http://www.flickr.com/photos/28618433@N05/?saved=1
I believe this will get you pictures of the worst examples of the problem. I think it looks worse in the glare, but maybe not. I have not yet applied unthickened epoxy to the entire inside of the hull, so the untreated areas above the tape are not problematic. I appreiate your input, suggestions and optimism. Also, in the first post I meant unthickened, not untreated. Thanks again, Marty
Marty,
I hate to say it, but if it were my boat I'd remove the glass tape and try again. There's just too much air and unwetted glass for me to trust that seam. The glare is good, it shows up all the problem spots.
Carefully heating the tape with a heat gun, as Charlie says in the other thread, is probably the best way of removing the tape. It should just pull off with pliers.You may have to hit a few spots with a sander, too, once the boat cools off again. Once the glass is completely gone, you can smooth the fillet and surrounding wood with a light sanding.
Now, to avoid a repeat of the problem, lay out a piece of plastic (the 4 or 6 mil polyethylene dropcloth from the paint section of the local DIY store is perfect) on a flat surface that is long enough to hold the longest piece of tape you need for your boat. A workbench is great, but the floor will do. Cut the glass tape and leave it on the plastic for now.
Apply a very thin coat of very stiff epoxy/woodflour putty to the fillet. The idea is to just fill the dings from the previous attempt. Then, once it sets up a bit but is still soft (maybe 10 minutes), brush it with some unthickened epoxy to completely smooth the surface. It'll end up much smoother than if you'd tried sanding it.
As soon as that's done (don't wait for the epoxy to cure), take your tape and wet it out on the plastic sheet. Use whatever method works for you (I like to just pour the epoxy onto it and work it in with gloved fingers) as long as when you're done the tape is completely transparent and saturated with epoxy. When that's the case, roll up the tape.
Take it over to the boat and unroll it down the fillet. Use your gloved finger or a squeegee (again, I like the gloved finger because of the control it gives me, but others work better with a squeegee) and smooth the tape onto the fillet. Work air bubbles and excess epoxy to the sides.You can scrape the excess epoxy onto the rest of the interior so that it won't be wasted.
This technique is known as wet-on-wet pre-impregnated (pre-preg) glassing among the pros. It has the advantages of needing less time and sanding than waiting for a complete cure between fillets and glassing, as well as separating the wet-out and lay-up operations. This way, unless the wet-out is perfect, you don't proceed to the lay-up and you don't end up with dry, white glass in the seams.
The final thing to remember is that if the tape doesn't look good, pull it up before it cures and try again.
Good luck,
Laszlo
PS - because of all this extra work, you might want to consider ordering a bit more epoxy and woodflour.
Laszlo, that tip is one for all builders to print off and save. I think your investment of time to write it out so clearly and thoroughly will pay dividends for other builders.
Heck, wish I'd had it when I did my fillets, back in the day. (John's Sharpie isn't a REAL kayak, of course, but it does have fillets, just like the boats y'all are building)
One other point to add to Laszlo's outline is to pre-stick one end of the tape. I've found there to be much more control if I cut my tape to length then epoxy say just 1/2" of the end and let it set. Then, as Lazslo describes, complete your fillets then lay the tape. The anchored end of the tape stops it from creeping up and creasing as you are embedding it in the semi-cured fillet. You can prepare all your tape pieces this way in advance of laying your fillets...it may be an extra step but it sure saves a ton of aggravation and keeps everything under control.
A great quote from Ted Moores (Bear Mountain Boats) in the current edition of WoodenBoat magazine...."Control is the most important lesson I have learned as a boatbuilder. Control in execution is what gives us the freedom to be creative. When control becomes a state of mind, projects progress smoothly and safely..."
Although Ted was referring to rolling a 30' launch within his shop, I find his wisdom also applies to small steps like laying fillets and tape....
Chris
Chris, I didn't understand this part:
"cut ... tape to length then epoxy say just 1/2" of the end and let it set. "
Is this after you have pre-wetted the tape on the poly drop cloth?
Sorry for the confusion....I don't pre-wet my tape. First, I mix a small batch of fillet mix and put a small fillet at the end of each seam. Let this cure then cut all the tape to length and anchor the end (1/2") in this small fillet. Let this cure and then start your full fillet seams. Let the full fillet cure for a few hours then remove your masking tape (if you've masked) and start laying the tape in with unthickened epoxy. I use a rounded squeegie made from a thick plastic container.
It may sound like a lot of steps but it probably only adds a few hours to the job and, like I mentioned, you have a lot of control and no frustration.
Also...I don't tape cockpits...just bulkheads...I prefer laying a full piece of 6oz. 'glass in the cockpit.
Chris
Camper,
You say the nicest things - sometimes :-).
Chris,
The whole point is to pre-wet the tape so that only perfectly wet-out tape gets anywhere near the inside of the boat. On the other hand, I do like the anchor idea. I wonder if it'd be possible to apply adhesive tape to the last inch or so of the glass tape, pre-wet it and then maybe temporarily staple the taped end to the boat before unrolling the seam. Seems to me that might be the best of both worlds.
As far as eliminating the tape entirely, that depends on the boat's design. On some it may be OK, but on others it could cause trouble. The designer may have been counting on that extra glass. One should always check with the designer before modifying glass layup schedules (unless one wants to take over as designer). Another thing to keep in mind is that the combination of a taped seam and 4 oz glass can actually be stronger and lighter than 6 oz glass by itself. Again, one should always check with the designer before making mods.
Have fun all,
Laszlo
Chris, thanks for the clarification.
Laszlo, I had the same thought about fixing the end, as Chris suggested, but some other way that would be compatible with the pre-wetting philosophy. At the time, I though he meant pre-wetted tape, so I was guessing he meant to use some sort of adhesive tape or something.
Even though it is now clear that Chris uses non-pre-wetted tape (I am a convert to the other approach), the idea of stabilizing the tape end some other way seems like a good one. It would allow you to always draw AWAY from the tape ends toward the middle--which can be easier because there's not a bulkhead blocking the tool--without dragging the tape out of position and having to shove it back somehow.
I’m fence-sitting on the pre-wetting approach…applying unthickened epoxy with an acid brush directly to the anchored piece of tape over the semi-cured fillets and then smoothing with a shaped squeegie seems much less messy. I’ve never had a problem with under-saturating the tape with this method. Whatever works for you though…
Sure can't argue with the results! Wow.
I'm not won over, but the reason is not black-and-white. It is this: I suspicion that this is a case where the more skilled craftsman will tend to be happier with your method, whereas the pre-wetting approach will appeal more to novices, for being more idiot-proof. That leaves some craftsmen/persons who, like L., just happen to prefer the pre-wetting method.
(Note: I am trying to stay on my "nice" binge, here, by stretching the "craftsman" label. What L. is, really, is just an old geezer who doesn't have enough sense to stop building boats.)
(Note: what Camper’s actually saying is that Laszlo really is a "nice" old geezer "craftsman" who doesn’t have enough sense to stop helping others build and use small boats.) Need more!
Geezer? I'm younger than GeorgeK and I've never heard anyone call him a geezer. You're backsliding, Camper. :-)
Laszlo
Chris, Your fillets don't seem to be as dark as most I've seen. How do you prepare your fillet material? thanks, Phil
Phil....I use West System fillers but you should be able to get the same results with other products. My goal is to make a mix that creates strong small fillets, is smooth to spread and blends well with the okoume colour (not an issue if you're painting the interior). I start with silica and white microfibers to thicken to fillet consistency. This creates a cloudy white mixture and strong fillets. For colour I then add a touch of Mircolight which is a tan fairing filler and then just a pinch of Micro balloons to deepen the colour. Although the micro balloons are purplish, adding just a pinch to the mix adds just the right tint to the fillet mix. In the photo below you can see the new fillets curing and then their appearance under 6oz. 'glass and 2 coats of epoxy in the cockpit.
Chris