Talk Composites - The Forum for Advanced Composites

Skinning (High Temp) Problems

http://www.talkcomposites.com/Topic823.aspx

By Alank - 2/23/2012 10:56:17 AM

Hi, First project a motorcycle exhaust (silencer end can part) cover.
Made an aluminium backing plate to the shape I wanted then tried to skin this as per instructions.
First the epoxy seems too runny, the basecoat ran to the edge of the domed baseplate before it went tacky.
Assume you need an even cover of basecoat so can't just do it thinner. Topcoat runny too but tried to rebrush after an hour - also took a long time to cure ?

Put part in oven as per HDT cure but got golden marks in the resin just over 1mm diam. Did it get too hot or for too long ?

Thanks for any advice before I try again, can't see I can sand out the marks or recover the baseplate so its back to stage 1 & make a new baseplate!

Assume carbon is ok for this application as the whole outer sleeves are often carbon and the end part of mine is carbon.

Alan.
By alan - 3/15/2012 11:17:21 PM

Hi,

I posted the original but 'lost' the sign in. Curing was at about 20c. You need to put a thickish base coat to ensure its sticky all over and get a good colour depth (I was covering aluminium then a white coloured part).

I tried again and same problem, worked around by rebrushing and applying a second coat after it had partially cured (put mixed resin in freezer to delay curing - seemed to work !)

Didn't bother with the oven part of the curing.

I bonded the finished item to my exhaust with some high temp silicone. This remained bonded so far and no noticeable degradation due to heat from exhaust to carbon part !

Other problems have been fraying of cloth during application and distortion of weave pattern round contours - think I may try prepreg cloth another time.

Alan