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Hockeystud87
09-10-2018, 11:04 AM
My KF got a little hangar rash (Sorry Grandpa) and I'm wondering what options there are to touch up the paint?

If I paint over it will it blend well or is it going to be obviously touched up?

30 year old paint but still looks sharp.

ddalme
09-10-2018, 11:34 AM
the only way to know is to do it-might have to mix up several times to get the right shade

Hockeystud87
09-10-2018, 12:52 PM
the only way to know is to do it-might have to mix up several times to get the right shade

I'm just worried there won't be any way to match cause the paint will have been faded. I guess you just lighten it up.

Dave S
09-10-2018, 12:54 PM
Al,


Other than matching the potentially faded color, the big issue will be exactly what kind of paint was used. If you have polytone - count your blessings as is can be feathered and blended well. Extra points if you have the polyfiber manual in that case as it covers repairs quite well.



If it is urethane - it's hard to do a partial panel and get it to look right because the urethane polymerizes on curing and does not re-dissolve in the solvents for a good blending.


One way to figure out if you have polytone is to dampen a rag with MEK and wipe on some small hidden area you won't notice - lacquer thinner will likely work too. Polytone will dissolve on the rag and urethane will not.

avidflyer
09-10-2018, 03:29 PM
Even quicker way to look for poly fiber is look at the inside of the fabric. If it's pink, you are seeing the first poly brush coat. Poly brush can come in clear as well, but I don't think it's used very often. I think the MEK will desolve the Randolf's finishes as well. JImChuk

rosslr
09-11-2018, 02:22 AM
and if it is Polytone, and a colour (other than white) you wil need to use white first I believe, as a base for any colour. Polyfibre manual explains it all.
r

aviator79
09-11-2018, 05:00 AM
Even quicker way to look for poly fiber is look at the inside of the fabric. If it's pink, you are seeing the first poly brush coat. Poly brush can come in clear as well, but I don't think it's used very often. I think the MEK will desolve the Randolf's finishes as well. JImChuk

True, but Poly Fiber often has a urethane top coat, so you still need to know what's on top before you spray it.

If the rash isn't too bad, you might be able to touch it up with a brush and unthinned or minimally thinned paint. If it's urethane, there's really no good way to make an invisible repair without painting the entire surface. If it's not a show plane though, you can make it good enough. One way is to "back mask" the area to be painted. On each side of the repair area, cover THE REPAIR AREA with masking paper and tape the edge. Then fold (but don't crease) the masking paper away from the repair area so that instead of a hard line , your mask line is curved away from the surface. This will make a soft feathered edge around the area.

fastfred
09-17-2018, 08:45 AM
This question is also a fabric repair question.
I noticed on my plane there several air bubbles in the fabric over the fuel tank. Some as large as 6 inches in diameter . Has anyone ever seen this and can it be repaired? I has always been hangered

Esser
09-17-2018, 09:54 AM
I think so most planes are covered and painted ona rotisserie they can Take a slightly different shape when mounted to the plane. Hit it with an iron with Teflon paper and see if you get the bubble down. You could take a large gauge syringe and try to inject some poly brush underneath it first too

aviator79
09-17-2018, 11:15 AM
Maybe a small hole to let air out, and then an iron like Josh suggests. The iron might mar the finish, but you could then repair the finish. I would probably not inject polybrush underneath it on top of the fuel tank. Being underneath the top coat, the solvent won't have anywhere to evaporate to, and you might actually make the bubble worse.

Full disclosure: I'm not a covering expert; I'm just thinking about what I might or might not do. Rather than taking my advice, you should probably call Consolidated Aircraft Coatings and ask them. I called them for tech support once and they were very helpful.

fastfred
09-17-2018, 11:29 AM
I will try that/

Tomfox
07-27-2019, 01:49 PM
I have recently noticed fine bubbles and paint softening around my right fuel tank - some in center and some in edges of tan. This is on top. I followed the poly manual painting. Are there any ideas on the cause. I took a pic but am not sure how to attach it to this message. There it is
Tom Livermore Kitfox S7 Supersport22800

Dave S
07-27-2019, 02:53 PM
Tom,

At first thought - it looks like some sort of agressive solvent dripped on the surface. What makes me think something dripped n the top is the tapes look to be unaffected/not lifted.

Probably only two possibilities - something either dripped on the top or soaked up from underneath.

Questions - 1) Polytone or aerothane?
2) Is this directly over the tank top or off to the side of the tank over the wing void?

BTW - looks like you did a good job on the tapes - the pinked edges are stuck down well like they should be.:)

Tomfox
07-27-2019, 03:39 PM
It is poly tone/ poly brush etc.

There are several spots. Some are right at the tank edges ( picture is at the rear edge of the tank), but then there are some spots in away from the edge toward the tank center. It is only the right wing.
There are some edge spots up the sides of the tank also. It is only in the tank area, not over the wing void.

My first attempt at repair will be to wipe spots clean down to fabric with with MEK , then redo all coats including silver of course. Comments?

is it possible that I did not put adequate poly brush on before fabric and this is the tank bonding glue doing this? Your comment on top down attack would negate this - good thought though.
or perhaps I spilled a lot of fuel (I use auto gas and 100LL) and it got trapped and caused this?

Thanks
Tom

Dave S
07-27-2019, 04:06 PM
It is poly tone/ poly brush etc.

My first attempt at repair will be to wipe spots clean down to fabric with with MEK , then redo all coats including silver of course. Comments?

is it possible that I did not put adequate poly brush on before fabric and this is the tank bonding glue doing this?
Tom

Tom,

I think your approach to the repair is perfect. One of the beauties of having polytone is the ability to do this on a spot repair. It is apparent you have studied the Poly Fiber manual well.

The process of dissolving off the top coat and intermediate coats may reveal what is going on if it is coming from underneath (or not). Also possible that the cause might not be apparent either. If it looks good underneath - should be fine with the repair.

The fact that only one wing is affected might indicate that the tank bonding glue might not be the source - the stuff cures pretty well in a fairly short amount of time.

After your repair, one of two things should happen - either it will be stable and remain as it should (which is what a person wants) or the problem may repeat itself (hopefully this won't happen).

Wishing you good luck with the repair.