bias-cut tape application

I will be glassing the hull of a ches17LT this weekend.  I plan on adding bias-cut glass to the keel and chines.

My question is: when do you apply the tape?  My feeling is to apply it after the saturation coat, before the first fill coat.

Does anyone have input?

Tim


8 replies:

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RE: bias-cut tape application

Tim,
The easiest way is to apply all layers of cloth dry, then saturate them all at once. My preference is to wet out one layer at a time, immediately adding and wetting out extra layers, then squeegee them all together. If you add cloth after the underlying epoxy has cured, be sure to wash and sand the cured epoxy first.
-Wes

RE: bias-cut tape application

Hi Tim,

 I applied mine after I put on the full layers of fiberglass (let them cure overnight), same time as I was putting on my first fill coat.  You could do everything at once, but I found wetting out 3 layers at the same time a little tricky to get all the air bubbles out when I did it underneath the deck, so I'm glad I did it the way I did where it would show on the hull. 

The main idea is to put the tape on top of all the other layers of fiberglass so that when you sand everything smooth at the end you're not sanding through the  full layers.  Some people use the thick tape that is used for inside seams for this application, but I chose to use my own bias-cut tape that I cut from spare 4 oz. cloth because the thick tape has REALLY thick edges that take lots of fill coats to smooth out.  I didn't have a problem with edges raveling on the tape I cut.  

Kathy

RE: bias-cut tape application

Tim,

If you're a beginner, go with Kathy's method. It's much easier to control. Saturating all three at once the way Wes suggests is faster and eliminates problems with blush, but it is more suited for a production environment with experienced professionals, low-viscosity resins and vacuum bags.

There's definitely a knack to it, and not just to avoid the bubbles. If not done correctly it uses excess epoxy, so you could end up running out of epoxy and having a heavy boat. Amateurs can do it, but probably shouldn't try it on their first boat.

You can apply the next layer as soon as the first one has cured enough not to be tacky when you touch it.

Good luck,

Laszlo

 

RE: bias-cut tape application

Thanks guys for responding so quickly.  I plan on cutting my own strips as Kathy suggested as I had some air bubble problems inside the hull with the woven seam of the manufactured tape.  Glassing the cockpit humbled me a bit so I will follow the advice from Laszlo to work more slowly in steps of letting the saturation coat kick a bit then apply the tape during the fill coat.

Turns out, after a good cleaning of the hull and close inspection under halogen shop lights, the sanding gods have decided not to have mercy upon my progress.  Back to the hardware store to trade green sheets from my wallet for more sheets of 220.  Ugh. 

The good thing though is that our brewing bretheren have seen fit to release their seasonal spring ales which make the sanding flow with a bit more ease.  I work outdoors as a surveyor and I saw a number of trees in full flower today near the waters of Gig Harbor.  Time to pick up the pace.

Tim

 

RE: bias-cut tape application

To Twofootartist, you mentioned here that to add more glass to cured glass, you should wash and sand before adding more.  Wash with what?  Vinegar/water?  We are thinking about adding some glass around the coaming of our boats.  Just wondered about this.

 

Dawn

RE: bias-cut tape application

I use no-blush epoxies and just wipe things down with a little denatured alcohol to get rid of the dust. If you're worried about blush, then plain water is fine to get rid of that.

The sanding is to rough up the surface for a better bond. It's only needed if the epoxy has cured to the point where sanding makes dust. If it makes balls that clog up the paper, you can skip the sanding. Depending on the epoxy type and temperatures, that can be up to 3 days between coats with no sanding needed.

Laszlo

 

RE: bias-cut tape application

Is the epoxy which ships in the kits no-blush?

-- James

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