Plug and Mould Sanding and Preparation

Sanding plugs and mould preparation 

Facing harsh conditions with salt, water and wind, marine surfaces need to be built to last. It all starts with the hull and for that, you need a plug and mould  to construct a frame that gives the boat or watercraft its shape and strength.
In the process, sanding plugs and moulds, with different surfaces, are important steps.  

One of the keys to success in plug and mould construction is proper surface preparation of the plug. Any imperfections on the surface will be transferred to the mould, and then to future parts made from that mould.

A smoother outer surface on the mould will require less work on the finish.

With Mirka’s net and multihole abrasives, ergonomic sanders and efficient dust extraction improve work safety and allow you to work faster and more efficiently.

Plug preparation and sanding

With Mirka's solution, you can work on many different marine surfaces, for example when you want to level out an uneven polyurethan surface of a plug or prepare your plug by sanding polyester. 
We recommend machine sanding with Mirka's Abranet® range, Galaxy, and Novastar discs. File boards (coarser grits) are recommended to shape the plug. 
You can also use Abranet strips and hand sanding blocks together with a file board. Use the block with an interface pad for edge and contour sanding to keep the plug shape and avoid sanding thru coating.

Mould preparation and sanding process

When preparing to sand a mould gelcoat surface, start the sanding with Abranet or Iridium and coarser grits, to level the surface structure. You can use finer grits to prepare the surface for polishing. Both machine sanding or hand sanding is possible. To reduce scratch patterns, sand with finer grits and use Microstar. An interface can also be used when sanding to further reduce the scratch patterns. If required and you need to reduce scratch patterns even further sand with a hand-held sander and fine grits of Abralon J3, if necessary) After this, you can wipe and clean the surface with a Mirka microfibre cleaning cloth and then move on to the polishing.

Why would you choose a Mirka solution?

  • Save time and money –you can cut costs and reduce working hours
  • Sand and polish safely without strain – Mirka's tools and abrasives are ergonomic and efficient

  • Improve the quality of work – The finish is excellent, with less effort

  • Water-based polishing compounds that are more effective, yet sustainable and user-friendly, combined with our tools and polishing pads you will get the perfect system for your surface

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Prepare for success – why surfaces matter when creating plugs and moulds

Prepare for success – why surfaces matter when creating plugs and moulds

Why do you need an even and smooth surface on a plug?

The plug is the start for creating moulds and requires a smooth and even surface. The plug is an exact replica of the object that you want to produce. One of the keys to success in mould construction is proper surface preparation of the plug. Any imperfections on the surface will be transferred to the mould, and then to future parts made from that mould. 

Why do you need to have an even and smooth surface on a mould?

There are two types of moulds, male and female. Male moulds are faster and cheaper to make. Each part produced will have a rough outer texture that will need more work on the finish. Female moulds are often more expensive, but they require less work on the finish because every part gets a smoother outer surface.

Water-based polishes– A better choice for both you and the environment

All polishes that Mirka produces are water-based. There are many benefits of choosing a water-based polishing compound.

  • Effective permanent removal of scratches -> Solvent-based compounds tend to lose gloss after cleaning the surface with a degreaser as they only temporarily hide the scratches. Water-based compounds, on the other hand,  remove the scratches permanently.
  • No hazardous chemicals -> safer for the operator
  • Sustainable  -> Water-based polishes are better for the environment and do not contain benzene or similar hazardous chemicals.

“Solvent-based polishes may be effective in the short run, but they are more damaging and harmful, both for the user and the environment"

OK with Kim?

Do you get covered in dust when sanding? Save your lungs and your wallet by switching to dust-free sanding.

Sanding without dust – save your health, time, and money

Mirka is a pioneer in dust-free sanding solutions. How is Mirka's dust removal so effective?  Thanks to the multi-hole pad on the Mirka DEOS Delta sander and Mirka's original dust-free net abrasive Abranet. 
When sanding without dust you get:

  • Health benefits: stop dangerous dust from getting into your lungs
  • Cost-saving: use fewer abrasives, since Abranet lasts longer
  • Money-saving: spend less time cleaning, and move on to the next job instead
  • Faster sanding: clean abrasives cut better

Read more about all of the benefits of dust-free sanding

Nautor's Swan, Finland

Marine customer stories

Mirka products and solutions have an important role in reaching the desired quality and finish when it comes to building spectacular yachts. For Finnish yacht builder Nautor, a high-quality finish is about respecting the company’s roots and heritage, and it takes the best kind of power tools and abrasives to accomplish that. Benny Brännbacka from Nautor shares with us what it means to collaborate with Mirka, and how important client satisfaction is when building Nautor’s Swan yachts.

"Working with Mirka is very good, we are continuously collaborating."