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Reinforcing a "used" glass cowl

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Old 07-21-2010, 05:53 PM
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SeamusG
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Default Reinforcing a "used" glass cowl

There's always a challenge .

I am refreshing a plane that has a pretty light weight fiberglass cowl. It's a used cowl (home for a 4-stroke) so there's been a bunch of fuel in and around the cowl. I am repainting the cowl white (was painted white / yellow / red). The sanding has been completed and the exterior is ready for "prime" time (pun intended). I've cleaned the cowl several times with dish washing soap and water. The cowl has been cleaned with alcohol too.

What else would you suggest to clean the cowl inside and out?

There are a couple of places on the cowl that the old off-n-on has resulted in some stress cracks - very short cracks starting on an open edge and are maybe, maybe 1/8" (if that). I was thinking of simply brushing on some finishing resin (not epoxy - too brittle) to "help" reinforce the crack areas. I don't have any light glass (.5 - .75 oz. fabric) only the heavy stuff so I'm hesitant to add the heavy stuff as it would make things pretty rigid.

How would you suggest that I proceed to reinforce the cowl?

There are a couple of holes (one too many) for access to the HS &LSneedles. Any suggestions on repairing the "spare" hole? I was thinking that a piece of white Ultracote would do just fine (cowl will be white - of course ).

The more you find out the more you realize how little you really know!
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Old 07-21-2010, 05:55 PM
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Default RE: Reinforcing a

lay glass on the inside of the holes..overdrill holes when done and use rubber grommets to keep vibration down.
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Old 07-21-2010, 05:56 PM
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Default RE: Reinforcing a

OOPS! double post !!!
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Old 07-21-2010, 10:18 PM
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Default RE: Reinforcing a

If you don't have glass, a used dryer sheet works very well
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Old 07-22-2010, 07:54 AM
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Default RE: Reinforcing a

Minn,
Before or after they've been run through the dryer?
Thanks,
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Old 07-22-2010, 08:15 AM
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Default RE: Reinforcing a

Used = after

I epoxy CA hinge material on the inside of the cowl where the screws go through. Its about impossible to elongate holes with that stuff installed, its paper thin so it wont make the cowl stick out and its tough as nails.

Also sealing washers (washer on one side, thin rubber gasket on the other) on the cowl bolts are great for holding cowls and canopy screws. I get them from Ace Hardware or Home Depot.
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Old 07-22-2010, 08:51 AM
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Default RE: Reinforcing a


ORIGINAL: KW_Counter

Minn,
Before or after they've been run through the dryer?
Thanks,
KW_Counter
Oh, you mean you don't want that nice fragrance of a dryer towel blowing in the breeze when you fly? [X(]
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Old 07-22-2010, 08:58 PM
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Default RE: Reinforcing a

Not sure about that dryer sheet idea?

Have you seen the way stuff SPINS in the dryer? I have never seen it recover...
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Old 07-22-2010, 09:03 PM
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Default RE: Reinforcing a

Repair has commenced. SIG has quit supplying .75 oz. glass but Hobbico sells some .75 stuff.

Anew razor blade with the cutting matt made cloth cutting simple. The cloth stayed together a bit better if I laid a piece of wax paper on top. I dabbed Finishing Resin on the backside around the places to be reinforced. Simple to push the cloth into the resin and lightly smooth out. A 2nd coat of both resin and cloth followed after the resin had dried enough to no longer be tacky.

Will it work? Who knows - but it's fun trying.

Oh, btw - never use paint remover that includes "epoxy paint" on things like, um, ah - like fiberglass wheel pants. Oops. But they were really busted up (rationalize, rationalize, rationalize ...)

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Old 07-22-2010, 11:06 PM
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Default RE: Reinforcing a

New coffee filter paper with epoxy works as a filler, too. As does CA hinge material. You have to weigh down the CA material after coating both sides with epoxy. I fold a towel, put a piece of plastic wrap over that, set the cowl in that, glop on some epoxy and the reinforcement piece and then another piece of plastic sheet and a sand bag.

The towel takes up the shape and the sand bag presses the material in tight and removes air bubbles.
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Old 07-23-2010, 09:13 AM
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Default RE: Reinforcing a

Looking good! What will you be painting with?
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Old 07-23-2010, 10:32 AM
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Default RE: Reinforcing a

Going to try a white gloss epoxy paint. I'm going to use the sole remaining wheel pant as a test mule.

Update: the white epoxy paint is very thin so it's going to require several coats and because it's thin it runs very easily. Ijust may look for an alternative - any suggestions?

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Old 07-23-2010, 02:39 PM
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Default RE: Reinforcing a

What do you use to repair - fill - the gel coat?
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Old 07-23-2010, 03:07 PM
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Default RE: Reinforcing a

Im in process of painting a Funtana Cowl. Ive been testing on another cowl....so far this is what ive figured out and am using:

Primer - I used rustoluem ( the 2x coverage kind) in white. Went on easy. I choose to do several VERY LIGHT coats...almost just misting. Then give a few minutes to dry and repeat. Let it dry for 1 week and sand using very fine sand paper.

Using Lustrekote white - Heat the can in hot water for 15 minutes to thin the contents...and again - VERY LIGHT misting coats. Dry for 1 week.

Will use Lutrekote Clear to top.

There havent been any compatability issues with the primer and white.

Spray seems to run very easily if you put too much on. You must spray very very light coats.


I dont seem to be able to see any color mismatch between the ultracote covering and lustrekote spray(both white).

If you'd like, send me a PM. I plan on starting on the actual cowl this week. You can continue working on your frame and I'll let you know how mine turns out and if there are any issues you should be aware of.
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Old 07-23-2010, 03:27 PM
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Default RE: Reinforcing a

Thanks ro - I just talked with a local "consignment" builder / LHS owner. She goes to an automotive paint supply with a sample of the color to match (she's pretty much exclusively Ultracote) and they mix a batch and load it into rattle-can spray cans for her.

The epoxy paint that I used is "appliance" epoxy. It cures in 3 hours. The wheel pant came out with a very high gloss with a very smooth (no orange peel whatsoever).

I'm nearly finished filling the various holes and will give it a "shot" this evening. Oh, I do have a new ShowTime 50 cowl sitting on the shelf. Not gonna mess with this unless some goes really wrong.
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Old 07-23-2010, 08:36 PM
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Default RE: Reinforcing a

Things that I have learned:

    [*]Lite fiberglass (.75 oz.) leaves the cowl flexible but it doesn't have any weight and won't cover holes. Use it for reinforcing cracks or flexible areas[/list]
      [*]3 oz. fiberglass is stiff and works fine for back-filling holes (HS, LS needles, and fuel valves).[/list]
        [*]Finishing Resin makes easy work of filling the weave of glass but it runs - but it sands easier[/list]
          [*]30 min epoxy doesn't run but my particular bottles are way too thick for filling the weave of any weight of fiberglass (guess I need new 30 min epoxy)[/list]
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Old 07-23-2010, 09:06 PM
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Default RE: Reinforcing a


ORIGINAL: SeamusG

Thanks ro - I just talked with a local ''consignment'' builder / LHS owner. She goes to an automotive paint supply with a sample of the color to match (she's pretty much exclusively Ultracote) and they mix a batch and load it into rattle-can spray cans for her.

The epoxy paint that I used is ''appliance'' epoxy. It cures in 3 hours. The wheel pant came out with a very high gloss with a very smooth (no orange peel whatsoever).

I'm nearly finished filling the various holes and will give it a ''shot'' this evening. Oh, I do have a new ShowTime 50 cowl sitting on the shelf. Not gonna mess with this unless some goes really wrong.
They say auto paint is the best way to go, but you come across the problem of having to shoot it yourself. What does she charge you to have it in a can? if I could find it, I would def go this route.

Please show us pics of the epoxy paint job. Sounds like you did a great job. Let us know if its truly fuel proof too!
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