Refinishing ASW24

[youngbl...@gmail.com]

I have been working on the horizontal stab and the two elevators for the past two weeks. I have never seen such difficult gel coat to remove. I am no rookie at gel coat, have done many boats and a bit of glider repair, but this is a beast to remove. It took me six full days to remove the gel coat from the stab. Just today I did one elevator and will do the other tomorrow.
I am bringing it back up with acrylic urethane, so far so good, just a lot of work and a few drinks of rum. Bob

[youngbl...@gmail.com]

On Monday, September 7, 2020 at 5:40:31 PM UTC-4, youngbl...@gmail.com wrote:
> I have been working on the horizontal stab and the two elevators for the past two weeks. I have never seen such difficult gel coat to remove. I am no rookie at gel coat, have done many boats and a bit of glider repair, but this is a beast to remove. It took me six full days to remove the gel coat from the stab. Just today I did one elevator and will do the other tomorrow.
> I am bringing it back up with acrylic urethane, so far so good, just a lot of work and a few drinks of rum. Bob

Correction, a lot of rum

[markm...@gmail.com]

What are you using to remove the gel coat?

If using sandpaper, consider switching to Abranet in a fairly coarse grit. It doesn't clog up like regular sandpaper and lasts a REALLLY long time.

[youngbl...@gmail.com]

On Monday, September 7, 2020 at 5:55:34 PM UTC-4, markm...@gmail.com wrote:
> What are you using to remove the gel coat?
>
> If using sandpaper, consider switching to Abranet in a fairly coarse grit. It doesn't clog up like regular sandpaper and lasts a REALLLY long time.

Mark, I have thrown everything at it except dynamite, I am making progress, slow as it is , it will be very nice. I did Abranet in very course grit, just had to try most everything. Finally made some progress with some material from a local boat manufacturer, it did much better. I have built back up the stab and a final sanding before applying the urethane. I might try the rudder next and then move on to the fuselage. The wings are very good, even after a good sanding and hard wax. My wife flies this old girl most of the time, but I do get in it from time to time, it is a great flying glider.

[John Sinclair]

Removing gelcoat is a real bear, but it shouldn’t take that long! We use an electric DA, like RIDGID with 60 grit pad to remove 50% Down to where the underlying cloth starts to show. The remaining gelcoat is much softer. Works best on flat surfaces like the a stab.
Be very careful on concave surfaces like the underside of the elevator. If memory serves me, it should take something like 24 hours to completely strip a 15 meter bird.
Hope this helps,
JJ

[markm...@gmail.com]

Specifically, are you using just plain old manual sanding or are you using any sort of power sander? And yes, power sanders can be way too "enthusiastic" and cause significant damage to the top epoxy layer if you slip up and/or lose your focus and concentration.

[youngbl...@gmail.com]

60 grit is like using Charmin on the underside! This thing laughs at 36 grit, and yes the electric tools have been used, Mirka 40 wet does a bit of removal.

[John Sinclair]

We have found that 36 grit mostly rides on top, but 60 grit is fine enough to start removing the top hard coat and get down to the softer underlying stuff. Dual action (DA) is a must and it greatly reduces the risk of digging in.

[youngbl...@gmail.com]

I have used many Abranet grit pads and custom made blocks. The best so far is the Mirka 80 with the cushion pad beneath the Adranet pad, this is used in a very slow rotation of the sander, speed seems to cut less than a slower rotation. Speed also increases your risk of gouging and also heats up the surface much to my dislike. Fiberglass Supply Depot in Ft. Pierce , Florida has the best supply of abrasive supplies and tools one would ever need, check them out online, great people and huge supplies of products. Bob

[uncl...@earthlink.net]

80 grit has more rocks in contact and, from my experience, gives a quicker and better result. I use random orbital and Mirka Gold 80 grit sticky back paper with soft backing pad.
"there must be an easier way".
Nope
Stick with it Bob.
UH

[Neal Alders]

I recall UH years ago telling me sanding German sailplane gel coat is like trying to smooth out a piece of jagged granite with wet toilet paper.

Never forgot that one. LOL

[youngbl...@gmail.com]

On Monday, September 7, 2020 at 5:40:31 PM UTC-4, youngbl...@gmail.com wrote:

> I have been working on the horizontal stab and the two elevators for the past two weeks. I have never seen such difficult gel coat to remove. I am no rookie at gel coat, have done many boats and a bit of glider repair, but this is a beast to remove. It took me six full days to remove the gel coat from the stab. Just today I did one elevator and will do the other tomorrow.
> I am bringing it back up with acrylic urethane, so far so good, just a lot of work and a few drinks of rum. Bob

Scales tell the tell of the removed gelcoat. Before weight of the stab with the elevators removed was 11 pounds 13 .8 oz. after removal of the gel the weight was 10 pounds 12.8 oz or a net loss of 1.lb, are you surprised??
The elevators weighed 1.91 and 1.95 respectfully, left and right. after removal of the gel the weights were 1lb 6.9 oz and 1 lb 7.0 oz. I have completed gel removal on the stab and elevators and are now rebuilding the surfaces. Only used two boxes of band-aids on my fingers and drank two bottles of good Cuban rum.

[markm...@gmail.com]

Only used two boxes of band-aids on my fingers and drank two bottles of good Cuban rum.

So, can we assume that the R/B ratio of one bottle of rum to one box of Band-Aids can be used as a measure of performance? Try three bottles of rum and report back with the results. If you end up needing a tourniquet, please let us know.

[youngbl...@gmail.com]

On Tuesday, September 8, 2020 at 9:14:39 PM UTC-4, markm...@gmail.com wrote:
> Only used two boxes of band-aids on my fingers and drank two bottles of good Cuban rum.
> So, can we assume that the R/B ratio of one bottle of rum to one box of Band-Aids can be used as a measure of performance? Try three bottles of rum and report back with the results. If you end up needing a tourniquet, please let us know.

Mark, the ratio is consistent with the measure of pain! I liken this ordeal to a couple of other projects that I have tackled in the past, I basically said to myself ,"What the hell did I do this for". The tourniquet suggestion is a great idea, not sure that it would stop the flow, but certainly would prolong the suffering.
On to the next step in this ordeal, will be building back up with filler and primer and on to the final coat or two or three of acrylic urethane then sanding down to 3000 grit and buffing, I might need more rum.

[Charlie M. (UH & 002 owner/pilot)]

On Tuesday, September 8, 2020 at 12:12:37 PM UTC-4, neala...@gmail.com wrote:
> I recall UH years ago telling me sanding German sailplane gel coat is like trying to smooth out a piece of jagged granite with wet toilet paper.
>
> Never forgot that one. LOL

I heard the same thing from the same person over 40 years ago.....I tend to stick to final sanding and polishing.....

[Richard Pfiffner]

If a low number grit does not easily take off the hard finish use a finer grit until it cuts easily then move to a 80 or 65 grit. An electric grinder with adjustable speed is what I have used. In my opinion an orbital is not needed. Use no pressure on the sander let the paper cut.

http://www.craggyaero.com/ventus.htm

Richard
www.craggyaero.com

[Colin Roney]

Rum? Can`t stand it. It`s like drinking liquid rubber. Why not try a good
Scottish single malt whisky. Your working progress will benefit.

At 02:05 09 September 2020, Richard Pfiffner wrote:
>On Tuesday, September 8, 2020 at 6:30:53 PM UTC-7, youngbl...@gmail.com

>wro=

>te:
>> On Tuesday, September 8, 2020 at 9:14:39 PM UTC-4, markm...@gmail.com

>wro=

>te:
>> > Only used two boxes of band-aids on my fingers and drank two bottles

>of=

> good Cuban rum.
>> > So, can we assume that the R/B ratio of one bottle of rum to one box

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> Band-Aids can be used as a measure of performance? Try three bottles of

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>m and report back with the results. If you end up needing a tourniquet,

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>ase let us know.
>> Mark, the ratio is consistent with the measure of pain! I liken this

>orde=

>al to a couple of other projects that I have tackled in the past, I

>basical=

>ly said to myself ,"What the hell did I do this for". The tourniquet

>sugges=

>tion is a great idea, not sure that it would stop the flow, but certainly

>w=
>ould prolong the suffering.=20

>> On to the next step in this ordeal, will be building back up with
filler

>=

>and primer and on to the final coat or two or three of acrylic urethane

>the=

>n sanding down to 3000 grit and buffing, I might need more rum.
>
>If a low number grit does not easily take off the hard finish use a finer

>g=

>rit until it cuts easily then move to a 80 or 65 grit. An electric

>grinder=

> with adjustable speed is what I have used. In my opinion an orbital is

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[youngbl...@gmail.com]

Thanks for the suggestion Colin, I could never forgive myself for drinking Scottish Whiskey, I would be contributing to the Kennedy dynasty and for that I could never forgive myself. Rum is much better, we call it the juice of the Caribbean gods, many a pirate sailed these blue waters while indulging it that fine roasted sugar cane fermented nectar. I will keep your suggestion in mind just in case the rum gets too depleted. Bob

[dtarm...@gmail.com]

I think he meant, use the Scotch to strip the gelcoat. That might work...

[Martin Gregorie]

Do the Kennedy Clan still have dibs on that post-Prohibition money-
spinner? Enquiring minds want to know.


--
Martin | martin at
Gregorie | gregorie dot org

[Martin Gregorie]

On Wed, 09 Sep 2020 08:27:30 -0700, dtarmichael wrote:

> I think he meant, use the Scotch to strip the gelcoat. That might
> work...

Scotch is a bit smooth for that: use Hokonui, a bootleg spirit that used
to be (and maybe still is) brewed and distilled in the deep south of the
South Island, NZ. Rough as guts, traditionally sold in brown glass beer
bottles with a label showing an atomic mushroom cloud. It'll strip
anything, not just stomach linings.

[Chip Bearden]

What UH said. He allowed me to supply a huge number of hours of work when we refinished my ASW 24 a few years ago. With two guys in the workshop (sometimes three), it was actually enjoyable sanding and talking soaring. But it takes a long time. I'm sure there's an easier way but I haven't talked to anyone over the years who's found it.

I recall there were spots--areas, actually--especially on the fuselage, where the gel coat just seemed a lot harder to sand than in other spots. And it was unrelated to whether it was over a seam where you would expect to encounter a slightly different gel coat/hardener ratio. Maybe it was where the factory had patched defects in the gel coat coming out of the molds?

One other thing--and I'll defer to UH and JJ on this--is that I wouldn't have started with the stab and elevators. The elevators and ailerons were the touchiest surfaces for me to sand, both removing old gel coat and finish sanding PU. The narrow chord combined with slightly concave surfaces meant it was really easy to sand through. And, of course, due to weight/mass balance considerations, we couldn't just spray on a whole bunch of stuff and sand some of it off. The sharper leading edge of the stab and the tight compound curves around the fairing for the rudder are a little fussy, also.

I had done some contouring/profiling on wings in previous years but was otherwise a rookie. If I were approaching it again, I would do it the way UH did. The first winter we did the fuselage (sans horizontal tail). The surfaces were big and relatively easy to sand and the consequences of slight imperfections were smaller. The compound curves, especially on the forward fuselage, were less of a problem than I had thought. In all, it was a good project on which to learn some technique.

The next winter we did the wings and tail. We were very careful with the wings because I think I have a "good" '24 and didn't want to have that little edge disappear in the dust. So we pulled leading edge templates from one wing and used those when applying the filler/primer. UH also wielded the grinder when we did the "B" leading edge mod and then we used templates to profile the outer portion of the wings where that applied (the leading edge is less sharp on the ASW 24B on the outer wings).

Sanding the big surfaces--fuselage and wings--went faster than I thought. My biggest mistake was not wanting to swap in new sandpaper often enough. It was still cutting but just not as fast. UH will laugh or be moved to tears for all the times he encouraged me to change paper and I declined. :)

It was a therapeutic, educational, and rewarding experience. And the glider still goes great and looks like new. We even did a few upgrades: e.g., UH's fuselage vent and filling in the factory water dump ports on the wings.

Chip Bearden
JB

[youngbl...@gmail.com]

Martin, I do believe that the Kennedy clan still gets royalties on every bottle of Scotch whiskey imported to this country. Just recently a Kennedy was finally defeated for political office in Mass, what took those people so long. Maybe that Kennedy could come on down and help sand gelcoat now that he is out of work.

[John Sinclair]

Roger on changing sanding pads often .........they’re expensive, but nothing compared to what the labor is costing. Also a good idea to weigh the controls before starting and check and record the trailing edge weight (balance). Easy on the prime and paint on all control surfaces. I have had to sand off and repaint controls that didn’t check out after painting. Use a respirator when spraying AU! If you smell the stuff, your killing brain cells!
Enjoy!
JJ

[Martin Gregorie]

:-)

[youngbl...@gmail.com]

Chip, the therapeutic part of this comes from me not listening to the wife complaining about not being able to fly her glider. The educational part derives from my approach to spending more time doing things than required, but they are done correctly. The rewarding part of this ordeal is that I know P1 would be happy to see the old girl looking great again.

[Chip Bearden]

Agreed, JJ, although UH might argue that my labor cost was pretty low. Or high, depending on whether he still recalls what a PIA I was worrying about tinkering with the airfoil. :)

We took it VERY easy on the control surfaces and actually came out a little to the good, IIRC, when measured against factory specs. The downside was more than one sand through. IIRC, he finally finished off the last elevator and winglet when I was at my real job one day rather than take a chance on another sanding/spraying/sanding cycle with me on the job! My hat is off to you guys who do/have done this full time. It's a huge amount of work and a few seconds of inattention can result in hours more.

UH did the spraying but I hung around to watch a bit. Respirator, of course, and he was wearing the full positive pressure treatment. I also wore a pretty effective dust mask when dry sanding (old gel coat). I had one left over that I tossed in my toolbox. When the 'Rona first hit, I went downstairs and checked: sure enough, N95. I haven't been able to find any more since then, though.

My one physical effect was "trigger finger" from clutching sandpaper on rubber sanding blocks with all the finish sanding I did. It took over six months to go away from the fingers of both hands.

JB

[Papa3]

Now on my fourth refinish project in a club environment, I'll just say that it's an acquired taste. The fun part doing it with a club is that you can sometimes enlist lots of help. Our record is 10 (ten! ) RO sanders all grinding away at once on a pair of Grob Twin wings. Makes fast work of a really nasty project. The downside is managing "free" labor. You pretty quickly identify three sub-groups:

- Those who get it. A few minutes of dual and you're okay letting them work more-or-less independently until a new skill is required.
- Specialists. They lose interest in the boring stuff, but they can be counted on to spin a wrench or work on tricky sub-projects (like divebrake caps or control surfaces).
- Gophers. These are the ones who really want to help, but end up creating twice as much work with sand-throughs, flat spots, or destroying equipment. I assign them critical tasks like going to get lunch/beer or making hardware store runs.

Speaking of which... off to the shop tomorrow or Friday to put a couple coats of primer on LS3 Flaperons. Now there's a crazy-ass piece of work...

P3

[stephen...@sympatico.ca]

> Now on my fourth refinish project in a club environment, I'll just say that it's an acquired taste.

> P3

If you can taste it, your mask is on wrong!

[youngbl...@gmail.com]

Well the end is in sight, I am spraying the final coats of primer and sanding down to a super smooth and blemish free surface prior to spraying paint. I should be finished this weekend and work toward balancing the elevators and then on to sealing and a final check. I am trying to find the balance specs on the 24, if anyone has them it would be greatly appreciated. Bob

[uncl...@earthlink.net]

Elevator Mass- .64 to .79 kg
Elevator moment- 1.4 to 1.8 kg-cm
Section 5.4 of maintenance manual
UH

[youngbl...@gmail.com]

I did a pre paint balance evaluation and things looked very good. I concluded that by applying the paint I will be within the good margin. I did spray the topcoat of paint and tomorrow I will re check to determine my precise number. Thanks for the info. Bob

[youngbl...@gmail.com]

I am right on the numbers, these elevators turned out beautiful, maybe the best paint job that I have ever done. My friend at the gliderport told me they shined like a diamond in a goat's ass, wow, that must be really good, just wait until they are polished. Bob

[2G]

What paint and equipment did you use?

Tom

[youngbl...@gmail.com]

Tom, I did things a bit differently, I have restored many antique cars and have worked with many paint and filler systems. Acrylic urethane is the only way to go, because of many properties of the chemistry and the ability to repair, buff, and durability. I do like epoxy primer as my second coat, a good filler prior to the epoxy primer is a must, it really helps the finish process. Once you get down to the fiberglass , after the removal of all the gel coat it would benefit you to seal the surface prior to the epoxy primer, I found this out the hard way.
The process continues until you have bloody fingers from sanding and sanding and sanding, I am very critical of my work, so I might just expect more than some. Spraying Acrylic Urethane is not difficult, just time consuming and once yo have learned the tricks of the paint you will develop your own application methods that work well for you.
My preference for paint is Nason, 2k single stage, it if from Axalta, or previously Dupont. Don't get too hung up on different paints, there are only about three manufactures that make them all. Transtar 2 in 1 primer filler is a great product, works well and compatible with most all paints.
Mika abrasives are very good, I even used them wet with great results. I tried many combinations of abrasives and found that each has a special need. Do not be afraid to tackle your own projects, you may be surprised at your finished product. Bob

[youngbl...@gmail.com]

On Monday, September 7, 2020 at 5:40:31 PM UTC-4, youngbl...@gmail.com wrote:
> I have been working on the horizontal stab and the two elevators for the past two weeks. I have never seen such difficult gel coat to remove. I am no rookie at gel coat, have done many boats and a bit of glider repair, but this is a beast to remove. It took me six full days to remove the gel coat from the stab. Just today I did one elevator and will do the other tomorrow.

> I am bringing it back up with acrylic urethane, so far so good, just a lot of work and a few drinks of rum. Bob

After countless hours of removing gel coat and filling , priming, sanding, sanding, sanding and then painting only to sand down, repaint and sand to 3000, I have finished! The scotch did not budge the gel coat, my fingers need rest, and my spray gun is finally clean again. I spent the last day buffing and doing a bit of sanding and buffing again. Now comes the fun part, putting it back together so my wife can have her ASW24 back.

[Dan Marotta]

How about posting some pictures, Bob.  Of the '24, not you... :-D

Dan

--
Dan, 5J

[youngbl...@gmail.com]

Dan, let me see what I can do, Eileen is nagging me to death about not being able to fly her 24. Just today she told me that I should re surface the entire glider, I need more rum. Bob

[Colin Roney]

I humbly stand corrected! Clearly the `Juice of the Caribbean Gods`is far
superior to a rotten old Scottish Malt Whisky. Sounds like you`ve achieved
the impossible. Well done. I presume the glider is now up for sale.

At 22:20 20 September 2020, youngbl...@gmail.com wrote:
>On Sunday, September 20, 2020 at 4:18:06 PM UTC-4, Dan Marotta wrote:

>> How about posting some pictures, Bob. Of the '24, not you... :-D=20
>>=20
>> Dan
>> On 9/20/2020 2:09 PM, youngbl...@gmail.com wrote:=20

>> > On Monday, September 7, 2020 at 5:40:31 PM UTC-4,
youngbl...@gmail.com

>=
>wrote:=20

>> >> I have been working on the horizontal stab and the two elevators for

>t=

>he past two weeks. I have never seen such difficult gel coat to remove. I

>a=

>m no rookie at gel coat, have done many boats and a bit of glider repair,

>b=

>ut this is a beast to remove. It took me six full days to remove the gel

>co=

>at from the stab. Just today I did one elevator and will do the other

>tomor=
>row.=20

>> >> I am bringing it back up with acrylic urethane, so far so good, just

>a=
> lot of work and a few drinks of rum. Bob=20

>> > After countless hours of removing gel coat and filling , priming,

>sandi=

>ng, sanding, sanding and then painting only to sand down, repaint and
sand

>=

>to 3000, I have finished! The scotch did not budge the gel coat, my

>fingers=

> need rest, and my spray gun is finally clean again. I spent the last day

>b=

>uffing and doing a bit of sanding and buffing again. Now comes the fun

>part=

>, putting it back together so my wife can have her ASW24 back.

>> --=20

>> Dan, 5J
>
>Dan, let me see what I can do, Eileen is nagging me to death about not

>bein=

>g able to fly her 24. Just today she told me that I should re surface the

>e=

[youngbl...@gmail.com]

Colin, I am so glad that you have been transformed from that old nasty scotch whiskey to the juice of the Caribbean Gods..
The 24 is not for sale, it belongs to my wife and I would never be allowed in the house again if I sold her favorite glider.