Log Home Finishing uses several methods to clean and prepare wood prior to applying finish. To remove an existing finish there are basically three options, pressure washing along with a chemical finish remover, media blasting and sanding the log cabin.
We use the Surface Tek media media blast unit with walnut or corn cob and we usually advise do-it-yourself log homeowners to use chemical finish removers along with pressure washing because the process can be easily accomplished by an average log homeowner and since it is less susceptible to surface damage it results in a more attractive finished surface on the cabin. However, when performed by an experienced log home professional, media blasting can effectively and efficiently remove the most stubborn existing finish from the cabin. We do recommend that you first inspect a log home that has been media blasted before making your final decision about which method of finish removal you want to use.
Log Home Media blasting consists of using corncob grit, walnut shells, glass beads, baking soda, dry ice or recycled crushed glass to abrade the finish off the wood or logs. We prefer walnut since it is very efficient, relatively inexpensive and does not impregnate the log homewith material that can later mold. Plus it is very safe for the environment.
Once a log home has been media blasted there are two steps that are often overlooked but need to be followed:
Step 1. Blow off as much dust and debris from the logs as possible using compressed air.
Step 2. Wash the log wall down with a quality log wash no more than four days prior to staining. It is not necessary to use a pressure washer, a garden hose will do. Clean from the bottom up and rinse from the top down. Rinse well and allow the wood to dry before applying a color coat or Prelude Clear Wood Primer. This removes all of the loose wood fibers and dust that may still be remaining on the surface of the logs and ensures better adhesion of the finish to the logs.
Sanding Log Home
Log Home Sanding can effectively remove an existing finish from logs but it is time consuming and a lot of work. The use of sanding disks rather than sandpaper can save you both time and money but you need to be careful not to create swirl marks in the wood. When sanding exterior surfaces never use anything finer than 80 grit sandpaper or coarse sanding disks.
Water-based film forming finishes require some wood texture for good adhesion, especially on exterior log home surfaces. Osborn Buffing Brushes work great for removing raised wood fibers (feathers) that may have resulted from aggressive pressure washing but they are not suitable for removing finishes.
A sanded log home wall is not clean! Always wash down sanded log home walls with two cups per gallon Log Wash solution no more than four days prior to staining. It is not necessary to use a pressure washer, a garden hose will do. Clean from the bottom up and rinse from the top down. Rinse well and allow the wood to dry before applying the first coat of finish.
Using a Chemical Finish Remover
It is always best to use log finish removers supplied or approved by a log home chemical supply company. Never use log finish removers containing potassium or sodium hydroxide. They disrupt the chemistry of the logs on the log home and can lead to discolorations appearing under the finish on the cabin. Before purchasing any log stain remover be sure to obtain a sample and test it on your existing log staining to see how well it works. Log Home stain removers do not dissolve log finishes, they only soften them enough to allow the log home finish to be removed with pressure washing.
Tools for Log Home Maintenance
Before you start have all of the log home maintennace tools that you will need at hand and be sure that they are clean and in good working order. These may include:
Paint brushes Paint scraper for log home
Stiff nylon brush (never use a wire brush) Airless sprayer*
Wet and dry rags Water hose to clean around log home
Gas powered pressure washer with an output of 2 to 3 gallons per minute (gpm) Tarps
Recommended safety equipment such as eye protection and rubber gloves.
Before you start your log home maintenance project be sure to remove downspouts and cover or mask off any areas that you don't want to strip. Log Home Finish and stain removers will soften both stains and paints for your log home restoration. You may wish to protect the log home window and door trim with plastic sheeting during the log home restoration. If you do get some log home finish remover on an area that you don't want to strip, immediately wash it or wipe it off with a wet rag. If you have a wood deck or porch floor that you want to protect it's best to cover it with a tarp. Although neither S-100 nor Smart Strip is highly toxic to plant life it is best to either cover plants or wet them down prior to starting then rinse them off when stripping is complete.
Application and Removal
Step 1. Thoroughly read the label and be sure to wear the proper safety equipment and eye protection. Starting at the bottom of the log home wall apply the log finish remover with a brush or airless sprayer according to the directions for use. Be sure to follow the directions pertaining to the application rate; if applied too thinly the finish remover may not work and you will have wasted your time and money. Be sure to give the product time to work. On hot dry days work on small sections of a log wall at a time so that it does not dry out.
Step 2. Allow the log home finish remover time to soften the finish. It may take 30 minutes or several hours depending on the existing finish, product and temperature. If you see that the S-100 is beginning to dry, mist it with a light spray of water. For drying Smart Strip apply another coat on top. In colder weather conditions it may take many times longer for the finish to soften than it does in warm or hot weather. On cool days you can apply the finish remover to the entire wall late in the afternoon or early evening and leave it on overnight. Neither S-100 nor Smart Strip will damage the wood or cured Perma-Chink sealant even with prolonged contact.
Step 3. Once the log home finish has softened use a pressure washer to remove the chemical stripper along with the finish. The use of a 15 degree fan tip works well. Start at the bottom of the wall and work up. You don't want to wash away the chemical stripper from those areas you are not ready to strip. Hold the pressure washer wand at a 30 to 45 degree angle from the wall (3A). The objective is to “peel” the softened finish off of the surface, not blast it off with a lot of water pressure (3B). This will help avoid gouging the surface and severe feathering. If there are some spots of remaining intact finish try scraping them off with a paint scraper or a stiff nylon brush before they dry.
Step 4. Once the entire log wall is completed, begin the rinsing process starting at the top of the wall and work your way down. Rinsing off all remaining chemical residue and bits of loose log stain is very important for the long term performance of the new log home finish stain.
Step 5. If after rinsing there are still remnants of old log stain or paint remaining on the log home wall, repeat the process until all of the existing finish is removed. It is not necessary to reapply the stripper to the entire wall. Only use it on those areas that need it.
Step 6. Once the entire log wall is completely bare rinse the entire log home wall starting at the top and work your way down. Allow the wall to dry before making your final evaluation.
Step 7. If pressure washing the wall has feathered the surface you may wish to lightly sand it or use an Osborn Brush to remove the feathered wood fibers. Never use sandpaper or Osborn Brushes finer than 80 grit on exterior surfaces. Sanded or brushed surfaces MUST be washed with a two cups per gallon Log Home Wash solution and the surface allowed to dry before the first coat of finish is applied.
Feathered Surface Brushed Surface
Which is the best way to remove an existing stain from logs, media blasting or chemical stripping? Like most questions of this nature there is no definitive answer, it depends on the log home. Both methods of removing an old log home finish from a log home have their positive and negative attributes and the results depend as much on the competence of the person or persons doing the work as much as the method used. But for the sake of comparison we'll look at the features of each method in order to help you make a more informed decision about which method you choose to use.
Although log home media blasting can be accomplished by a homeowner it does not lend itself well to a do-it- yourself project since it requires the rental of an industrial size air compressor as well as the Media Blaster unit. Although the objective of log media blasting is to strip off the existing log finish or uv damage from the logs it also removes the top layer of wood in the process. Since media blasting can be a very aggressive procedure, in the hands of someone inexperienced with media blasting a lot of damage can be done to the surface of the wood in a very short period of time. That's one reason that media blasting is best left in the hands of professionals who have had some prior experience.
In general we take the position that media blasting should be the last resort rather than the preferred method of removing an existing finish. We often receive calls from homeowners who are virtually in tears after seeing what media blasting did to their beautiful log home. They call us wanting to know what they can do to restore the logs to their original smooth surface. The sad news is that the only way to restore the surface is lots of hand sanding. Of course when properly accomplished by an experienced individual who knows what they are doing, media blasting followed by Osborn brushing can result in a fairly smooth surface. However, this is more the exception than the rule.
Some Advantages of Log Home Media Blasting
•Does an excellent job removing most paints and stains.
•Fairly quick and cost effective.
•Avoids water getting into the home but dry dust and blasting media will most probably penetrate into the interior of the home.
•Since the blasting media consists of either recycled crushed glass or organic materials like corncob grit or walnut shells there is little chance of well or water contamination.
Disadvantages of Log Home Media Blasting
•Media blasting changes the surface characteristics of the wood.
•In addition to roughening the surface it increases the surface porosity.
•Many people consider a media blasted surface unattractive and the only way to restore the wood to a smooth surface is with lots of hand sanding.
•Having enough blasting media on hand is critical. You don't want to run out in the middle of a wall since it may take two or three days to have additional material shipped to your location.
Chemical stripping a log home refers to the use of finish removers used in conjunction with a pressure washer. Since chemical strippers only soften an existing finish they must be used along with a pressure washer to actually remove the finish from the wall. As opposed to media blasting, chemical stripping is much more user friendly since all it takes is a general purpose pressure washer available at most do-it-yourself outlets or equipment rental locations and either our S-100 or Smart Strip Finish Removers. A pressure washer is quite a bit easier to handle than media blasting equipment and although aggressive pressure washing can still do some surface damage, it's fairly easy to fix with a light sanding or an Osborn Buffing Brush.
The main advantage of log home chemical stripping is that the use of proper procedures can result in a beautiful smooth clean surface. So why do some stain manufacturers recommend media blasting over pressure washing? Media blasting logs significantly increases the porosity of the surface thus giving an inferior finish better adhesion since the rough surface gives the finish more surface area to grab onto.
Some Advantages of Chemical Stripping
•Does an excellent job when correct procedures are used.
•User friendly. Takes little expertise and no special equipment is required.
•One wall can be refinished at a time.
•Results in a more attractive surface.
Disadvantages of Chemical Stripping
•Water will get into the home.
•Need to protect plants and shrubs from chemicals.
•May take more than one application to completely remove an existing finish.
•Must thoroughly rinse any applied chemicals before applying finish.
Log Home Finishing LLC has experience in pressure washing, media blasting, and sanding of log homes. Some jobs require all 3 prep steps. If you are thinking of re-staining or finishing your log home it is likely that you will need some of these preparation steps. Log Home Finishing will help you decide what is best for your log home or cabin.