{"id":5699,"date":"2016-07-25T16:44:57","date_gmt":"2016-07-25T13:44:57","guid":{"rendered":"https:\/\/revistadinlemn.ro\/?p=5699"},"modified":"2023-08-15T11:52:38","modified_gmt":"2023-08-15T08:52:38","slug":"recommendations-for-spray-varnish-application","status":"publish","type":"post","link":"https:\/\/revistadinlemn.ro\/en\/2016\/07\/25\/recomandari-pentru-aplicarea-lacului-prin-pulverizare\/","title":{"rendered":"Spray varnish application recommendations"},"content":{"rendered":"

Film-forming materials - varnish, paint, primer, sealer, insulator, varnish - can be applied by various methods. The most common industrial method is spraying. But it can also be used for DIY projects. Those who are just starting to refinish a piece of furniture in their home or occasionally refinishing a small wooden object will most likely turn to the brush. But there are also hobbyists who have taken it to the next level and find that a small compressor and spray gun is not a big investment. It's a good investment because spray application results in a more even, well spread film and application time is much shorter.<\/p>\n

\"correct
photo source: wallgoldfinger.net<\/figcaption><\/figure>\n
Spray application in factories<\/h5>\n

In industry, spray application is preferred because it adapts to the shape of any object. Most finishing products can also be applied by spraying. In contrast to DIY, industry uses more powerful guns that are much more durable and durable. Simple spray guns or pumps can be used.<\/p>\n

The spraying method is more diversified, more adapted to the purpose and final result. The materials are applied by conventional spraying, low or high pressure, air mix, air less, electrostatic, automatic. I will detail these methods on another occasion. Right now I have set out to make some general recommendations for spraying under normal conditions, i.e. when it comes to compressor, gun and conventional spraying. They may seem trivialities to the connoisseur, but I think it does no harm to be reminded of them from time to time.<\/p>\n

\"small
small quantity application
photo source: canadianwoodworking.com<\/figcaption><\/figure>\n
Spray gun nozzle recommendations<\/h5>\n

The nozzle is the orifice through which the material exits the gun under pressure. It is of different sizes and must be adapted to the material to be applied. For products with high fluidity and which must be applied in small quantities, such as ageing patinas, nozzles of 0,8-1,0 mm are recommended.<\/p>\n

For fluid products that are applied in larger quantities (baths), the recommended nozzle is 1.2-1.4 mm. For varnishes, primers, sealers to be applied under normal conditions, without special requirements, a nozzle thickness of 1,8-2,0 mm is recommended. When applying viscous, thixotropic products (such as exterior water-thinnable varnishes), the recommended nozzle is 2,5-3,0 mm.<\/p>\n

Conventional spray application pressure<\/h5>\n

The recommended pressure for normal (conventional) application is 2.5-3.5 atm. But the general tendency is to work at much higher pressure, 5 atm or even more. The explanation of those who do this is that it gives better productivity. This is the wrong approach.<\/p>\n

Indeed, the fact that the lacquer comes out of the gun more and faster makes us work faster. But the loss of material will be much greater and the quality of the film poorer. The amount of lost varnish that does not settle on the object to form the film is called over spray<\/em>, will be much higher.<\/p>\n

The high pressure will also prevent the material from settling evenly and forming a good-looking film. Also because of the high pressure, some of the sprayed varnish will dry in the air, settling on the surface as dust. The still-wet varnish will trap the dust and fix it, resulting in a rough and glossy film. In factories they say the film is gassed<\/em>.<\/p>\n

\"high
high pressure
photo source: achitettodileo.it<\/figcaption><\/figure>\n
Adjusting the lacquer spray, the distance between the workpiece and the nozzle, the movement of the gun in relation to the plate<\/h5>\n

Before starting spraying, the spray pattern must be adjusted. For a quality application, the spray pattern should be neither very tight, like a thread, nor very open, like a shower. Optimum application is obtained with a horizontally tight and vertically open spray.<\/p>\n

The spraying distance should be 15-20 cm. Less than this distance will result in a streaky film, and when the distance is greater the film does not settle evenly and gassing may occur. To avoid gassing when finishing fitted furniture the back must be removed. Thus over spray does not remain inside the furniture body.<\/p>\n

The movement of the hand over the finishing panel is translation, not rotation, and the hand always remains at the same distance from the panel.<\/p>\n

The hand holding the pistol should be in line with the arm, forming a continuous straight line. If your hand is held up or down at an angle to your arm, you will tire more quickly because your nerves and blood vessels are strangled<\/em>and the quality of the film will suffer.<\/p>\n

For a correct and even application over the entire surface, the spray must go beyond the edges of the workpiece, and stripes<\/em> of applied material to overlap 30%. A trick to avoid gassing is to apply the varnish starting from the side next to you and working toward the far side. This will cover any varnish dust that has fallen on the piece with fresh material. When there is good exhaustion we can spray in the usual way, from the far side towards the near side.<\/p>\n

\"distance
distance to the object
photo source: achitettodileo.it<\/figcaption><\/figure>\n
\"translation
translational motion
photo source: dummies.com<\/figcaption><\/figure>\n
\"application
bottom-up application
photo source: ognigiorno.it<\/figcaption><\/figure>\n
Requirements for spray guns<\/h5>\n

Spray application of waterborne products is done with stainless steel spray guns. Stainless steel spray guns can also be used for the application of solvent-based products. So to avoid problems with rust, it is best to buy a stainless steel gun.<\/p>\n

If viscous products need to be applied and the compressor does not provide the necessary pressure to get the material out of the gun, you can use special guns for such products. They create pressure inside the nozzle of the gun forcing the material out. If you frequently apply viscous products, but don't have the money to buy a pump, such a gun is very helpful.<\/p>\n

After the application of chemically hardened A+B type materials (polyurethane, acrylic, polyester, etc.), the gun and the circuits must be thoroughly washed. If left with the material in them, the lacquer hardens inside and the gun cannot be used. Washing is done with lacquer solvent (organic solvent or water), spraying the solvent until it comes out of the gun clean.<\/p>\n

At the end of the working day the gun is taken apart and washed thoroughly, leaving the parts in the thinner. This prolongs the life of the nozzle and therefore of the gun. If not well maintained, the nozzle will change diameter over time with repercussions on the quality of the film.<\/p>\n

\"gun
gun and accessories
photo source: aliespress.com<\/figcaption><\/figure>\n

As there is more to say about spraying, I will come back to the subject soon. In the meantime I await your questions on the subject.<\/p>","protected":false},"excerpt":{"rendered":"

Materialele peliculogene – lac, vopsea, grund, izolator, lazur\u0103 – se pot aplica prin diverse metode. Industrial, cea mai r\u0103sp\u00e2ndit\u0103 dintre ele este pulverizarea. Metoda poate fi \u00eens\u0103 folosit\u0103 \u0219i \u00een cazul proiectelor de bricolaj. Cei care \u00eencep s\u0103 recondi\u021bioneze o pies\u0103 de mobilier din cas\u0103 sau finiseaz\u0103, ocazional, un mic obiect din lemn vor apela […]<\/p>\n","protected":false},"author":5,"featured_media":5719,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_seopress_robots_primary_cat":"none","_seopress_titles_title":"","_seopress_titles_desc":"","_seopress_robots_index":"","footnotes":""},"categories":[2177,2185,2175],"tags":[703],"class_list":["post-5699","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-echipamente-vopsire","category-finisare-diy","category-finisaje","tag-pulverizarea-lacului"],"_links":{"self":[{"href":"https:\/\/revistadinlemn.ro\/en\/wp-json\/wp\/v2\/posts\/5699","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/revistadinlemn.ro\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/revistadinlemn.ro\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/revistadinlemn.ro\/en\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/revistadinlemn.ro\/en\/wp-json\/wp\/v2\/comments?post=5699"}],"version-history":[{"count":15,"href":"https:\/\/revistadinlemn.ro\/en\/wp-json\/wp\/v2\/posts\/5699\/revisions"}],"predecessor-version":[{"id":36462,"href":"https:\/\/revistadinlemn.ro\/en\/wp-json\/wp\/v2\/posts\/5699\/revisions\/36462"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/revistadinlemn.ro\/en\/wp-json\/wp\/v2\/media\/5719"}],"wp:attachment":[{"href":"https:\/\/revistadinlemn.ro\/en\/wp-json\/wp\/v2\/media?parent=5699"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/revistadinlemn.ro\/en\/wp-json\/wp\/v2\/categories?post=5699"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/revistadinlemn.ro\/en\/wp-json\/wp\/v2\/tags?post=5699"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}