Model Boat Mayhem
Technical, Techniques, Hints, and Tips => Painting, Finishing and Care. => Topic started by: Capt Podge on June 03, 2015, 10:37:49 pm
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Up to date, I've always finished my models with a spray (matt) varnish.
On a recent visit to Halfords, I noticed their tins of Lacquer. Will that give the same finish / protection as varnish ?
Regards,
Ray.
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YES as long as the paint on the model is halfords paint and not bruched on enamels....if the latter then stick to varnish
Dave
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Thanks Stavros - will do :-))
Regards,
Ray.
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I've just sprayed a model which was painted with Halfords Red Primer (not the Plastic type). I used their Clear Satin Lacquer. Here's the results - looks pretty damn good to me. Mind you, at eight quid for a 300ml can it's not exactly cheap, but the kit was £250 and who knows how much extra the finishing resin and paints were, so what the heck?
DM
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Makes it look like an expert did it :}
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That's probably why it's so pricey!
DM
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Bit of reading for you.....
( http://www.doityourself.com/stry/what-is-the-difference-between-varnish-and-lacquer )
Although the differences between varnish and lacquer are fairly subtle, there are some contrasts between the two that need to be pointed out. These differences will help you decide what type of product to apply to a surface in order to achieve the best possible exterior finish.
What is Varnish?
Varnish is a clear, hard solution that is principally applied to wood to give it a glossy finish while forming a protective film around it. Varnish consists of a resin, a drying oil and a thinner or solvent. Since varnishes have very little color, they can also be applied over a wood stain to enhance the shine of the wood.
What is Lacquer?
Lacquer is a type of solvent-based product that is made by dissolving nitrocellulose together with plasticizers and pigments in a mixture of volatile solvents. Lacquer also contains a solution of shellac in alcohol that creates a synthetic coating, causing it to form a high gloss surface. The name lacquer derives from the Portuguese name 'lac,' which is a form of resin expelled from certain insects.
Aesthetic Differences between Varnish and Lacquer
Both varnish and lacquer provide shiny and glossy finishes to the surfaces of furniture and fixtures. While lacquers can come in clear or a coloured coating, varnishes tend to be completely transparent and are rarely produced in any other color. Flatting agents are often added to varnishes, which produce a semi-gloss or satin sheen finish, while lacquers are available with many different sheen levels, ranging from high gloss to ultra matt. This allows you to decide on a preferred finish.
Differences in Durability
While both varnish and lacquer produce hard and durable finishes, the plasticizers put into lacquer give it a more hard-wearing finish than varnish. Some lacquers can produce extremely hard finishes which not only look beautiful when painted onto woodwork, but are also highly resistant to damage, particularly from acid, alkali, water and abrasions. Because varnish is less durable, many people choose to use lacquer than varnish to finish woodwork projects.
Differences in Application and Drying
Whilst the process of application is similar, varnish is usually brushed on and lacquer is normally sprayed on. One of the main differences between varnish and lacquer is that the latter is much quicker to dry. Lacquer, due to its evaporating solvents, will always dry on a surface much quicker than varnish. As lacquer is naturally glossier than varnish, one coat is usually sufficient, while varnish may require several coats.
Flammability
When lacquer is processed, it is dissolved in a highly flammable solvent that contains toluene or butyl acetate and xylene. To minimize the risk of combustion, lacquer is usually sprayed onto a surface inside a spray booth that vacates any over-spray. Varnish is much less flammable and is typically brushed on. One way of knowing the difference between varnish and lacquer is that if the product is prepared to be brushed on, it is usually varnish. If it is formulated to be sprayed on, it is usually lacquer.
Different Uses
Essentially, both varnish and lacquer can be applied to wooden surfaces to give them a glossy finish. However, because of the highly durable properties in lacquer, it also makes a good metal finisher. Consequently, lacquer is often baked onto the inside of food and drink cans.
( http://www.ukworkshop.co.uk/forums/difference-between-lacquer-and-varnish-t39510.html)
There are basically three types of finish:
* evaporative
* reactive
* coalescing
In simplified terms evaporative and reactive finishes work as follows:
Evaporative finishes use alcohol, acetone and lacquer (cellulose) thinners as solvents and thinners. Lacquers and shellac fall into this group. The solids are soft and string like in solution but as the solvents evaporate they lock together in a solid mass like dried spaghetti. Successive layers burn in to one another and form a contiguous whole. The solvent will re-soften the film, eg, lacquer thinners will soften cured lacquer, and alcohol softens cured shellac.
Reactive finishes use solvents such as white spirits and naphtha. Oil varnishes and linseed oil are reactive finishes change chemically when they cure, unlike evaporative finishes. At cure the solvent/thinner evaporates the resin cluster tighter together, and then a chemical reaction occurs causing the resins to cross link in a different chemical format-- it's sometimes described as being like loose scaffolding that suddenly bolt together. You need to scuff sand between layers of cured finish so that the subsequent applied layer has something to grip on to effectively. The solvent won't re-dissolve the cured film, eg, white spirits does not soften cured oil based varnish.
You didn't ask about other finish types so I won't describe them except to say that water based finishes generally fall into the coalescing category. Slainte.
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Couldn't you just have left it at the link, Martin? I thought I was losing the will to live halfway through that lot..............and "slainte"?? The man is clearly deranged (the result of drinking varnish........................or lacquer?).
Good paint-drying weather, innit? O0
DM
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Martin was just giving us the plain unvarnished truth Dave - be grateful...
Colin
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{-) {-)
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Max Factor Nakalaka
Adds Lustre to your Cluster
{-) {-)
Ned
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:-)) Either the fumes or the sun got to em this afternoon Martin,I started treating the decking with that Ronseal stuff but had to give up it was drying quicker than I could brush it on so SWMBO has let me off,so I am sitting on patio with ice cold beer and large slice of cake,as an old school modeler I use vanish most of the time as the lacquer smell always make me feel ill,bit like the old dope we used on our planes back in the day,Ray. :-))
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It said on the tin put 3 coats on, but it's far too warm....... I'll paint it another day when it's cold. {-)
Sparkly and me have the same idea..... Patio and beer :-))
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Well Martin you have surpassed yourself this time...you done me out of a job
Dave................WAS the resident paint expert