Over the past several years we have discovered many things about cleaning wood and existing finishes. First and most importantly is that chlorine bleach is not the best product to use. In addition to its potential for damaging the finish and bare wood fibers, its use and misuse contribute to specific problems including the loss of film adhesion, discolorations due to tannin extraction, streaks, blotches, and premature failures of the finish system. We have also discovered that many wood and deck cleaners available at paint and hardware stores, home improvement centers and Do-It-Yourself outlets contain components that interfere with the proper performance of our finish systems.

Therefore, we have decided that the only cleaning products approved for use with our finishes are those products supplied or recommended by Perma-Chink Systems, Inc. We are not doing this to increase our sales of cleaning products. It is because we have tested our cleaning products with our finish systems and have confidence that when properly used and applied, their use will result in the best possible appearance and performance of the final LIFELINE finish. We can not say the same about the use of other types and brands of wood cleaners, and strongly discourage their use with any of our LIFELINE stains.

Guidelines for Cleaning Bare Wood Prior to Applying Lifeline Stains

New Log Homes

1. If the wood has not grayed, wash the surface with a two (2) cups per gallon Log Wash™ solution and a pressure washer no more than seven (7) days prior to staining. Smooth log siding should be washed using Wood ReNew™. Rinse well and allow the wood to dry.

2. If you are finishing Western Red Cedar, Redwood, Walnut, or Mahogany, use Cedar Wash™, a ready-to-use cleaner, instead of Log Wash for better surface preparation and finish longevity on these specific wood substrates.

3. If there are signs of grayed wood, use Wood ReNew according to the label along with a pressure washer. Rinse well and allow wood surfaces to dry before staining. If more than seven (7) days pass before the home is ready for staining, wash the surface with a two (2) cups per gallon of water Log Wash solution, rinse well with a garden hose, and allow wood surface to dry.

4. If, after steps one or two, there are still dark streaks or discolorations on the surface, use a solution of OxCon™, which contains oxalic acid, on the entire wall according to the directions for use. Rinse well and allow the wood to dry before staining.

Older Log Homes That Have Had a Previous Finish Removed

1. If there are no signs of gray surface wood, wash the surface with a two (2) cups per gallon Log Wash solution no more than seven (7) days prior to staining. Rinse well and allow the wood to dry.

2. If you are finishing Western Red Cedar, Redwood, Walnut, or Mahogany, use Cedar Wash, a ready-to-use cleaner, instead of Log Wash for better surface preparation and finish longevity on these specific wood substrates.

3. If there are areas where grayed wood is still evident or if the wood has darkened after the finish was removed, use Wood ReNew according to the label along with a pressure washer. Rinse well and allow the wood to dry before staining. If the wood has darkened or more than seven days has passed before the home is ready for staining, wash the surface with a two (2) cups per gallon of water Log Wash solution, rinse well with a garden hose, and allow the wood surface dry.

4. If, after steps #1 or #2, there are still dark streaks or discolorations on the surface, use OxCon, an aqueous oxalic acid solution, on the entire wall according to the directions for use. Rinse well and allow the wood to dry before staining.

Log Homes with an Existing Finish That is Still in Good Condition

1. If a maintenance coat of Lifeline stain or topcoat is going to be applied over an existing Lifeline finish, wash the coating surface with a two (2) cups per gallon Log Wash solution no more than seven (7) days prior to staining. Pressure washing is not recommended. Rinse well and allow the wood to dry. For maintenance cleaning of finished surfaces that are not going to be stained or top-coated, use a one (1) cup per gallon Log Wash solution.

A NOTE ABOUT RINSING

No matter what product you use to clean bare wood, nothing is more important than making sure you have adequately rinsed the surface. Any chemical residue remaining on the surface can have serious consequences later on. We always recommend using pH Strips to make sure that the surface of the wood has been sufficiently rinsed. A pH between 6.5 and 7.5 indicates the surface has been properly rinsed. pH Strips are available at most pool supply dealers, aquarium supply shops and Perma-Chink Systems, Inc. They are not expensive, are very easy to use and a great tool to ensure adequate rinsing.

How To Prevent Mold And Mildew

Learning about Mold and Mildew

Mold and mildew are terms that are used interchangeably since they refer to the same living micro-organisms. For simplicity we’ll refer to them as molds. Molds encompass a wide range of fungal species that can live on the surface most materials, including wood. They require air, water, and food. Their color is usually white or black, but can be just about any color. If the growth is green, it’s probably a plant-like organism called algae.

The molds that concern us live on wood fibers or even on finished surfaces. Bare green wood is very susceptible to mold growth since the high moisture content provides lots of available water, and the wood’s nutrients are readily available as food. Many types of mold grow on green wood. They vary from black spots to white tendrils (commonly called dog hair). All mold growth MUST be removed before any of our LIFELINE™ finishes are applied.

Use Specialized Cleaners not Bleach

While common household bleach has traditionally been used to remove mold, it should never be used on bare wood surfaces. It is fairly easy to remove mold and prevent their reappearance underneath our finishes without having to use caustic wood-damaging chemicals like chlorine bleach. Wood cleaning products like Wood ReNew™ and Log Wash™ usually do an excellent job when used correctly.

Know Where Mold and Mildew Grows

All of our exterior stains and topcoats contain dry film preservatives that help prevent the growth of mold on the surface of the finish. They do not prevent the growth of mold on the substrate under the finish. That’s why it’s so important to thoroughly clean the surface prior to applying the first coat of stain or primer. Mold spots forming under a finish is an indication that the surface was not properly cleaned during preparation. The only way to remove them is to strip the finish down to bare wood to get at the mold.

Occasionally shaded, warm, moist environments can create conditions so conducive to mold growth that they can overcome the preservative or mildewcide additives contained in the finish.

Prevent Mold and Mildew

One way to handle this type of situation is to thoroughly clean the walls with Log Wash and then apply a coat of Advance™ Clear Topcoat mixed with a Mildew-X additive. Just be aware that the addition of Mildew-X will diminish the reflectivity – or gloss – of Advance Gloss.

A final thought about maintenance of exterior finishes: An occasional wash with Log Wash will help keep the surface clean and mold-free. If needed, a maintenance coat of Lifeline Advance will renew the water repellants, UV inhibitors, and the mildewcides. Cleaning and maintaining your exterior finish will protect the wood and maintain the appearance of your home, including keeping it free of surface mold.

For many years oxalic acid has been one of the most commonly used products for brightening and preparing wood surfaces for a coat of stain. Why? Prior to the introduction of organic solvent finish removers in the late 1990s, the most popular paint and stain removal products were caustic chemical strippers which contain sodium or potassium hydroxide. They are still sold at most paint stores, and although quite caustic and somewhat hazardous, they have been used for over 100 years and are relatively inexpensive.

One negative feature of using any hydroxide stripper is that it’s extremely high pH turns the wood dark. After a hydroxide stripper is used, it is standard procedure to apply a solution containing oxalic acid to the wood to bring the wood back to its original color prior to the application of a stain. That’s how Oxcon attained its original description as a “Blonding Agent.” There is also a belief that since it is an acid, it helps “neutralize” any hydroxide residue remaining in the wood, thus preventing wood fiber degradation due to the presence of highly alkaline chemical residue.

Since oxalic acid does do a good job restoring the color of the wood after the use of sodium or potassium hydroxide, as well as removing metallic tannate discolorations, over the years it gained a reputation as being a “cure-all” for other types of wood discolorations as well. One reason is because many discolorations that were attributed to mold were in fact not mold, but metallic tannate or inorganic stains. Somehow oxalic acid also got a reputation for helping remove grayed or photooxidized surface wood fibers. In reality, it does not do a very good job and there are other products, like our Wood ReNew™, that are much more effective.

If not properly applied, oxalic acid can do more harm than good when it comes to preparing the surface for a water-based film forming finish like Lifeline™. Film-forming water-based finishes rely on the integrity of the surface fibers to assure adhesion to the wood. If the surface fibers are damaged and the film does not have intact fibers to bond to, peeling of the applied finish can result.

We have found in our testing that the use of concentrated oxalic acid, or even a small amount of residual oxalic acid left on the wood, can seriously affect the adhesion properties of water-based finish systems.

Like chlorine bleach, oxalic acid is subject to being easily misused. For example, even when properly diluted to our labeled instructions, if left on the wood too long, especially in hot dry conditions, the water will begin to evaporate and the concentration of the acid solution increases proportionally, eventually reaching a point where damage to the wood fibers can occur. Another potential problem with oxalic acid solutions is that when they react with alkaline compounds, they form oxalate salts which are quite insoluble and almost impossible to rinse off with water. They, too, can interfere with the adhesion of water-based finishes.

Most finish removers that are used today contain organic solvents that don’t darken the wood. Since oxalic acid does not remove grayed wood fibers or organic discolorations like brown stain, blue stain, or mold and mildew stains, what are the valid uses for Oxcon oxalic acid?

1. Oxcon oxalic acid is the only product that removes inorganic discolorations of metal tannates and rust. If, after stripping and cleaning the surface, there are still dark colored streaks or blotches, there is a chance that a solution of Oxcon will remove them. This includes some types of “water marks.”

2. If the stripping and cleaning process has turned the wood dark, a solution of Oxcon may help lighten it up.

To properly use Oxcon here are some guidelines that must be followed:

1. Make sure that any product that was previously applied to the wall has been thoroughly rinsed off prior to the application of the Oxcon solution.

2. Oxcon is a concentrate and MUST be diluted with four parts water. That’s one gallon of Oxcon mixed with four gallons of water. The use of a more concentrated solution won’t work any better and will damage the wood.

3. Don’t leave it on the wood for more than 15 minutes. If it’s a hot, dry day, wet the wall down before applying Oxcon and keep misting it with water to keep the acid concentration from getting too high. Never, ever allow Oxcon to dry on the wood. If oxalic acid crystals form from evaporation, they will be almost impossible to remove by rinsing with cold water.

4. After using Oxcon, adequate rinsing is mandatory. While rinsing, pay particular attention to any cracks or crevices where the Oxcon solution may have puddled. No one should ever use Oxcon without having pH strips at hand. Just a trace of oxalic acid left on the wood will seriously affect the adhesion of the finish.

After reviewing a number of past adhesion issues, we found that many of them were attributed to the use, or more accurately misuse, of oxalic acid. There is no reason to routinely use oxalic acid in a stripping and cleaning process just because it has been done it for years. Only use oxalic acid when it’s absolutely necessary. Sometime less is definitely best.