wet sanding

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wet sanding

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mango

Posts: 158
Joined: Apr. 2 2019

wet sanding

Hey guys!
When wet sanding during a french polishing process, some people seem to do it with water, others use oil. What are you using? Perhaps oil is better because it won't let the wood swell that much in case it accidentally comes in contact with it?

REPORT THIS POST AS INAPPROPRIATE | Date Jul. 4 2023 8:25:38

silddx

Posts: 570
Joined: May 8 2012
From: London

RE: wet sanding (in reply to mango)

and what grades of paper, what kind of oil?

REPORT THIS POST AS INAPPROPRIATE | Date Jul. 4 2023 17:49:50

RobF

Posts: 1611
Joined: Aug. 24 2017

RE: wet sanding (in reply to mango)

I’ve used oil and pumice as a form of wet sanding for small areas when applying the polish, basically I gently rub the oil/pumice at the area needed and then continue to French polish right over the spot. I’ve tried it as a lubricant for paper but the problem is if you sand through you’re introducing the oil directly to the wood, aided by an abrasive. Depending on how the wood was sized at the beginning this can present problems. I generally dry sand for full levelling using automotive abrasives and will use water only for spot levelling in the final phases or during repairs. This all just applies to shellac finishes and of course everybody has their own methods, so nothing is set in stone.

REPORT THIS POST AS INAPPROPRIATE | Date Jul. 4 2023 22:06:06

estebanana

Posts: 9358
Joined: Oct. 16 2009

RE: wet sanding (in reply to mango)

quote:

ORIGINAL: mango

Hey guys!
When wet sanding during a french polishing process, some people seem to do it with water, others use oil. What are you using? Perhaps oil is better because it won't let the wood swell that much in case it accidentally comes in contact with it?

Either oil or soapy water with wet and dry paper, but only after a significant bodied up film of shellac is on, as Rob says, because you can burn through.

Better still is to not wet sand, but use a different dry abrasive called Assilex.

_____________________________

https://www.stephenfaulkguitars.com

REPORT THIS POST AS INAPPROPRIATE | Date Jul. 5 2023 0:16:22

ernandez R

Posts: 742
Joined: Mar. 25 2019
From: Alaska USA

RE: wet sanding (in reply to mango)

Hay Brother, good to see you are still at it!

I use Naphtha.

But like Rob I dry sand only early in the game. For the top I use only a vary well worn 320g. Back and sides a well worn 220g.

I spit coat with a folded Cotten pad wet with no oil as many passes as I can get in a day then let dry overnight. I sand fairly aggressively in the morning. 4-5 days and don’t even think about polishing with the Munaca with oil until I’ve got things well sealed and leveled accordingly. Always seems I get a few pits in the rosette and bindings which I drop fill medium CA with a toothpick. I totally ruined my last WRC top when I accidentally used the ultra thin CA around the bonding, you’ve been warned :/

The top:
Once I’m into polishing mode with oil and wool filled Cotten covered manuca I pad throughout the day then in the following morning I pre clean scrupulously with Naptha then I sand with a small block about 4cm long and 2cm wide, long edges rounded but short edges square. Two layers of paper towel as a pad between the block and paper.

Clean, clean, clean!

I’ll start with well worn 400g w&d, then 600g a day or two into it, then 1200g. A lot of zen here as to how or when. Seems oil is too thick for 600g or finer. I like to use worn/used paper as I find they don’t have any rogue grit that causes a deep scratch.

Clean is the name of the game, I’ve buggered a couple tops when I let some crud get in the mix.

I only ever sand perfectly with the grain.

I drop the Naptha on the sandpaper.

I keep a clean folded section of paper towel to wipe the sandpaper clean fairly often.

After about two passes I’ll clean the whole surface with a damp Naptha paper towel. Then go at it again.

Took me longer to write this then to do it ;)

Get your game on doing the back first. I Like to do the back, get my grove on, then the ribs and neck and I save the top for last.

I take notes and got a simple checklist for drops of fluid, manuca passes, paper grits, shop temp and humidity.

First time with Naptha or oil or water( screw water, asking for trouble) make a test panel and use it first!

And remember: only ever sand, wipe, and clean with the grain

HR

ps. Last three guitars I shellacked the top without the fretboard, oh man what a breeze and no more janky polish right there at the fretboard/rosette/upper bought. Pali who posts here from Spain does it that way, I gave it a try and… ¡olé!

pps. I use these common black short nap floor mats in the shop to line the work benches, fibers are only about 4-5mm high, I found that they are perfect for cleaning the shellac dust out of the sand paper fibers as I’m dry sanding one or two passes with the paper then a few quick wipes on the rug and ready for another pass on the wood.

_____________________________

I prefer my flamenco guitar spicy,
doesn't have to be fast,
should have some meat on the bones,
can be raw or well done,
as long as it doesn't sound like it's turning green on an elevator floor.

www.instagram.com/threeriversguitars

REPORT THIS POST AS INAPPROPRIATE | Date Jul. 5 2023 0:31:19

estebanana

Posts: 9358
Joined: Oct. 16 2009

RE: wet sanding (in reply to mango)

Forget wet sanding all it does is sand off your fingertips.

Get Assilex and never wet sand again ~ this is the better option to wet sanding. It’s also ten times faster and easier to control. You can sand the whole guitar in five minutes, wipe it a cloth and be back on the padding instantly.

I found this stuff 15 years ago when it arrived on the market and people are just starting to discover it. I showed this to a professional French polisher who did the finish work for a well known classical maker and they adopted it right away.

It’s designed for level cutting with a foam block backing, it was developed for leveling surfaces in auto body paint preparation. It cuts down the hills and swirl marks better than wet sanding.

I don’t work for this company, but if they sponsored guitar makers I’d shamelessly sign up for free products.

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REPORT THIS POST AS INAPPROPRIATE | Date Jul. 5 2023 1:04:51

ernandez R

Posts: 742
Joined: Mar. 25 2019
From: Alaska USA

RE: wet sanding (in reply to estebanana)

S.
What girls do you like to have in the shop?

Are they standard sized sheets?

I’ll look around Amozon and see what I can get through them, been meaning to for a while now.

Can one wet sand with this stuff?

Bed bound at the tail end of coved, a bit of post Paxlovid rebound it seems but not as bad as I feared…

HR

_____________________________

I prefer my flamenco guitar spicy,
doesn't have to be fast,
should have some meat on the bones,
can be raw or well done,
as long as it doesn't sound like it's turning green on an elevator floor.

www.instagram.com/threeriversguitars

REPORT THIS POST AS INAPPROPRIATE | Date Jul. 5 2023 1:17:39

estebanana

Posts: 9358
Joined: Oct. 16 2009

RE: wet sanding (in reply to ernandez R)

quote:

ORIGINAL: ernandez R

Hay Brother, good to see you are still at it!

I use Naphtha.

But like Rob I dry sand only early in the game……

Dude, Naphtha? That’s a horrible idea. You’ll end up like my situation with dermatitis from hell. You shouldn’t be recommending solvents to come in contact with your hands, even with gloves it’s going to come in contact with your skin barrier chemistry. It’s not a good idea and I recommend you stop doing it for the sake of your health.

Your boss should be informed and spank you when you do this. You think getting stepped on my a moose is was inconvenient? You do not want messed up hands.

_____________________________

https://www.stephenfaulkguitars.com

REPORT THIS POST AS INAPPROPRIATE | Date Jul. 5 2023 1:23:12

estebanana

Posts: 9358
Joined: Oct. 16 2009

RE: wet sanding (in reply to mango)

I would also implore people to take my sanding advice seriously because not only do I know the consequences of exposure to chemicals that may sensitize your skin, who better to take advice from than someone such as myself who possesses a throughly abrasive personality?

_____________________________

https://www.stephenfaulkguitars.com

REPORT THIS POST AS INAPPROPRIATE | Date Jul. 5 2023 2:24:03

estebanana

Posts: 9358
Joined: Oct. 16 2009

RE: wet sanding (in reply to mango)

What in Christ is that over there?
I don’t know m’lord.
Are you kidding me?
I’m afraid it’s……

Yes it’s wet sanding, and in this day and age.

How barbaric! It’s like throwing us back to the time of the Hittites.
Damn. Bloody crusades aren’t what they used to be, wet sanding on a crusade?
Bloody depressing isn’t it?
I should say so my good squire.

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_____________________________

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REPORT THIS POST AS INAPPROPRIATE | Date Jul. 5 2023 3:00:29

RobF

Posts: 1611
Joined: Aug. 24 2017

RE: wet sanding (in reply to ernandez R)

quote:

ORIGINAL: ernandez R

S.
What girls do you like to have in the shop?

Are they standard sized sheets?

I’ll look around Amozon and see what I can get through them, been meaning to for a while now.

Can one wet sand with this stuff?

Bed bound at the tail end of coved, a bit of post Paxlovid rebound it seems but not as bad as I feared…

HR

Here you go HR, this is the supplier I’ve used: https://eagleguys.com/

I think they mainly provide to the automotive industry but they told me quite a few luthiers and guitar making shops have been ordering full sets of grits. The sheets can also be sourced on eBay shipped from Japan but I liked dealing with them and found they were very reasonable and accommodating even with shipping to Canada. 3M made a similar product that also worked well, but I’m not sure if they’re still producing it.

One of the advantages of the new style abrasives is they are designed to cut evenly without stray grit pieces cutting deeper than the rest. You don’t need to save up used/worn sheets using this stuff.

REPORT THIS POST AS INAPPROPRIATE | Date Jul. 5 2023 3:49:26

estebanana

Posts: 9358
Joined: Oct. 16 2009

RE: wet sanding (in reply to ernandez R)

quote:

ORIGINAL: ernandez R

S.
What girls do you like to have in the shop?

Are they standard sized sheets?

I’ll look around Amozon and see what I can get through them, been meaning to for a while now.

Can one wet sand with this stuff?

Bed bound at the tail end of coved, a bit of post Paxlovid rebound it seems but not as bad as I feared…

HR

I’m going to make an order for more Sky Blue Assilex soon, I’ll send you some sheets to sample, they’ll fit in an envelope.

_____________________________

https://www.stephenfaulkguitars.com

REPORT THIS POST AS INAPPROPRIATE | Date Jul. 6 2023 12:08:21

JasonM

Posts: 2058
Joined: Dec. 8 2005
From: Baltimore

RE: wet sanding (in reply to mango)

Someone on the foro once suggested odorless mineral sprits. I dont know why they call them odorless! Still obnoxious stuff. At least Naptha wont evaporate as fast.

Mango, which number are you on now?

REPORT THIS POST AS INAPPROPRIATE | Date Jul. 6 2023 14:52:13