rambo

My Feedback: (1)

I've advertised for a replacement cowling for my no longer produced hanger 9 cap 232 120 size plane,but so far no results.My question is this,I have a cowling but someone cut holes for engine in wrong place plus has cracking in some areas.Is there any way to repair it without adding a lot of weight?If theres a article on the subect please advise me.I've been into this hobby for better than 25 yr's but this would be my first real attempt at fiberglass work except on glassing wing centers etc.Thanks

Ed Smith

If the cowl is manufactured from epoxy or polyester resin then epoxy resin can be used for the repair. If the cowl is made from polyester resin then polyester resin must be used for the repair. Most polyester resins will not cure over epoxy.

Thoroughly degrease and clean the inside of the cowl. Rough up the inside with sandpaper. Inside the cowl lay in a layer of say 4-6oz cloth over the damaged areas and holes to be blocked. When this has cured rough up the outside damaged areas. Fill all cracks, holes etc with a mixture of resin and microballoons. When this has cured sand smooth. Fill remaining spots with body putty, sand prime, fill, sand, prime, fill etc, etc, etc until you are satisfied you have a paintable surface. Paint.

Ed S

DHG

My Feedback: (7)

Ain't that right, Ed?

(Mostly I just follow him around hoping to sneak a sip out of a rum glass he's left unattended momentarily ... but sometimes I can actually do some good.)

Mr. Scotch Whistleblower

Ed Smith

I never leave Rum glasses unattended.

I think had it right. Epoxy can be used over both, Polyester over Polyester.

I think Duane you have been sipping from too many unattended glasses!

Ed S

rambo

My Feedback: (1)

Do you buy K&B epoxy or mix epoxy and alcohol?I've done the epoxy alcohol deal for wing centerbay reiforcements.I appologize for my ignorance but fiberglass work is something i've always been afraid to do much of.Thanks again

Ed Smith

I never thin epoxy resin. Thinning changes the physical properties of the mix. Thinning reduces the strength and in some cases, not all, the resin wil not cure "Hard" it stays kind of gummy. Many people do thin the resin and say there is no difference. Thinned resin may suit their needs but it does make a difference.

There is a difference between epoxy glues, hobby store finishing resins and regular epoxy resins. I also understand that if one's resin use is limited to small fix-up jobs once in a while there is little justification for the cost of the relatively large minimum quantities that composite suppliers have available, usually a qt at about $40 with hardener. Try and find another aeromodeller that does this work, He/She may even fix ypur cowl.

Ed S

Ed S

Tired Old Man

My Feedback: (1)

There is definately a difference in epoxy resins. Most hobby shop resins are not well suited to laminating, only bonding. West Systems, Systems Three, and certain Z Poxies are designed for laminating. The first two are the better pair. There are others, but usually have to be mail ordered. The two noted here can be found in many boat and marine repair shops.

Ed is right. You can use an epoxy over a polyester if it's been well cleaned and roughed up. Polyester will not cure over epoxy no matter what you do. I learned that the hard way. What kind of rum was that?