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#1
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On Tuesday, April 4, 2017 at 10:18:43 AM UTC-4, wrote:
After removing all the gelcoat, a friend recommended applying a very thin cloth known as Vail to fill most pinholes. We brushed on epoxy and rolled on the Vail, followed with thin peal-ply, then squeegee'd it out with excess resin toward the trailing edges of the wing. Not sure it worked all that well and took two of us 4 hours + $400 bucks for Vail, resin and peal-ply. In some areas (near spoilers), we trapped some resin between the Vail and peal-ply which was full of pin holes! I think the concept is good, but next time I believe I'll skip the Vail and just brush on epoxy and cover it with peal-ply. The resin has got to fill most pin holes and the peal-ply will leave the surface ready to prime. Would like to know what others are doing? JJ Simpler and Cheaper method, used at one of the most well known refinishers in the country: blow stripped wing off very well to clear voids in glass. when filling /priming with 2081 (or your filler of choice), just before spraying, start by mixing up a small batch of filler, and squeegee it onto the wing (or whatever) with a plastic bondo spreader. it fills the holes, improves the bond, doesn't add measureable weight, and the incremental cost is a few cups of filler. |
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...start by mixing up a small batch of filler, and squeegee it onto the wing (or whatever) with a plastic bondo spreader...
The problem I and others have had with that approach is that the filler does not wet out the surface of the pinhole very well. Even though it fills the pinhole, it does not establish a bond with the surface. Often, the pneumatic pressure of the air in the pinhole forces the thick filler back out, so you get only a very shallow fill over the top of the pinhole. As it ages and the wing (or whatever) flexes, the filler is likely to break free from the interior surface of each pinhole. Then the pinholes start mirroring through the finish paint, and eventually might start cracking in a checkerboard pattern. Squeegeeing on a couple quick skims of runny epoxy helps wet the interior surface of each pinhole, and forms a rounded meniscus over its sharp irregular internal contour. Filler sprayed or squeegeed over the epoxy skim has a better surface to bond to, and there is less internal volume in each pinhole for air that repels the filler and impedes the bond. --Bob K. |
#3
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I'm with you, Bob! That's why I think I'd brush on an epoxy coat (maybe squeegee'd) and then peal-ply everything, so she's ready to accept prime without any sanding needed. OBTW........please shoot me if I ever take on another re-finish job! My son and I bid a set of LS-6 wings at $40/hr................we got $25/hr
NEVER AGAIN JJ |
#4
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On Thursday, April 6, 2017 at 5:49:39 PM UTC-4, Bob Kuykendall wrote:
...start by mixing up a small batch of filler, and squeegee it onto the wing (or whatever) with a plastic bondo spreader... The problem I and others have had with that approach is that the filler does not wet out the surface of the pinhole very well. Even though it fills the pinhole, it does not establish a bond with the surface. Often, the pneumatic pressure of the air in the pinhole forces the thick filler back out, so you get only a very shallow fill over the top of the pinhole. As it ages and the wing (or whatever) flexes, the filler is likely to break free from the interior surface of each pinhole. Then the pinholes start mirroring through the finish paint, and eventually might start cracking in a checkerboard pattern. Squeegeeing on a couple quick skims of runny epoxy helps wet the interior surface of each pinhole, and forms a rounded meniscus over its sharp irregular internal contour. Filler sprayed or squeegeed over the epoxy skim has a better surface to bond to, and there is less internal volume in each pinhole for air that repels the filler and impedes the bond. --Bob K. that has not been my experience. it's worked pretty well for me for the last several years, during which time i've done a few dozen refinishes. also, filler seems to be less viscous than runny epoxy. and you can spray right over, immediately afterwards without any sanding. i also believe that it does create a good bond, especially since there is a mechanical bond in there. i have not had any problems with filler pushing back out of the pinholes. in fact, there is a soft of capillary action, and it seems to soak in like a sponge. i remember doing a wingtip that was heavily crazed, by squeegeeing some resin. it was messy, and not so nice to sand afterwards. no question, your method works well, but i think mine does too. there advantages to both. |
#5
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Let me pass on a good trick to deal with Kevlar fuzz. If you accidentally sand into a Kevlar layer, you find it won't sand, it just fuzzes up! We soaked the exposed Kevlar with CA (cyanoacrylate) from the local hobby shop, then hit it with Fix. This left it stiff as a board and simply scrapped most of it off with a sharp razor blade.
Also had raw Kevlar exposed at the trailing edge of flaps and ailerons. These areas must be sealed up or the Kevlar will "wick" in moisture! We got some 1 oz fiberglass tape (1" wide) and 1" peal-ply. Wet it out and wrapped it around the trailing edges, held in place with masking tape orientated for/aft. JJ |
#6
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On Friday, April 7, 2017 at 8:49:33 AM UTC-4, ND wrote:
On Thursday, April 6, 2017 at 5:49:39 PM UTC-4, Bob Kuykendall wrote: ...start by mixing up a small batch of filler, and squeegee it onto the wing (or whatever) with a plastic bondo spreader... The problem I and others have had with that approach is that the filler does not wet out the surface of the pinhole very well. Even though it fills the pinhole, it does not establish a bond with the surface. Often, the pneumatic pressure of the air in the pinhole forces the thick filler back out, so you get only a very shallow fill over the top of the pinhole. As it ages and the wing (or whatever) flexes, the filler is likely to break free from the interior surface of each pinhole. Then the pinholes start mirroring through the finish paint, and eventually might start cracking in a checkerboard pattern. Squeegeeing on a couple quick skims of runny epoxy helps wet the interior surface of each pinhole, and forms a rounded meniscus over its sharp irregular internal contour. Filler sprayed or squeegeed over the epoxy skim has a better surface to bond to, and there is less internal volume in each pinhole for air that repels the filler and impedes the bond. --Bob K. that has not been my experience. it's worked pretty well for me for the last several years, during which time i've done a few dozen refinishes. also, filler seems to be less viscous than runny epoxy. and you can spray right over, immediately afterwards without any sanding. i also believe that it does create a good bond, especially since there is a mechanical bond in there. i have not had any problems with filler pushing back out of the pinholes.. in fact, there is a soft of capillary action, and it seems to soak in like a sponge. i remember doing a wingtip that was heavily crazed, by squeegeeing some resin. it was messy, and not so nice to sand afterwards. no question, your method works well, but i think mine does too. there advantages to both. I've seen some times when trapped air pushes the filler back out of the pinhole to some degree. The reason I went to the roller method is that each individual area gets multiple passes from at least 2 different directions which I have found minimizes this. I also have found that I can get a more uniform surface with the roller than I can with a squeegee. I've done it both ways and still occasionally find that the squeegee helps. Sanding this filler back flat does no new damage to the surface where sanding epoxy is harder and, I have found, more prone to adding more damage. I have not seen any pinhole repairs come back to the surface with this technique. It's worth noting that there are several ways to skin this cat. UH` |
#7
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JJ and Uncle Hank, do you shot PPG Concept right over the polyprimer or do you use a PPG primer also?
Thank you |
#8
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Just redid my wings with Hank. Here is the primer he had me order....
Web address http://www.autorefinishsupply.com/ Product:PCL907-GL PCL Poly Primer White - Gallon |
#9
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On Thursday, April 13, 2017 at 12:39:49 PM UTC-4, Charles Waldo wrote:
Just redid my wings with Hank. Here is the primer he had me order.... Web address http://www.autorefinishsupply.com/ Product:PCL907-GL PCL Poly Primer White - Gallon That is the polyester surface filler. This is followed by epoxy primer when painting with AU, UH |
#10
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I just spot sprayed 3 areas with Concept AU after modifying the root rib area IAW the Salve modification to the Genesis-2. I let the paint cure for 2 days, because parts were sticking out of the shop and I couldn't close the doors to heat the shop (70 day/40 nite). Today I wet sanded it out with 600, then buffed the new paint out with liquid buffing compound (with water) and a wool buffing pad. The 600 scratch marks are completely gone and the paint has a high luster with only one buffing. However, the sanding scratches in the old paint (in the blend area) are quite visible and I was forced to remove them with traditional methods, 800, 1000 then several buffing passes with increased pressure and adding water to the buffing compound to increase the cutting action on the old hard paint.
So, what does this mean? Countless hours can be saved on a complete re-finish job by sanding the paint out while it is quite new and green enough that the 600 scratch marks are completely removed by the cutting action of the buffing pad and compound + water. JJ |
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