QuickTalk 3 - Q-TIPS
- Category: Q-Talk Articles
- Published: Friday, 30 April 1982 07:11
- Written by Jim Masal
- Hits: 1421
Have trouble keeping your tools clean? 5F5 Nonflammable Paint & Varnish Remover will take off cured epoxy and Bondo. Do not get it on foam! One drop will eat one heck of a hole. This particular product is made by Sterling-Clark-Lurton Corp. of Malden, MA but there must be a similar product available most places. (Pete Bliss, #515).
Carving wheel pants from scrap is the pits. The micro joints are almost impossible to carve nicely. Get together with another builder and buy a block of foam.
Consider making your wing templates out of thin aluminum. Although it sounds like a lot of work, it really isn't. A $7 chassis nibbler (Radio Shack) can be used for the initial sizing if you rough cut the templates to within 1/8". If you're ham-fisted like me and undercut, simply bang the heck out of it with a hammer (expanding the metal near the undercut) and continue. Use a bastard file and sandpaper to finish to smoothness required. Better still, buy a previous builder a case of beer and use his templates.
If you can't get tubing benders, you can still make decent small radius bends by filling the tube with water and freezing. The frozen water will keep the tube from collapsing.
Glue sandpaper to a thin (less than 1/8") wood board or your fiberglass practice piece. This can be used to bevel the wing sections during jigging to achieve the 1/16" max spacing in just a few seconds. Similarly, glue sandpaper to a 3" wide piece of flexible wood or plastic for final fitting bulkheads and gas tank. (Bob Falkiner, Q2-Canada)
Five minute epoxy parts can be transferred to mustard/catsup squeeze bottles for easy measuring of small amounts. Microballoons can likewise be put into the new drip-free spout containers for controlled dispensing.
On large and medium surfaces with easy access (wing, fuselage, etc.), I have used stippling rollers rather than brushes with great success. These rollers are sold in some paint stores in 9" lengths just like paint rollers. The ones we've used to look like a mottled gray, short-napped carpet material, which we cut into 3" lengths for short roller handles. A stipple roller has an excellent ability to pick up epoxy from wet areas and redistribute it uniformly over the entire area. Timesavings is roughly equivalent to the difference between painting your living room with a brush versus a roller. Incidentally, a paint roller is NOT the same and will not do the job. A glue or paste roller can work, but not as well.
To achieve those dozens of micro radii, try a small cheap oil painter's palette knife available in most discount department stores. It lays down a nicer bead than your finger, yet gets into most tight spots. (Jim Masal, #457)
The builder of a kit must not take any given dimension for cloth or other materials as being correct without first measuring them for application on his or her project. Small differences in each aircraft make plans-given dimensions subject to error, sometimes quite large.
Control of temperature within the optimum range for the epoxies used helps a lot in making the layups go easier. The epoxies themselves should be a little warmer than the room temperature to start with each time. Nothing is worse than cold epoxy.
I have found the best tool after the Dremel is the hack saw blade with a special frame for working the blade with a free end. Use very small teeth. (William Deane, #145)
Another way to keep the epoxy and resin at the proper temperature. Use fish tank heaters. They have thermostats, which allow the temperature to be controlled at the optimum. (Jerry Marstall, #2271)
When cutting metal tubes, use a tube cutter, not a hacksaw. This gives parallel sides; especially important when making small spacers.
Rutan updated the instructions (for final finishing) whereas QAC has done nothing at all. After using several quarts of Featherfill and finding that it will NOT fill as per plans, I was advised of Rutan's update appearing in "Canard Pusher" dated July, 1979 and I quote:
"FEATHERFILL: Some builders have not read their newsletters and are still experiencing problems with Feather Fill. This newsletter bulletin supercedes all previous instructions including Section V on finishing. Before attempting to apply Featherfill surface must be dry, dull and clean! A "fog" or "tack" coat (very light coat) of Featherfill should be sprayed or brushed on and allowed to "tack" up for 10-20 minutes. Now mix up a batch of Featherfill (must be thoroughly mixed using a paddle or wire in a drill press) and mix 25%-50% microballoons by volume into the Featherfill. Use a 2" brush, and brush it all over the part you are working on. Allow this to cure thoroughly, then dry sand using new 100 grit and a spline. As soon as you see glass high spots, quit. Again brush on Featherfill/microballoons in any remaining low places, allow to cure and sand with 100 grit and spline. Generally these two applications as described above will be sufficient for all but the worst surface, three applications at the most. You should use 1-1/2 gallons at the most on a VariEze."
I followed these instructions and had no problem thereafter. Cut this out and save yourself some grief. (Ron Thornton, #1014-Canada)
In cutting and handling fiberglass, lay glass cloth out flat and align the fibers in straight lines. Place foam piece at correct angle to fibers on glass. Stick masking tape all around periphery well outside foam item. Cut glass along outer edge of tape. Hold by tape when placing glass down on resin. Tape helps keep glass in shape and fibers straight. Cut tape off after placing glass down before stippling. (Neal Current, #399)
Do you know the proper procedure for the simple act of removing the spark plugs? Always remove the bottom plugs first. (Quickies may have trouble doing this-Ed.) After the bottom plug is out, bring the piston up to top dead center, then thoroughly air blast the cylinder interior through the bottom plug hole. Then remove the top plug and again air blast through the top plug hole. The idea is to blast out any little carbon particles that might be broken loose by plug removal and subsequently get lodged under an exhaust valve head, holding the valve open so that it burns and then sticks open. When that happens, you don't just lose 25% of your power in a four-cylinder engine. You lose closer to 80%
How do you reinstall those plugs after thoroughly cleaning them? Coat (only) the threads with anti-seize compound, then using a torque wrench, tighten them to the recommended torque value. After a few minutes, go back and loosen them and then retorque them. Simply torqueing any threaded object only once is not a valid method. You have to give the metal molecules time to creep a little because whether you realize it or not, metal is a "plastic". That is, it can be formed under pressure. It will yield.
Get in the habit at the end of each flight to check the belly of the airplane for any significant oil streaks. Look downstream of the breather, too. Engine wear raises crankcase pressure, thus expelling more oil vapor. Ring blow-by raises oil temperature and adds combustion by-products to the oil, thus discoloring it faster. Get in the habit also of sticking a paper towel in the end of each exhaust pipe. The color of the soot will tell you if your engine is running too rich or lean. A newly removed spark plug's electrode area will also be a telltale for each cylinder, showing mixture distribution inequities. (stolen from EAA #168 Newsletter)
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