orange peel sanding - how much?

[jimmyhopps]

Highly leveraging the advice on this forum, i successfully applied my blotch control and dye (many thanks - debrief later when its all said and done).  Yesterday, I applied my first ever coat of spray finish via the Earlux 5500 to the 6’x3’ table top. Enduro Var gloss. I now have orange peel after a complete dry.

I have sanded this orange peel down a bit with 320 paper and wonder how far to go? In some spots, it seems i have gotten it completely smooth, but in most of the table, i have just sanded off the tops of the peel – i can see shinny low spots between each peak which didn’t get the sand paper.

I know Enduro Var is very good at self leveling, but before I try a 2nd coat, should I sand it all the way smooth or will it just fill in the low spots itself? I have dye stain under the coat, so very hesitant to go too far.  I read on a car finish blog where every says add a few more layers of finish before sanding smooth, but this isn't the same i suspect. 

Could use advice on the peel of course as well. I think that i was holding it 8-10” from the table top. i have a 1.5mm nozzle and the screw opened 2 full turns. I know that i should hold the gun slightly lower, but Do i need more/less liquid coming out the gun? 
Thanks in advance.

[wdwerker]

Be cautious sanding too much after the first coat. Take extra care near edges and corners. I have been spraying for so long that most of my adjustments are intuitive , so I would be afraid to offer any advise on that. Sometimes I put 2 or 3 thin coats on before I sand because touching up when you sand through the stain/dye can be a nightmare.

I was taught to pay special attention to edges and corners when spraying to make sure they are given an adequate coat. I sand tabletops using a cork block to flatten off the tops of problems like orange peel. I use a sanding sealer for it's build and easy sanding . I don't know if Enduro Var has one or if it's compatible.

[Rick Mosher]

A rule of thumb no matter what you are spraying, it should look like a sheet of glass when wet. If it is rough when it's wet it probably needs more reducer. With oil based finishes you can get away with some roughness in the spray as long as you apply it wet enough the slow drying finish will flow out on it's own.

 

 As far as your orange peel now, the scuff sanding on an oxidizing type finish is all that creates adhesion with the next coat. So shiny spots won't adhere as well. You are also correct that you don;t want to sand so much you go through the color (known as a burn through) The solution is to now use a red scotch brite pad or sanding sponge which due to it's soft nature will rough up those lower areas enough to create adhesion between coats.

 

 With the next coat you should be able to use a firm sanding block and get the finish completely flat before the final coat.

[4-Square]

<Highly leveraging the advice on this forum>

Well, that was your first mistake... After that, the rest is just fruit of the poisonous tree...

 

Your best bet is to get feedback directly from Earlux5500 users -- hopefully ones who shoot GF-EV... LumberJocks has several long threads on the 5500 an if memory serves, shooting GF-EV with the 5500...

 

I'll try to provide some feedback, but it may be of limited value since I don't use a 5500...

 

First off, I've shot GF-EV. It's a good product and lays-out well - it's not a great product, but a good one... So the good news is that it can be done...

 

And where there's good news, there's also not-so-good news...

 

The following applies to HVLP. Things change when you get into LVLP, RP, Ariless, etc... Also note, HVLP as the dinosaurs right before the asteroid hits -- HVLP is already extinct, but just doesn't know it yet... If woodworkers are going to invest in a spray setup, look into LVLP, RP, etc... I strongly suspect some states will disallow HVLP in the fairly near future... As another side note, you'll get much better results from WB coatings going LP... But that's another discussion... I know one must balance $$, quality, etc. But if all possible, invest in as good a system as you can afford... A decent spray setup pays for itself over time -- if not $$, then in headaches...

 

Back to the OP...

 

The key to off-the-gun surfaces with WBs is atomization... It's true of solvent-based, but even more so with WB... The reasons why are out-of-scope. Another note, this situation will improve over the next few years as WB coatings evolve...

 

When WBs came-out, HVLP manufacturers specified larger orifices to handle the thicker coatings -- this was the orthodox position... The resulting surfaces were OK, but not in the same league as NCL (the gold standard)... I'm not sure who gets the credit, but if there were a Nobel Prize for HVLP, he/she would have received it for discovering that upping the pressure and forcing the coating through a finer orifice will vastly improve atomization and lay-out a superior surface... As of now, high pressure /w small orifice is the current state of practice...

 

You can follow the discussions over on LumberJocks (I think there is another good one on Woodweb), but I believe the current recommendation is an orifice of 0.8 give or take. The issue for the 5500 is there might not be enough psi to force GF-EV through a 0.8 orifice... I don't know, but someone with a 5500 and shooting GF-EV can provide input... Also, GF-EV is a good finish, but not the only good finish. You may be able to lay-down an off-the-gun WB surface using the 5500, but just not with GF-EV...  With 2/3 stage turbines, my recommendation is low-VOC pre-cat lacquers... They are more forgiving than most of the WBs that I've shot... Again, someone with a 5500 can give you more info.

 

I know it's not a popular notion, but it is what it is... 2/3 stage HVLP lacks both the PSI and CFM to shoot many WB finishes well. My definition of 'well' is that the surface is done, right off-the-gun -- no further processing required (except for high-gloss)... I know marketing literature and sponsored talking heads claim otherwise, but quite frankly, they are paid to... One component to HVLP is the HV part -- and 42CFM isn't even in the same ballpark as the 4/5 stages at 110-140CFM. The other component is the LP part -- and by low, the inventors of HVLP didn't envision 2.2psi -- they were thinking 5/6psi... It's not that the 5500 is bad spray gear, it's that you have to map the capabilities of the tool to the coating you're trying to shoot.. 2/3 stage is great for shellac, dyes, equalizer tints, most solvent coatings, etc... That's a lot of capability... But woodworkers are being pushed into WB (whether they want to go or not) and, for now, most WB coatings need a bit more push... You can certainly shoot WB with the 5500, but you might have to accept that panels will require post processing -- it's just a trade off.

 

The advice about sanding finishes is quite correct. To safely sand-back, you need enough solids to have something to sand... Part of the issue with WBs is that many conventional formulations don't bite-in layer-on-layer ---  leaving you with one of several problems that can be tricky to fix. I won't go into detail on this -- someone else can walk you through that particular minefield.

 

Good luck.

[estesbubba]

I wouldn't read too much into the look of the first coat. Lightly sand to scuff the surface and spray a 2nd coat and see how it looks. I've found a nice wet coat that actually looks like orange peel off the gun will level out nicely.

[Jerry_in_SD]

Hope you don't mind the late response.  I am by no means an expert at finishing but I have followed a similar finishing schedule but I applied stain vs. dye and applied Enduro Var satin rather than gloss via an Earlex 5500  

 

It sounds to me that you have the fluid turned up too much and are applying too much finish.  When there is too much fluid the atomization is poor and the droplets are too big and don't level out as well or sounds like in your case not at all.  There is no air control on the Earlex so fluid control is all you have.   I would try dialing back on the fluid.  I start with the needle closed and then turn out the needle until I see that fine mist.  You can kind of tell when the spray gets too heavy as you dial out the needle.  

 

BTW, when you have the wet coat on with EV, it will look like orange peel when viewed with raking light but will flow out as it dries.  When I first started spraying I thought I messed up but it leveled out fine.  Charles Neil in his DVD course on spraying waterborne finishes also shows the same effect after spraying and also notes that the finish will level out before drying.  I would recommend his DVD course.   He uses GF High Performance which is similar in behavior to GF Enduro var.   I like the Enduro Var for its slight amber tone it provides on my projects.  

 

As Charles points out in his DVD,  If you should have a couple coats on before agressive sanding to prevent burn through.