How To Fix Common Gas Tank Repair Problems

Gas Tank Repair

The problems:

There are three possible problems with both plastic and metal gas tanks.

  • Pin hole leaks
  • A crack in the tank
  • A hole in the tank.

We will cover how to repair each problem for both plastic and metal gas tanks.

Issues of Concern:

Gas tanks have thin walls, making cracks difficult to repair.  Our recommendation is to always reinforce the repair of a crack in a gas tank.  When you use a Tech-Patch to reinforce the repair, you don’t need to repair the crack.   The patch will stop all leaks.

When there is a problem with a metal tank, there is often a loss of substrate due to corrosion.  That substrate needs to be rebuilt.  The Filler, used in conjunction with an SI adhesive, will rebuild that tank and that repair will not corrode.

When there is a hole in either a metal or plastic gas tank, the only repair we recommend is a Tech-Patch.

Items Needed

For Plastic Gas Tank Repair

  • A Deluxe Kit or higher.
    • An SI structural adhesive
    • Poly Prep – adhesion promoter for polymers
    • An Activator/Accelerator.
    • Filler
  • A heat gun or hair dryer.
  • Coarse sand paper

Items Needed

For Metal Gas Tank Repair

  • A Basic Kit or higher
    • An SI structural adhesive
    • An Activator/Accelerator
    • Filler
  • Coarse sand paper.

Metal Gas Tank Pin Hole Leaks

Repair steps:

  1. Make sure surfaces are clean.
  2. Aggressively rough the surface with coarse sand paper.  60 grit.  This step is critical.  You must get down to the base metal.
  3. Wipe the surface with a soft cloth.
  4. Run beads of an SI adhesive in the problem area.  Spread the adhesive into a thin layer.
  5. Sprinkle the Filler on the adhesive.  Set will occur in seconds (collect excess Filler to reuse).
  6. Run beads of SI adhesive in the problem area.  Spread the adhesive into a thin layer.
  7. Spray a VERY light mist of Activator/Accelerator on the SI adhesive.
  8. Repeat 6 and 7.

Poly Plastic Gas Tank

  1. Make sure surfaces are clean.
  2. Aggressively rough the surface with coarse sand paper.  60 grit.  This step is critical.
  3. Wipe the surface with a soft cloth.
  4. Saturate the surface with the Poly Prep.  Once a poly is primed with Tech-Bond’s Poly Prep, that poly is primed forever.
  5. Warm the surface with a heat gun or hair dryer.  Warm to very warm, not hot (approximately 115 degrees).  You don’t want to fry the SI adhesive.
  6. Run beads of an SI adhesive in the problem area.  Spread the adhesive into a thin layer.
  7. Sprinkle the Filler on the adhesive.  Set will occur in seconds (collect excess Filler to reuse.
  8. Run beads of SI adhesive in the problem area.  Spread the adhesive into a thin layer.
  9. Spray a VERY light mist of Activator/Accelerator on the SI adhesive.
  10. Repeat 8 and 9.

Cracks In A Metal Gas Tank

Make sure that, other than the crack, the tank is in good shape.  That the walls are sound and there are no other problems.

  1.  Make sure surfaces are clean.
  2. Aggressively rough the surface with coarse sand paper.  60 grit.  This step is critical.
  3. Wipe the surface with a soft cloth.
  4. Run a bead of an SI adhesive on one edge of the crack.  The entire edge.
  5. Bring the two edges together.
  6. Spray with the Activator/Accelerator.
  7. Run a head of SI adhesive on the seam.  Spread over the seam.
  8. Sprinkle the Filler on the SI adhesive.  Set will occur in seconds.
  9. Run a head of SI adhesive on the seam.  Spread over the seam.
  10. Spray a VERY light mist of Activator/Accelerator on the seam.
  11. Repeat 9 and 10.

Strengthening The Repair of a Crack in a Metal Tank

Option 1 – Using sports tape as a reinforcer.  Cut your strips of tape before you start.

  1. Apply beads of SI adhesive to the repaired area.  Do not spread.
  2. Place the strips of sports tape on the rough area.  Keep overlap to a minimum.
  3. Apply a head of SI adhesive all the way around the perimeter of the tape.  Then apply beads to the middle of the tape.  Spread, making sure the edges are covered.
  4. Spray a VERY light mist of Activator/Accelerator on the patch.
  5. Repeat 3 and 4.

Option 2 – using a Tech-Patch.   Please see Tech-Patch instructions.

Cracks in a Plastic Tank

Plastic tanks crack, especially lawn mower gas tanks, because they were exposed to direct sunlight.  If left in direct sunlight again, the tank will again expand, and the repair will crack.  For that reason, Tech-Patches are recommended.  Tech-Patches will expand as the plastic tank expands.

For Holes In Plastic or Metal Gas Tanks

For holes in either plastic or metal gas tanks, Tech-Patches are recommended. Please see Tech-Patch instructions.

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