Narrowboat painting tips, advice and recommendations
This guide has been produced to give you advice and recommendations on how to paint your narrowboat and achieve a high quality long lasting finish with Symphony Narrowboat Paint. It details how to control the application environment, levels of preparation and application guidelines. We advise you read the technical and safety data sheets prior to use.
What should I consider when painting a boat?
It is important to consider environmental conditions when applying Narrowboat Paint. The ideal coating temperature is between 10°C to 20°C. If the temperature is too high the paint will not flow. In damp and cold conditions, the paint will take longer to dry. The gloss finish can suffer from damp through blooming. This will give the Gloss paint a matt appearance.
We do not recommend that narrowboat paint products are applied at temperatures below 5°C. The relative humidity should not exceed 60%.
Drying times will vary considerably depending on conditions. At 20°C, you should allow at least 16 hours between coats. This time can double at lower temperatures. It is advisable for applicator to ensure the paint film has been given sufficient time to dry between coats.
If the coating has been left for several days we would recommend lightly abrading the surface before applying the next coat.
What about the holding primer on brand new manufactured boats?
New boats are coated with a holding primer by the boat manufacturer. It is important to establish the type of primer has been used.
If it’s a single pack holding primer, we would recommend it being fully removed back to bare metal before painting. We would recommend using and orbital sander and Mirka Abranet Ace HD discs. This is to reduce the risk of micro-blister from moisture trapped in the primers surface.
If it’s a high Build Two Pack (Epoxy) moisture resistant primer, it should be fully abraded to ensure adhesion of the Symphony Narrowboat Paint Undercoat.
How should I prepare bare Steel Surfaces?
The steel should be degreased using a high strength degreaser. This should be used in conjunction with heavy duty cleaning cloths. These should be changed frequently to avoid re-depositing any contamination onto the surface. The surface should ideally be Shot Blasted prior to the first coat of primer.
Alternatively, it can be sanded by machine or wire brushed to remove any rust. At this point a coat of Ferrozinc rust treatment can be applied to any remaining pitted rust. The surface should be cleaned down using Panel Wipe and then wiped over with a Tack Cloth to remove and remaining dust.
How many coats of Symphony Narrowboat Primer should I apply?
We recommend two coats of Symphony Narrowboat Primer should be applied by Brush or Roller application in accordance with the Product Data Sheet. Allow a minimum of 16 hours between coats. No flatting is required between coats unless it has left for several days.
Do I need to key the coating at this point?
At this point it should be lightly abraded with a red, medium SIA 6120 siafleece pad to ensure a high level of adhesion between coats. The surface should be wiped over with Tack Cloth to remove any remaining dust. Please see Narrowboat Preparation & Painting Specification for recommended painting guide.
How many coats of Symphony Narrowboat Undercoat should I apply?
We recommend three coats of Symphony Narrowboat Paint Undercoat should be applied with a minimum 16 hours between coats. No flatting is required unless it has been left for more than several days. In this case it should be lightly abrading with red, very fine SIA 6120 siafleece or 400 Grit free-cut SIA 1748 siarexx fine Paper Roll by hand.
The surface should be cleaned down and wiped over using Tack Cloths to remove any remaining dust. It should be applied by synthetic Brush (Purdy Monarch Elite or RODO Premier Synthetic Brush) or Roller (RODO Gloss HD Foam Mini Roller) application in accordance with the Product Data Sheet. Please see Narrowboat Preparation & Painting Specification for recommended painting guide.
What should the film build be like at this point?
At this point the two coats of Symphony Narrowboat Primer and three coats of Symphony Narrowboat Paint Undercoat, without any flatting should have achieved a total dry paint film build of approximately 150 microns.
After a minimum of 16 hours the undercoat can be sanded to give a smooth surface for the application of Symphony Narrowboat Topcoat. We recommend a red, very fine SIA 6120 siafleece or 400 Grit free-cut SIA 1748 siarexx fine Paper Roll by hand. The surface should then be cleaned down and then wiped over with Tack Cloths to remove any remaining dust.
At this point we would recommend after sanding you still have a minimum dry film build of 110 microns. If the readings are below 110 microns, another coat of undercoat will be required.
How many coats of Symphony Narrowboat Topcoat should I apply?
We recommend three coats of Symphony Narrowboat Topcoat be applied by synthetic Brush (Purdy Monarch Elite or RODO Premier Synthetic Brush) or Roller (RODO Gloss HD Foam Mini Roller) application in accordance with the Product Data Sheet. A minimum of 24 hours should be allowed between coats. No flatting is required unless left for more than several days. At this point the surface should be lightly abraded to achieve adhesion between coats. The surface should then be cleaned down and wiped over with Tack Cloths to remove any remaining dust. A light flatting can be given to the second coat topcoat using a red, very fine SIA 6120 siafleece to achieve a smooth surface before the final coat of topcoat is applied.
What is the minimum film build required?
The three coats of Topcoat over the previous coats applied should achieve a minimum of 200 microns’ total dry film build. This needs to be achieved to ensure a good level of protection against the environment.
We highly recommend investing in a digital paint thickness gauge from Amazon.