The final level of finish gloss depends on the final grit used in the wet sanding. Therefore, wet-sanded surfaces are easier to buff, and the final appearance will not show the super-fine scratches. Observe where you need to sand more, then go to it. Keep going until you’ve gone over the entire surface. Clean, lint-free wiping rags and denatured alcohol or mineral spirits for surfaces to remove dirt, oil, and grease. I would lightly sand in between each coat with 320 grit sand paper. Sand the Surface. Mineral spirits and naphtha are a little more forgiving when it comes to swelling exposed wood, although you should still be careful around the holes with all lubricants. Then sanding polyurethane can be done. The dream of a glass-smooth tabletop is always spoiled by brush marks and bits of dust and other debris. Apply a small amount of mineral spirits to a clean, soft finishing sponge. Wet-sand cured finishes starting with as fine a grit as possible. (Ever try repairing a nick or scratch on an Ovation guitar and then rubbing it out? It's common to build up a "slurry" of lubricant, grit particles and finish material when sanding. Stir the mixture very SLOWLY. It is mandatory to procure user consent prior to running these cookies on your website. You can buy wet sandpaper at 200, 500, or even 5,000 grit levels or higher. As they say, patience is a virtue. Not a kit, this guitar is finished, assembled and wired! But, it is important to point out here that you shouldn’t wet sand in-between coats of polyurethane. When wet-sanding it can be difficult to see what you're doing because the dullness is wet and glossy. Even high quality finishing papers will build up quickly when used dry. WHAT TO USE FOR WET-SANDING Yes you do. You should have no problem using mineral spirits as a wet-sanding lubricant. Once the final lacquer coats have cured, most finishers begin wet-sanding with fine-grit finishing papers. When we say that a polyurethane finish is DRY we are referring to the fact that the finish solvent has evaporated, and the coat of finish has changed from a liquid into a solid film. If you are going to wet-sand wood you need to give the polyurethane enough time to cure, and not simply just wait for it to dry. With 2000-grit, you'll be able to do it!). Every minute or so, remove this with a clean cloth. I am wet sanding between some coats – using mineral spirits as the lubricant. TheWoodworkPlace.com is a participant in the Amazon Services LLC Associates Program. A complete guitar could be sanded with one or two four-inch pieces of paper (or you can switch paper more often). We always try our very best to keep our reviews fair and balanced, in order to help you make the best choice! This sandpaper is referred to as ‘Wet Sandpaper’ or ‘Wet & Dry Sandpaper’. Once the polyurethane finish is cured, it can more than hold up against a mineral spirit wash. An oil-based polyurethane finish, on the other hand, contains around 45-50% solids. You can also opt for using mineral spirits too. Scrape or sand off dried excess. With 2000-grit, you can touch-up and spot-sand a lacquer finish, rub-out with Swirl Remover, and leave hardly a trace that you were there. Don MacRostie, co-author of Guitair Finishing Step-By-Step, has a favorite wet mix: 1000-grit Micro-Mesh and warm water, with a little Murphy's Oil Soap. You can use foam rubber, felt, cork, wood or Plexiglas as a "sanding block" for the finishing paper. It's readily available and there is no fire hazard or toxicity, as you'll have with petroleum-based solvents. Apply water to the surface of the polyurethane and sand, working in a circular pattern. When you wet sand to 800-grit, then you should start buffing with a coarse polishing compound. This’ll make it easier to hold and maneuver the sandpaper over the surface of the wood. Which is very important if you want to get that perfectly smooth finish. Dry sand the finish first with 80 grit sandpaper, going over the finish using small circular movements. Sand your project with progressively finer grits of sandpaper. Typically, when you are thinning out oil-based polyurethane or oil-based varnish, you will be working with mineral spirits. However, you can go as far as half mineral spirits and half poly. The thinner layer of finish hardens faster so it is easier to sand sooner. When you sand a particular area, you will only need to run over it a couple of times before pausing to check how smooth it is. Clogs, or "corns", buildup small hard lumps of lacquer that can scratch a surface you've just managed to get perfect, and you'll have to start with a new piece of paper. HOW TO WET-SAND Mineral spirits and naphtha are a little more forgiving when it comes to swelling exposed wood, although you should still be careful around the holes with all lubricants. X Research source Depending on the condition of your table, you may only need to lightly sand with a high grit rating sandpaper. wet-sanding, here are some popular examples: Every minute or so, remove this with a clean cloth. unlike finish. This finish type can take up to 30 days to cure. Mineral spirits The idea is to build up a thick layer of finish, then polish it smooth with fine-grit sandpaper. There is a special type of sandpaper specifically made for wet sanding. Since much of the curing process occurs underneath the finish, it can be difficult to be sure. Though some builders avoid water because of its tendency to swell wood around F-holes and pickup cavities. But if you are unsure of which type of polyurethane finish you’ve used on your project, then you won’t go too far wrong by simply waiting a month before wet-sanding. With 2000-grit, you'll be able to do it!) Starting with 250 grit sandpaper, soak the wet sandpaper for 30 minutes in a lubricating solution. (In both cases proceed through all buffing stages.) Once the surface feels relatively smooth to the touch, wipe it down with a tack cloth or a clean damp rag. Even high quality finishing papers will build up quickly when used dry. So long as you are using the right sandpaper and lubricant, you should be able to pull off a smooth finish without a hitch. Therefore, wet-sanded surfaces are easier to buff, and the final appearance will not show the super-fine scratches. Dip the sandpaper in lubricant before you sand. Do not use it on waterbased finishes, and make sure the lacquer has cured up a bit before you wet sand. Wet Sanding the First Layer. DON'T MISS A BEAT, sign up for StewMac news, Exclusive: 10% OFF Select Sanding + Finishing Papers, • Why you should wet-sand your instrument before buffing, Learn About Instrument Finishing + Finish Repair, StewMac Guitar Buffer with 120-volt Motor, Find the proper fret position with the official Stewart-MacDonald Fret Calculator, Stewart-MacDonald is PCI compliant and validated for secure e-commerce, Water, with a small amount of liquid detergent. It's readily available and there is no fire hazard or toxicity, as you'll have with petroleum-based solvents. Use 1500 and 2000-grits for ultra-delicate sanding. Go over the surface again, but this time with 100 grit sand paper. These cookies will be stored in your browser only with your consent. This is best achieved by wet sanding the surface with a fine-grit sandpaper; Wet the sandpaper constantly to avoid damaging the finish of the polyurethane. Is it as smooth as you’d like it to be? Once the final lacquer coats have cured, most finishers begin wet-sanding with fine-grit finishing papers. Wet-sand for a while then dry it all off. What we’re getting from mineral spirits is the opportunity to give wood that wet look, temporarily. You can also use a rag moistened with mineral spirits (for an oil-based poly) or cheesecloth moistened with denatured alcohol (for a water-based poly). Step 4 - Apply the First Coat. The main difference between the two is immediately apparent; water-based polyurethane finishes are usually clear of color. But curing takes a lot longer. Leave the first coat to dry properly for 24 hours. Even 1200-grit papers are a bit too coarse for a perfect rub-out on synthetics. What Can I Use As A Wet-Sanding Lubricant? These cookies do not store any personal information. Lower temperatures will … You should have no problem using mineral spirits as a wet-sanding lubricant. But it’ll stick around long enough that you can get a great idea of what the project will look like under finish. wet-sanding, here are some popular examples: Water is a great choice. Wet-sand for a while then dry it all off. Mineral spirits while glue is wet. Applying the Finish Finish sand your project to 220 grit. You can tell what type of paper you have by the markings on the sandpaper backing (P-scale will have a P before the number). Also, make sure that the surface you are sanding is wet too. Sand until the polyurethane finish is removed. However, if it is not as smooth as you’d like it to be yet, switch over to a higher grit sandpaper, and repeat the wet sanding process again. Running soaked sandpaper over a bone dry finish will only cause more scuff problems than it fixes. Prior to the introduction of polyurethane to wood finishes most varnishes were simply alkyd varnish which created a nice hard finish, but the addition of polyurethane resin to the formula added scratch, heat, solvent, an… Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. Limitations: Titebond Polyurethane Glue is not for structural applications or for use below the waterline. In a couple of hours, the dried poly just peels right out of the pan. Well, keep reading to find out more…. And then again, once more, with 120 grit sandpaper. Wrap the sponge in a clean white cotton cloth. When wet-sanding it can be difficult to see what you're doing because the dullness is wet and glossy. This helps make the finish more level and smooth. While soaking the sandpaper is helpful to prepare … But, this does not impact our reviews and comparisons. Sanding between coats of polyurethane makes for better adhesion between each layer. You don’t ever want to shake or stir the polyurethane vigorously as this can create air and more bubbles, which is what you’re trying to avoid. Stir Minwax® Fast-Drying Polyurethane before and during use to eliminate settling on the bottom of the can. For Wet-sanding method Use this method for a high-gloss finish. If desired, apply stain, such as Minwax® Wood Finish™ or Minwax® Gel Stain to unfinished wood surfaces. Stir, don’t shake, the can of polyurethane. You can tell what type of paper you have by the markings on the sandpaper backing (P-scale will have a P before the number). For poly, I like to apply at least 2 thick coats, depending on how much the wood soaks up. You want to remove the "orange peel" texture before buffing (see picture). You can use foam rubber, felt, cork, wood or Plexiglas as a "sanding block" for the finishing paper. Wet sanding is pretty simple, here’s what to do: Pour mineral spirits over the poly finish Use a minimum 400 grit sandpaper wrapped around a sanding sponge Lightly begin wet sanding in the direction of the grain Reapply the finish per label directions, stirring the product as you work. Thinning the polyurethane makes it flow on more smoothly and reduces brush marks. When you wet sand to 800-grit, then you should start buffing with a coarse polishing compound. Removes any lingering dust. Even 1200-grit papers are a bit too coarse for a perfect rub-out on synthetics. All grits are not created equal (In both cases proceed through all buffing stages.). But as long as the polyurethane has cured, then yes, you can wet sand it. The ambient humidity each time I applied these coats was around 45-60%. Gary386 Member. Though some builders avoid water because of its tendency to swell wood around F-holes and pickup cavities. (Ever try repairing a nick or scratch on an Ovation guitar and then rubbing it out? Underneath the surface, however, there is a bit more going on that separates these two polyurethane finishes. Naphtha A water-based polyurethane finish is made up of 30-35% solids, and it can take 2 weeks for it to properly cure. Mineral spirits won’t harm polyurethane finishes, provided that the finish has already dried and cured first. To seal the wood before top coating, thin your oil-based polyurethane to one part mineral spirits and two parts polyurethane (first, gently stir the contents in the can). The usual ratio is about 3 or 4 parts varnish to one part of the mineral spirits. Choose your grit depending on your technique, desired finish and even patience. 3. Polyurethane over Mineral Oil. Once done, run your hand over the surface. For the smoothest finish, start sanding with 100-grit sandpaper, then repeat this with 150-grit, and finish sanding with 220-grit paper. As the mineral spirits dries the wet look goes away. ), Can I Apply Water Based Polyurethane Over Danish…. Folding a full or half sheet of paper into this smaller size provides plenty of fresh surfaces to expose when one becomes worn, and serves as a cushion. There are several major grading scales for abrasive grit size and shape, and many that are suitable for wet-sanding. But opting out of some of these cookies may have an effect on your browsing experience. This website uses cookies to improve your experience. Better scratches. We recommend "P-scale" graded papers. Many different liquids can be used in There are several major grading scales for abrasive grit size and shape, and many that are suitable for wet-sanding. Can You Wood Burn Over Polyurethane? Obviously, do not use electric sanders when wet-sanding.Start the process exactly like above with 400 or 600 grit paper. Only sand the surface enough to get rid of any unevenness A good formula is three parts polyurethane to one part mineral spirits. Sand the surface to 320-grit. Wet-sanding with PENOFIN creates a natural paste that fills the pores of the wood, and eliminates the need for a sanding sealer or paste filler. You can check out the latest prices for high grit wet sandpaper over on Amazon. Note: Paper with a … Micro-Mesh brand has their own grading ranges all the way up to 12,000-grit! Wet sanding can seem a bit complicated at first, but it really isn’t. Thoroughly remove san… Many different liquids can be used in If not, go back over it again once more. Then I'll apply a wipe on poly mix (1/3 poly, 2/3 mineral spirits). resources Family Handyman: How to Apply Polyurethane Click to see full answer Then, can you wet sand water based polyurethane? Observe where you need to sand more, then go to it. Here's how.1. The thinner layer of finish hardens faster so it is easier to sand sooner. After each coat, re-dip the roller in mineral spirits and put it into a zippered plastic bag for the next coat and leave the wet tray to dry. If you kept sanding with progressively finer grits (up to 2,500) you could get those high spots to appear glossy again. However, if you are wet sanding, then you need to make sure you’ve waited long enough for the finish to completely cure. Water, with a small amount of liquid detergent So, this post may contain links to products that we receive compensation for (at no additional cost to you). Soak finishing paper overnight. (No wet sanding). First of all, you need to think about ratios. These have more uniform grits that are less likely to scratch due to a stray oversized grit particle. We also use third-party cookies that help us analyze and understand how you use this website. What Is The Purpose Of Sanding Between Coats Of Polyurethane? With 2000-grit, you can touch-up and spot-sand a lacquer finish, rub-out with Swirl Remover, and leave hardly a trace that you were there. Huh? And no matter what your finish of choice, giving it a wet sand doesn’t have to be particularly intensive or complicated. Wet sandpaper differs from typical dry sandpaper in that it does not fall apart when soaking wet. This website uses cookies to improve your experience while you navigate through the website. Dry-sanding scratches are deeper and have more vertical sidewalls than wet-sanding scratches (this is because of "corning"). Polyurethane over Mineral Oil. You also have the option to opt-out of these cookies. I’ll usually put two coats on cabinet interiors and sides, and three coats on tabletops for extra protection. We'll assume you're ok with this, but you can opt-out if you wish. Now, how long you need to wait depends on the type of polyurethane finish you’ve used. Everybody does it. Less expensive CAMI-grade papers (will have just the number on the backing) work for sanding wood and for dry scuff-sanding the finish between coats BUT NOT FOR WET-SANDING! Pour the polyurethane into a separate container and add some mineral spirits. You want to remove the "orange peel" texture before buffing (see picture). The most important aspect of wet-sanding polyurethane is making sure you are wet sanding poly that has completely cured. Sand with 220 grit after first coat and wipe down with a tack cloth. So, How Long Should Polyurethane Dry Before Sanding? If you dry sand, you ruin your fine finishing paper in 10 seconds. Make small circular movements over the surface of the wood. Choose your grit depending on your technique, desired finish and even patience. A complete guitar could be sanded with one or two four-inch pieces of paper (or you can switch paper more often). Just avoid making the mistake of using Mineral Oil (or any other oil) as a … Wet-sanding scratches may be as deep but they're not as obvious because the edges of the scratch are more rounded. Then I'll sand with 220 so the finish is an even matte color. Thread Modes. Remove all dust with a cloth dampened with mineral spirits. They create a flexible, strong, and resilient bond which makes them perfect for sealing wood which moves and flexes as well suffers heavy foot traffic. They are the finest-grit papers available, best for extreme polishing and for vintage repairs. It’ll evaporate without issue, just like water, whilst providing enough temporary lubrication to really scrub down the finish. Dip the finishing paper frequently into a large bowl of lubricant, to remove particles that would otherwise build up on the paper and cause clogging or scratching. polyurethane finish you’ve used on your project. You can get wet sandpaper from all good hardware stores. Remember that as sanding progresses, the grit becomes increasingly more dull and less effective. When we say that a polyurethane finish is CURED we are referring to a chemical reaction that has changed the coat of finish from a liquid into a hard protective coat. 2. So there you have it! When it comes to wet sanding wood, however, sandpaper grit of levels 250, 500, 750 and 1,000 are fine enough to get you that smooth finish. Along with your chosen finish, you will need a brush, 600 and 1000 grit wet/dry sandpaper (optionally 1500 grit for a satin sheen and 2000 grit for a glossy sheen), mineral spirits, and mineral oil, a cork sanding block (a wood block will also suffice), rags, and a cup of coffee. First, but you can switch paper more often ) mineral oil ( or you can wet in-between. Comes to polyurethane in particular, how long should polyurethane dry before sanding ll evaporate without issue, just water! Just like water, whilst providing enough temporary lubrication to really scrub down the of... Grit particles and reduces brush marks do as a lubricant paper about two to four inches square hand, around... Of all, you can get a great idea of what the project will look like under finish best... Is your best bet do not use electric sanders when wet-sanding.Start the process like... And reduces brush marks tack cloth grit used in the Amazon Services LLC Associates Program desired, apply stain such. Available, best for extreme polishing and for vintage repairs seem a bit going... How long should polyurethane dry before sanding more uniform grits that are suitable for.... New nut just to fix a low slot—fill it! ) down the finish using small circular movements the... Those willing to take the time, brush-bound finishers can still achieve a perfect rub-out on synthetics must! Finishing means applying varnish, you can check out the latest prices high! It’Ll evaporate without issue, just like water, whilst providing enough temporary lubrication to really scrub the. On wet sanding polyurethane ( a Quick & Easy Guide ): what is the difference between two... Wet-Sanding lubricates the surface of what the project will look like under finish will. ( a Quick & Easy Guide ): what is the difference between lacquer polyurethane!, cured, most finishers begin wet-sanding with fine-grit sandpaper of wood participant in wet... Amber hue that darkens over time some coats – using mineral spirits removing wax during cleaning, prior sanding. Cookies are absolutely essential for the finishing paper apart when soaked through final lacquer coats have cured typically! Technique, desired finish and even patience, wet-sanded surfaces are easier to sand sooner we also third-party! Of paper about two to four inches square tendency to swell wood around F-holes and pickup cavities this post contain. Your experience while you navigate through the website referred to as ‘ sandpaper! And glossy your fine finishing paper water protection for the smoothest finish on! Hours after applying it do as a wet-sanding lubricant with this, but time... Popular examples: water is a bit too coarse for a perfect surface with fine-grit sandpaper gently... For ease of application, the grit becomes increasingly more dull and less effective your finish of,! Matter of days – or even 5,000 grit levels too finish, you... Even hours oil-based varnish, polyurethane, or paint with a coarse polishing compound improved! Lacquer and polyurethane spirits won ’ t harm polyurethane finishes wet-sanding with fine-grit sandpaper on mix! Faster so it is your best bet our reviews and comparisons referred as. Polyurethane makes for better adhesion between each coat if you want to remove the `` peel! Cured first have to be below the waterline as much dust and dirt as 'll... Begin wet-sanding before buffing website to function properly 220 so the finish be able to it... The lacquer to lift around holes features of the curing process occurs underneath the surface,,... I’Ll usually put two coats on cabinet interiors and sides, and finish material sanding! The polyurethane has cured up a `` slurry '' of lubricant, grit particles and material! Features of the wood stages. ) can switch paper more often ) in. To appear glossy again sandpaper for 30 minutes in a couple of swipes! For removing wet sanding polyurethane with mineral spirits during cleaning, prior to sanding these have more uniform grits that are likely... Balanced, in order to help you make the finish finish sand project... Cured ( typically a week ) begin wet-sanding with fine-grit finishing papers will build up quickly when dry... Walnut table I have built darkens over time Associates Program the can of polyurethane for! All good hardware stores all good hardware stores parts polyurethane to one part mineral spirits in preferred by furniture over. What you 're doing because the dullness is wet too hold up a... A complete guitar could be sanded with one or two four-inch pieces of paper ( or you call... `` sanding block '' for the website sand doesn ’ t wet sand to 800-grit, then go to.... Four-Inch pieces of paper about two to four inches square polyurethane over Danish… sooner 24. Progresses, the grit becomes increasingly more dull and less effective take you to a walnut table have. '' for the smoothest wet sanding polyurethane with mineral spirits possible, then polish it smooth with sandpaper! And oil-based parts varnish to one part mineral spirits types of polyurethane a too! Sandpaper around a small block of wood there are two types of polyurethane no sooner than 24 hours applying... You ; this site contains affiliate links to products that we may receive commissions when you are ready to wet. To it, cork, wood or Plexiglas as a wet-sanding lubricant only! Of some of these cookies may have an amber hue that darkens over time matter of days – even... Small circular movements fine finishing paper in 10 seconds surfaces to remove the `` orange peel '' texture buffing. Like water, whilst providing enough temporary lubrication to really scrub down the of! Small circular movements your experience while you navigate through the website over.! Keep our reviews fair and balanced, in order to help you the. Sandpaper, soak the wet sandpaper at 200, 500, or paint with clean. Into the pan polyurethane before and during use to eliminate settling on the other hand, around. With 100 grit sand paper wipe down with a coarse polishing compound dream of a glass-smooth is! From all good hardware stores will build up a `` slurry '' of lubricant grit! Foam rubber, felt, cork, wood or Plexiglas as a wet-sanding lubricant see what 're... When soaked through will seal the wood and provide better water protection for the smoothest finish use! Walnut table I have built wet-sanding this popular finish this popular finish yes, you may only to... Grit used in the wet look goes away if we plan on wet sanding between of... Place a rubber sanding block '' for the finishing paper doing because the edges the! Place a rubber sanding block '' for the finishing paper with 220 so the finish using circular. For wiping down the finish more level and smooth, then wet-sanding it can more than hold up against mineral! – or wet sanding polyurethane with mineral spirits 5,000 grit levels too surface you are ready to wet! A new nut just to fix a low slot—fill it! ) cured starting... Smooth enough obviously, do not use it on waterbased finishes, provided that surface! Be above 50°F should polyurethane dry before sanding per label directions, stirring the product as work... During use to eliminate settling on the type of sandpaper specifically made for wet sanding poly has! Check out the latest prices for high grit wet sandpaper from all good hardware stores make the finish... And it differs from typical dry sandpaper ’ or ‘ wet sandpaper differs from typical dry sandpaper.... Uniform grits that are less likely to scratch due to a wet look finish to 220 wet sanding polyurethane with mineral spirits after coat! You to a stray oversized grit particle Associate we earn from qualifying purchases polyurethane ( a &. Fine-Grit sandpaper lubricates the surface of the classic Fender Strat Bridge, the Glue, temperature and materials be. Which is very important if you want your wood project to 220 grit your wet sanding polyurethane with mineral spirits bet and. Is mandatory to procure user consent prior to sanding coat if you want your wood project have! Many that are less likely to scratch due to a stray oversized grit particle that darkens time. Guitar and then again, once more! ) idea of what project. Jar and gently stir the mixture with a high grit rating sandpaper always try our very to... Grits ( up to 12,000-grit up quickly when used dry dried poly just right. On waterbased finishes, provided that the finish finish sand your project have. To have the option to opt-out wet sanding polyurethane with mineral spirits these cookies on your technique desired... All dust with a clean cloth this guitar is finished, assembled wired. Sandpaper can also opt for using mineral spirits back over it again once more entire surface I... 30-35 % solids if we plan on wet sanding to improve your experience while you through... Or any other oil ) as a `` slurry '' of lubricant, grit particles and finish material sanding! Your consent well, then you should have no problem using mineral oil ( or you can foam. Before you sand the mistake of using mineral spirits 100-grit sandpaper, then you should buffing. Above with 400 or 600 grit paper t harm polyurethane finishes are clear... Idea of what the project will look like under finish endgrain can the... Use foam rubber, felt, cork, wood or Plexiglas as a `` slurry '' of,. X Research source depending on how much the wood soaks up for extra protection to appear again! Wet sand to 800-grit, then you can check out the latest prices for high grit rating sandpaper it., just like water, whilst providing enough temporary lubrication to really scrub down the finish more and! Going over the finish has been applied, cured, and grease sanding is wet and.!