Author Topic: Sanding Hardwood Plywood  (Read 5147 times)

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Offline Steven Owen

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Sanding Hardwood Plywood
« on: November 20, 2017, 04:51 PM »
I’m going to have some projects coming-up next year that will require he use of hardwood plywood.  What are some of your reccomendations for sanding techniques with hardwood plywood for a stained, dyed surface with a laquer or varnish top coat?

Your dealing with a thin veneer.  The biggest mistake you want to avoid is damaging/thinning out the first layer of the veneer.

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Online SRSemenza

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Re: Sanding Hardwood Plywood
« Reply #1 on: November 20, 2017, 04:56 PM »
  I have narrowed it down to one thorough pass with 180 grit. Once in a while 220. But that's all it really needs.  Have used both 3mm and 5mm stroke random orbit sanders. The veneer is very thin but doesn't really need much sanding. I have never gone through unless really overdoing trying to even up a solid edge band or something.

   If talking true baltic birch  , that is usually a bit rougher to start and then I do 150 followed by 180.

Seth
« Last Edit: November 21, 2017, 07:36 PM by SRSemenza »

Offline Holmz

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Re: Sanding Hardwood Plywood
« Reply #2 on: November 21, 2017, 03:00 AM »
The optimal may be a belt sander with a frame for controlling the depth.
I have some 240, 320, and 400 belts coming, so I am not speaking from a lot of experience... yet.

A 1/2-sheet is good for spreading out to a large footprint - so that the surface stays flat.
I have one that works like a champ, but it takes 60% longer than a 6" random orbital - even though it has the same watts.
I usually also move it in the grain direction out of habit.

For only just smoothing it, then a 6" random is good with ~180 or 240.

Which ever way one goes, a kiss with a Mirka or Festool hand block 'inline with the grain' is what I commonly do... mainly out of habit.

Offline McNally Family

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Re: Sanding Hardwood Plywood
« Reply #3 on: November 21, 2017, 04:55 AM »
@Holmz

When I wanted to hang a few sheets of plywood to hang tools on, and  practice my finishing at the same time, I used the Festool RS2 with a finer sandpaper, then the Festool hand sanding blocks, which (as Holmz pointed out), work particularly well between coats.  The extremely flexible Festool HSK D21.5 hose that attaches to the hand sanding block make this process a breeze. 

For my practice finish, I used about 3 coats of WATERLOX (take ventilation seriously with this product).  The results are certainly extreme for plywood that is hanging in a basement workshop, but you practice wherever and whenever the opportunity presents itself.
« Last Edit: November 21, 2017, 05:08 AM by McNally Family »
GREEN: In order of purchase = | CT26  |  RS 2 E | Hose w/ Sleeve 3.5m | 115mm X 226mm Hand Sanding Block | 80mm X 133mm Hand Sanding Block | HSK D21.5 5m hose | CT Boom Arm Bundle Set | 1080 Plate for custom MFT | OF 1400 EQ Router (metric) w/accessories | SYS-Rock BR10 | Cordless Sander RTSC 400 Set |  Cordless Delta Sander DTSC 400 Basic | Linear Sander LS 130 | PDC 18/4 set | CXS  2.6Ah Set | Installer Cleaning Set (2018 version) |  New style Festool hose D 27/32 x 3,5m AS/CT | Replacement Hose Garage | Remote control CT-F I/M-Set | MFH1000 work stool | Next purchase: TBD

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Offline Pnw painter

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Re: Sanding Hardwood Plywood
« Reply #4 on: November 21, 2017, 05:36 AM »
For stain prep I'll use my ETS EC 150 with 150 or 180 grit.

Many of the high-quality plywoods come pre-sanded from the factory, so they shouldn't need much prep. Side lighting the plywood can help you spot any areas that may need extra sanding.

Festool's new foam backed hand sanding abrasives would also be a good choice for this type of project. Not many dealers carry them, but after using them on several recent projects I've fallen in love with them.



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Offline Holmz

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Re: Sanding Hardwood Plywood
« Reply #5 on: November 21, 2017, 07:19 AM »
@McNally Family I use the Mirka block in the 230x115 mm size and more commonly the smaller 3"x8" size. The littler one is about the same width as the 25M rolls of abraidnet at $25/roll... so I cut a sheet worth off the roll and it is 20 cents/sheet. And it lasts ages.

The Festool is conceptually the same. so it is a lemon versus lime in color.

The large one takes the same sheets as the 1/2 sander, which is slightly different from the RS2, so I think the FT might take the same sheets as their large hand pad? Does it take screens or papers?
The main advantage of the screens is that finishes that load a paper require removal of the screen and a shake out... Then back on with the used screen for more work.

Often the plywood is so good it just take the "kissing of the hand block" and no power tool.

Offline kcufstoidi

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Re: Sanding Hardwood Plywood
« Reply #6 on: November 21, 2017, 08:06 AM »
Hardwood plywood covers a lot of possibilities and depending on source can be good to extremely poor. This can vary day to day even within the lift and supplier. It has a tendency in general to show an inconsistency in surface appearance under a raking light. This is due to the crap cores most are using. Personally I use plywood for building boxes wear the surfaces aren't seen and lighter weight is needed. I use PC, FX or MDF core for projects where flat is important. The inconsistency in the surface in hardwood ply makes burn through easier especially using a sander that covers a larger surface area as they have a tendency to hit the high spots more. ETS 150 with the regular pad works OK with 150/180 grit. Watch block sanding with Mirka abranet, in some situations you can get grid lines because of the way the paper in made.

John

Offline jobsworth

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Re: Sanding Hardwood Plywood
« Reply #7 on: November 21, 2017, 09:42 AM »
My only concern for sanding ply is sand through the veneer. One other thing you might want to consider is the plys core. Depending on what your plannig on doing with the ply. If you need perfectly flat ply for the application think a MDF core ply. They make a combo core ( forget the actual name) that has the layers of ply with a center of MDF they are usually flatter then reg core ply.

Saves ya sanding time to. If your not planning on staining the ply you can spend a little bit more money and buy is refinished.

as my man Sedge says " I hope this helps"

Online SRSemenza

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Re: Sanding Hardwood Plywood
« Reply #8 on: November 21, 2017, 09:49 AM »
Personally I think that a belt sander , even with depth control frame, is just asking to sand through the veneer.

In general it just doesn't need much sanding.

Seth

Offline Steven Owen

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Re: Sanding Hardwood Plywood
« Reply #9 on: November 21, 2017, 11:39 AM »
Personally I think that a belt sander , even with depth control frame, is just asking to sand through the veneer.

In general it just doesn't need much sanding.

Seth

I’d also think increase caution in handling and storing the plywood plays Big roll too.  I was thinking of keeping a roll of thin packing styrofoam to protect the sheets to prevent adding problems and scratches through mishandling.

If I plan to make a side business building wall mounted TV stands, I have to consider clever ways of reducing the weight for wall mounting to make the stand easier to lift and mount.  A combination of solid hardwood top and Hardwood plywood seems the way to go. 

I wonder how restistant an MDF core would be to warping under wieght.  High end audio equipment can add 250-400 lbs to a stand depending the set-up. MDF on it’s own can warp when a heavy load is not balanced well.  You see MDF warps in around the lift system Router tables all the time when the MDF cannot be reinforced.
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Offline J0hn

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Re: Sanding Hardwood Plywood
« Reply #10 on: November 21, 2017, 01:49 PM »
Half sheet sander with 180 grit. I have a Bosch that works great, good dust collection and covers a large surface area with good speed. Simple and the paper is cheap, I just buy Klingspor sheets in bulk.

Yep - one of the reasons why I bought the Bosch 1/2 sheet sander recently. 
https://www.amazon.com/Bosch-OS50VC-120-Volt-Finishing-Vibration/dp/B00B7EU1I4/ref=sr_1_fkmr1_2?ie=UTF8&qid=1511290062&sr=8-2-fkmr1&keywords=bosch+half+sheet


Offline Steven Owen

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Re: Sanding Hardwood Plywood
« Reply #11 on: November 21, 2017, 03:09 PM »
Half sheet sander with 180 grit. I have a Bosch that works great, good dust collection and covers a large surface area with good speed. Simple and the paper is cheap, I just buy Klingspor sheets in bulk.

Yep - one of the reasons why I bought the Bosch 1/2 sheet sander recently. 
https://www.amazon.com/Bosch-OS50VC-120-Volt-Finishing-Vibration/dp/B00B7EU1I4/ref=sr_1_fkmr1_2?ie=UTF8&qid=1511290062&sr=8-2-fkmr1&keywords=bosch+half+sheet

(Attachment Link)

I’m surprised how expensive the OS50VC is for Bosch sheet sander.  $539 Canadian.  Usually most Bosch’s are cheaper.
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Offline J0hn

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Re: Sanding Hardwood Plywood
« Reply #12 on: November 21, 2017, 03:19 PM »
Ouch

I looked up the exchange rate and $539 Canadian is $421 U.S.!


Offline McNally Family

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Re: Sanding Hardwood Plywood
« Reply #13 on: November 21, 2017, 03:43 PM »
Ouch

I looked up the exchange rate and $539 Canadian is $421 U.S.!

Last time I looked the Festool RS 2E was $410.00 US.
GREEN: In order of purchase = | CT26  |  RS 2 E | Hose w/ Sleeve 3.5m | 115mm X 226mm Hand Sanding Block | 80mm X 133mm Hand Sanding Block | HSK D21.5 5m hose | CT Boom Arm Bundle Set | 1080 Plate for custom MFT | OF 1400 EQ Router (metric) w/accessories | SYS-Rock BR10 | Cordless Sander RTSC 400 Set |  Cordless Delta Sander DTSC 400 Basic | Linear Sander LS 130 | PDC 18/4 set | CXS  2.6Ah Set | Installer Cleaning Set (2018 version) |  New style Festool hose D 27/32 x 3,5m AS/CT | Replacement Hose Garage | Remote control CT-F I/M-Set | MFH1000 work stool | Next purchase: TBD

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Offline Steven Owen

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Re: Sanding Hardwood Plywood
« Reply #14 on: November 21, 2017, 04:03 PM »
Ouch

I looked up the exchange rate and $539 Canadian is $421 U.S.!

Last time I looked the Festool RS 2E was $410.00 US.

$580 Canadian.  The Bosch is only $40 cheaper.  Amazon Canada is on some serious dope.  Look at Canuck tool.
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Offline Holmz

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Re: Sanding Hardwood Plywood
« Reply #15 on: November 21, 2017, 04:04 PM »
Personally I think that a belt sander , even with depth control frame, is just asking to sand through the veneer.

In general it just doesn't need much sanding.

Seth

It does seem counter intuitive.
Which is where some factual evidence is worthwhile. (which I do not have).

However there are belt made up to at least 1000, and the sanding is linear.

I would grab the belt sander before considering an RO-# sander, but I do need to get the frame still.
I threw it out there so people with experience could weight in, and plywood is generally flat so it is different than a slab of wood for a table.

The last time I used a framed bet sander was 25 years ago and on oak it still took all day.
It is only fast when you make a mistake  [big grin]

Offline Holmz

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Re: Sanding Hardwood Plywood
« Reply #16 on: November 21, 2017, 04:05 PM »
Ouch

I looked up the exchange rate and $539 Canadian is $421 U.S.!

Last time I looked the Festool RS 2E was $410.00 US.

$580 Canadian.  The Bosch is only $40 cheaper.  Amazon Canada is on some serious dope.  Look at Canuck tool.

So we can ignoring the cost then...
Which one is better? (How and why)

Offline J0hn

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Re: Sanding Hardwood Plywood
« Reply #17 on: November 21, 2017, 04:22 PM »
In the US - there is an $80 difference in price between the Bosch and the Festool.

BUT - don't forget that Bosch doesn't illegally 'Fix the Price' (for which Festool was fined ~$7 million in Europe)   Bosch has a current promotion for $30 off  :)

Here are the reviews on Amazon - I am very happy with the Bosch


Offline Steven Owen

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Re: Sanding Hardwood Plywood
« Reply #18 on: November 21, 2017, 04:43 PM »
In the US - there is an $80 difference in price between the Bosch and the Festool.

BUT - don't forget that Bosch doesn't illegally 'Fix the Price' (for which Festool was fined ~$7 million in Europe)   Bosch has a current promotion for $30 off  :)

Here are the reviews on Amazon - I am very happy with the Bosch

(Attachment Link)

If the cost difference was only at the exchange rate, Canadians should be paying $430 - $450.  We get screwed on duties and border taxes making it $530 Canadian.

Let’s not digress, the Bosch OS50VC looks a like a good option for hardwood  sheet sanding.  It has a more modern anti-vibration system.
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Offline Holmz

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Re: Sanding Hardwood Plywood
« Reply #19 on: November 21, 2017, 04:45 PM »
In the US...

Does the Bosch have the Velcro on the base?
Amazon and others sell the abraident in 230x115 (which my 1/2-sheet takes).

At the end of the day he sander just wriggles the paper, so there is not much to say other than orbit size, rpm, power and vibration.
But a good 1/2-sheet is still a pleasure to use.

Online Cheese

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Re: Sanding Hardwood Plywood
« Reply #20 on: November 21, 2017, 04:59 PM »
Personally I think that a belt sander , even with depth control frame, is just asking to sand through the veneer.

In general it just doesn't need much sanding.

Seth

It does seem counter intuitive.
Which is where some factual evidence is worthwhile. (which I do not have).


Hey Holmz, I wouldn’t let a belt sander get within 20’ of the veneered ply. The maple ply I’m using now has a veneer that is less than .020” thick, that is under .5mm. It doesn’t take much of a whoops moment to suffer a catastrophic result.

As others have said, the ply is very smooth in the as-purchased condition and only needs a quick “kiss and a promise” to prepare it for finishing. I own a RS 2 and I wouldn’t even consider breaking it out for sanding ply. The ETS EC or the Mirka of your choice would also be my choice. Maximum material removal is probably in the .001”-.002” range, likely much less than that. We’re not trying to remove planer blade marks.

However if you’re trying to remove an applied finish from the ply, then that’s a different story.

Offline rvieceli

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Re: Sanding Hardwood Plywood
« Reply #21 on: November 21, 2017, 05:26 PM »
For 1/2 sheet sanders, IMHO the Makita BO4900v is the real value. Does a great job. Takes normal half sheet sandpaper, but also has velcro on the pad and the vacuum hole pattern exactly matches Festool 1/2 sheet paper. 

They normally run in the $165 to 185 range. Toolnut has it listed for 187 and there is a $25 off $100 or more promo running.

https://www.toolnut.com/makita-bo4900v-finishing-sander.html

Amazon has it for $170 without the promo available.

https://www.amazon.com/Makita-BO4900V-Variable-Speed-Sander/dp/B0000789HT/ref=sr_1_1?ie=UTF8&qid=1511302352&sr=8-1&keywords=makita+bo4900v

I've had one for more than 5 years and it's still going strong.

It does need a small adapter tube for the Festool hose since the dust port is slightly smaller than the Festool offerings. But you can get one at Home Depot.

I don't think that the Bosch will take the Festool paper, doesn't have the velcro.

Ron


Offline Peter Halle

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Re: Sanding Hardwood Plywood
« Reply #22 on: November 21, 2017, 06:12 PM »
Belt sanders with adjustable frames are rarer here in North American than rare.

Peter

Offline Michael Kellough

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Re: Sanding Hardwood Plywood
« Reply #23 on: November 21, 2017, 06:26 PM »
Belt sanders with adjustable frames are rarer here in North American than rare.

Peter

Rarer than rare is right.

I skipped this thread so far because the first two replies were right on the money.

I have three half sheet sanders.  A thirty year old Porter Cable, a Bosch, and most recently the RS2. I keep reading about how much people like them and I get suckered into buying another but I rarely use any of mine. IMO they're too slow. Part of the problem (I think) is that the platen is rarely flat so you're really only sanding with a fraction of that "half sheet".

Offline Steven Owen

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Re: Sanding Hardwood Plywood
« Reply #24 on: November 21, 2017, 07:19 PM »
Personally I think that a belt sander , even with depth control frame, is just asking to sand through the veneer.

In general it just doesn't need much sanding.

Seth

It does seem counter intuitive.
Which is where some factual evidence is worthwhile. (which I do not have).


Hey Holmz, I wouldn’t let a belt sander get within 20’ of the veneered ply. The maple ply I’m using now has a veneer that is less than .020” thick, that is under .5mm. It doesn’t take much of a whoops moment to suffer a catastrophic result.

As others have said, the ply is very smooth in the as-purchased condition and only needs a quick “kiss and a promise” to prepare it for finishing. I own a RS 2 and I wouldn’t even consider breaking it out for sanding ply. The ETS EC or the Mirka of your choice would also be my choice. Maximum material removal is probably in the .001”-.002” range, likely much less than that. We’re not trying to remove planer blade marks.

However if you’re trying to remove an applied finish from the ply, then that’s a different story.

I find it interesting you would consider using a random orbital on sheet plywood.  Most people reccomend orbital sheet sanders for the job.  My biggest concern with using a random orbital on such a thin veneer would be a higher potential for swirl marks even with a light touch. 
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Offline J0hn

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Re: Sanding Hardwood Plywood
« Reply #25 on: November 21, 2017, 07:19 PM »
This is the European version of the Bosch Sander.  I don't know what the differences are, if any - but it's a pretty good video.  (I had the Porter Cable 1/2 sheet sander also 30 years ago, and I would say that the Bosch has come a loooooong way since  then)

Read some of the reviews on Amazon and note that the reviewers were not given the sander or paid for the endorsement like Festool used to like to do

reviews at the bottom of the page


Online SRSemenza

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Re: Sanding Hardwood Plywood
« Reply #26 on: November 21, 2017, 07:34 PM »


I find it interesting you would consider using a random orbital on sheet plywood.  Most people reccomend orbital sheet sanders for the job.  My biggest concern with using a random orbital on such a thin veneer would be a higher potential for swirl marks even with a light touch.

Really?  I can't imagine wanting to use orbital over random orbital unless a delta or non-round pad is needed. I have always felt the swirl marks were more likely with orbital than random orbital. Interesting.

In any case when I use an ETS150/5 or /3 on thin veneer plywood (really thin) one pass with 180 does the job and no marks and no sanding through.

Seth

Online RobBob

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Re: Sanding Hardwood Plywood
« Reply #27 on: November 21, 2017, 08:01 PM »
For 1/2 sheet sanders, IMHO the Makita BO4900v is the real value. Does a great job. Takes normal half sheet sandpaper, but also has velcro on the pad and the vacuum hole pattern exactly matches Festool 1/2 sheet paper. 

They normally run in the $165 to 185 range. Toolnut has it listed for 187 and there is a $25 off $100 or more promo running.

https://www.toolnut.com/makita-bo4900v-finishing-sander.html

Amazon has it for $170 without the promo available.

https://www.amazon.com/Makita-BO4900V-Variable-Speed-Sander/dp/B0000789HT/ref=sr_1_1?ie=UTF8&qid=1511302352&sr=8-1&keywords=makita+bo4900v

I've had one for more than 5 years and it's still going strong.

It does need a small adapter tube for the Festool hose since the dust port is slightly smaller than the Festool offerings. But you can get one at Home Depot.

I don't think that the Bosch will take the Festool paper, doesn't have the velcro.

Ron

FWIW, I am very happy with my Makita 1/2 sheet sander, too.  A real bargain.

Offline Mismarked

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Re: Sanding Hardwood Plywood
« Reply #28 on: November 21, 2017, 08:13 PM »
I managed to sand through the veneer on walnut ply with an ets 150.  Maybe it was low quality ply, but although the plywood looked really flat to me it actually had high spots that burned right through.  Maybe a sander with a smaller or softer pad that would not try to flatten everything. I would not be confident using a belt sander. 

Offline Michael Kellough

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Re: Sanding Hardwood Plywood
« Reply #29 on: November 21, 2017, 08:16 PM »


I find it interesting you would consider using a random orbital on sheet plywood.  Most people reccomend orbital sheet sanders for the job.  My biggest concern with using a random orbital on such a thin veneer would be a higher potential for swirl marks even with a light touch.

Really?  I can't imagine wanting to use orbital over random orbital unless a delta or non-round pad is needed. I have always felt the swirl marks were more likely with orbital than random orbital. Interesting.

In any case when I use an ETS150/5 or /3 on thin veneer plywood (really thin) one pass with 180 does the job and no marks and no sanding through.

Seth

Hmmm, must be because you observe the results instead of going by what others say.

The big soft random swirls from a random orbit sander are much less apparent than the concise little eclipses of a simple orbital sander.

There should be some technical terms to distinguish the random orbits (a particular point on an abrasive disk takes) of an ETS sander from the repeating (Spirograph-like) orbits an RO sander in geared drive makes, but I don't know them.

I am familiar with the visible results and random orbit is way superior to orbital. I stopped using orbital whenever possible as soon as the Porter Cable RO came out thirty something years ago. I never bought another orbital sander until I got into the Festool lineup.

Offline Michael Kellough

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Re: Sanding Hardwood Plywood
« Reply #30 on: November 21, 2017, 08:19 PM »
I managed to sand through the veneer on walnut ply with an ets 150.  Maybe it was low quality ply, but although the plywood looked really flat to me it actually had high spots that burned right through.  Maybe a sander with a smaller or softer pad that would not try to flatten everything. I would not be confident using a belt sander.

In that case a soft pad and a fine abrasive (180 or more) is about all you can do with a machine.

Hand sanding is a last resort.

Festool USA does not pre-approve the contents of this website nor endorse the application or use of any Festool product in any way other than in the manner described in the Festool Instruction Manual. To reduce the risk of serious injury and/or damage to your Festool product, always read, understand and follow all warnings and instructions in your Festool product's Instruction Manual. Although Festool strives for accuracy in the website material, the website may contain inaccuracies. Festool makes no representations about the accuracy, reliability, completeness or timeliness of the material on this website or about the results to be obtained from using the website. Festool and its affiliates cannot be responsible for improper postings or your reliance on the website's material. Your use of any material contained on this website is entirely at your own risk. The content contained on this site is provided for informational purposes only and does not constitute professional advice.


Offline Steven Owen

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Re: Sanding Hardwood Plywood
« Reply #31 on: November 21, 2017, 09:12 PM »


I find it interesting you would consider using a random orbital on sheet plywood.  Most people reccomend orbital sheet sanders for the job.  My biggest concern with using a random orbital on such a thin veneer would be a higher potential for swirl marks even with a light touch.

Really?  I can't imagine wanting to use orbital over random orbital unless a delta or non-round pad is needed. I have always felt the swirl marks were more likely with orbital than random orbital. Interesting.

In any case when I use an ETS150/5 or /3 on thin veneer plywood (really thin) one pass with 180 does the job and no marks and no sanding through.

Seth

I was thinking more about human error when sanding veneers.  The rectangular shape of larger sheet sanders force you to stay with the grain when sanding. 
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Online Cheese

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Re: Sanding Hardwood Plywood
« Reply #32 on: November 21, 2017, 11:03 PM »
I find it interesting you would consider using a random orbital on sheet plywood.  Most people reccomend orbital sheet sanders for the job.  My biggest concern with using a random orbital on such a thin veneer would be a higher potential for swirl marks even with a light touch.
I was thinking more about human error when sanding veneers.  The rectangular shape of larger sheet sanders force you to stay with the grain when sanding.

Large 1/2 sheet sanders are great for keeping a large surface flat when you have a lot of resawing/planer marks to remove. However, when the surface is already flat they really don't offer any additional magic that any 125/150 sized ETS EC type sander can provide. Using fine grit papers, the dwell time over any specific spot is really minimal because the area is already flat and the surface is already relatively smooth. The veneered ply you're purchasing doesn't have a 40-80 grit surface finish, if it did you probably wouldn't purchase it in the first place.

Per the random orbital swirl mark observation, a random orbital sander in woodworking vernacular, is also known as a DA (dual action) sander in the automotive finish trade. I purchased my first pneumatic, National Detroit DA version in the late 60's or early 70's and still own it. The DA sander has been the go to sander for the automotive/motorcycle paint restoration business for the last 50+ years. As far as I know it may still be...unless laser surface treatment techniques suddenly became more popular when I walked away from the computer and took the dog for a walk.  If so...that'd be cool.  [cool]

What other, more highly defined surface, is offered to the general public than the painted surface of a new automobile?  Be it a Suburu or a Mercedes, what surface is smoother, has virtually no orange peel and exhibits no swirl marks than a new automobile?  These surfaces were probably prepped using DA sanders.

In wood working semantics we refer to them as "piano finishes" or "polished lacquer" finishes, when in reality we are really trying to replicate automotive type finishes on wooden materials.  [tongue]  And we are using random orbital sanders to produce that finish.

Whoops...I forgot to include these photos. Maple ply, purchased from the cheapest-of-the-cheap big boxes, Menards. Sanded with a ETS EC 125 wearing a 150 sized pad, using 240 Granat and finished with 3 coats of GF water based clear poly, hand sanded between coats with Festool 400 grit foam backed squares.     
« Last Edit: November 22, 2017, 12:34 AM by Cheese »

Offline Steven Owen

  • Posts: 347
Re: Sanding Hardwood Plywood
« Reply #33 on: November 22, 2017, 01:07 AM »
I find it interesting you would consider using a random orbital on sheet plywood.  Most people reccomend orbital sheet sanders for the job.  My biggest concern with using a random orbital on such a thin veneer would be a higher potential for swirl marks even with a light touch.
I was thinking more about human error when sanding veneers.  The rectangular shape of larger sheet sanders force you to stay with the grain when sanding.

Large 1/2 sheet sanders are great for keeping a large surface flat when you have a lot of resawing/planer marks to remove. However, when the surface is already flat they really don't offer any additional magic that any 125/150 sized ETS EC type sander can provide. Using fine grit papers, the dwell time over any specific spot is really minimal because the area is already flat and the surface is already relatively smooth. The veneered ply you're purchasing doesn't have a 40-80 grit surface finish, if it did you probably wouldn't purchase it in the first place.

Per the random orbital swirl mark observation, a random orbital sander in woodworking vernacular, is also known as a DA (dual action) sander in the automotive finish trade. I purchased my first pneumatic, National Detroit DA version in the late 60's or early 70's and still own it. The DA sander has been the go to sander for the automotive/motorcycle paint restoration business for the last 50+ years. As far as I know it may still be...unless laser surface treatment techniques suddenly became more popular when I walked away from the computer and took the dog for a walk.  If so...that'd be cool.  [cool]

What other, more highly defined surface, is offered to the general public than the painted surface of a new automobile?  Be it a Suburu or a Mercedes, what surface is smoother, has virtually no orange peel and exhibits no swirl marks than a new automobile?  These surfaces were probably prepped using DA sanders.

In wood working semantics we refer to them as "piano finishes" or "polished lacquer" finishes, when in reality we are really trying to replicate automotive type finishes on wooden materials.  [tongue]  And we are using random orbital sanders to produce that finish.

Whoops...I forgot to include these photos. Maple ply, purchased from the cheapest-of-the-cheap big boxes, Menards. Sanded with a ETS EC 125 wearing a 150 sized pad, using 240 Granat and finished with 3 coats of GF water based clear poly, hand sanded between coats with Festool 400 grit foam backed squares.   

All good points.  I’ve always tried to understand the purpose of sheet sanders and where they fit in.  If you had a Rotex with a hard pad, would it not erase the need for sheet sander?

The goal many of us have with hardwood plywood is not making it look like it’s plywood for a laugh. You want to stain hardwood plywood to blend seamlessly with the solid wood elements in a product.  You don’t want the client to look at a finish thinking it looks like plywood.

Festool CT Midi, Festool ETS 125, DF 700 Domino Coming Soon

Offline Holmz

  • Posts: 4010
Re: Sanding Hardwood Plywood
« Reply #34 on: November 22, 2017, 02:48 AM »
Personally I think that a belt sander , even with depth control frame, is just asking to sand through the veneer.

In general it just doesn't need much sanding.

Seth

It does seem counter intuitive.
Which is where some factual evidence is worthwhile. (which I do not have).


Hey Holmz, I wouldn’t let a belt sander get within 20’ of the veneered ply. The maple ply I’m using now has a veneer that is less than .020” thick, that is under .5mm. It doesn’t take much of a whoops moment to suffer a catastrophic result.

As others have said, the ply is very smooth in the as-purchased condition and only needs a quick “kiss and a promise” to prepare it for finishing. I own a RS 2 and I wouldn’t even consider breaking it out for sanding ply. The ETS EC or the Mirka of your choice would also be my choice. Maximum material removal is probably in the .001”-.002” range, likely much less than that. We’re not trying to remove planer blade marks.

However if you’re trying to remove an applied finish from the ply, then that’s a different story.

Well how is plywood made?
And how are veneers made? and how are their surfaces prepared?
Whether or not knowing that has any bearing, I am not sure.

As the frame can be adjust to not even touch the belt to the wood means that the only place for possible trouble is at the edges.


...
All good points.  I’ve always tried to understand the purpose of sheet sanders and where they fit in.  If you had a Rotex with a hard pad, would it not erase the need for sheet sander?
....

A >4" by >8" surface with the mass over the top of it... is less prone to wavyness than a5" circle with a handle hanging off the back.

I will often use 80 or 120 to flatten with a 1\2-sheet, and then bust out the DEROS (180/240) to make it smooth when on solid wood .

Offline McNally Family

  • Posts: 613
  • Festool Atomic Phaser Particle Blaster (APPB Set)
Re: Sanding Hardwood Plywood
« Reply #35 on: November 22, 2017, 07:35 AM »
I managed to sand through the veneer on walnut ply with an ets 150.  Maybe it was low quality ply, but although the plywood looked really flat to me it actually had high spots that burned right through.  Maybe a sander with a smaller or softer pad that would not try to flatten everything. I would not be confident using a belt sander.

Here are the hand sanding block products I like to use, particularly between coats of finish.  No electricity required, other than what is needed to run my CT26.  It also helps that I own the correct size sandpaper for these tools:

Festool 496963 115mm X 226mm Hand Sanding Block
http://www.bobmarinosbesttools.com/hand-sanding-block-115mm-x-226mm/p/496963/

Festool 496962 80mm X 130mm Hand Sanding Block
https://www.festoolproducts.com/festool-496962-hand-sanding-block-80mm-x-130mm.html

Festool 495019 Hose HSK D21.5 5m
https://www.festoolproducts.com/festool-495019-hose-hsk-d21-5-5m.html

Festool 498527 Plastic Universal Brush Nozzle
https://www.festoolproducts.com/festool-498527-universal-brush-nozzle.html
GREEN: In order of purchase = | CT26  |  RS 2 E | Hose w/ Sleeve 3.5m | 115mm X 226mm Hand Sanding Block | 80mm X 133mm Hand Sanding Block | HSK D21.5 5m hose | CT Boom Arm Bundle Set | 1080 Plate for custom MFT | OF 1400 EQ Router (metric) w/accessories | SYS-Rock BR10 | Cordless Sander RTSC 400 Set |  Cordless Delta Sander DTSC 400 Basic | Linear Sander LS 130 | PDC 18/4 set | CXS  2.6Ah Set | Installer Cleaning Set (2018 version) |  New style Festool hose D 27/32 x 3,5m AS/CT | Replacement Hose Garage | Remote control CT-F I/M-Set | MFH1000 work stool | Next purchase: TBD

RED: // Mafell P1cc  //  MT55cc  // Next purchase: TBD

Offline kcufstoidi

  • Posts: 768
Re: Sanding Hardwood Plywood
« Reply #36 on: November 22, 2017, 07:43 AM »
Personally I think that a belt sander , even with depth control frame, is just asking to sand through the veneer.

In general it just doesn't need much sanding.

Seth

I’d also think increase caution in handling and storing the plywood plays Big roll too.  I was thinking of keeping a roll of thin packing styrofoam to protect the sheets to prevent adding problems and scratches through mishandling.

If I plan to make a side business building wall mounted TV stands, I have to consider clever ways of reducing the weight for wall mounting to make the stand easier to lift and mount.  A combination of solid hardwood top and Hardwood plywood seems the way to go. 

I wonder how restistant an MDF core would be to warping under wieght.  High end audio equipment can add 250-400 lbs to a stand depending the set-up. MDF on it’s own can warp when a heavy load is not balanced well.  You see MDF warps in around the lift system Router tables all the time when the MDF cannot be reinforced.

 In my experience building custom units for the last 15 years proper design and construction methods are essential when using any material. Any veneer with a core material will sag whether its hardwood or not. For what you just said about the units you're going to build off the shelf material is going to be disappointing. Custom laid veneers matched to the hardwood components on an FX, classic or MDF sandwich core would give the best results. Again in my experience your goto sander would be something with similar specs to an ETS 150/3, its an easy to use relatively light unit that does not give swirls if used properly.