the same building.
What is the minimum order quantity for bonded components?
We supply in bulk. The minimum run is 10,000 pieces per part number, per compound, or quoted against the part where geometry or tooling makes that unrealistic. Prototype and first-article lots sit outside the minimum. On a bonded part with a bought-in insert the insert lead time usually sets the schedule rather than the moulding, so tell us your call-off pattern with the volume.
What are your payment and delivery terms for international orders?
TT and LC accepted, discussed per order. Ex-works Nashik or FOB Nhava Sheva. Commercial invoice, packing list and certificate of origin are issued with every consignment. Production is three to four weeks from drawing approval, or two weeks on an express basis where we have confirmed capacity.
10 · ENQUIRIES
Request a Bonded Component Quotation
Send the insert drawing and the rubber section, and tell us the insert finish, the load direction and the medium. Or send the part that failed and we will tell you whether the bond or the compound let go. Our engineering team responds within 48 hours with a compound and bonding-system recommendation, dimensional confirmation and a quotation.