Preparation, Sanding & Storage

5 Preparation, Sanding & Storage Video Lessons

10 Preparation, Sanding & Storage FAQs

Why did my remaining Arm-R-seal thicken in the can?

Oil-based topcoats are "oxidizing" products which means that the moment it is introduced to oxygen, a chemical reaction will cause the finish to begin to harden. As topcoat is used, the empty space in the can is filled with air, furthering the curing process. 

Tips to ensure your Arm-R-Seal remains in great working condition:

  1. Decant the amount of Arm-R-Seal you will need into a foil covered bowl or paper cup and reseal the can right away. Every minute the can is open, the stain is curing.
  2. Be sure to thoroughly clean the chime and the lid of the can to assure a tight seal.
  3. Add Bloxygen to remove excess oxygen from your can of finish before sealing. 
  4. Store your sealed cans upside down.
  5. Transfer any unused finish to a smaller container once finished with your project.

Add plastic wrap before sealing? 
We have not tried it, but you get the idea. Anything to prevent contact with air is the key.

Can I Use Steel Wool with Water Based Finishes?

No, because the particles can become embedded and rust. Some alternatives are Klingspor Synthetic Wool and Meka Mirlon 1500 synthetic wool.

Steel wool is still an acceptable option for oil-based finishes. GF recommends using "oil-free" 0000 wool from Liberon because it doesn't shred as easy as hardware store brands.

Why Did the Existing Finish Develop a Haze While Prep Cleaning with Denatured Alcohol?

White haze can develop when preparing an existing lacquer finish for re-coating. The haze needs to be removed before applying another finish.

To correct during oil based applications such as Gel Stain, sand lightly with sandpaper or a gray Scotch-Brite pad and then wipe down the surface with mineral spirits. Once the mineral spirits has dried completely, apply Gel Stain.

To correct for water-based applications, just sand lightly or scrub with a gray Scotch-Brite pad and wipe off the dust. Never use mineral spirits when using a water-based finish.

I Prep Cleaned My Project with Mineral Spirits But Now I Want to Switch to Water-Based Products. What Should I Clean My Surface with?

Good catch - never use mineral spirits to prep clean before applying water-based finishes.

You can correct this problem by cleaning again with a 50/50 mix of denatured alcohol and water.

Let your project dry 24 hours before applying water-based products.

What is the Difference Between 220-Grit Sanding Paper and 220-Grit Sanding Pads?

Although both items are labeled as 220-grit, the pads are softer with a less aggressive scratch pattern. With use, a 220-grit pad will soften very quickly to the equivalent of 400-grit sandpaper - making sued pads ideal for finish sanding between layers of topcoat or prep sanding an EXISTING finish.

220-grit sandpaper is too aggressive for finish sanding but works well for the final round of prep sanding of open-grained raw wood such as Cherry, Pine, Maple, Birch, or Alder.

Pads are our favorite. The pads last a long time, can be rinsed to remove sanding residue and also have the benefit of being flexible, making corners and edges much easier to sand.

What is the Difference Between Denatured Alcohol and Rubbing Alcohol?

Rubbing alcohol is a generic term and is usually manufactured with isopropyl alcohol.

Denatured alcohol contains ethanol and is engineered to discourage recreational human consumption by including additives that are poisonous, bad tasting, bad smelling or nauseating.

A 50/50 mix of either rubbing alcohol and denatured alcohol will work for prep cleaning. Both have good solvents that will remove dirt and grime.

How Can I Prevent Gel Stain from Hardening in the Can?

As the Gel Stain is used, the volume of stain in the can is displaced with air, causing the stain to start curing. Gel Stains harden up more quickly than liquid oil stains for all the reasons folks love them - the extra colorants and solids within the stain that provide such great coverage also harden up more quickly than other stains.

During storage, the oxygen or moisture that's sealed in the container continues to cure and thicken your stored product, ruining the leftovers. Here are some tips to ensure your Gel Stain remains in great working condition.

  • Decant the amount of stain you'll need into a foil covered bowl and reseal your can right away. Every minute the can is open the stain is curing.
      
  • Be sure to REALLY clean the chime and the lid of the can to assure a tight seal.
     
  • Use Bloxygen to help remove excess oxygen from your can of finish to help preserve it longer.
     
  • Store your sealed cans upside down.
     
  • Transfer any unused stain to a smaller container once finished with your project or buy Gel Stain in smaller cans to begin with.
     
  • Plastic Wrap??  Haven't tried it, but you get the idea! Anything to prevent contact with air is key. 

Watch Tips on Storing Leftover Wood Finishes here.

How Can I Remove Silicone Contamination to Improve Adhesion On My New Finish?

There are no guarantees with silicone - it is almost impossible to remove. Unfortunately, silicone contaminants, often from dusting sprays, do not become apparent until a new finish is applied and generally cannot be removed from the surface, only moved around and possibly sealed - a bane of the refinishing industry.

You need to power clean the existing finish and put on some type of barrier coat:

  1. Power clean the surface by scrubbing with a strong detergent such as Spic and Span and warm water combination with a gray Scotch-Brite pad. After that, clean with denatured alcohol full strength.

    How to Power Prep Existing High Use Finishes for Stain or Paint here.
     
  2. Apply 3 coats of dewaxed shellac. Allow each coat to dry thoroughly.
     
  3. Then cross your fingers and test, test, test your entire finishing schedule in a small area before proceeding with the entire piece.

In most cases, you will need to strip and sand, but even then there is no guarantee of success. If the silicone has gotten into the wood through cracks in the old finish, you may not be able to get it all removed. 

Protect yourself in custom refinishing contracts with a clause similar to this: 

We cannot warrant finishes over an existing piece of furniture. If products containing silicone (such as dusting sprays), oil soaps or waxes have been previously used on the piece, they may contaminate a new finish and prevent adhesion. In these situations, it is best to strip and sand the entire piece. Occasionally, a previous wax finish or silicone may be impossible to completely remove.

________ (Initials) I acknowledge that this piece has never been waxed/polished with a silicone-based dusting spray or cleaned with oil soaps. 

________ (Initial) I have no knowledge of previous cleaning products used but realize that they may have been applied by previous owners.

How Do I Prep Kitchen Cabinets with an Existing Finish Before Painting or Recoating with a Stain?

This response is true of prepping and existing finish on furniture, but kitchen cabinets are more problematic because they are work areas where grease, steam, food splatters and oil from hands are common. Prep is basically degreasing and abrading the surface for better adhesion. Oil or substances on hands really show up on a failed re-finish around doorknobs and hands if the surface is not cleaned thoroughly.

Because of this, General Finishes believes there is no such thing as a "no prep" paint. We would be leading our customers down the path failure if we touted our products as such. Dirt, grime, oil from hands, wax, dusting sprays that contain silicone, oil soaps or wax prevent good adhesion causing the possibility of chipping, peeling and flaking - all signs of a failed finish. This is the number one reason we see for finish failure. The second is not allowing enough dry time.

The heart of the problem is that we often don't know what was used on the cabinets previously. If dusting sprays that contain silicone have previously been used, the risk of finish failure is high. There are no guarantees with silicone - it is almost impossible to remove. Here are our recommendations. It sounds like a lot of work because it is - charge more.

CLEANING AND PRIMING:

  1. Scrub with a degreasing detergent such as Spic and Span or Dawn soap first. Follow with a thorough rinse to remove all the soap.

    WATCH this video about cleaning with Dawn detergent.
     
  2. Clean with a 50/50 mix of water and denatured alcohol. Let your piece dry thoroughly.

    We prefer a 50/50 mix of denatured alcohol and water because it does not contain phosphates, is inexpensive, is readily available and does not require rinsing. You can use commercial furniture cleaners but check the label for phosphates - they will leave a residue behind that requires rinsing.
     
  3. Scuff sand with a 320 Grit Klingspor Ultra Flex Sanding PAD (or 400 grit sandpaper) and remove the dust. There are other sanding PADS out there - just make sure the grit is not too aggressive or you man sand down corners and edges down to bare wood.
     
  4. Put down a coat of General Finishes Sanding Sealer. GF Sanding Sealer can be used over cleaned and prepped existing finishes that will create a strong barrier with superior adhesion properties. The resin particle is larger so it builds fast, and finish sanding is a breeze.

    (Note: We cannot comment on other sanding sealers because several on the market state dry times that are so short that our paint and stains would fail.)
     
  5. You can apply Gel Stain over the sanding sealer after 24 hours.
     
  6. You can apply paint or water based stain over the sanding sealer after 3 hours.
  7. You can apply a white primer over the sanding sealer if you want to color correct for a white paint.

Watch how to power prep high use furniture finishes for stain or paint.

OTHER CLEANING INFO:

  • You can use vinegar, bleach or ammonia solutions, but our experience shows they are usually not aggressive enough for kitchen cabinets. We do not recommend using ammonia with water-based finishes as it can cause the finish to blush (turn white).
     
  • Never use steel wool with water based products because the particles can become embedded and rust. Some alternatives are Klingspor Synthetic Wool and Merka Mirlon 1500 synthetic wool.
     
  • Steel wool is still an acceptable option with oil-based finishes. GF recommends using oil-free 0000 wool from Liberon because it doesn't shred as easily as the hardware store brands.
     
  • NEVER USE mineral spirits to prep clean before applying water-based finishes. You can correct this problem by cleaning again with a 50/50 mix of denatured alcohol and water. Let your project dry 24 hours before applying water-based products.

PROTECT YOURSELF
There are two ways to protect yourself:

  1. Use a contract and have customers sign off on a warranty. It is extremely exhausting and frightening to be faced with a customer angry over a failed finish. You cannot warrant a finish over unknown substances. Here is a suggestion for your contracts:

    We cannot warrant finishes over an existing piece of furniture without knowing the history. If products containing silicone dusting powders, oil soaps or waxes have been previously used on the piece, they may contaminate a new finish and prevent adhesion. In these situations, it is best to strip and sand the entire piece. Occasionally, a previous wax finish or silicone may be impossible to remove.

    ______(Initials) I acknowledge that this piece has never been waxed/polished with a silicon-based dusting spray or cleaned with oil soaps.

    ______(Initials) I have no knowledge of waxes, silicone-based dusting sprays or oil soap products being used on my cabinets.
     
  2. Take the most used drawer or door in the kitchen and test your finish schedule first. And charge for it.

How Do I Prep MDF Before Painting?

MDF (Medium Density Fiberboard) is tricky because there are several grades of MDF and the quality varies.

If you cannot determine the quality of the MDF, play it safe and use best practices. The concern is with the edges and ends. The core of MDF is compressed sawdust, glue and resins so when you apply paint to those areas it soaks right up.

Sand the edges and ends very well with 150-grit sandpaper, then apply a light coat of filler (such as Timbermate water-based wood filler or even joint compound). That will seal the open pores, making it easier to obtain a smooth and consistent finish when painting. The sealing of the ends is even more important than wood because MDF will swell upon contact with moisture.

The front and back of MDF are pressed and sanding during production, but should also be primed with a primer such as Kilz, Bin 123 Primer, or General Finishes Stain Blocker to ensure a better outcome. Then follow with two coats of paint. MDF is not as absorbent as natural wood, so wait 2 days between coats of paint or primer.

Also, MDF also tends to cast a brown color. If you are using a white paint, you can apply a coat of a light gray paint such as General Finishes Seagull Gray Milk Paint first to counter the brown instead of primer, and then apply a few coats of white over it. Let each coat dry 2 days before adding the next.

As always, we recommend that you test your procedure on a hidden area of your project to ensure the product adheres well and desired color.