Wendy Posted November 14, 2006 Share Posted November 14, 2006 We want to paint a very large and high wall using the compressor. Will take too long using a brush. First attempt resulted in no paint at all spraying out as it seems way too thick for the nozzle. What do I do here..? what do you use here to thin the paint down? Link to comment Share on other sites More sharing options...
maude Posted November 14, 2006 Share Posted November 14, 2006 Hi.so many different paints here,read the can to see what the dilution or thinning medium is -could be water, white spirit or special solvent.The sprayer instructions will also give a viscosity reading for the size of nozzle,and a small test pot to usually time a measured amount of the paint.It will have to be diluted to the sprayer makers figures, with the correct diluter.Gud Luk Maude Link to comment Share on other sites More sharing options...
Gluestick Posted November 14, 2006 Share Posted November 14, 2006 Spray Painting always appears so simple!Sadly, it isn't.Painting a building -e.g.- is normally carried out using what is called a "Pressure Pot": this is simply a large reservoir which holds the paint, which is then forced along the material hose and atomised in the gun using compressed air.The type of nozzle (Air Cap) is pretty important as is what is called the Fluid Tip.Spray Guns come in two basic types: suction (paint pot underneath) and Gravity Feed (paint pot on top).Thus the first step is what sort of gun? The next is what sort of paint?Some form of thinners is normally essential (unless the paint is supplied -Gun Ready - unusual).The viscosity of the paint will be determined by a combination of experience and manufacturer's recommendations: and ambient temperature, as this obviously affects the viscosity.Paint too thin and it will run and sag into "Curtains": paint to thick and it won't atomise out of the nozzle and will be applied in blobs.Finally, the air pressure is also critical. If using a pressure Pot, the feed pressure is set at the pot (normally they have a built-in regulator) and for the atomising air at the gun.The normal trick of the trade, is to test out the spray pattern on a piece of scrap sheet material. Paint sprayers tend to use the wall of their workshop! Which is why you see different stripes of different colours!The "Fan" (which is the width of the paint spray pattern) should be a continuous spread of paint (depending on variables and gun, can be anywhere between 4 inches and one foot) and the density must be even with no patchy bits in the middle.When you spray, you (normally) cover a swathe from left to right or reverse and overlap each swathe, marginally, to ensure you have coverage as the extreme ends of the fan tend to be a bit spotty.If more convenient, by the simple expedient of twisting the nozzle through 90 degrees, you can spray swathes vertically.The distance of the gun from the work is also critical: too near and the paint will blob: too far away and it will be spotty.Don't forget to clean out the nozzle, fluid tip, aircap etc each time you stop, or they will block Use thinners and the correct bristle brush: never ever be tempted to poke out orifices with a bit of thin wire, you will ruin the jet.Good luck. Link to comment Share on other sites More sharing options...
Nick Trollope Posted November 14, 2006 Share Posted November 14, 2006 There is only 1 way to spray emulsion - I assume that this is what you are doing, HVLP - high volume, low pressure. Gear available from any Brico for 99€. Done plenty.High pressure sprayers (per car spraying) won't work. Tried plenty! Link to comment Share on other sites More sharing options...
Chancer Posted November 14, 2006 Share Posted November 14, 2006 I bet they are trying to use an airless vibrating jobby spray gun. Link to comment Share on other sites More sharing options...
Wendy Posted November 15, 2006 Author Share Posted November 15, 2006 We bought the compressor from Leroy Merlin last year, on special, for 99 euros, it sprays the water fine but never thought using the paint would be so darn complicated!. Thanks for all the suggestions though. It came with only one nozzle. Not really impressed with the white spirit on sale here, Ive used oodles of it and it wont even remove the el cheapo water based paint from the brushes!. Thanks again to all for the advice. Link to comment Share on other sites More sharing options...
Gluestick Posted November 15, 2006 Share Posted November 15, 2006 Sadly, wen, that sort of small compressor simply doesn't have the "Grunt" for the job you need to accomplish.Fine for atomising small quantities of low viscosity liquid - like water - and even for painting very small areas with (e.g.) timber treatment.Use it for chuffing up the tyres on the wheelbarrow!In order to effectively paint large surfaces, you need at minimum as I suggested, a paint pot and probably 8 cubic feet FAD (That's Free Air Delivered, which is simply the expression of the pumping capacity of the compressor pump) working at 60-70 PSI.That means roughly a two horsepower motor, for single phase and a large reservoir (Air Tank), too. Which is quite a big compressor set.Sorry, haven't quite caught up with metric measures on certain engineering aspects, yet, but give me time! [blink]Nick's advice is excellent: HVLP: Screwfix offer them (Earlex) and there are plenty on the net at tool and equipment vendors. I checked, and BricoDepot's is a bit small. Link to comment Share on other sites More sharing options...
Nick Trollope Posted November 15, 2006 Share Posted November 15, 2006 Most Brico's sell the Earlex "spraystation" - 99€. I have sprayed 2 houses with one; you need to apply more coats than with a roller and make sure you have the viscosity exactly correct (use the viscosity cup/RTFM), but they do work & well, too. Link to comment Share on other sites More sharing options...
Cassis Posted November 15, 2006 Share Posted November 15, 2006 [quote user="wen"] Not really impressed with the white spirit on sale here, Ive used oodles of it and it wont even remove the el cheapo water based paint from the brushes!. Thanks again to all for the advice.[/quote]White spirit is no good at all for cleaning water based paint off anything. Use water! Paint that is soluble in water is insoluble in white spirit and vice versa. [:)]Totally agree with Gluey and Nick regarding high and low pressure paint systems. I can't understand why manufacturers tend to give away a paint sprayer with compressors that are not suitable for the job, unless it's to con people into believing they can spray paint with a small compressor. Link to comment Share on other sites More sharing options...
Chancer Posted November 15, 2006 Share Posted November 15, 2006 Yes NickI have a crepinator and it works very well, for small areas using sandtex or crepi type paints I have had success using a "schutz" underseal gun.Both times with a 3hp compressor Link to comment Share on other sites More sharing options...
Wendy Posted November 16, 2006 Author Share Posted November 16, 2006 Thanks Gluey, the arguments between the OH and the 2 teenage sons over 'how-to-do-the-job-properly' were unbearable. Now we all know why nothing was working! I'm thinking we should hire one for a few days. Thanks for the advice everyone, its all been very helpful...and solved one or two disputes as well. Link to comment Share on other sites More sharing options...
Nick Trollope Posted November 16, 2006 Share Posted November 16, 2006 [quote user="Chris Head"]I've had an idea! This isn't a wind up...honestly!This is a small sandblasting gun, if it'll spray sand it's got to spray paint![/quote]It will - in vast quantities! It will empty that 1L pot in a few seconds, I'd guess. That nozzle probably has an I/D of 3-4mm. Try it with some water & let us know how wet you get. I double dare you. Link to comment Share on other sites More sharing options...
Chris Head Posted November 16, 2006 Share Posted November 16, 2006 You're on Nick! At least this dare is somewhat safe than the last one...erm, I think. Link to comment Share on other sites More sharing options...
Chris Head Posted November 16, 2006 Share Posted November 16, 2006 As you say Nick, the pot was one litre. It took 52 seconds for the pot to start to sputter, upon opening the pot there was 5 mm of water left in the bottom. The spray was even and fantastic, more than suitable for spraying masonry paint.WOW what a discovery!All say 'thankyou Chris'! Link to comment Share on other sites More sharing options...
Gluestick Posted November 17, 2006 Share Posted November 17, 2006 [quote user="wen"]Thanks Gluey, the arguments between the OH and the 2 teenage sons over 'how-to-do-the-job-properly' were unbearable. Now we all know why nothing was working! I'm thinking we should hire one for a few days. Thanks for the advice everyone, its all been very helpful...and solved one or two disputes as well.[/quote]My pleasure, wen. So now it seems that this forum is also a Family Counselling Service, too![:D]More seriously, the probable hire cost of the spraying equipment, would exceed the capital cost of buying an HVLP Earlex system as Nick suggests. I have a big Earlex steamer and it's excellent quality.And if you look after it (cleaning, rigorously, after each use), it will last for years: and will spray a wide variety of materials from Xolophene, to emulsion, to wood preservative for fences etc.A sound investment. Link to comment Share on other sites More sharing options...
Gluestick Posted November 17, 2006 Share Posted November 17, 2006 [quote user="Chris Head"] As you say Nick, the pot was one litre. It took 52 seconds for the pot to start to sputter, upon opening the pot there was 5 mm of water left in the bottom. The spray was even and fantastic, more than suitable for spraying masonry paint.WOW what a discovery!All say 'thankyou Chris'![/quote]I wonder how well the sandblaster gun would actually atomise paint, though Chris?[blink]Even if it did, you would probably have to also wear skates to move fast enough along the wall or finish up with big "Curtains".[:(]However, you might create a new decorative genre for walls............................... Link to comment Share on other sites More sharing options...
Chris Head Posted November 17, 2006 Share Posted November 17, 2006 Well it atomised the water beautifully, I can only imagine that paint would slow it down a little...I might have to copywrite the technique.... I can feel a new amplifier coming on [:D] Link to comment Share on other sites More sharing options...
Gluestick Posted November 17, 2006 Share Posted November 17, 2006 I think the problem would be, Chris, that without an aircap, all you would have is a sort of heavy "stripe" of paint!I have an old paraffin/oil gun, very similar to your sandblaster gun; they were used for chassis spraying, spring spraying etc and we used to use these for-degreasing engines etc, with Gunk type material.This "Atomises" light fluids, but doesn't, of course, create the essential fan spray, where the paint is firstly atomised by the material nozzle and then swirled into an even, wide, swathe of correctly atomised paint droplets. And, of course, different aircaps are used for different materials and this aspect is very critical. Different aircaps are used even for identical paints, but different applications, such as metallics, two-pack cryoacrylates, cellulose, air drying synthetics, acrylics etc. And as for oil-bound, emulsion....................It is the impression that one can spray any paint, simply by thinning it down: and of course, one can't, as quite often, the amount of thinner required to reduce the viscosity, has a destructive affect on the paint and its drying system.And of course, your gun's overspray would be horrendous. Link to comment Share on other sites More sharing options...
Chris Head Posted November 17, 2006 Share Posted November 17, 2006 Yeah but just imagine the fun Gluestick! Link to comment Share on other sites More sharing options...
Gluestick Posted November 17, 2006 Share Posted November 17, 2006 [:D][blink][:D] Link to comment Share on other sites More sharing options...
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