Orange Peel effect?

[bevans]

I could use some advice from the experts here. I made a cabinet top out of oak and after putting on some teak oil and waiting a week before I worked on it again I applied a water based poly finish to it. The first coat went on well but after I lightly sanded the surface it felt dry to the touch and the surface was dusty not rolled lumps of poly when sanded. I went ahead and applied a 2nd coat I can see and feel a rough surface that I suspect is what is called orange peel. I waited about 3 hours after the first spray. My 1st question is, What is the best way to remove the orange peel surface? For example 400 grit sand paper, wet paper/sponge, RO 90 at 320 grit paper....other?

Another question and perhaps even more important what would have caused this? The temperature was about 65 degrees, fairly humid (just after a rain) but moved the piece into a climate controlled area to dry over night at about 65 degrees. I have heard about this but have haad pretty good luck this past year on numerous projects without seeing this effect.

Thanks in advance

Bruce

 

[mouppe]

I think orange peel is usually caused by the solvent evaporating before the finish hits the surface. Try holding the can or gun closer to the surface.

I can't help you with the other questions, sorry.

 

[tiralie]

Bruce:
My guess is that humidity is the problem, that and timing. Waiting a little longer for the first coat of Polyurethane to dry would have helped you here.

You probably don't have true fish eye but a poor adhesion of the first coat to the second coat which creates small ripples throughout the coating.

I wouldn't as a rule use a solvent based product under a water borne product. I think you probably would have had better luck if had used a solvent based Polyurethane.
If your goal is to use teak oil as a way to prep the oak for the finish, a water based linseed oil emulsion (Target) or thinned (50/50) Shellac and distilled water work well to raise the grain an prep the oak.
In most cases if I have or know that I am finishing with a water borne finish over an solvent based coating I will use a shellac based sealer or a vinyl sealer to ensure I get a good bond.
If you have done this (recipe) before and it's worked, it is most likely the humidity.
If it were me I would probably start sanding with as open grit as I could get away with 80? because the Polyurethane will soften with the heat generated by sanding and clog up the finer grit quite quickly. Once I had the majority of the Poly off I would then move up progressively to finer grits.

Tim

 

[bevans]

Thanks Tim. I think with your you are absolutely correct with your analysis. I will take your advice although I am a little nervous about using 80 grit. Thanks for your help, I really appreciate you taking the time to discuss correct application technique and helping me out.

Bruce

 

[tiralie]

Thanks Tim. I think with your you are absolutely correct with your analysis. I will take your advice although I am a little nervous about using 80 grit. Thanks for your help, I really appreciate you taking the time to discuss correct application technique and helping me out.

Bruce

Agreed if the ripples are relatively minor something finer would be more appropriate.
Good luck.
Tim

 

[mastercabman]

Maybe needs to be thin out a little?
Orange peel is usually from the material not leveling.So more likely drying too fast.
It could also be too much air not enough fluid at the tip?
Also could be spraying too far out.

 

[fdengel]

http://www.highlandwoodworking.com/sprayingorangepeel.aspx

 

[bevans]

After reading a few of the responding posts and associated links I believe a combination of conditions led to the undesirable spraying outcome. I had the setting on too fine of a spray and it was drying before contact with the surface as the spray gun was held too far away from the cabinet top and the humidity and temperature were not optimum for a good dry before I sprayed the 2nd coat. Live and learn....thanks all who responded.

Sanding out the troubling area helped a lot but I fear I went a little too deep in a couple areas as a few places look a little "dull" at a certain angle while the rest looks pretty good. It looks a lot better and will be okay. After 7 cabinets and 3 coffee tables without incident I thought I knew what I was doing but got a little careless on this one.

Bruce

 

[tiralie]

Bruce:
Just curious what system (turbine HVLP, HVLP etc.) did you use for your spraying and what kind (brand) of polyurethane did you use.
Because polyurethane does not "burn in" like lacquers I find them a little more unforgiving.
Tim

 

[bevans]

I use a Fuji Mini-Mite 3 HVLP sprayer. I just started using General brand waterbased poly and have used Varathane in the past also with good luck. I think that my problems this time started with a poor choice of timing with high humidity, cool temps and not being patient enough to let the first coat dry longer. I must have been a little heavy with the spray in a couple places because the surface looked and felt dry but the problem areas may not have been completely dry.

Bruce

 

[tiralie]

I use a Fuji Mini-Mite 3 HVLP sprayer. I just started using General brand waterbased poly and have used Varathane in the past also with good luck. I think that my problems this time started with a poor choice of timing with high humidity, cool temps and not being patient enough to let the first coat dry longer. I must have been a little heavy with the spray in a couple places because the surface looked and felt dry but the problem areas may not have been completely dry.

Bruce

Thanks Bruce.
I was also curious which brand of Teak oil you used and why you use(d) teak oil before you apply the polyurethane?
This is not a criticism, but interested in this technique. I have seen others ask about doing this but have never done it myself.
Tim

 

[Ken Nagrod]

Bruce,

It sounds like what you're talking about is dry spray, not orange peeling.  Orange peeling is more visual.  It looks like the outside surface of an orange peel.  It happens from poor atomization of the material being sprayed or the material applied manually, not "laying down" evenly.  Most of the time it can be leveled out with sanding and reapplied in multiple coats.  Dry spray occurs when the material being sprayed dries in the air, before hitting the object and you can feel the roughness to the finish and see it as a dull gritty look.  Spray gun distance, air pressure, material flow, temperature and humidity have to be taken into account, especially when you don't work inside a controlled booth or shop.  Too much humidity can blush the finish giving it a milky appearance.  That's moisture that's either on the object surface under the coating or in your actual spray stream as you're applying the finish.  Best advice would be test pieces done under very similar conditions to the final product.

 

[Scott B.]

Bruce

I think what is happening is that the temperature is really on the warm side at 65*, and waterborne poly dries really fast, especially out of an hvlp. I think the finish was drying before it could level.

Cool the temp down to 50* during spraying and leveling. Once it is leveled, crank temp for curing. Thats what works for me.