I picked up a 9' wingspan used Byron Original Christen Husky that has a circular hole about 1 1/2" in diameter in the starboard side of the fiberglass cowling to accomodate a Super Tiger engine. I'll be using a gas engine, so I need to patch that hole.

I could sure use some advice on the best way to patch it as I don't have any experience working with composites. The cowling appears to be in very good condition.


Thanks in advance

Mik

I have a Spacewalker I had to do this to, this is how I did it.

First wash the cowl with soap and water, then detergent and water, finally clean the inside of the cowl with a degreaser or acetone(SP?).

The spacewalker's cowl is kind of flat sided so I taped a piece of mylar on the outside, card-stock and wax-paper will also work. I then laid the cowl hole side down, and from the inside laid in three layers of glass, on 3/4 oz. the others 6 oz. After the epoxy cured, I pulled off the mylar, sanded with some 220, then used some of the red stuff that comes in a big tube to fill in the small line where the patch and the old cowl meet, in my case it looked like a circle the size of the old cylinder head drawn with a pen. The just paint, mine came out perfect and was pretty easy to do.

You might try Iron Bay Model they can make a new one but not know what it will cost

We can make you a new cowl for 46.86 plus shipping.

Archie Stafford
Iron Bay Model Company
Service Manager

If the cowl is ABS, there is a good chance the epoxy will not adhere permanently.

What I do with ABS is:

Thoroughly clean the cowl with soap and water. Then go over the inside with some alcohol and a CLEAN RAG.

Cut some 2oz - 6oz fiberglass cloth to cover the hole and extend about 1 1/2 - 2" beyond the hole. In your case you will need a piece about 5" across. Lightly scuff the inside of the cowl in the patch area with some 100 - 150 grit paper. Clean the residue off with some alcohol and a clean rag.

Adhere the patch to the inside of the cowl with THIN CA. I use a piece of 1/8" music wire to push the fiberglass into the little grooves and gullies.

After the patch is glued in place and dry, fill the outside with spot putty (red stuff, comes in a tube, can be found at Wal Mart, Home Depot, Lowes or an auto supply house ).

When dry, sand, prime and paint.

For about $5.00 in materials it may be worth trying before spending the money on a new cowl.