Best sander for between finish coats

[minimalist]

I currently have an RO150 FEQ which I'm very happy with for surface prep.  My next project is quite a large one - 16 panels measuring 8ft x 1.5ft each.  These will sprayed with water borne pigmented satin lacquer - 2 coats primer and 2 coats lacquer.  Sanding between coats is critical to ensure that the final coat of lacquer is smooth.  In the past I've sanded by hand with sponges of various grits and managed an acceptable finish.  Given the size of this next project I'm not keen on trying to complete it totally by hand.  I'd like to use the RO150 but think that it will probably be too heavy and aggressive on the lacquer.  I'm interested to hear what recommendations others may have for a sander that will suit my finishing requirements.

Michael.

 

[Bill]

Several of our customers who specialize in finish work have purchased the Linear Sander #567777.

Since the motion of that sander is fore-and-aft, it is unable to make swirl marks and has a far range of abrasives available.  The feedback from those using that sander has been very positive.

Bill

 

[fcraven]

For finish coat sanding--done by hand. I would consider using the little rubber shaped thingies (that's a technical term), and I do like the idea of the linear sander. My experience comes from fine enamel paint finishes, not lacquer, so your milage may vary. My concern was always with going so through to the primer, but on the primer coats, I used lots of power sanding. 'Twas so long ago...

Fred

 

[ROb McGilp]

Hi Michael,

I too have a RO150FEQ (here we say the FEQ stands for Far East Queensland ;D) and while I dont usually use laquer or stain, I have on occasion, used MinWax's Wipe On Poly with great results using 1500grit pads. However, I do routinely friction seal oils into timber, up to 4000g. Festool make a black foam pad in grits of 500, 1000, 2000 and 4000.  It may be worth trying these. They can be dampened down with whatever solvent you are using and can be washed and reused. I think Bob Childress can tell you more about where to get them in the US.

Regards,

Abert

 

[Bill]

If by "black foam pads" you are refering to the Platin 2 products, those have a stearate coating that may interfere in some finishing applications.  The Platin 2 abrasives are intended for auto body applications.

Bill

 

[ROb McGilp]

Hi Bill,

Yes they are the Platin 2 products. I have used them with Danish, Scandinavian, Tung and a number of proprietary oils with no harm. They were actually introduced to me by a Festool Agent. But even using 1500g on a waterbased "plastic" shouldn't create problems from my experience. (which I'll admit, is limited to Wipe on Poly.)

Regards,

Albert

 

[Bill]

Hi Albert,

I havent done much in the way of finishing, but I have heard a lot about stearates causing issues and thought I would pass that on.  Just something to watch out for.

Bill

 

[minimalist]

Thanks for the ideas.  I will investigate the linear sander.  I was also thinking about the ES125 - only because in one of my finishing books it looked like the author was using one on the primer coats.  As far as abrasives are concerned, I thought the higher grit Brilliant2 range would be o.k.  The Platin2 S400 might work for scuff sanding the first coat of lacquer.  As the product I'm using is a satin finish I don't need to rub out the final coat.  The key thing is making sure all the underlying coats are as smooth as possible.

 

[ROb McGilp]

Hi Bill,

Thanks for letting us know. Its definitely something to watch for if things don't come up as expected.

Regards,

Albert

 

[Dan Clark]

Michael,

Check out Jerry Work's Festool Sanders Manual:http://www.festoolusa.com/Web_files/Getting_the_most_from_Festool_sanders.pdf.  He builds furniture and cabinetry at a very high level, and has written (IMO) the best single manual on Festool Sanders.  His manual doesn't cover much of how to use them; it covers WHEN to use which one.

Regards,

Dan.

 

[EdL]

I have had really good results using my ES125 sander for between finish coats. Usually use 220 grit paper and set the speed around "4".

Ed

 

[Tech]

For a project that large, consider the RS2 or the ETS150/3 Random orbital. You said pigmented so that might dictate the final grit you use. I get better results with darker finishes if I finish out with higher grit. RS 2 paper is available in 400 grit Brilliant. When doing this before by hand, what was your final grit used? Do you plan to rub or buff out? Waterbornes need a tooth for mechanical bond and I've seen adhesion problems if sanded much past 400. Don't overlook the RS 2, I think it's the under emphasized champion of the Festool Lineup and it's hard to beat for those big flat surfaces.

 

[Tim Sproul]

I'd like to use the RO150 but think that it will probably be too heavy and aggressive on the lacquer. 

Get the appopriate pad and abrasive/polishing mop combination and you won't have any difficulties.

I'd suggest you look into a 150/5, 150/3 or the RS2E since they pretty much self balance where as the RO units require you pay full attention for the entire time.  I use my 150/3 when going for high gloss on larger work.  Otherwise, the RO150 works really well too.  IME (see disclaimer below), I've not had to worry so much about getting all the nibs out between coats if I'm after glass smooth.  I've had to be sure to use a topcoat with 100% burn-in and then polish the final coat out to glass smooth.  The 100% burn-in is probably optional but it sure gives you a lot better safety margin for cutting through layers.  Otherwise, there are always a few nibs and dust specs that get on the final coat...no matter how careful I am about the air cleaners and such.  I can apply several (4+) coats of topcoat and sand down between each with 400 - 600 grit or I can not sand down between.  The results are the same for me either way.  I have to polish the final coat to get glass smooth.

Which water borne do you use?  I've only used Target Coatings water borne products but have been very happy.  I should also qualify my response with some disclaimers.  I'm not a pro.  As an amateur, I'm avid but lack years and years of experience.

 

[minimalist]

For a project that large, consider the RS2 or the ETS150/3 Random orbital. You said pigmented so that might dictate the final grit you use. I get better results with darker finishes if I finish out with higher grit. RS 2 paper is available in 400 grit Brilliant. When doing this before by hand, what was your final grit used? Do you plan to rub or buff out? Waterbornes need a tooth for mechanical bond and I've seen adhesion problems if sanded much past 400. Don't overlook the RS 2, I think it's the under emphasized champion of the Festool Lineup and it's hard to beat for those big flat surfaces.

Thanks for the tips. 

I'm using Norton sanding sponges in the following schedule: first coat of primer - sand with 150 grit; second coat of primer - very light sand with 150 grit (if necessary) followed by 220 grit; first coat of lacquer - sand with 320 grit; final coat of lacquer - no sanding.  Becase the final product is a satin finish, I'm not going to do any rubbing out.

Looking at the Brilliant 2 abrasives, I think I will probably need to use 220/320/400.  In terms of the sanding the first coat of lacquer (i.e. scuff sanding) the Platin 2 and Titan 2 range look promising.

 

[minimalist]

I can apply several (4+) coats of topcoat and sand down between each with 400 - 600 grit or I can not sand down between.  The results are the same for me either way.  I have to polish the final coat to get glass smooth.

That's quite interesting.  I guess I'm being diligent with sanding after each coat as this is my first experience with pigmented lacquer.  The substrate is MDF and it's quite amazing to see how the primer highlights any roughness on the flat surfaces, even though before spraying it feels smooth enough.  Of course, the cut edges have to be really well prepared and sealed otherwise the water borne coating just soaks into them like water on a sponge.  I'm going to do a couple more test pieces and try just one sanding step - this would certainly improve my turnaround time.

Which water borne do you use?  I've only used Target Coatings water borne products but have been very happy.  I should also qualify my response with some disclaimers.  I'm not a pro.  As an amateur, I'm avid but lack years and years of experience.

I'm not a pro either but I researched which product to use quite extensively.  I'm using the ML Campbell Polystar system and am very happy with the results.  Ideally to get the type of finish I want, I should be using either a pigmented 2K or polyester product for excellent build and durability.  Unfortunately I don't have the equipment or facilities to deal with such a coating and personally don't want to be exposed to solvent based coatings.

I was worried initially that a water borne pigmented lacquer would end up being like latex (i.e. a soft plastic like finish).  The Polystar product is anything but.  Once cured long enough it is hard as a rock.  The primer is a very high solids product and does need some thinning to enusre that it flows out nicely.  Thus far I've not had to thin the lacquer at all, even though I'm using an HVLP spray system.  Of course you are at the mercy of the weather - I had to stop spraying the last couple of days as the humidity around jumped to over 90%.

 

[Dave Rudy]

I've had to be sure to use a topcoat with 100% burn-in and then polish the final coat out to glass smooth.  The 100% burn-in is probably optional but it sure gives you a lot better safety margin for cutting through layers. 
[/quote

Tim,

Pardon the dumb question, but what is "100% burn-in"?

 

[Tim Sproul]

Pardon the dumb question, but what is "100% burn-in"?

Not a dumb question.  Before I investigated film finishes, I had no idea what "burn-in" meant either.

100% burn-in means that there is no transition between different coats.  If a finish doesn't have 100% burn in and you apply 5 coats, you have 5 separate layers of finish.  If you were to sand those 5 coats down only in the middle of a panel, you'd literally see all 5 coats as separate layers.

For a finish that has 100% burn-in, it is as if you applied only a single coat....even though you applied 5 coats.

Shellac has 100% burn-in.  Nitrocellulose lacquer is another.  Target Coatings USL is a third.  I'm sure there are others.

 

[Dave Rudy]

Thanks Tim.  Helpful answer.  I've decided to start working with target coatings, based primarily on Jerry Work's advice and experience.  I haven't used them before. I will save this thread for future reference.

Dave