Help with Wheel Pants

[JHildreth]

The attached picture is one of a pair of wheel pants I plan to use on my next plane.  I don’t have any experience using molded wheel pants so I am seeking help on how to mount them.  I am not sure of the origin of these pants.  My best guess is they are from a Brodak Vector 40 ARF, but they are not like the pants advertised on the Brodak web site.  Those advertised are molded fiberglass.  The pants I have are injection molded.

My questions are:

1.   What is the best way to mount them?  The LG is Brodak aluminum struts for profile planes.
2.   How to paint them?  The molded plastic feels sort of rubbery and I am not sure what the initial base coats should be.

Joe

[Mike Alimov]

These wheel pants are supplied with every Vector and SV11 arf /arc, and are made from HDPE (high density polyethylene).  Due to the choice of material, virtually no paint will have chemical adhesion to the surface. However, we've had good results by sanding the surface with 220 grit, spraying Rustoleum primer for plastic followed by Rustoleum high gloss, both rattle can products found at Ace Hardware and such. I believe that paint adhesion was purely due to the texture created by sanding.

[Avaiojet]

I wouldn't use them. Purchase a couple of carbon fiber or "light" fiberglass ones, possibly from another modeler.

Sometimes all they have left is the gear. 

As far as dope, I wouldn't go down that road, but that's me.

One hole won't do it, you need two fasteners to keep them from rotating "if" you want them that stationary/fixed.

Not sure, but I may have a pair of glass pants someplace? Could be a tad heavy seeing they were for R/C.

If interested, measure the ones you have and I'll check. I may have used them to make the pants for the Texaco 13?

[Avaiojet]

Actually Charles, the axle is one of the things that holds the pant in place along with the upper nut/bolt or screw.  I have used Brokak dope on mine and it held up for some time.  Wheel pants do take a beating, especially on the bottom, so the paint does wear off there. I agree that fiber glass or carbon fiber pants will be better.

Yes, Those axle's go back 30 or so years probably more. I may have a few here in unopened packages.

Do you want them?

[Dan McEntee]

I've heard of heating the surface of the plastic with a propane torch before painting. Don't know how it would work on something so small.

   I don't know if "heating " is the correct term to use, but in the printing business this is called "Corona Treatment" (I'm pretty sure) and is used to microscopically etch the surface of plastic materials so that they can be printed on with common printing methods. I worked for two contract over wrapping companies and we used plastic film for wrapping all sorts of stuff, and a lot of it was Corona Treated so that anything from offset types of printing to ink jet printers would work on it. Most often it was either randomly printed with a logo or label, and maybe a registration mark if needed. The treatment was just passing the plastic under a flame at a specific speed during the winding and/or slitting process. I don't know specific temperatures, but I couldn't tell the difference between treated and untreated just by looking at it or by feel. But it did make a big difference when trying to print on it. I worked at a plastic injection molding place for a couple of years recently and we had a small machine called a "Offset Pad Printer" that we used to print logos on plastic pill bottle caps. It had a turn table to hold the caps and it rotated as the printing pad cycled and did it's thing. It had one station that had a small propane fed burner that in effect did the same thing. I never had to mess with that part of the machine so don't know any specifics about that either, but it looked like the end of the smallish flame just tickled the cap surface and it passed by, and again, I could not tell the difference by feel or looking at it but the ink would smear very easily if the burner was not on. If you had some scrap plastic wheel pants to experiment with, you just want to get a solid, but smallish flame established on whatever torch you have and just make a quick pass over the material. allowing the end of the flame to touch the material. I wouldn't expect to see any difference, and test painting would have to tell the tale. Test a piece with out treating and then test a piece after treating it. for our uses it may be more trouble than its worth. But it is a proven concept and process used in industry.
   Type at you later,
    Dan McEntee

[EddyR]

 I would not use them .they are huge and heavy!
Ed

[Avaiojet]

I would not use them .they are huge and heavy!
Ed

And the nut on the end is overkill.

[JHildreth]

Thanks again to those who responded to my recent post about finding this topic.  I thought I would pass on the results of tests I have just completed on painting these wheel pants.

The post by Mike identifying the material allowed me to do a little more research on possible primers.  I found references to four products that seemed likely prospects.

                    Rustoleum Specialty Plastic Primer
                    Krylon CoverMaxx Primer
                    XIM Plastic Bonding Primer
                    Krylon Fusion All-In-One Primer + Paint

The only product that I could find in the stores I tried was the Krylon Fusion All-In-One.  I also decided to give the Klass Kote primer another try thinking epoxy might also work.  I had used the Klass Kote as the first primer coat on my unsuccessful attempt, but I had sanded 95% of it off using the coat primarily as a filler.  In the second test I used it as a 100% coverage coat.

My results are as follows:

     I painted a wheel pant each using the Krylon Fusion primer and the Klass Kote primer.  I let the primers cure for 3 to 4 hours before peel testing with various tapes.

     The Klass Kote Primer adhered slightly better than the dope I was using in my first attempt as I mentioned in my other topic.  It did not peel off when using either regular 3M masking tape or the 3M blue masking tape.  However, the 3M blue vinyl tape peeled the Klass Kote Primer off readily.  I was surprised at this.  I expected the regular masking tape to be the worst case since it seemed to have the most tack.

     The Krylon Fusion product  did not peel off with any of the tapes.  This is very encouraging.  The question now is will the Krylon paint soften or bubble with over coats of the dope colors I will be using.  Since I damaged the primer doing my tests I sanded it all off using 400 wet-or-dry so I can reapply a smooth base coat for the next tests.

     Stay tuned for further results.

Joe

[Tim Wescott]

I wouldn't expect an epoxy paint to reach full strength until 24 hours at the very least, especially if your shop is cold -- you may want to check the directions.  I wouldn't be surprised at 48 hours to a week at cool room temperatures, or maybe an hour or two of baking.

So -- unless the directions specifically say 3 hours at the temperature you were maintaining your shop it's probably not a fair test.

[frank mccune]

        Very good thought Tim!

         Well done,
   
          Frank

         

[Gary Dowler]

Here’s a set of carved balsa wheel pants I made for my Super Chipmunk. Very light. Gear leg stuffs between two small pieces of ply, then a gear strap holds it in place.

[Gary Dowler]

Other side

[JHildreth]

Tim,  your observation about my use of a very short curing time is probably correct.  The time I quoted is based on the length of time that I have found works for sanding purposes between coats.  If I were to try it again I would wait at least 24 hours before doing a peel test.

I have now run the test of spraying a dope based color coat over the Krylon primer + paint.  The dope covered the Krylon nicely and did not cause any bubbles or lifting.  At this point, even if the Klass Kote primer would stick given an appropriate cure time, I would recommend using the Krylon on relatively small parts of this material because of the convenience of using a "rattle can".

Joe