Post by Sonny on Jan 29, 2005 9:07:31 GMT -7
There are three different filler compounds that I've found will do almost any job of filling and shaping that needs to be done. I'm sure there are others, but these work for me.
1. The Goldberg Products "Model Mate" from Tower is a very light weight, light duty filler, good for minor dents, gouges, pinholes, etc. Sands very easily, dries fairly quickly, and comes in either white or balsa tint.
2. A very good one for approximately the same purposes as the one above, except that I use it for larger, wider filling purposes, because I think it's a bit stronger, is Bondo Glazing and Spot Putty. It's a dull red, and comes in a red and white tube, 4.5 ounces, part # 907. It applies smoother and easier than the Model Mate, sands beautifully with fine grades of sandpaper, and is not affected by water, oil, or gasoline. It's great for small fillets, like at the junction of the vertical and horizontal stabilizers. It's a bit heavier than the Model Mate, but most of it gets sanded off, so it's not a problem with that, at least so far. It dries to sand in less than 30 minutes at 70°. I buy it at Wal-Mart, and it's in the automotive section. Inexpensive, too.
3. For places where structural strength is a factor, the best I have found is "Poly-Fiber Superfil," from Aircraft Spruce and Specialties, part # 09-28250. It's a light weight two-part epoxy filler, and is used in full scale aircraft applications, too. When ready to use, it's a blue paste, and will sort of flow at first, but becomes stiffer in a few minutes, and at that time you can shape it in just about any way you need. The model I'm doing currently has pretty wide wing fillets, and I made most of the structures from this filler. I cut some fillet bases to shape from 1/64 inch ply, and laid them down in position on the wing while it was installed on the fuselage, made some simple concave formers, glued them in place against the fuselage sides and the top side of the fillet bases, and then filled in the whole area between the bases and the fuselage sides with this filler. When fully cured, I took some pieces of dowel, various diameters, wrappped sandpaper around them, and sanded the fillets to a nice contour, and that job was done. 'Course, you need to put some wax paper or thin plastic sheet between the wing and fuselage before you lay the bases down and start gluing and filling, because there may be small cracks or openings between the fuselage and the base, along it's length, and without the barrier, you could find the wing glued to the fuselage in places. Anyway, this stuff is great for small or large repairs and filling jobs, and it's epoxy strong, but light. It sands well, though not as easy as the other two I mentioned. Better than any other epoxy product I've tried, though. It's slow drying. Eight hours to cure, twelve hours for curing to sand, at 77°. The pot life is one hour at 77°. Their catalog is at:
www.aircraftspruce.com
Sonny
1. The Goldberg Products "Model Mate" from Tower is a very light weight, light duty filler, good for minor dents, gouges, pinholes, etc. Sands very easily, dries fairly quickly, and comes in either white or balsa tint.
2. A very good one for approximately the same purposes as the one above, except that I use it for larger, wider filling purposes, because I think it's a bit stronger, is Bondo Glazing and Spot Putty. It's a dull red, and comes in a red and white tube, 4.5 ounces, part # 907. It applies smoother and easier than the Model Mate, sands beautifully with fine grades of sandpaper, and is not affected by water, oil, or gasoline. It's great for small fillets, like at the junction of the vertical and horizontal stabilizers. It's a bit heavier than the Model Mate, but most of it gets sanded off, so it's not a problem with that, at least so far. It dries to sand in less than 30 minutes at 70°. I buy it at Wal-Mart, and it's in the automotive section. Inexpensive, too.
3. For places where structural strength is a factor, the best I have found is "Poly-Fiber Superfil," from Aircraft Spruce and Specialties, part # 09-28250. It's a light weight two-part epoxy filler, and is used in full scale aircraft applications, too. When ready to use, it's a blue paste, and will sort of flow at first, but becomes stiffer in a few minutes, and at that time you can shape it in just about any way you need. The model I'm doing currently has pretty wide wing fillets, and I made most of the structures from this filler. I cut some fillet bases to shape from 1/64 inch ply, and laid them down in position on the wing while it was installed on the fuselage, made some simple concave formers, glued them in place against the fuselage sides and the top side of the fillet bases, and then filled in the whole area between the bases and the fuselage sides with this filler. When fully cured, I took some pieces of dowel, various diameters, wrappped sandpaper around them, and sanded the fillets to a nice contour, and that job was done. 'Course, you need to put some wax paper or thin plastic sheet between the wing and fuselage before you lay the bases down and start gluing and filling, because there may be small cracks or openings between the fuselage and the base, along it's length, and without the barrier, you could find the wing glued to the fuselage in places. Anyway, this stuff is great for small or large repairs and filling jobs, and it's epoxy strong, but light. It sands well, though not as easy as the other two I mentioned. Better than any other epoxy product I've tried, though. It's slow drying. Eight hours to cure, twelve hours for curing to sand, at 77°. The pot life is one hour at 77°. Their catalog is at:
www.aircraftspruce.com
Sonny