BYYB Forums

After extensive reading of the forum, I am left with this question as to the finishing of the hull of my PC.

Thus far, I have filled and sanded all the screw holes with bondo. Applied the 6oz fiberglass cloth, and coated with the dreaded of all polyester resin. The results were good, not too much bubbling, happy builder.

Many in the forum are indicating that polyester is a sin in boat building. Not providing much in the way of water protection, and all the "micro cracks" from stress and impact.

Now to the question; if at this stage I decide that I am a millionaire and buy epoxy resin, can I roll a coat over the polyester? Will the 2 products stick to each other? If so, will epoxy provide a good external layer over the polyester substrate. (this is my most pressing question)

Will this "increase" the durability of the polyester, additional waterproofing, etc...

Next, many that say polyester will not stand up as long, if this is my only option, when should I plan the funeral for? 3 yrs, 10yrs?

Finally, as a filing agent for the weave, can I mix silica powder to thicken? With this cause capilary action of water into previous layers?

Thanks for all the advise to this point members, all that have replied have been invaluable. For some reason I am becoming more anxious at this glassing stage because I realize that this thing is going to have to float at some point.

Run this up the flagpole and see who salutes.

Sean Stepney

Unfortunately, I'm old enough to have a fair bit of experience with this exact set of conditions.

Back in the 60's and early 70's many wooden boats were sheathed with polyester and fabric, in hope of water proofing them. It wasn't long after that the owners wanted something to "fix" the previous "fix", so different strategies were tried. Lots of things were tried and ultimately, nothing worked as well as removing the original sheath and applying a new epoxy set fabric sheath.

This said, epoxy does stick to polyester. In fact, it sticks to polyester better then polyester sticks to itself.

The best thing you could do is some investigating first, then repairs, then hope for the best.

For the investigating part, find a blister or bubble in the fabric and slit it open with a razor knife. If it's full of resin or too tough for your knife, hit it with a grinder to cut through the fabric. Next get a pair of vise grips (why do they call pliers a pair?) and attached them to the now exposed edge (tight) and then give it a good yank at near 180 degrees (a good one, no wimpy stuff, try to hurt it). What was the result? One of three things will happen: one is the damn thing is stuck really well, because you saturated the wood carefully and the cloth to resin ratio is right or you didn't get it quite right but had a lot of resistance to peeling off or it unzipped along the fabric warp, like a piece of silk stocking or canvas cloth. I suspect you'll find one of the last two scenarios is true, in which case you should strongly consider you next options.

If it's well stuck you're in business. Grind out all the bubbles, fill them in with thickened epoxy, then put at least 2, preferably 3 coats of epoxy over the whole shooting match. This will form a "barrier" coat and will water proof the sheathing, then paint it good.

Polyester will not stick to epoxy (hell, it has a hard time sticking to itself), so don't even try.

To answer your questions:

Quote:will epoxy provide a good external layer over the polyester substrate

Yep.

Quote:Will this "increase" the durability of the polyester, additional waterproofing, etc...

To a degree, but the bond is subject to the polyester/wood interface.

Quote:when should I plan the funeral for?

With reasonable care, you'll get old before she wears out on you, but this said, most people don't provide reasonable care. Wooden boats can not tolerate neglect for very long and this is where the sheathing questions will come back and bite you in the butt. If cared for she'll do well, if neglected, even just for a short time, she'll bite your ass (her way of letting you know how she feels about the neglect stuff).

Quote:as a filing agent for the weave, can I mix silica powder to thicken?

Yep, but you'll regret it because it'll be darn hard to sand. Use Qcells or similar as a fairing compound (like WestSystem 407 or 410) which is easy to sand, feathers out nicely and will not make you curse like a drunken sailor.

Quote:With this cause capilary action of water into previous layers

Nope, not if it's set in epoxy and well mixed.

Thank you for the information Paul, but suddenly feel like I am going to throw up in my hand.  I feel like I am in a doctors office and am asking for the Doc to " give it to me straight, I can take it"........

The option of removing the layer of poly is out of the question, as the pile of 24" belts will attest.

I can accept that this boat is going to have a finite lifespan, but the internet search that went on last night (into today) have left me with the impression that i have 2 good summers, then a rum soaked flamming effigy. Holy crap, I have had better luck with a discarded TV box and 3 roles of duct tape!!!!!!!!

The question is; are there any builders out there who have used polyester on a trailer sailer, and please give me a current age of your boat. Additionaly, include a rough number of hours in the water in a typical year.

I am trying to justify this all as the learning curve in building, and yes, I am already planning the next build design and I am not even competed the first one. ( infectious bastard).  Clearly I will already be doing things differently on #2, but the first boat had better impress the sh*t out the CEO before funding is given.

Thanks for the couch time forum members, I might be able to look at her again. It is funny how an inanimate pile of lumber can project a sense of betrayl.......

I'm a member of a number of discussion forums where I consider it my job to dispel myths. The "polyester on wood being the death to all" myth is one. No, polyester isn't very good on wood. No, it doesn't last very long, but on the other hand, it's not going to start melting into the soil like the Wicked Witch of the North either.

Again, given good care, it can be handed down to your children (yea, now it's their problem) as a gift. Again, given poor care, she'll quickly require initially minor repairs, then move to major repairs. This is true of any wooden boat, regardless of the resin system used, though admittedly, polyester will be quicker to this end compared to epoxy.

You generally don't have to grind off the sheathing with a belt sander. I'd never remove these sheathings if I had to do that. In most cases the bulk (90%) of the sheathing comes off with a little persuasion (big sheets of material). The vise grip test I mentioned is the very first thing I do in accessing the sheathing. Yes, it's destructive, but if the sheathing is well stuck, you will not be able to pull much more then an inch or two of fabric before it breaks (some putty and paint and it's gone). This is an easy repair to make well again and offers a lot of information about the sheathing. If on the other hand the vise grip test produces a 3 foot long strip of sheathing, you need to consider how well the rest of the sheathing is stuck. So, the question you need to ask yourself is, how well is my sheathing stuck. Or perform the test. If you have more then several bubbles, then it's likely the sheathing is questionable and should be tested.

Even if the sheathing is covered in bubbles, she could live with this for several years. Naturally, the situation will become worse as time goes by, but if you started a repair routine, fixing the worst of them as the years pass, you'll be into it for a decade before wholesale changes need to be made, which isn't such a bad trade and the "one that must be obeyed" will likely be easier on you.

With reasonable care you'll get many years of life out of your polyester coated boat.  Most older "plastic" boats out there are made with polyester resin and lived out in all conditions for decades.

Yes - once water gets behind the coating through cracks and dings you will start to get delamination but that will take quite a bit of time and a certain amount of abuse.

In my own case, it took me 4 years to build my Weekender and it's sat un-painted under plastic sheeting for those Canadian winters and summers for much of that time.  I hope to actually get to use it some this summer having finally launched at the tail end of autumn last year.  There are no signs of damage at all for me with the boat just sitting there.

Things I have learned to make cheaply built boats last are:
- Keep it covered when not in use
- Don't let water sit in it (I have a cockpit drain and a hard cover plus I usually have it under plastic)
- Do regular inspections and fix anything wrong right away.

Good luck with your project and be confident that given care, your boat will last many years.

Thanks for the reply all, I have a much better understanding after reading forum.
I was fortunate enough to be in viking plastics in edmonton purchasing gelcoat and was directed to a local builder.  He showed me a sailboat that he built in 1971 with poly, and is in prestine condition. His recommendations echo your own Andrew, with garage storage and attention to surface moisture, iso marine poly is a very acceptable coating.  Opinions on the net are one thing, a tactile example is one hell of a hard thing to debate.....

This week I will be tinting the gelcoat and righting the hull again, at which time I will post some pics.

Thanks to everyone,

Sean Stepney

sorry about nthe delay, but i believe in the mantra "shut up and build"

she will hit the water tomorrow........

a few more pics due to the 4 limit.....

That's a fine looking boat there Cap'n - good luck with the launch.

Very nice job, Sean.  How long did the build take?

Dave