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HDW TD ASSEMBLE ABS COWLS AND WHEEL PANTS
Cut some
strips of
heavy (4- to
9-ounce) fiberglass
cloth about
2 inches wide
for the cowl and
about 1 1/2 inches
wide for the
wheel pant;
you'll use them
to reinforce the
seams from the
inside. If the
plastic is somewhat thin, you can fiberglass the entire inside instead
of just the seam. Also have some smaller pieces of cloth handy for
oddly contoured areas and to add reinforcement to mounting holes
or other weak areas. Now lay the strips of cloth into place over the
seams. To simplify this job, spray a light coat of contact cement on
the cloth; this will help hold it in place when you brush on the epoxy.
Mix about 1/2 ounce of slow-curing epoxy in a graduated cup (smaller
batches have a longer working time). Thin the epoxy a little by adding
some rubbing alcohol to it; a thinner mixture more easily soaks
through the cloth and onto the plastic. To apply the epoxy, use
disposable acid brushes; they are easily bent to reach into nooks and
crannies. Apply enough epoxy to the cloth to thoroughly wet it but not
so much that it runs all over the place, and then check for voids; apply
more epoxy as necessary. Work small areas at a time, and then move
to a different section. Allow the epoxy to cure for several hours.
After the putty has cured, roughly block-sand the
filler to shape with 60-grit sandpaper. Check to
see whether any additional filler is needed, and apply as
necessary. Now switch to 150-grit and start to smooth
out and feather the filler into the surrounding areas.
Constantly check the filler for low spots and fill them if
necessary. Because you're using a sanding block, the
putty on the high spots are sanded out while the putty in
the low areas gets left behind. Next, lightly wet-sand the
entire part with 400-grit wet
82 MODEL AIRPLANE NEWS
After the epoxy has cured, trim away any excess cloth. Now the parts
are ready for you to remove the seams and apply the putty. Many
putties are available; most modelers have their favorites. I like to use
3M Acryl-Blue Glazing Putty, available at auto-parts stores. This putty
dries quickly, doesn't shrink and feather-sands nicely. You can also
make a filler paste of epoxy and baby powder. Use an artist's spatula
to apply the putty to the part and smooth it out. Work the putty into the
seam and the surrounding area. I applied tape to one half of the cowl
so I wouldn't put any putty where it isn't needed. Once the putty starts
to set up, remove the tape. Be sure to work in a well-ventilated area!
or dry sandpaper to help remove scratches left behind by the previous sanding.
Just be careful not to sand away the putty. Thoroughly wash the parts to clean
off any finger oils and dust in preparation for priming. Because I covered my
model with Top Flite MonoKote, I used LustreKote primer. Whichever paint system
you use, check its compatibility on some scrap plastic first.
Now that you have primed your parts, they should look just like primed
fiberglass parts. With a little effort, time and basic building skills, you will
have made a cowl and wheel pants that are as durable as fiberglass, and
you will have saved yourself some money in the process. So when your next
kit includes ABS plastic parts, don't chuck them out; build them and amaze
your flying buddies with your finishing skills. ±
LustreKote; distributed by Great Planes Model Distributors Co., P.O. Box 9021,
Champaign, IL 61826-9021; (800) 637-7660; fax (217) 398-0008; www.greatplanes.com.
MonoKote; distributed by Great Planes.
Top Flite; distributed by Great Planes.