My Pearl Build

[Jim Dodd]

Have a little time while I'm waiting for the seal coat to set enough to lay out the glass.
Here's a few pics.

This last pic should have been first. This is how I set things up. A few cups filled with resin, and then with the pump on just the hardener, Even I can't mix them up !


Jim

 

[Alan Gage]

That looks great, Jim. Nice design work on the bottom. Hope the fill coat hardened up before bed time!

Alan

 

[Jim Dodd]

These cool temps really slow the cure rate ! Couldn't get the glass on until 9:00 PM Monday. In spots it was still slightly tacky at 7:00 AM Tuesday.
Added extra layer of S-glass on top of a 6oz main E-glass layer.

WE need a discussion on weather the extra layer should go underneath, or on top ! I always put it on top. I realize it's a pain to scrape and sand the outside edges, but the lump left by the layer underneath, forces you to sand into the main layer on top, thus creating a weak spot in the glass.
I see other builders do this (not vacuum bagging). What say you ?

2:00 PM Tuesday. Second fill coat on, I'll wait 1 1/2 hrs for the Third coat. Adding a fill coat while the previous coat is still tacky, nearly eliminates runs.
Have two bias strips on each end (wide one first)

Love thoses white "cigar" roller covers. seems like the resin goes farther, and no foamy roller covers.

Jim

 

[memaquay]

I’m not one of these high tech guys, but I have built around 25 strippers. The last 20 have had double layered bottoms, with the football underneath the main piece of glass. I have never noticed an edge where the two mate up. It is basically gone after wet-out, and certainly buried after the fill coats. Never had a problem sanding either. It seems to me to be a lot of extra work to do the pieces separately and the have to deal with that outside edge.
Here’s a shot before wet-out

Immediately after wet-out

And immediately after the last fill coat

When I get back to work on it, hopefully by the beginning of May, I’ll show you detailed shots of the sanding, particularly in the are where the edge meets.
I think the trick is to get excellent penetration with the wet out, and then a tidy application of fill coats without a lot of runs, so that sanding is usually just a light buffing once around with 150.

Same idea goes for me with coverings on the stems too, I do those before I apply the main cloth. They get buried as well.

 

[Alan Gage]

If I'm adding multiple layers of E-glass up to the water line or at the stems I'm happy to bury them under the full cloth. Like Memaquay I've never found the slight bump to be objectionable and many times not even noticeable.

On my current build I, like you're doing now, used S-glass as my extra layers. In that case I wanted it on the outside to take advantage of its increased resistance to wear rather than allowing the weaker layer of E-glass to take the initial hit. It was a lot of work getting a nice transition with the layers on the outside. Particularly, it seemed, because the S-glass was so much more resistant to the sandpaper. Or maybe it was just my imagination. I could have done a better job getting a neat edge before wet out and saved myself some work.

I've been thinking the last couple days I should laminate a couple pieces of wood with E-glass and S-glass and see how long it takes to sand through each.

Alan

 

[memaquay]

Yes, to be sure I have not used s-glass, so can't comment on how it would turn out.

 

[BWCA66]

Been having this discussion with my son as we are about to embark on building a stripper, can you guys add some thoughts at to the weight of the glass you are using for each layer? Never worked with S glass either.

 

[stripperguy]

I can't speak for the others, but I generally use 1 1/2 layers of 4 oz E glass in and out. Plenty strong enough for my uses, I have built some hulls to be super strong using 1 1/2 layers of 6 oz, but that makes for a heavy boat, IMO. I have also used 3.25 oz E glass, but the weight saving was minimal and it took a long time to wet out (tight weave).
How old is your son? My son began helping with wet outs when he was 6 years old, helped my daughter build a customer's boat when he was 7.
It's never too soon to start building boats and memories...

Have you chosen a design yet? You know, it's hard to build just one!!

 

[BWCA66]

My son is 33, we built one a few years ago but my involvement because of time was basically ripping the strips and doing the bead and cove. He pretty much did the rest. Thinking back he thinks he just used 8 oz E glass, 1 layer in and out. That's what led to our discussion today. Basically I'm the one helping out but hope to be more involved in the whole process this time. We going for a slightly modified 15' Chestnut Chum design.

Hey Jim, your boat looks great, sorry to steal your thread here, just trying to get some ideas before embarking on a build.

 

[Jim Dodd]

I set up several tests, as my roller was full, and I had extra resin in the cup.

Tonight.
On 1/4" Pink foam board, I wet out a strip of E-glass, and a strip of S-glass. I want to test stiffness. And to see which one delaminates first.

Then I overlapped a few patches to check thickness . I put multiple coats of resin on this test. I want to see if my sander will detect the difference. If the weave shows up at the lap, then I will know. If not, I'm going to make a radical turn around in my technic !

No problem on the Highjack ! I'm as guilty as the next guy. So long as we leave politics and religion out of it, I'm OK !

Jim

 

[Jim Dodd]

I'm seriously thinking of going the 4oz route on my next stripper. It's not only the weight of the cloth, but the extra resin you presumably would use.
Especially on a solo, I think it would be the way to go. Putting extra glass in the stress areas makes a lot more sense !

Jim

 

[Holmes375]

I've worked with 6 oz S cloth quite a bit on my kayak builds. S cloth doesn't wet out the same as E cloth. Even when completely filled you can see a ghost of the cloth pattern if you look at the right angle. Not an issue unless you plan to use your boat as a mirror If I recall S cloth came about due to military spec requirements for a fiberglass cloth stronger and more durable then the conventional E cloth.

As Alan mentioned using S cloth under E cloth wastes the increased abrasion resistance of the S cloth. And doing so will not give you that nice transition of E cloth over E cloth. You want stiff? S cloth will deliver. If you have a complex curve to do cut the stuff on the bias. It ain't a great conformer.

My kayaks see rough duty thus I added a football/stem layer of S cloth to most of them. The trick to getting a user friendly seam transition is to do the ol' tape trick. Our first layer of E cloth has been laid, wet out and cured just enough that we can lay our S cloth. Using 2" mask tape layout the shape of your football. Attach a drip skirt around this. Lay the cloth and wet it out. If you know your resin well enough you'll know when to come back for the "green" stage. If you don't, babysit it. When its just cured enough to where you can carefully lift the mask tape away from the hull without lifting the cloth and, using a large Exacto knife with a fresh blade, cut the cloth at a shallow angle at the inner tape-to-cloth union. Tedious at first but you'll quickly get the feel of lifting the tape and running the blade. I use a fresh blade for each side. You now have a clean edge that is easily addressed with a carbide scraper. A large two handed scraper is preferable. This will take most of that edge away. Follow up with an 80 grit hand block moving slowing as the paper will just plug up with the green epoxy if you go too fast. Tack it off and finish the fill coats for the complete hull.

BTW, after you do the initial wet out on the S cloth keep an eye on it for a while to make sure it is indeed completely wet out. S cloth is thirsty stuff.

 

[memaquay]

Very interesting! I had remembered reading somewhere, years ago, that S cloth wasn't suitable for strippers, so I never approached it. Seems like it might be a good option for the bottom. I have to admit though, with two layers of six ounce e-glass, I haven't experienced any trouble, and we use our canoes very hard, just like royalex. I did use a ten ounce e-cloth on one of the 20 footers I built, and it worked pretty well, although was difficult to fill, and ended up not being as hardy as the double 6 ounce.

 

[Holmes375]

I think much of that opinion probably stems from the S cloth not truly being crystal clear when buried. The ghosting is really quite minimal, more noticeable on lighter wood like Northern White cedar and such.

It is very durable stuff though. I did a small kayak for a lady who just abuses the heck out of her hulls with the way she launches. Her boat is 5 years old now and still looking good. I anticipate cleaning it up and adding another layer in the next year or so.

That kayak pictured is now 11 years old and has been in two hard crashes. One was severe enough that I incurred a couple broken toes when it happened. That was my first build and its probably over-built but it sure has held up. It has hundreds of miles on it now. The boat is a Nick Schade design, a low deck Night Heron, 18' long with a 20" beam.

Last year I helped a friend build a small lapstrake drift boat for his fly fishing addiction. We used a layer of S cloth on it as the final layer. It has only one season under its gunwales so far but these boats really get the abrasion abuse as they are often drug across the shallow gravel beds to access the hot fishing spots. Turned out to be a nice little drift boat and something different to work on.

I think S cloth would be a natural for the larger tandem canoes, especially those being used harder than the casual recreational paddler might do. You might want to build a couple small test panels from scrap strips and apply an E cloth under S cloth layup to see what you think of it.

Pleasant waters to ya.

 

[Canotrouge]

I use S glass on paddles and it is as clear as I can see... The s cloth is really superior to e glass that is for sure. And I got told by a composite guru that S glass on a 45 bias, will give you more stiffness, so you can go thinner on the wood!!

 

[Holmes375]

Interesting factoids from the Sweet Composites web site:

Fiberglass Yarn 101

This is an introduction to fiberglass yarn terminology, just in case anyone is interested. (This is just for background — we sell only finished laminating fabrics. We do not sell yarn.) First, we’ll look at the chemical composition of the glass and the difference between E-glass and S-glass. E-glass, which stands for Electrical, is the common, all-purpose type. When someone justs says, “fiberglass,” (s)he almost invariably means E-glass. S-glass, which stands for high-Strength, is stronger and stiffer and more expensive. What is commonly called S-glass nowadays is actually S2-glass. The original S-glass, sometimes called military S-glass because it was developed for military applications, is somewhat stronger than S2 glass but it is extremely expensive, due to stringent testing and certification requirements of the military. There is no chemical difference between S and S2. The stringent mil-spec testing will pass only the highest quality material, while the commercial S2 material may be slightly less strong and still pass its test. I’m told that military S-glass is now called lot glass because it is made in a lot or batch, which is then certified as to the processing parameters. It has few commercial applications due to the high cost. S2 glass was developed in the 1960s by Owens-Corning to bridge the gap between E-glass and mil-spec S-glass. When I speak of S-glass I am really speaking of S2-glass and that is generally true in the industry today. Compared to E-glass, S-glass provides about 40% higher tensile and flexural strengths, about 10 to 20% higher compressive strength and flexural modulus, and greater abrasion resistance.

Glass Composition, % by weight
Component	E-Glass	S-Glass
Silicon dioxide	52 - 56%	64 - 66%
Calcium oxide	16 - 25%	Trace
Aluminum oxide	12 - 16%	24 - 26%
Boron oxide	5 - 10%	—
Sodium & Potassium oxides	0 - 2%	Trace
Magnesium oxide	0 - 5%	9 - 11%
Other oxides & fluorides in trace amounts to make 100%.

 

[Canotrouge]

Great info.

 

[Holmes375]

What weight S glass do you use in your paddle making?

 

[Canotrouge]

If I'm right, I got the 6oz, I think that is the lightest that Sweet composite carried. and I don't think I would go lighter... The other day we were going to the pool session, and my daughter(7 years old) put her paddle against the Honda(Element) at the back... I thought it was in the vehicle, so I backed up... Hear and feel some thing funny, stopped, and sure enough, the paddle is stuck under the front tire... I had rolled over it. I drove forward and picked it up, the only damage was a few small pebbles that went thru the glass into the cedar wood of the blade. easy fix.

 

[Alan Gage]

Jim, I may have asked this before but is "Pearl" the model name or is that your name for the hull? Where did the plans come from?

I have to admit though, with two layers of six ounce e-glass, I haven't experienced any trouble, and we use our canoes very hard, just like royalex.

You know, I kind of use you for a benchmark when I'm trying to figure out what layup to use on a hull. I look at the amount of tripping you do with your strippers and the conditions you do it in and think to myself, if two layers of 6oz glass is good enough for Mem then I can get by with one. Or maybe two layers of 4oz.

As you've seen I can get pretty wrapped up in specifications and looking at different materials that may or may not be stronger but it's hard to argue with empirical evidence.

Alan