First spray painting results - yuk!

[Dengue]

The attached photos show my first efforts at sparay painting, and I was using a new Earlex HVLP starter kit. The timber was plywood, cabinet grade sanded to 240 grade, and the paint was waterbased Solver sealer / primer/ undercoat. The paint was thinned with 10% volume of water, and stirred before spraying, after testing with the viscosity cup supplied.

On testing, I noted lots of small blobs amongst on the overspray on a rough piece of ply ( see overspray.jpg below - you can see the file name by moving the cursor over the photo)

When doing my first pass on my sanded workpiece, it was a very thin coating, with the timber visible beneath ( see first pass.jpg below). You will see the small dollops of paint amonst the fine spray.

When doing several passes, cracks appeared in the timber ( see cracks.jpg below). Prior to painting, there was absolutely no evidence of any crackes in the timber - it was very, very smooth

I would really welcome any and all comments on what has gone wrong with each of the above.

After doing the first pass, I then immediately did another pass, at right angles to the previous passes. Should I have let this dry first before doing a 2nd coat?

After finishing, at the end of the day, I cleaned the pot, the spray nozzle at the front after removing it from the gun, re-assembled and I ran water through the spray gun until it was clear. Should I go further with the cleaning process and dismantle the gun completely, or is this a once in a blue moon job??

[horse123]

hi there,
Yes you need to wait min of 2 hrs before recoating.Did you sand the piece first?
I always strain the paint before use .
Yes you need to be sure your gun is always clean as this can cause some of the trouble you are having,
Also are you using an air compresser ? if so you, I set mine @ around 35 psi.
You say there were no cracks in the first place , but you can see in your first pic they are there already,
To fix this i mix timbermate & water to a paste smother the top let it try (30im approx)
then sand back & then undercoat.
see above pic
cheers horse

[horse123]

here is one i,ve just finished spraying

[Master Splinter]

The first pic is a textbook example of dry spray. Open up the fluid nozzle more, or drop the air pressure, or thin the paint more (in roughly that order).

It should go on pretty much like painting with a sheet of liquid - you've got to go slow enough for this to happen, but not too slow so that you get runs. Roughly three seconds per lineal meter of spraygun motion is a ballpark figure.

Having said that, I find that water based paints tend to spray better with airless spray, but that could just be me. Water based paint just doesn't seem to bite into the previous layer and re-dissolve it like solvent based.

As for times between coats - usually it is the 'flash off' time - 30-60 seconds with solvent based paint - so 30 minutes with water based sounds about right to me, but the tin should tell you recoat times.

[Dengue]

many thanks for your comments Master Splinter & horse, I will give it another go and try to get a sheet of liquid paint flowing from the gun. I was laying down a thin mix as seen in the 2nd photo and going back and forth over it until there was enough coverage.

The dressing table looks great.

[mailee]

Water based paint is never easy to spray. I always use solvent paint for my work as it is better in my dusty shop. Water based has to be sprayed lightly and do not attempt to put any great build on in one coat (it separates and fish eyes like mad) It also picks up dust more due to the slow drying times. It should also be filtered at least twice before use, (it is mainly pigment so clumps easliy) As for cleaning out the gun, there is no need to strip the complete gun down but clean around the nozzle and remove the air cap and leave it in soak in the thinner which in this case is water. I recently attempted painting a project in water based paint and had all of the problems you describe and ended up removing the paint and re painting with solvent. (cured the problem) I do spray water based paint for a living but it is in a booth with all of the commercial fittings so no real problem, but it is not really a DIY paint for a dusty workshop. HTH.

[munruben]

Having said that, I find that water based paints tend to spray better with airless spray, but that could just be me..

No, its not just you MS, water based paints should really be applied with an airless spray gun. The conventional air spray method will not atomize water based paints the same as airless equipment. It can be done but time consuming and a hassle. If you must spray with a compressor I suggest strongly that you use an oil/solvent based paint and this will give excellent results. A bit more skill is required though to achieve this but well worth the effort.

Jill! the cracks were already in the timber before you started painting but this has been addressed in the above posts.

[Bob38S]

Jill,

I have had some success spraying water based from a compressor by using Floetrol as the main thinner rather than just water - it thins the paint so that it goes through the gun but does not seem to go watery thin as happens if you thin too much with water.

The Flood Company Australia

Check it out, try it if you wish and let us know how you get on.

Regards,
Bob

[Dengue]

I found this web site provides an excellent list of spray painting problems and how to address them. The photos of each type of problem are excellent!



The books that I have found most valuable are:

• Spray Finishing and Other Techniques by Tauton Press
• Finishes and Finishing Techniques by Tauton Press

hope this helps other beginning spray painters, and the not so new ones too

[wixy]

Other than this issue, how have you found the Earlex unit?

[Dengue]

how have you found the Earlex unit?<!-- google_ad_section_end -->

Hi wixy, I have only used it once, and boy, the turbine was noisy at 86dB. Interesting how the hose was so hot too. I wasn't expecting air to be blowing all the time out the gun nozzle whenever the turbine was on. And I wasn't expecting everything to be plastic, except the air cap and the fluid needle.

Not sure the overspray is much less than a normal compressor driven spraygun

So here I am with a half face mask and two big canisters, ear muffs and glasses, and a head band to stop heavy perspiration falling on my glasses and on the work ! And in the tropics too

The plastic air cap ring at the front is easy to cross thread. The gun is easy to dismantle and clean, and the only control on it is the fluid adjusting screw.

Apart from the water based paint problems, I think the gun will be OK.

Regretting getting the Earlex brand, as the only Earlex rep in Australia is Crommelins in WA, and they don't carry any of the Earlex Spraystation spares, so have to wait on parts to be sent out from UK through them. Earlex won't send direct.

Regretting just finding out the consensus on this forum is that the Wagner Airless spraygun is better for water based paints than the HVLP unit

[wixy]

Thanks very much for the thoughts.

[Dengue]

Sorry to be so blunt, wixy, but I thougth I would get my first impressions down quickly, calling it as it is. Like those word association tests where you have to say the first thing that comes to mind without thinking about it

[wixy]

No worries! I appreciate it. I have been eyeing off the Earlex Pro for a while now and it's good to hear what owner's think about it.

[Dengue]

No worries! I appreciate it. I have been eyeing off the Earlex Pro for a while now and it's good to hear what owner's think about it.

Wixy, I only have the Earlex 1900 starter spray station, not the big expensive Pro outfit