201 Cowling Advise?

[John Mininger]

The top cowling on my 1977 J is going to need some fiberglass work in the not-too-distant future. It has a lot of spyder cracks, and the holes for the Camlock (or in my case, CLoc) fasteners are getting rather enlarged.

I talked to a local aircraft paint shop. They said that it would be a very labor-intensive job. If I’m looking at thousands of dollars anyway, I might consider a Lopresti cowling. But I have no idea what they cost, or if they’re even available anymore.

Anyone have any suggestions?

[EricJ]

I've put thin washers behind some of the fasteners on mine where the holes have gotten a little big.   That works quite well but does require occassional attention to keep the retainers in place.    Or you can just deal with the fact that when you take the cowl off some of the camlocs will fall out and need to be kept separate.    

[PT20J]

I would check with a place that does boat repairs. Check the Service Manual - the fiberglass is supposed to have a fire retardant mixed in.

I seem to recall that Byron @jetdriven did extensive rework on his cowling. Maybe his shop will take it on.

Modworks had an STC for a reinforcement to the center hump. They are long gone, but maybe someone has the details on how to reinforce the cowling.

[Niko182]

Give Brian Kendrick’s a call. He can probably help you, or lead you in the right direction. He does fiberglass repair, but he’s in Texas.

http://www.mooneysupport.com/contact/

[A64Pilot]

Fiberglass is real easy, fire wise it’s a different resin, I don’t think there is an additive, but there may be. Ideally in my opinion use Epoxy it’s worth the little bit of extra money, only downside of Epoxy is you can’t Gelcoat it, but you don’t airplane parts anyway.

A boat guy can do a better job for much less money, it’s what they do every day.

[EricJ]

It's not so much a fiberglass repair as it is that the steel piece embedded in the fiberglass that retains the fasteners gets worn.    To fix that would be a very significant repair job on the cowl.   It can certainly be done, it's just not a small repair.

[N201MKTurbo]

The fire retardant additive is antimony trioxide. You can find it on EBay.

https://www.ebay.com/itm/325420943122?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&mkscid=101&itemid=325420943122&targetid=1529314448590&device=c&mktype=pla&googleloc=9030090&poi=&campaignid=20382379140&mkgroupid=151098995226&rlsatarget=pla-1529314448590&abcId=9316959&merchantid=102015680&gad_source=4&gbraid=0AAAAAD_QDh_uKv_5xwiDj0wQmyYmcR-3I&gclid=EAIaIQobChMI8ZCOzIL_hAMVG8rCBB3KqwgDEAQYBCABEgKp0fD_BwE

[N201MKTurbo]

3 hours ago, EricJ said:

It's not so much a fiberglass repair as it is that the steel piece embedded in the fiberglass that retains the fasteners gets worn.    To fix that would be a very significant repair job on the cowl.   It can certainly be done, it's just not a small repair.

Actually, it isn’t that hard. Just sand down the fiberglass with your air sander and peel it out. You could make a new one out of shim stock. Lay it in and fiberglass it back in place. When I redid my cowl about 15 years ago, I had all 5 strips out and put them back in.

The five strips are one on the top cowl, one on each side of the bottom cowl and two more, one on each side of the prop ring.

[jetdriven]

It’s epoxy, but not all epoxy  is the same. We use MGS . Structural Aircraft epoxy. That’s what specified in the Cirrus repair manual, for example. Hardware store epoxy is about 10% as strong as this stuff and the boat resin fiberglass Polyester MEKP cured stuff from the hardware store is about one percent as strong as this. You might as well use some old bedsheets and some fish, glue and save your customer some money on materials because the outcome is going to be the same. Added Weight and nothing else. 
but if you use MGS and real structural aircraft, fiberglass or carbon fiber, you can make it pretty good repair. I’ll see so many poor repairs on airplanes that come in here with Brown hardware store fiberglass, chop strand mat and resin.