Dural boats are valued for their strength, durability and corrosion resistance, but even they are not eternal. Dough The most loaded part of the hull, which takes on the impact of rocks, friction on the ground and water pressure, over time, there are scratches, dents, and in neglected cases, through holes or corrosive pockets. You can not postpone repairs: even a small crack can lead to depressurization of compartments, loss of buoyancy or complete failure of the boat.

In this article, we will discuss stage-by-stage From damage diagnosis to final sealing, you'll learn what materials are suitable for dural, how to cook aluminum alloys properly, and why a conventional grease won't work here, and you'll also learn the common mistakes that shorten the life of the boat after repair.

If you've never welded or worked with metal, some of the operations are best left to the professionals, but most of the damage (such as scratches or small holes) can be repaired by yourself, provided that the technology is strictly adhered to. Dural does not tolerate a home-made approachUsing inappropriate materials (e.g., epoxy resin without reinforcement) or temperature disturbance will cause the patch to fall off after several outlets.

Diagnosis of damage: when repair is possible and when not

Before you start to use tools, you need to assess the scale of the problem. Dural boats are repairable, but there is a critical condition in which recovery is not economically feasible. 30% floor area or the metal has become brittle (determined by tapping – a deaf sound signals internal destruction).

Pay particular attention to:

  • 🔍 Scratches and scuffs. Even shallow damage to the paint coating over time leads to the oxidation of the metal.
  • 💥 Dumps. - they violate the geometry of the body and can become a hotbed of stress, which will lead to cracks.
  • 🕳️ Through holes - require urgent repairs, as water enters the body compartments.
  • 🧪 Corrosion stains White coating (aluminum oxide) or loose areas indicate the beginning of the destruction of the alloy.

Use for accurate diagnosis ultrasonic thickness gauge (e.g. models) Elcometer 456 or DeFelsko Positector 6000It will help measure the residual thickness of the metal, if it's smaller. 1.5 mm - requires patch reinforcement or complete replacement of the section.

⚠️ Attention: Do not ignore small cracks of length. 2-3 cmIn the dural, they tend to crawl under load, like when you hit a rock at speed. 30+ km/h Even a microcrack can turn into a gap of length. 10–15 cm.

Materials and tools: what will be needed for repairs

To properly repair the dural bottom, welding alone is not enough; you need a set of materials that each perform a different function, from protecting the metal to restoring strength, and here is a verified list of brands and analogues.

Material/tool Appointment Recommended brands Estimated price (2026)
Aluminum filler rod stamps ER4043 or ER5356) For welding cracks and holes ESAB, Lincoln Electric, Svarog from 800 /kg
Two-component epoxy glue (with reinforcement fibres) For patches for small holes 3M Marine Adhesive Sealant 5200, Poxipol from 1,200 RUB / tube
Anti-corrosion soil (zinc or chromium-based) Metal protection after cleaning Duralac, Alodine 1200 from 1,500 /l
Polyurethane or epoxy paint (for aluminum) Final coverage International Intergard 264, Hempel Hempadur from 2,000 /l
Abrasive materials (paper sandpaper) P80–P220, metal brushes ) Cleaning before repair 3M, Mirka from 300./oop.

Durali welding is fine. argono-argono-argo (TIG) with AC current function (e.g., Fubag IR 200 or Blueweld Prestige 186AC/DCThe power shall be at least equal to 150-200 Ato boil metal thickness 2-4 mmThe alternative is gas-weldingBut it requires more experience.

📊 What tools do you have to repair the boat?
A soldering iron and an epoxy
Argono-arc welding
Gas welding
I'll buy it.

3. Surface preparation: the pledge of durable repairs

The quality of training depends on Up to 70% success of the repairThe dural is coated with an oxide film that interferes with material adhesion and welding, and if it is not removed, the patch or seam will quickly peel off, and the preparation process includes 4 mandatory steps:

  1. Mechanical clean-up Removing paint, rust and oxides with a metal brush or a grinder. sandblaster (if possible)
  2. Degreasing - rubbing with acetone or a special cleaner (Loctite 7063Don't use gasoline or solvent 646, they leave the film behind!
  3. Evilization - processing orthophosphoric acid (10% solution) to remove oxide residues. 5-10 minutes.
  4. Soil application After the scaling, cover the surface immediately. chromate (for example, DuralacThis will prevent re-oxidation.

If you repair a hole, cut out the damaged area. thin-disk (for example, 1.0 mm) stepping back from the edge to 10-15 mmThe edges of the cut should be flat, without barbs. mill-cutter - they give a more neat edge.

⚠️ Attention: Never use it to clean up the durals. sandpaper The iron particles are pressed into the aluminum and become hotbeds of corrosion. aluminum-oxide or silica.

Repair methods: from patches to welding

The choice of technology depends on the type of damage, and we'll look at three main ways, from the simplest to the professional.

Epoxy glue patches (for holes up to 5 cm)

Suitable for minor damage where high strength is not required (e.g. on the bow of a boat or in low-load areas). reinforcement fiberglass or aluminum foil.

Step by step:

Remove paint and oxides from the area around the hole | Cut patch from fiberglass (on the 2-3 cm More holes) |Put epoxy glue on both surfaces |Put the patch and remove air bubbles with a roller |Continue 24 hours. temperature +20°C-->

To increase the strength can be used double-patch In this case, after drying the first layer, drill holes along the edge.∅ 2-3 mm) and rivets (aluminum or stainless) pull the structure.

Duralee soldering (for cracks up to 10 cm)

With a soldering iron 100-150 W You can fix cracks, but only if they're not in high load areas (e.g., on the keel). flux (Castolin Aluflux or Harris Stay-Silv) and zinc solder (Castolin 192).

Technology:

  1. Warm up the soldering iron until 350–400°C.
  2. Put flux on the crack and solder.
  3. Melt with solder, evenly filling the damage.
  4. After cooling, remove the residues of the flux with water (it is corrosive-active!).

Argono-arc welding (for serious damage)

It's the most reliable method, but it requires skill, and welding the duralee makes it difficult. high-heat conduction And you have a tendency to deformity. You can use the following settings:

  • 🔥 Current: 60-120 A (depends on the thickness of the metal).
  • ⚡ Polarity: alternating current (AC).
  • 💨 Argon consumption: 8-12 l/min.
  • 📏 Diameter of tungsten electrode: 1.6-2.4 mm (for metal thickness) 2-4 mm).

Weld with short stitches (2-3 cm), let the metal cool. After welding, be sure to forge the seam round-hammer Remove internal stresses and prevent cracks.

💡

If you don't have experience welding durals, practice on an unnecessary piece of aluminum of the same thickness. Dural AMG5 or AMG6 (most common in boats) behaves differently than regular aluminum!

Sealing and anti-corrosion protection

Even a perfectly executed repair will not prolong the life of the boat unless it protects the metal from moisture and salt water.

  1. Application of anticorrosive soil - Use it. chromate (for example, Alodine 1200They form a passive film on the surface that blocks oxidation. 1-2 hours.
  2. Seam sealing - That's the right thing to do. polyurethane sealant (SikaFlex 291i or 3M 5200Apply it from the inside and outside of the seam.
  3. Colouring - Use it. double-paint It's epoxy or polyurethane-based, it's elastic, it doesn't crack when you deform the body. 2-3 layers with intermediate drying.

For additional protection of the keel and the most vulnerable areas can be used rubber (Plasti Dipor polyureaThese coatings are resistant to abrasive wear and impact.

⚠️ Attention: Don't use durali to paint. nitro-paintThey don't provide enough adhesion to aluminum and they peel off through the aluminum. Seasons 1-2Only specialized. sea-paint!

6. Common mistakes and how to avoid them

Experienced craftsmen know: repairing a dural boat is a 80% and 20% of the work. Most problems arise from rushing or choosing the wrong materials.

  • 🔥 Metal overheating during welding Dural loses strength at temperatures higher 400°CUse it. heat-discharger (Copper plates) and weld with short stitches.
  • 🧴 Use of car putty - it's not designed to come into contact with water and will fall off in a few weeks. sea-stuff!
  • 🔩 Black metal rivets - they rust and they shatter the dural around them. aluminum or stainless rivets (AD-3 or AD-4).
  • 🎨 Painting without primer - the paint will lie unevenly and quickly peel off. mandatoryEven if the surface looks clean.

Another common problem. wrong geometry of the body after repairIf the patch or seam protrudes above the surface, it creates additional resistance to water and impairs driving performance. grind the seam in face. with the base metal.

What happens if you don’t remove the oxide film before welding?

Aluminum oxide melts at temperature 2000°C against 660°C The seam will not be boiled to the depth of the seam, and it may look normal on the outside, but when it is loaded (for example, when hitting a wave), the seam will crack.

7. Post-repair test: how to check leakproofness

Before launching the boat, be sure to check the quality of the repairs, even a slight leakiness can lead to flooding of the compartments.

  1. Visual examination - whether there are cracks, bubbles on the paint or insulators in the seam.
  2. Soap solution testing Put it on the seam and inject air from the inside (like a compressor).
  3. Hydraulic test Fill the compartment with water and leave it on 12-24 hoursIf the level is unchanged, the leakage is normal.
  4. Water test - I want you to lower the boat in shallow water and inspect the bottom, and pay special attention to the repair area and rivets.

If you find a leak, don't panic. loose-rack or stainlessYou just need to tighten the rivets or put an extra layer of sealant.

💡

Even after a successful test, the first 2nd exit 3 Avoid extreme stresses (jumping from waves, hitting rocks) and let the materials become polymerized.

FAQ: Frequent questions about repairing dural boats

Can you cook dural with a conventional inverter (MMA)?

Technically, but highly recommendedDural requires protection of the molten metal with argon, otherwise the seam will be porous and brittle. MMA inverters (e.g., Resanta SAI-190) do not provide a stable arc at alternating current, which is critical for aluminum alloys. special electrodes for aluminum (OSA-1 or OSA-2), but the quality of the seam will be lower than in TIG welding.

Which glue is better for patches: epoxy or polyurethane?

For dural boats epoxy (for example, 3M 5200 or Poxipol), since he:

  • Possesses high-adhesion after proper preparation.
  • It is not destroyed by salt water.
  • Can be reinforced with glass fabric for additional strength.

Polyurethane adhesives (e.g., SikaFlex) are inferior in strength but suitable for sealing seams or temporary repairs.

How much does it cost to repair the bottom of a dural boat in the service?

Cost depends on the complexity of the work (2026, average prices in Russia):

  • Patch on the hole (up to 10 cm)from 3 000 ₽.
  • Welding of cracks (up to 20 cm)from 5 000 ₽.
  • Replacement of the bottom section (from 30×30 cm)from 15 000 ₽.
  • Complete anti-corrosion treatmentfrom 20 000 ₽ (Includes sandblasting and painting).

The price is usually not entering the price of materials (fill rod, paint, etc.).

Can I paint the dural with car paint?

No, categoricallyAutomotive paints (even "metallic" paints) are not designed to:

  • Constant contact with water (especially salt water).
  • Abrasive effects of sand and gravel.
  • Deformation of the hull during impacts.

Through Seasons 1-2 This paint will bubble and peel off, baring the metal. sea-paint on an epoxy or polyurethane basis.

How often should I inspect the bottom of a dural boat?

Recommended frequency of inspection:

  • After every major blow. (e.g., a topping up or collision).
  • Before and after the season - even if the boat was stored on land.
  • Every 50 motor hours (for motorboats).
  • Every 2-3 years - complete diagnosis with measurement of metal thickness.

Pay attention to sound-shift when tapping on the bottom: a deaf knock signals internal corrosion or detachment of the metal.