# Wet Sanding?



## Cinnamonxv

Sorry im all new to this. What is wet sanding? do you need to do it after the coats of lacquer?


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## Hypno Toad

I've done wetsanding for oil, but not for lacquer (yet). From what I understand you do a fine wetsanding job after many coats of lacquer (after it has cured), before you buff and polish the surface. It smooths and flattens the surface so you don't get any light refracting off of it, it helps make that mirror finish. Wet sanding is applying soapy water to very fine waterproof sandpaper (600+ grits). Basically, the water lubricates the surface so the sandpaper doesn't leave any (or as many) fine scratches while you sand. After that, you buff with polishing compounds to further smooth the surface.

Correct me if I'm wrong, please. I don't want to be giving false info.


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## shoretyus

Wet sanding and buffing is a process to level the finish on a guitar .. be it poly or lacquer. I use lacquer. I start sanding 600, 800, 1200, 1500 2000 grits wet and fry paper using water as a medium. I then buff with at rubbing compound then a scratcb and swirl remover.


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## rhh7

IMO, wet sanding with mineral spirits is a much better idea than wet sanding with water.


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## shoretyus

Water can creep into unsealed holes and swell wood yes. But the cheap guy in me wins out sometimes


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## ajcoholic

rhh7 said:


> IMO, wet sanding with mineral spirits is a much better idea than wet sanding with water.


are you meaning to say mineral oil? When I was in woodworking college (many years ago.. ) we used to wet sand finished using a thin minerl oil/water mixture. I personaly use plain water with a drop of dishsoap in it. 

The main purpose of wet sanding is to prevent loading up of the sand paper. When you dry sand, the material you are removing has a tendency to gum up, and clog the paper, and also form small bits of finish which can cause issues whrn you sand (basically scratch the finish and create marks). Wet sanding with any liquid flushes away the waste material removed, and keeps the sandpaper clean.

Wetsanding also keeps the finish cool - and when rubbing out/sanding a soft finish like lacquer, prevents the finish from being heated past the point where it will become sticky and cause a mess..

AJC


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## Alain Moisan

Hi all.



ajcoholic said:


> I personaly use plain water with a drop of dishsoap in it.


Same here.



ajcoholic said:


> The main purpose of wet sanding is to prevent loading up of the sand paper. When you dry sand, the material you are removing has a tendency to gum up, and clog the paper, and also form small bits of finish which can cause issues whrn you sand (basically scratch the finish and create marks). Wet sanding with any liquid flushes away the waste material removed, and keeps the sandpaper clean.


It is also my understanding of the purpose of wet sanding



ajcoholic said:


> Wetsanding also keeps the finish cool - and when rubbing out/sanding a soft finish like lacquer, prevents the finish from being heated past the point where it will become sticky and cause a mess.


That is especially true for lacquer, although polyurethane or polyesther finishes are less sensible to heat.

Alain Moisan
Les Guitares Moisan
www.guitaresmoisan.com


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## rhh7

"Mineral Spirits, also called Stoddard solvent, is a petroleum distillate commonly used as a paint thinner and mild solvent. Outside of the United States and Canada, it is referred to as white spirit. In industry, mineral spirits is used for cleaning and degreasing machine tools and parts. According to Wesco, a supplier of solvents and cleaning equipment, mineral spirits "are especially effective in removing oils, greases, carbon, and other material from metal." Mineral spirits may also be used in conjunction with cutting oil as a thread cutting and reaming lubricant.

Artists use mineral spirits as an alternative to turpentine, one that is both less flammable and less toxic. Because of interactions with pigments, artists require a higher grade of mineral spirits than many industrial users, including the complete absence of residual sulfur. Odorless Mineral Spirits are mineral spirits that have been further refined to remove the more toxic aromatic compounds, and are recommended for applications such as oil painting, where humans have close contact with the solvent."(Wikipedia)

I am just learning how to refinish guitar necks. During the Christmas holidays, I took two Squier guitar necks down to bare wood, sanded off the logos, then sprayed them with nitrocellulose laquer, lightly tinted with amber. After curing for about a week, I wet sanded to 800 grit, using mineral spirits. I am very pleased with how these necks turned out, and I will post pics here in the very near future.


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## Cinnamonxv

Soo from what i just read wet sanding pretty much cleans up the lacquer? and after u wet sand u polish? how would i polish the lacquer?


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## Hypno Toad

Cinnamonxv said:


> Soo from what i just read wet sanding pretty much cleans up the lacquer? and after u wet sand u polish? how would i polish the lacquer?


I guess if you don't have a buffing arbor, a drill buffer would be a good alternative. You can do it by hand but it's more time consuming and you'll need more practice. I suppose you'd want to use some fine polishing compounds along with that too. It's basically liquid with very fine abrasives in it. You have to be careful while buffing not to go too hard on any areas, you don't want the buffing to heat up the surface. Ive heard some people also like to apply a coat of wax as the last step. Not sure how you go about doing that, my guess would be that's done by hand; you may want to google that if you're curious..


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## fraser

wet sanding, when done using progressively finer grits of paper, levels out the laquer- gets rid of imperfections, like the inevitable fish eyes-
its not possible to get a good gloss finish if there are high and low spots, etc- once you get up into the higher grits you are removing the scratch marks from earlier grits, as well as perfecting the "smoothness"-
i use the water/ dishsoap mix that the others mention, and i use those little square rubber erasers you get from school supply, or the dollar store, as my wetsanding blocks.
as for polishing, well i never go beyond car wax polish applied by hand, or burnishing with denim, myself. wiser folks will have better ideas.


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## Dieter Billinger

sanding and wet sanding is an essential step in getting a good high gloss lacquer finish. Lacquer alone will not produce the type of finish found on nicely made instruments. Here is what I do.
1 -afterr the final coats of lacquer it is imparative to let the lacquer cure for 5 or 6 days prior to doing anything to it. 
2 - a quick light sanding with 400 grit sandpaper to level the finish. 
3- This is followed by wet sanding with 600 and 1000 grit emery paper.
4 - I then use micro mesh abraisive pads starting with 2400 then 3200, 3600, 4000, 6000, 8000 and 12,000 in succession. These are also used wet.
5- I wipe the guitar dry and let it sit for an hour or so.
6- Now comes the final buffing. I use 3" X 14" cotton buffing wheels rotating at 600 RPM One wheel gets loaded with Menzerna buffing compound and the other wheel is left dry. 

The buffing is the real trick in getting a high gloss finish. The sanding and wet sanding only levels the surface and successively diminishes sanding scratches.
It taks many days and many hours to do this right If there is a quicker way I wish I knew about it.

best regards
Dieter


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## Cinnamonxv

fraser said:


> wet sanding, when done using progressively finer grits of paper, levels out the laquer- gets rid of imperfections, like the inevitable fish eyes-
> its not possible to get a good gloss finish if there are high and low spots, etc- once you get up into the higher grits you are removing the scratch marks from earlier grits, as well as perfecting the "smoothness"-
> i use the water/ dishsoap mix that the others mention, and i use those little square rubber erasers you get from school supply, or the dollar store, as my wetsanding blocks.
> as for polishing, well i never go beyond car wax polish applied by hand, or burnishing with denim, myself. wiser folks will have better ideas.


erasers? as in blocks u use to erase led? does it really? work that save me alot of money


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## rhh7

I polished my lacquer using a very soft, clean cloth and Brasso.


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## fraser

Cinnamonxv said:


> erasers? as in blocks u use to erase led? does it really? work that save me alot of money


yeah- dollar store eraser- for erasing pencil. about an inch anna half long- 3/4 or so inch wide- you know the ones- little rectangle things.
well, i think theyre perfect for this-
- they flex and bend, so they can follow lots of edges and contours nice
- on a flat surface, they stay flat
- theyre really cheap


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## Cinnamonxv

fraser said:


> yeah- dollar store eraser- for erasing pencil. about an inch anna half long- 3/4 or so inch wide- you know the ones- little rectangle things.
> well, i think theyre perfect for this-
> - they flex and bend, so they can follow lots of edges and contours nice
> - on a flat surface, they stay flat
> - theyre really cheap


 Amazing  Thaanks x458483739586746736302958573464647584875475475763465636537584357


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## Rich Rice

I've tried many different liquids for wetsanding, and each has its merits/pitfalls. The soapy water (just use a drop of soap, almost none) does a good job, but will ruin your piece by seeping into little holes like bridge screw holes- and swelling the wood which either cracks the surrounding paint or creating high spots that you will sand through the color.. either way, it has wrecked many otherwise beautiful paint jobs. Plain water is less slippery, but presents the same problems. Drying in between passes of the sandpaper can help reduce this problem, but water is thin and wood is like a sponge.

Mineral spirits works faster, cuts much faster than water, so take extra care along edges and contours. Don't try to get it done all at once, go gently and consistently. Again, it stays fairly wet and you will want to wipe the dirty liquid off your finish very often. Another downside is mineral spirits can chemically attack some finishes. Always test in an inconspicuous spot before slathering a solvent on your new finish.

I bought Wool Lube through Woodcraft, thinking it would be something special, it feels like oily soap. Works OK, but I don't think it's any better than dish soap. I ended up diluting it with water, as it is quite thick, and it acted exactly like soap. 

The wetsanding agent I like best is Naptha. It works alot like mineral spirits, won't raise the grain, and dries more quickly. A few drops sprinkled on a small area at a time will allow nice wetsanding action, then I wipe the freshly sanded area with a slightly dampened paper towel or soft cotton cloth and rinse my sandpaper under warm water to keep the paper clean.

A trip to the automotive store will get you some lacquer swirl remover (such as Meguiar's No.9), and you can rub up a gorgeous deep gloss by hand with an old tee shirt dampened with the Swirl Remover. The trick is to find a balance between wet and dry. Be aware that the swirl remover will continue to remove some of the finish, and the shine is achieved from the action of polishing, not the pressure applied. You need a little heat generated by rubbing, but don't go nuts or you can rub through- then back to square one. Best of luck!


Afterthought- *MAKE SURE YOUR LACQUER IS FULLY CURED BEFORE DOING ANY OF THE ABOVE* Uncured lacquer is still soft, takes more work to get a good finish, and it will dull down a little as it continues to cure. Lacquer continues to cure and harden over time, shrinking and gassing off. If you can let the project hang for a couple of weeks it will be easier to achieve stellar results.


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## ajcoholic

Mineral spirits is pretty harsh on the skin, ie, will pull the natural oils out of the skin and dry your hands. I cant work with goves on so its out of the questions. Naptha - well, that is a pretty volotile solvent and creates a lot of fumes... I wouldnt suggest using naptha unless you are in a very open space, with very good ventilation and absolutley NO chance or source of ignition. Also, hell on the hands. Both can also enter the bloodstream through the skin, and will over long term contribute to illness.

I have a system, where I keep a box of blue shop towels next to me. I dip the paper in the small bowl of water, shake off the excess, and then sand for a minute or so, then wipe down with the towel. I also drill all my holes in the body and neck before finishing and there is enough finish that gets into the holes to seal off the water from entering the bare wood.

You can do what you want, but having an open tin of Naptha, and using it as a sanding lubricant with it splashing all over, is scary to me. Again, Naptha is a FAST evaporating solvent and can explode like gasoline if you have a source of ignition. Most of "us" here are doing this in the home/basement/garage and if you reccomend something, please give proper safety precautions as well.

AJC


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## Rich Rice

*Always use caution with any solvent.*

Good point. I tend to assume that folks will see the warnings written all over the containers in big letters.

I grew up refinishing antiques for my mother, an Interior Designer, and have handled all manner of chemicals (solvents, strippers, and paints/stains/shellacs) since about age 9 or 10. Early in my working life, I cleaned machines with Carbon Tetrachloride, Benzine, Naptha, and other carcinogens which have mostly been taken off the market, then spent 13 years soaked in Acetone, Rubber Rejuvenator, and various acids (Muriatic, Sulphuric, Phosphoric mostly) while employed as a Lithographer- not to mention all the different inks.. I hve been lucky as well as careful.

I'm doing all this in my home shop, and have always been keenly aware of safety issues. I cannot stress safety enough in every aspect of luthiery, from machinery, chemicals, adhesives... always please be careful.


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