Rock Chips

[JJ Sinclair[_2_]]

I have always hated to do dings & things. Put a dab of paint in a chip and it runs out! This year I tried something new (to me anyway) I placed my left wing on saw-horses with leading edge up, then went along with a little repair kit consisting of a thimble of acetone, a thimble of catalyzed paint, a Q-tip and a tiny 1mm paint brush. At each ding, I wiped it with acetone to remove wax and crud, then dipped my little brush in the paint thimble and put a dab of paint in the ding trying to get about a level amount of paint in there. Then I laid a 1" square patch of wax paper over the ding and held it in place with a 3" piece of masking tape. This kept the paint in place and prevented any runout. Worked slick as a whistle, with most chips disappearing all together. It helps to have the paint as thick as possible (I used AU with 4:1 mixing ratio), then fixed the rock chips with the rather thick paint. After my dings were all fixed, I added 2 parts reducer to the mix and sprayed the wing tips, push-rod exit fairings and a bit on the rood rib area. The sprayed areas had been prepared by filling gouges with Bondo, then body putty in any scratches I could see with a drop lite. Sanded the area to be painted with 220 dry and wiped it down with acetone to remove any wax that survived the sanding. Masked off the area and set my little spray gun with just enough air to atomize the paint, the fan just above zero, and low flow. This reduced the over-spray to almost nothing.
Next day I wet sanded the edge of painted areas with 600 wet and buffed it out a tad. Everything took about 5 hours!
Cheers,
JJ

[FreeFlight107]

On Monday, December 22, 2014 5:21:11 PM UTC-8, JJ Sinclair wrote:
> I have always hated to do dings & things. Put a dab of paint in a chip and it runs out! This year I tried something new (to me anyway) I placed my left wing on saw-horses with leading edge up, then went along with a little repair kit consisting of a thimble of acetone, a thimble of catalyzed paint, a Q-tip and a tiny 1mm paint brush. At each ding, I wiped it with acetone to remove wax and crud, then dipped my little brush in the paint thimble and put a dab of paint in the ding trying to get about a level amount of paint in there. Then I laid a 1" square patch of wax paper over the ding and held it in place with a 3" piece of masking tape. This kept the paint in place and prevented any runout. Worked slick as a whistle, with most chips disappearing all together. It helps to have the paint as thick as possible (I used AU with 4:1 mixing ratio), then fixed the rock chips with the rather thick paint. After my dings were all fixed, I added 2 parts reducer to the mix and sprayed the wing tips, push-rod exit fairings and a bit on the rood rib area. The sprayed areas had been prepared by filling gouges with Bondo, then body putty in any scratches I could see with a drop lite. Sanded the area to be painted with 220 dry and wiped it down with acetone to remove any wax that survived the sanding. Masked off the area and set my little spray gun with just enough air to atomize the paint, the fan just above zero, and low flow. This reduced the over-spray to almost nothing.
> Next day I wet sanded the edge of painted areas with 600 wet and buffed it out a tad. Everything took about 5 hours!
> Cheers,
> JJ

Sounds great JJ, the only thing I would change is to use the acetone FIRST, then sand, otherwise the sanding can grind the wax & crud into the gel coat.

[[email protected]]

JJ is kind of new to this repair stuff. The reminder is important and accurate but he would learn the lesson better by watching all the tiny little paint discs fall out during the summer.

[jfitch]

On Monday, December 22, 2014 5:21:11 PM UTC-8, JJ Sinclair wrote:
> I have always hated to do dings & things. Put a dab of paint in a chip and it runs out! This year I tried something new (to me anyway) I placed my left wing on saw-horses with leading edge up, then went along with a little repair kit consisting of a thimble of acetone, a thimble of catalyzed paint, a Q-tip and a tiny 1mm paint brush. At each ding, I wiped it with acetone to remove wax and crud, then dipped my little brush in the paint thimble and put a dab of paint in the ding trying to get about a level amount of paint in there. Then I laid a 1" square patch of wax paper over the ding and held it in place with a 3" piece of masking tape. This kept the paint in place and prevented any runout. Worked slick as a whistle, with most chips disappearing all together. It helps to have the paint as thick as possible (I used AU with 4:1 mixing ratio), then fixed the rock chips with the rather thick paint. After my dings were all fixed, I added 2 parts reducer to the mix and sprayed the wing tips, push-rod exit fairings and a bit on the rood rib area. The sprayed areas had been prepared by filling gouges with Bondo, then body putty in any scratches I could see with a drop lite. Sanded the area to be painted with 220 dry and wiped it down with acetone to remove any wax that survived the sanding. Masked off the area and set my little spray gun with just enough air to atomize the paint, the fan just above zero, and low flow. This reduced the over-spray to almost nothing.
> Next day I wet sanded the edge of painted areas with 600 wet and buffed it out a tad. Everything took about 5 hours!
> Cheers,
> JJ

'JJ is kind of new to this repair stuff.'

That there is kind of funny!

[Ian[_2_]]

On 23/12/2014 03:21, JJ Sinclair wrote:
> I have always hated to do dings & things. Put a dab of paint in a
> chip and it runs out! This year I tried something new (to me anyway)
> I placed my left wing on saw-horses with leading edge up, then went
> along with a little repair kit consisting of a thimble of acetone, a
> thimble of catalyzed paint, a Q-tip and a tiny 1mm paint brush. At
> each ding, I wiped it with acetone to remove wax and crud, then
> dipped my little brush in the paint thimble and put a dab of paint in
> the ding trying to get about a level amount of paint in there. Then I
> laid a 1" square patch of wax paper over the ding and held it in
> place with a 3" piece of masking tape. This kept the paint in place
> and prevented any runout. Worked slick as a whistle, with most chips
> disappearing all together. It helps to have the paint as thick as
> possible (I used AU with 4:1 mixing ratio), then fixed the rock
> chips with the rather thick paint. After my dings were all fixed, I
> added 2 parts reducer to the mix and sprayed the wing tips, push-rod
> exit fairings and a bit on the rood rib area. The sprayed areas had
> been prepared by filling gouges with Bondo, then body putty in any
> scratches I could see with a drop lite. Sanded the area to be painted
> with 220 dry and wiped it down with acetone to remove any wax that
> survived the sanding. Masked off the area and set my little spray gun
> with just enough air to atomize the paint, the fan just above zero,
> and low flow. This reduced the over-spray to almost nothing. Next day
> I wet sanded the edge of painted areas with 600 wet and buffed it out
> a tad. Everything took about 5 hours! Cheers, JJ
>

I have owned 3 gliders that have been refinished with "2K" polyurethane
("Durathane K" or similar). My "touch up" process has evolved along
these lines:

- Examine and mark the dings so you don't miss any later.

- Clean with acetone. (If you don't get it clean you end up with a
"water mark" stain).

- Sand out dings and clean again.

- Mix a batch of 2K primer with harder (this has a pot life of half a day).

- Touch in the dings with primer and a small brush. Wait about an hour
for it to harden enough not to run, then apply a 2nd coat and even a
3rd, until the primer is built up above the surrounding paint. The same
batch can be used for all of the coats as it drys faster in the thin
layer on the wing than it cures in the pot.

- Wait for the primer to cure. (24 hours to a week).

- Finish with wet and dry, 220 and finer, till the surface is restored.
Note the finish you get at this stage is the finish you get on the final
job. Take time and be careful not to go too deep. It should look like a
new wing, there will just be a grey or yellow stain depending on the
colour of the primer.

- Mask off to catch the overspray. Spray with an aerosol "appliance
white" spray can for a quick repair on the airfield - the repair is
nearly invisible. Spray two or three thin coats. It drys in less than an
hour. Be careful not to get any runs.

- Alternately for a near perfect finish, use 2k white paint and an
airbrush - but that requires airbrush spray equipment, time for mixing,
cleaning and another 24 hours for the paint to cure.

- Sand with 600, 800, 1200, 1500 wet then polish. Sand carefully as the
colour layer is very thin. I use a backing wood piece wrapped in a
chammy with the wet and dry wrapped around that. It sands gently and
evenly but cannot restore any shape. The paint layer is too thin for
fixing contours anyway.

But even if I cut all the corners and use aerosol, it still takes over 5
hours, and at least two sessions!

Ian

[[email protected]]

On Monday, December 22, 2014 7:21:11 PM UTC-6, JJ Sinclair wrote:
> I have always hated to do dings & things. Put a dab of paint in a chip and it runs out! This year I tried something new (to me anyway) I placed my left wing on saw-horses with leading edge up, then went along with a little repair kit consisting of a thimble of acetone, a thimble of catalyzed paint, a Q-tip and a tiny 1mm paint brush. At each ding, I wiped it with acetone to remove wax and crud, then dipped my little brush in the paint thimble and put a dab of paint in the ding trying to get about a level amount of paint in there. Then I laid a 1" square patch of wax paper over the ding and held it in place with a 3" piece of masking tape. This kept the paint in place and prevented any runout. Worked slick as a whistle, with most chips disappearing all together. It helps to have the paint as thick as possible (I used AU with 4:1 mixing ratio), then fixed the rock chips with the rather thick paint. After my dings were all fixed, I added 2 parts reducer to the mix and sprayed the wing tips, push-rod exit fairings and a bit on the rood rib area. The sprayed areas had been prepared by filling gouges with Bondo, then body putty in any scratches I could see with a drop lite. Sanded the area to be painted with 220 dry and wiped it down with acetone to remove any wax that survived the sanding. Masked off the area and set my little spray gun with just enough air to atomize the paint, the fan just above zero, and low flow. This reduced the over-spray to almost nothing.
> Next day I wet sanded the edge of painted areas with 600 wet and buffed it out a tad. Everything took about 5 hours!
> Cheers,
> JJ

I was flying with Dick Johnson at one of his Marfa Wave Camps about 15 years ago. I was looking at some rock chips on my wing and was probably jawing with some other guys about how to go about fixing them. Dick walks up, takes a look, then heads back to his trailer. He's got a mason jar of white stuff in his hand. I think "Wow - Dick is going to share some of his secret go-fast ultra finish sauce with us!". What's in the jar? Latex house paint - but the thick stuff from the bottom of the can. Dick shows me how he uses it on his Ventus - fills in great. He says something about "you guys and your shiny new gliders ..." and wanders back to his trailer. I confess that I still use a variant of the JJ's described method, but Dick's "wind doesn't have eyes, only fingers" way works too, especially for field repairs.

Mike Brooks
XL5

[Muttley]

Good Results with Gelcoat Filler from Plastic Padding. (Always ready Paste which will not drip!!)

[[email protected]]

On Tuesday, December 23, 2014 2:06:58 AM UTC-5, FreeFlight107 wrote:
> On Monday, December 22, 2014 5:21:11 PM UTC-8, JJ Sinclair wrote:
> > I have always hated to do dings & things. Put a dab of paint in a chip and it runs out! This year I tried something new (to me anyway) I placed my left wing on saw-horses with leading edge up, then went along with a little repair kit consisting of a thimble of acetone, a thimble of catalyzed paint, a Q-tip and a tiny 1mm paint brush. At each ding, I wiped it with acetone to remove wax and crud, then dipped my little brush in the paint thimble and put a dab of paint in the ding trying to get about a level amount of paint in there. Then I laid a 1" square patch of wax paper over the ding and held it in place with a 3" piece of masking tape. This kept the paint in place and prevented any runout. Worked slick as a whistle, with most chips disappearing all together. It helps to have the paint as thick as possible (I used AU with 4:1 mixing ratio), then fixed the rock chips with the rather thick paint. After my dings were all fixed, I added 2 parts reducer to the mix and sprayed the wing tips, push-rod exit fairings and a bit on the rood rib area. The sprayed areas had been prepared by filling gouges with Bondo, then body putty in any scratches I could see with a drop lite. Sanded the area to be painted with 220 dry and wiped it down with acetone to remove any wax that survived the sanding. Masked off the area and set my little spray gun with just enough air to atomize the paint, the fan just above zero, and low flow. This reduced the over-spray to almost nothing.
> > Next day I wet sanded the edge of painted areas with 600 wet and buffed it out a tad. Everything took about 5 hours!
> > Cheers,
> > JJ
>
> Sounds great JJ, the only thing I would change is to use the acetone FIRST, then sand, otherwise the sanding can grind the wax & crud into the gel coat.
> Wayne

JJ has taught me a bunch of stuff over the last 15 years or so. He has freely answered anything I asked.
From experience I would advise to do whatever task it is JJ's way first and then decide if there is a need to improve. I predict from experience that this will be rare.
UH