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Post by jfc on Dec 17, 2007 20:31:27 GMT
Having used both compressed air and HVLP i thought i had this spraying lark sussed but today i got a major blockage on the HVLP and as i need to get this job finished i went back to the compressed air . So now i'm thinking the compressed air has the edge as its alot quicker .
I have to add that the major blockage resulted in me covered in paint ;D
So for those that can spray what do you think is the better way ?
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Post by dom on Dec 17, 2007 20:39:37 GMT
Compressed, if you know what you're doing.
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Post by jfc on Dec 17, 2007 20:42:01 GMT
Is that why you use HVLP ;D Hang on .................. 1000 posts   |
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Post by dom on Dec 17, 2007 20:45:37 GMT
Woo Hoo, where's the prize you promised me ?
;D
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Post by jfc on Dec 17, 2007 20:48:01 GMT
erm ..... EBay saw on the way to you ;D I knew it was a good plan to buy them  |
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Post by mailee on Dec 17, 2007 20:51:26 GMT
Now you are confusing me  HVLP is the method the paint is delivered to the substrate. I use compressed air but it is sprayed using HVLP technology, IE, the gun is a High Volume Low Pressure one. All of our guns at work are HVLP and the only difference is the hoses need to be a larger diameter for the air flow. I have not used the Fuji type HVLP setup so cannot comment on this but do regularly use the Sata and De vilbis HVPL system so know this well. HVLP does require a larger volume of air to operate although the air pressure is much lower than traditional methods of spraying. HVLP allows a much higher solids content paint to be applied in one coat givng a much higher build per coat and so a quicker through put time. Our cars are panited at the rate of one every fifteen minutes and without HVLP we would struggle to acheive this using the multiple coat build up of traditional spray painting.  |
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Post by dom on Dec 17, 2007 21:00:41 GMT
You put your saw with your other sores |
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Post by engineerone on Dec 17, 2007 21:14:24 GMT
so you obviously did not do a proper clean up last time jason hvlp is realistically a better system and as has been said can be used with compressed air. you just need to sort other things out. the important thing is that hvlp allows a better finish and less wastage cause the paint solids need to be less thin, as i understand it. so you overall need less paint and thinners to do the job as with all things involving thinners etc, you need to clean up properly and rigorously every time. so what colour are you now ;D paul |
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Post by dom on Dec 17, 2007 21:28:21 GMT
Whiter than white ;D
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Post by engineerone on Dec 17, 2007 21:44:20 GMT
that's never gonna happen  paul |
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Post by Scrit on Dec 18, 2007 1:01:22 GMT
A couple of issues to do with HVLP versus compressor (high pressure); with high pressure there is much more bounce back of material off the piece which means much less of what you spray gets onto the workpiece. In HVLP this transfer rate from gun to workpiece is often between 65 and 75%, for high pressure systems 20 to 45% is much more typical (which is what Paul said, but I've quantified matters). That generally makes HVLP systems both cleaner and cheaper to run - providing you remember to clean out the guns, etc.........
The only reason that high pressure would be quicker is where you are comparing apples with oranges, i.e. a reasonable size high pressure rig versus a low-output DIY HVLP. Compare like with like (e.g. deVilbiss JGA on a 5HP compressor versus a 3-stage Wagner HVLP) and there's little difference in the speed of working as mailee says
Scrit
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Post by jfc on Dec 18, 2007 7:50:08 GMT
Ahhh yes sorry the gun for the compressor is a HVLP i think , gravity fed . What i'm saying is this one is better than that one but i thought that one was good but this one is better ;D
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Post by Dave S on Dec 18, 2007 13:20:28 GMT
Ahhh yes sorry the gun for the compressor is a HVLP i think , gravity fed . What i'm saying is this one is better than that one but i thought that one was good but this one is better ;D Ahh. Dave |
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Post by davyowen on Dec 18, 2007 13:24:58 GMT
I've used both LV and HV guns with a compressor and I can easily say that the higher volume gun is superior in every way.
I haven't used one of those high volume turbine jobbies so I can't compare them with a compressor, but for me the compressor has too many other uses to consider switching over (although I do wish they made the receivers out of something that didn't rust - god I hate getting on my knees and struggling to twist the tiny bloody drain valve!)
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Post by Scrit on Dec 18, 2007 14:57:27 GMT
I haven't used one of those high volume turbine jobbies so I can't compare them with a compressor...... The better ones can deliver as much material as a high pressure gun - the main difference is there's a lot less bounce back (overspray) so wastage factors are lower. Also there is no need for extra filtration as the turbines are oil free and all inlet air is filtered - so cissing (fish-yes) is less likely to occur. To my mind HVLP has only two downsides - it struggles with really heavy materials like latex house paint (hardly normal for cabinetwork) and the fact that the turbine warms the air means that you sometimes need to add extra solvent thinners to overcome the tendency of a few finishes to dry on the tip of the gun or not to flow properly. But then different guns do sometimes require slight adapotations in technique. If you already have a compressor set-up it may be worth looking at a "conversion" gun next time you replace a gun. These use air from the compressor (hence no problem due to the warming problem) but are otherwise the same as a turbine-driven HVLP gun ......(although I do wish they made the receivers out of something that didn't rust - god I hate getting on my knees and struggling to twist the tiny bloody drain valve!) Have you ever thought about sitting the compressor on a couple of blockwork piers? The area beneath then becomes storage space. Of course the other way is to fit an auto drain unit - home-cooked low-cost versions are possible Scrit |
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Post by davyowen on Dec 18, 2007 15:09:07 GMT
......(although I do wish they made the receivers out of something that didn't rust - god I hate getting on my knees and struggling to twist the tiny bloody drain valve!) Have you ever thought about sitting the compressor on a couple of blockwork piers? The area beneath then becomes storage space. If I was 7 feet tall I'd think about it but as I built my workbench to fit around the compressor, raising it up any more is no good being a short-ar*e  |
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Post by mailee on Dec 18, 2007 16:01:41 GMT
Aorry to butt in Scrit but it wmay be worth adding that if he has a compressor set up he must make sure that the CFM of the compressor will handle a HVLP gun as they use a larger volume of air to conventional guns. If of course he has a large reciever then this is no problem and it will handle it fine. |
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Post by Scrit on Dec 18, 2007 18:15:55 GMT
Sorry to butt in Scrit but it wmay be worth adding that if he has a compressor set up he must make sure that the CFM of the compressor will handle a HVLP gun as they use a larger volume of air to conventional guns. Especially the deVilbiss and Binks ones........ |
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pj
Junior Member
Posts: 88 
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Post by pj on Dec 20, 2007 9:57:06 GMT
With all this talk about spraying it seems that a lot of people use this as a method for finishing, but can I ask how you get a sufficiently dust free and heated environment to paint in if you are in a one room does all place? I have all the equipment for spraying, (used to repair motors) but I am put of by the fact that I would be de-nibing longer than it would take to finish by brush/roller etc.
Any answers?
Philip
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Post by davyowen on Dec 20, 2007 12:49:11 GMT
Organise your tasks so that you don't make any dust the day before you intend to spray. Give the workshop a thorough clean (vacuum everywhere that drafts can whip up dust, and anywhere that your booth extraction can pull dust from) and finally have a good air filter with sufficient airflow running during the cleanup and a few hours before you start spraying.
If you have effective dust collection at the machines then you shouldn't really have many problems though, so if you find that you have too much dust in the air to spray then it's time to get your extraction sorted out - your lungs will thank you, as will your finishes (even more so if they are solvent based ;D)
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pj
Junior Member
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Post by pj on Dec 20, 2007 23:27:44 GMT
Hi Davy, Your cleaning regime brings back memories, except after vacuuming I used to heat where I was painting, and then give the floor a mop over just before painting, which worked well. I think for furniture a make shift tent or similar with polythene doors would work well and certainly cut down on the cleaning necessary but getting enough light in there could be a issue. Also I would find it easier to heat a confined space rather than the whole working area. I agree that efficient dust removal is a must, but really most hobby machines have dust collection fitted as an after though and can sometimes be extremely hard to capture even with a good extractor You also need to be religious in using it, which sometimes in my case, may not always be what happens if it only a quickie etc.  I think the problem is that I just don't have the time to spend cleaning up to the level required for spraying. Thanks for your advice, and it has just reinforced what I originally thought. Philip |
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Post by jfc on Dec 20, 2007 23:59:25 GMT
I just put up a wet paint sign and get on with it ;D |
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Post by engineerone on Dec 21, 2007 0:30:10 GMT
when i used to spray old bikes, we rigged up a spray booth using plastic pipe and clear sheeting over it. easy to take apart, so storage is not a problem and cheap too. as for heating, it depends on what is in your shop again. actually all you are really looking for is the item not to be too cold.then all you need are some proper clothes to clean off the dust and start spraying. or do a jason ;D paul |
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HVLP is the method the paint is delivered to the substrate. I use compressed air but it is sprayed using HVLP technology, IE, the gun is a High Volume Low Pressure one. All of our guns at work are HVLP and the only difference is the hoses need to be a larger diameter for the air flow. I have not used the Fuji type HVLP setup so cannot comment on this but do regularly use the Sata and De vilbis HVPL system so know this well. HVLP does require a larger volume of air to operate although the air pressure is much lower than traditional methods of spraying. HVLP allows a much higher solids content paint to be applied in one coat givng a much higher build per coat and so a quicker through put time. Our cars are panited at the rate of one every fifteen minutes and without HVLP we would struggle to acheive this using the multiple coat build up of traditional spray painting. 
