Tips on Strip Planking
Oh no! Not strip planking! I know, time consuming, tedious, messy and inaccurate. Well, let’s try to take most of the work out of this process. The real key to making strip planking a much easier task is the method used to strip the balsa wood into accurate, beveled planking, and the adhesives used.

Cutting accurate strips is best done using a modified balsa-stripping tool. The Master Airscrew balsa stripper is ideal for this job. Glue a piece of ¼-inch-square hardwood to the long edge opposite the cutting blade as shown in the photo below.

Adjust the blade so it just touches the work surface. Adjust to cut strips about ³/₈-inch wide. Wider strips will not develop the shape required of the finished piece. Your first cut will not be used, but will be waste. Flip the strip 180° (end for end) making the following cut on the same edge as the previous cut. Do not turn the sheet over between cuts or the planking will be trapezoidal and thus useless. Strip as many sheets as required to cover the area to be planked.

Start planking on opposite sides of the fuselage and alternate until you meet at the centerline. This will help ensure you do not build in a warp. Alternate each strip plank edge angle to keep the seams between the two as close as possible. Very little filler material will be required when finished.

My favorite method of installing each piece is to place a bead of aliphatic resin (white glue) adhesive along the edge to come in contact with the previous sheeting. Then put medium-viscosity CA adhesive on those parts of the airframe that will come in contact with the new strip plank. Place the strip in place, pressing firmly into the edge of the previous plank or sheet. Wipe excess white glue from the surface with a damp paper towel.

Continue application alternating from side to side, until complete. Cut each piece where it meets the centerline stringer.

After each pass of the stripper, turn the main balsa sheet 180° (do not turn it over). This will result in shape "A." The first cut of the main sheet will look like "B." Use a plank with cut "B" where a flat surface meets a rounded one. All succeeding cuts will look like "A." Be careful not to cut a parallelogram like "C" this plank is useless for precision planking.

Upon completion, rough sand the planked areas to shape. Blow off the sanding dust and apply a lightweight filler material to any voids or gaps. Sand the surface smooth and glass with 0.50- or 0.75-ounce-per-square-yard fiberglass cloth and resin.

These illustrations were taken from a similar article published in Model Airplane News magazine.

The model can now be disassembled and finish sanded and glassed prior to canopy construction and addition of details.

Glassing the Model
This is an area where it seems everyone has his or her own favorite method. If you are satisfied with the way you are accomplishing this task, then, by all means stick to what works for you. If you are unfamiliar with this portion of the hobby or wish to try a different method, the following article is an explanation of how to "glass" your airframe. The article was written by Pat McCurry and was published in the September/October 2001 edition of RC SCALE International magazine.

McCurry’s Way: A step-by-step guide to glassing
Preparation: The key to getting a high quality, fast and lightweight surface of fiberglass onto a model is summed up in one word – preparation. Fiberglass does not cover up or hide imperfections in a balsa wood surface. For this reason it is important to thoroughly fill and sand smooth the entire surface that it to be covered with fiberglass. Once filling is complete, finish sand with 320 grit paper or lighter. Then use a vacuum cleaner or tack rag to remove ALL dust and debris from the surface. This will ensure a good bond of the resin to the surface. Also at this point you need to assemble all the other items you will need for the job so they are at hand when required. These items include rubber gloves, brushes, mixing sticks, plastic spreaders, paper towels and small mixing cups.

Begin by cutting a piece of cloth to cover each item that you wish to glass. You need only to cover one side at a time. For instance, if you are covering a wing, begin with the bottom. For a fuselage, try to cut a piece or two that will allow you to cover one entire side. Cut the larger pieces first and work down to the smaller, this will minimize waste.  The cloth need only be slightly larger than the piece itself as there will be no significant shrinkage. Make sure all cutting of the cloth is performed before you begin to glass. Find a table or space were you can layout all the pieces of the model with the glass (cloth) that you have just cut laying in position and ready to apply the resin. What we are aiming for is to have each section of the model dust free, with cloth in position on top of it so that all needs to be done is to apply the resin. This will minimize the handling of the cloth.

Mixing the Resin: I use Pacer’s "Z-Poxy Finishing Resin" which is a high quality resin with excellent flow characteristics. It requires an equal part of both the hardener and resin for accurate results. Combinations of more or less of one of the parts is unnecessary and thinning is not recommended. As this tend to affect the hardness and curing times. Also, thinning tends to leave resin ‘gummy’ and difficult to sand. If you are in cooler temperatures try to set the individual bottles in a pan of warm water before mixing. This will make the resin less viscous. Typically, epoxy-curing times are affected by temperature and thickness. That is to say it will cure faster in warmer weather and thicker applications. Resin will cure faster in a cup than when spread on to a flat surface such as a wing. For this reason, when mixing resin, only mix an amount that you can work comfortably with for approximately 20 minutes. While the resin will not be cured by this time, this is about as long as the resin in the cup will have the consistency that is best for spreading. For large areas such as a wing, we will mix up only about a third to half a cup of resin. As resin is emptied from the cup, another amount is mixed (in a new cup) and so on. It is far easier to work with in this way.

One of the most common mistakes when glassing a model is to mix up too much resin in the beginning (shortening curing time) and trying to work too large an area or too many pieces at once. By extending the working time you will risk having the resin begin to ‘gel’ on the surface, which leads to dragging of the cloth and an overall mess. Plan on mixing several smaller batched of resin throughout the glassing process. By doing so you will stay ahead of the problems that can lead to an undesirable situation.

Keep it Clean: Besides frequent replenishing of the resin supply, the major ingredient in a great glass job is to maintain a level of cleanliness. Once you are ready to glass and all the cloth is cut and in position on the respective pieces of the model and you have your gloves on, you should get a rhythm that goes like this. Mix a little resin and plan on doing the largest sections first, such as a wing. Depending on the size you are working you may need to mix a second or even third batch to complete the wing.

If you complete the wing just before the resin has cured, take a minute to clean the spreader and your gloves with thinners (acetone works very well). In fact, clean up any tools or surfaces that resin may have dropped on in the process before moving on to the next item to be glassed. Take the glassed wing away from the area you are working in and prepare to continue the process as if you are just starting. When working on smaller sections such as separate ailerons of elevators, you can glass several of these in a row before you need to clean up or mix new resin. Just try to keep in mind that it is easier to mix several small batches of resin than one large one and that keeping your hands and tools clean are very important. I cannot over stress these two points enough.

First set up an area away from the glassing table where you can leave the glassed items once they are done. This will keep the area you are working in from getting cluttered and keep the parts you just glassed from getting knocked over. As mentioned earlier, it is also a wise decision to have all of the parts to be glassed setting with the cloth already in place and ready for resin. By doing this you will minimize the possibility of handling the cloth with resin soaked gloves which could cause a big mess. You want to be able to pick up a piece from underneath, take it to the glassing area, and pour the resin from the cup directly on the surface with very little handling. It is easier to have to separate tables – one for staging the parts and the other for glassing.

Glassing the Model: Here are the steps I use for a light, perfect finish every time.

1. Apply or pour an amount of resin onto the surface (on top of the cloth) in the approximate center of the area you are going to work. It is better to start with too little an amount than to have so much that it begins to run off the edges.

2. Use the spreader to gently pull the resin out onto the surface as if icing a cake. Work one direction then the opposite (alternate). You will notice that as the resin saturates the cloth, the cloth will become transparent. This is an indication that the cloth is fully ‘wetted’ out.

3. Continue to carefully work the resin on the surface. What you want to avoid is pulling resin into holes such as servo pockets and gear wheel openings. Also avoid dragging the resin over the leading and trailing edges. You want to work right up to these points, then wipe the excess back resin back.

4. What we are aiming for here is to saturate the cloth with just enough resin to stick it to the balsa surface and pull rest of the resin away. DO NOT try to achieve a glossy or "coffee table’ appearance.

5. If you run into a situation where you have too much resin and it is beginning to run on you, don’t be afraid to simply wipe it away with a paper towel, you can always mix a little more.

6. With a little practice you will find that pouring small amounts of resin, working it out and then adding more is the proper way, rather than to simply dump a pile out and scramble to keep it from running everywhere.

7. Once you have worked the resin right up to, but not over the edges and various openings you will now need to use the brush to apply the resin. The brush works well to saturate the cloth around leading edges. Simply use it as if painting. For leading edges, I work or ‘paint’ about twelve inches or so at a time and then use a paper napkin to wipe away the excess. When wiping excess, do it in a chord wise or off-the-edge fashion so a not to displace the cloth.

8. When it comes to an opening, use the brush to apply just enough resin precisely where you want it – right up to, but not in the opening. Remember, neatness is a key factor to a great glass job.

9. Continue along with each piece of the model as above and set aside to dry.

10. When fully cured (at least four hours at 75°F), you can now go back to the sanding block and 100 grit to knock away the excess cloth that is surrounding each piece. It does not take much work and you are not trying to sand the model, you just want to clean up the edges so you can apply cloth to the opposite side.

11. When finished, you are going to repeat the steps for the other side of the work piece until all of the wood surfaces have a layer of cloth on them.

Sanding the Cloth: At this point the cloth has a very thin layer of resin over the top of it. So thin, that with just a few hard strokes with an 80 grit sanding block you could easily sand into the cloth. This is what we want to avoid. You will notice that when you run your hands over the surface that you just glassed (when dried) there may be a few spots that need a little smoothing. We want to just knock down these areas slightly with some 220 or maybe even some 320 grit paper. We are not trying to a slick surface yet; we just want to have it smooth enough so that we can apply a ‘flow coat’ of resin.

If there are arrears that have runs, you can attend to these with coarse paper, just be sure not to sand through the cloth. Your eyes and hands are the best instruments to tell when enough is enough. If the cloth begins to turn white, you have sanded too far and should stop. Move on and continue to give the model a light sanding in preparation for the flow coat.

Flow Coat: Basically speaking, the flow coat is the step that seals the cloth and gives you that extra hard surface that we are looking for, whereas the first step is merely to get the cloth adheres to the surface.

The flow coat is applied in exactly the same fashion as the first glassing steps using the same tools and methods. The only difference is we are doing it without any cloth this time – which makes it a lot simpler. Here again, we want to stay neat and not apply so much resin that it looks like a glossy coffee table. All you are trying to do is apply enough resin to fill the weave of the cloth and no more. Also, during this process it is a good time top paint the resin into areas such as wheel wells flight surface pockets where you want to seal the wood in preparation for paint but would not be otherwise able to apply a fiberglass cloth. Continue one side at a time as before until the entire model has a full coat to fill the weave. Set everything aside and let dry completely.

Now you can final sand the model. It’s best to start with 220 and move on up to at least 320 grit paper. If there are any areas that you have accidentally sanded through, you can easily apply a little resin and sand it out.

Priming: The model is now sanded and primed. I choose to use automotive catalyzed urethane primer/surfacer. Check with your automotive paint store to see what is currently available. This primer fills fast and it is lightweight and compatible with all finishes. Mix in accordance with manufacturers recommendations and apply with a ‘trim gun’ at the prescribed air pressure. I like to apply a ‘dry coat’ immediately followed by a ‘wet coat’. When dry, block sand with 320 wet and dry paper. Reapply as needed to low areas. When competed and sanded you will be able to see many areas of the base fiber glassed surface. As long as all imperfections are filled and the surface is smooth those exposed areas will not present a problem and, in fact, are an indication that too much primer (weight) has not been applied.

—Pat McCurry