flickroll

flickroll

Well Known Member
I had a set of the new style Van's tips shipped to me last fall. Today finally got around to fitting them to my RV-8. This is a retrofit installation - I'm removing the original ones. So I mounted the tips, after primary trimming, using duct tape to hold them on initially (no helper...), and drilled all of the holes with a #40 bit, then drilled them again with a #30. Fabricated the aluminum strips for the nutplates on the inside of the tips with 0.025 2024 T3. Then, I scuff sanded the area where I wanted to bond the aluminum strips. Thats when I noticed the problem. The sandpaper was loading up with some sort of gummy stuff. Then I wiped down the sanded area with MEK, and the glass got even more sticky feeling. After that, I wiped it down with denatured alcohol and all seemed well (not sticky). I then bonded the aluminum strips with a epoxy/cabosil mix and called it a day.

When I got home I mentioned this to my son who is an ME student at VA Tech. He interned last summer with a company that manufactures industrial components using vinylester resins. He said send the tips back to Van's - they either have too much catalyst or not enough. That's not really a possibility - the shipping cost would be really expensive. Besides, the tips have gel coat on them and they seem structurally sound. So....to you expert glass guys out there. Is there a problem? Will I have problems in the future getting paint to stick? I think there will be no problem with the paint as the gel coat seems well bonded. Or, will the gel coat eventully fail? Or...don't worry about it? Or....?

Thanks
 
Tough to tell

Hard to diagnos without seeing it. Here are some questions first.

1) Is the entire inside surface soft or just the edges?
2) How about the exterior? If you sand through a section of the gel coat, is that underlying area soft?
3) Is is tacky to the touch all the time or just after you cleaned it?

If in doubt, I'd consult with Van's. If it is defective, they should pick up the shipping. They may opt to send you new tips without the old ones.

If they are bad, it is likely caused by not enough catalyst or a not thoroughly mixed batch of resin.

This can generally be fixed by mixing some resin with a couple of extra drops of catalyst. A so called "hot" batch.

Finally, if sending them back isn't an option, see if you can talk directly to the manufacturer for instructions and recommendations. They may have a fix for you.
 
The glass is not really soft, it seems cured. However...they felt sticky when I used MEK prior to bonding the nut plate strips. After the MEK flashed off they feel OK. The nut plate strips are really stuck on after 24 hrs of cure. I'll call Van's, but I think they are probably OK. Thanks for your response.
 
It could have been the mold release compound gumming up the sandpaper. I think your son was referring to something called an amine blush which I do not think would make a gummy residue.

If your epoxy is sticking and the fiberglass hard you probably have nothing to worry about.
 
I suspect the wingtips are made with polyester resin, not epoxy. It definitely has that characteristic smell when you work with it. Im no chemist, but maybe MEK attacks polyester but not epoxy.
 
Paul Johnson said:
I suspect the wingtips are made with polyester resin, not epoxy. It definitely has that characteristic smell when you work with it. Im no chemist, but maybe MEK attacks polyester but not epoxy.
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Any parts from Van's that have white gel coat on the exterior are made with polyester resin.
 
N395V said:
It could have been the mold release compound gumming up the sandpaper. I think your son was referring to something called an amine blush which I do not think would make a gummy residue.

If your epoxy is sticking and the fiberglass hard you probably have nothing to worry about.
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Hey Milt, I see you live in Summit. I lived in McComb for 3 years in the mid 1980's. Our son was born there, and was a nice place to live.
 
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