Frequently asked questions
How much KEELBLACK will I need?
KEELBLACK is sold in 5 litre and 25 litre kegs. 15 litres will give at least three coats to a 72 foot narrowboat or widebeam, 10 litres for a 40 - 50 footer. This is based on treating the sides of the hull, gunnel to chine, but not the bottom. For hulls with a glossed top strip, allow approximately 20% less. Contact KEELBLACK for specific advice or consult the handy calculator on the BUY page.
How long do I need to book my dock for?
A weekend (three day) docking is really tight unless the weather is very dry with low humidity and should be avoided if possible. To use Fertan and KEELBLACK properly requires 12-24 hours for Fertan to work and between 36 - 48 hours for KEELBLACK to cure before re-launch. A minimum of a 4 or 5 day docking will give best results. Like any paint - solvent or water-based - curing time is ESSENTIAL for maximum longevity
How many coats should I apply?
On the first occasion you use KEELBLACK we suggest applying at least three THIN coats on the sides of the hull and, if you habitually treat the base plating, three THIN coats on the bottom. For normal docking frequencies of around 2 to 3 years, three coats on each docking would be preferable. If you dock annually then you may be able to reduce this to 2 coats. Call KEELBLACK for advice
How thickly should I apply it?
KEELBLACK MUST be applied
VERY THINLY unlike conventional bituminous blackings. Too thick or too many coats WILL result in slower curing time. This is because KEELBLACK is a very tough grade of bitumen which is designed to dry completely to a rock-hard finish. Conventional solvent-based blackings are designed to skin over whilst remaining slightly soft. Do NOT dilute the product - agitate before use and it is ready to apply straight from the keg
Will KEELBLACK go over existing coatings?
We have yet to find any solvent-based bituminous blacking that KEELBLACK will not stick to. It is really important to ensure that the previous coating is sound and completely adhered to the hull. KEELBLACK will NOT peel or flake but if it does come off a previously treated hull, it will either be as a result of the previous coating peeling and taking the KEELBLACK with it or as the result of an incompatible substrate. If you are not sure what is on your hull, try a small inconspicuous test patch and allow sufficient time to check if there is any reaction with KEELBLACK. Smooth Epoxy blackings MUST first be abraded to provide a good key. KEELBLACK does not adhere to Red Oxide and should not be used over, or mixed with, Owatrol
Can KEELBLACK be applied to bare steel?
KEELBLACK applied to bare steel (either old steel, shot, glass or grit-blasted back to bare metal or a new steel hull) will give the best possible finish. It is important that on new steel, the surface is degreased and any mill scale is removed before coatings are applied. Residual mill scale may eventually slough off, removing any blacking. It is important to ensure the steel has not been over-polished by the preparation. The most effective protection against corrosion will be obtained by applying KEELBLACK over Fertan (a highly effective zinc-phosphate rust killer and preventer obtainable from KEELBLACK). If you are short of time (e.g. a three day docking) do NOT use Fertan as this will require 24 hours to work. Instead, use a fast-drying zinc-rich grey primer which dries in 20-30 minutes. Once dry, apply KEELBLACK over this.
Can KEELBLACK be applied over rusty steel?
We recommend that any rust is treated with a good quality rust killer and preventer such as Fertan which lays down a zinc phosphate coating to prevent future rust. Rust will always try to work its way through and behind any blacking unless prevented. Unlike many other rust preventers and killers, Should any impact damage pierce the the zinc-phosphate coating, Fertan will prevent rust from spreading under surrounding blacking to adjacent areas.
Is the orange/ red growth at my hull’s waterline rust or something else?
You may have soft orange/ red corrosion at the waterline (often in rings but easily rubbed off leaving the water cloudy) and frequently leaving deep pits with a silver or white base after power washing. This is regularly but incorrectly assumed to be rust but is likely to be Microbial Corrosion (MIC). MIC cannot be cured with rust killers and to prevent further damage, MIC MUST be treated before reblacking. MIC occurs in many canals and particularly in arable cruising areas. See KEELBLACK download on Microbial Corrosion or call KEELBLACK for more advice. MIC is everywhere and no blacking is completely proof against it. Keelblack, being a thin coat, does however show if you have the problem much earlier than any other blacking allowing preventative measure to be taken.
Is KEELBLACK easy to apply?
KEELBLACK is very liquid with a similar viscosity to water making it really easy to use. One person can apply a single coat of KEELBLACK to a 60ft narrowboat with a smooth surface in less than an hour. And as the product dries very quickly, three coats can be applied in just one day making it easier, faster and cheaper for the yard or the DIY blacker. If time permits, allow a few hours between coats to assist curing. Do NOT try to spray standard KEELBLACK. A special sprayable version (KEELBLACK250) is available. Call KEELBLACK for details.
Does KEELBLACK have to dry between coats?
KEELBLACK dries very quickly but must be touch dry between coats. If it is applied THINLY then subsequent coats can be commenced after as little as 30-40 minutes. After the final coat KEELBLACK
MUST be allowed to cure for
AT LEAST 36 hours in the summer and
AT LEAST 48 hours in winter. Test with a fingernail for when fully cured. Curing of underwater areas ceases on re-immersion so allowing adequate curing time is
vital for maximum longevity. Topsides will continue to cure after launch allowing you to touch up any damage down to the waterline whilst afloat.
How is KEELBLACK different from other blacking products?
KEELBLACK is the only water-based bitumen emulsion on the market, drying to a rock-hard finish and shrugging off minor contact damage. Almost all other blacking products are solvent based and made from softer bitumen. With low viscosity and no solvents KEELBLACK is easy and safe to apply.
What are the advantages of emulsions over solvent-based blackings?
Being water based means that the surface to be treated does not have to be dry before KEELBLACK is applied. All solvent based products reccomend the surface to be completely dry as any dampness can affect their performance. This means that in winter or in periods of high humidity it is difficult to apply a non-water based blacking without expensive heat or de-humidification or additional time in dock without risking poor adhesion.
Why can’t I use a cheap black bituminous paint on my vessel?
You can, but first, soft bitumous blackings won't give you the mechanical damage resistance of KEELBLACK which is the second hardest grade of bitumen available and the hardest that can be emulsified. Secondly, virtually every bituminous paint is solvent based and therefore to optimise adhesion, these have to be applied to completely dried steel Uniquely KEELBLACK adheres to damp steel. Soft thick bitumenous coatings will disguise any early signs of MIC. Finally KEELBLACK will lower future costs by reducing days in dock through reduced cleaning time, faster preparation and easier application.
How long will KEELBLACK last?
This is a difficult question. most owners want their boats to be smart so cosmetics tend to drive recoating intervals. Accelerated wear tests [See Pdf on the website] suggest that KEELBLACK will significantly outlast even 2-pack epoxy. These tests were done in laboratory conditions and KEELBLACK has not yet been in use for long enough to corroborate this in practice. Repeat users report excellent longevity and no evidence of peeling or flaking. KEELBLACK will certainly outlast single pack bituminous blackings and should result in a reduction in cost and docking frequency.
Will KEELBLACK protect my vessel against contact damage?
No coating is proof against an attack by concrete or a stone lock structure but KEELBLACK will give you the best possible resistance and, if it is damaged, is easily re-coated even at the waterline with the repair blending into the original coating. KEELBLACK does not discolour significantly with age unlike 2-pack epoxies which tend to fade and go “chalky” or grey over time.
Does KEELBLACK have a shelf life?
Emulsions will always try to separate. If regularly agitated and kept warm KEELBLACK will last at least six months in the keg and it could last significantly longer if stored carefully If the product separates and the residue is soft (test with a rod or strong stick), the majority should recombine by stirring or shaking. If the residue is hard then it has reached the end of its life and should not be used but disposed of responsibly. In the winter it must be kept above at least 5° Celsius (40° Fahrenheit). Don’t buy too much! Any cost savings from buying in bulk will be nullified if the product is un-useable.
Are there any health issues associated with using KEELBLACK?
KEELBLACK is virtually odourless. With nil VOCs, it gives off no fumes thus for manual application KEELBLACK requires no masks or specialist protective clothing although we do recommend taking reasonable precautions when using the product. It is particularly suitable for live-aboad blacking in dock and for application in confined work spaces. KEELBLACK can be washed off when wet and removed with white spirit when dry.
What is the effect of KEELBLACK on the environment?
KEELBLACK Is inert when dry and easily removed with water when wet. It contains no biocides nor VOCs and satisfies EU legislation EN7375 for leaching into the soil and watercourses. A sister product is used in SSSI sites and by environmental organisations. Liquid KEELBLACK should not be poured into drains or watercourses but when dry and cured is completely harmless to fish and aquatic life. The smooth finish of KEELBLACK is unattractive to freshwater mussels and bi-valves and deters weed growth making cleaning at docking time faster and easier. Please note that the increasing presence of nitrates and sulphites in the water may encourage weed development and whilst KEELBLACK helps to resists such growth, it is not proof against the effects of an aggressively weed-friendly environment.