Selvage edge fiberglass question: 911

[Nosty]

Hi All,

I just glassed all the seams on my TTT with epoxy. It went smoothly, (amazing, isn't it?), but I foresee a problem tomorrow.

I used 3" selvage edged tape for all the seams. After everything started to cure, I noticed an approximately 1/16th" edge, (the selvaged edge), on all the seams.

Is this normal and, if so, am I supposed to sand this down before I apply subsequent coats? It was disheartening, considering the fact that all the lines were straight and I had very little trouble with bubbles or lifted tape, but the end result was an edge on one side of all the seams. If it's just a matter of sanding, (which I hate), I can live with it. I know that when I apply the next two coats of epoxy, these seams will still be there if I don't do something about it at this stage.

Has anyone else had this problem? If so, HELP, please!

Any assistance would be greatly appreciated.

Thanks.
Bria,

[doug hodder]

Yup....that happens. Let it cure up really hard and it should cut down pretty quickly with a fairly aggressive paper, 80 grit or so. I'd cut it down "feather" it in before I put on additional coats. If it's really bad I use a 4" grinder with a fine sanding disk on it. Without that selvage however, you would have been fighting loose glass strands and wavy tape all over the place. Doug

[Nosty]

Ah, thanks, Doug! I thought it was something I did. Well, I guess I did do it, but it wasn't my fault. That's a good thing.

I put it up for the night to dry. I'll hit it with the orbital sander in the morning. At least I know I'm not dealing with one of those things that only happens to me!

Thanks again. I really appreciate the response.

Have a great weekend.

Brian

[doug hodder]

Brian... you'll know when it's ready when it sands off in a powder. Whether or not it's ready depends on the temp overnight, your mix and humidity can play a factor. If it's loading the paper, it should sand clean..if not, don't waste the paper on it...it ain't ready! Doug

[rmclarke]

Brian,
Ditto what Doug said.....I removed the tape edges on my trailer with a Stanley Surform tool (me and grinders have cause some serious damage in my time )...just let it cure well. Here's a pic from when I did my boat after I taped around the centerboard. The surform took the big edge down quickly, then I feathered it like Doug said with a sander....then I clothed the bottom.


With the trailer, I just taped the edges.....after I feathered the edge I applied another coat of epoxy to the whole trailer. The edges 'disappeared' quite nicely.
Are you planning on putting fiberglass cloth over the whole trailer?

Richard

[S. Heisley]

Brian,

If you are using an orbital sander, I've found that the fiberglass tape edges sometimes catch on the holes in the sand paper. It's best to either manually sand down the edge just a bit before you use the orbital so it won't catch or use one of the afore mentioned methods.

[Rock]

Don"t know if you have any experience with a cabinet maker's card scraper. This worked for me really well on the freshly cured stuff. Sanding can just smear it around if it's not really hard yet.

The surform/cheeze grater thing worked for me but I tended to cut in with the edges of the tool scratching things up. Just my preference but the card scraper really eats up the rough tape and drips if u got 'em.

Eric

[Larry C]

The selvage edged is exactly the reason I no longer use tape. I make my own tape from cloth by cutting strips on a bias. These bias cut strips drape over tight corners with ease, have no selvaged edge to remove, and because the strips are cut on a 45* angle, there are no glass strands to fight. This saves $, time, and most of all the aggravation of removing the edge and trying to bury it in epoxy so it will blend with the surrounding glass.

I agree with Rock, use a cabinet scraper or a carbide scraper to knock down the edge. Sand paper loads up quickly, especially if used before full cure of a week or more. The other problem with sandpaper thats coarse enough to knock down the edge is you run the risk of cutting into the glass fibers beyond the actual selvaged edge. When you sand into the glass beyond the depth of the epoxy fill coats, your final finish will sparkle like diamonds in the sunlight. That won't be an issue if your just painting or covering with aluminum, but will look like hell if finished bright.

If you don't want the tape to show in your final finish, you will need to keep adding layers of epoxy to the tape to blend into the surrounding glass. This may take several applications of epoxy, scraping and sanding between each coat. Again, that's why I use bias cut strips.........

$.02
Larry C

[Nosty]

Thanks, everyone for the assistance.

It had hardened sufficiently to sand that edge to a feathered edge with the orbital sander and 100 grit pads. It took forever, but, after I got the first coat on this afternoon, the tape has almost disappeared. The next two coats should bury it completely.

I do appreciate all your responses.

Have a great weekend.

Brian