Extra layer of Cloth

[Jim Dodd]

Inspired by a recent discussion. The question of where to put the extra layer of cloth ? Some add the extra layer, on top of the main cloth layer. While others add it beneath the main layer

Putting the extra layer underneath, saves a lot of feathering. ! Which I'm all for !

Wanting to convert my method to this, I set up two tests.
In one test the E-glass was on top, and in the other test, it was on the bottom of the S-glass.
In both tests, I used one layer 6 oz E-glass, and one 6 oz layer of S-glass.
I miked both layers dry, and came up with .009 on each. Not very much. I haven't, but I will measure wetted out cloth.


I rolled on two coats of resin and let cure. I wish I would have added enough coats to completely fill the weave !
The lap joint was clearly visible.

Once cured, I used a straight edge carbide scraper and pulled it across the lap joint of the two layers. In both cases, the carbide scraper removed weave of the top layer, about a 1/4" wide.

Like I stated, I wish I would have completely filled the weave in this test !

Judging by this test, I will continue to place the extra layer, on top .

Any comments welcome as always !

Jim

 

[Holmes375]

I think placing the extra layer on top is best for areas such as the football where one is going for abrasion resistance. That extra layer can be considered a sacrificial layer taking the abuse without disturbing the integrity of the full base layer.

My last two builds saw 4 oz cloth on the inside. Easier to work and I like the texture of the 4 oz better for interiors. I did use an extra layer of 4 oz in the cockpit area from the aft bulkhead to the forward bulkhead (kayak) to stiffen the hull and increase impact resistance. In this application I put the extra layer in first using the tape trick method which is very easy with 4 oz E cloth. Transition is hardly evident at all and the boats seem to have held up well.

 

[Alan Gage]

Nice little test, Jim.

If I bury the partial layer I can see it when sanding but I usually don't worry about trying to get it perfect. Since it's on a turny part of the hull it doesn't seem to show up. More visible are any extra layers buried at the stems as the transition is easier to see when sighting down the keel line.

Like so many things with boat building I think it comes down to the builder and what they can tolerate. If using double layers of E-glass I'll probably continue to bury the partial layer as any transition left after sanding doesn't bother me. If using S-glass I'll put in on the outside and do a better job of getting as good of an edge as possible during wet out to save sanding. I like Holmes's method in your Pearl thread.

Alan

 

[Jim Dodd]

As the saying goes, there's more than one way to skin a cat.

We all develop our own methods !
This is a great place to share ideas !!!

Jim

 

[wgiles]

When you put two layers of cloth on, do you put the resin on each layer separately or both layers at once? If you put the smaller layer on first and filled it with resin, it would make sense to feather the edges and then put the second layer on. If you fill both layers with resin at the same time, it would make sense to put the smaller layer on top so that you wouldn't sand through the larger fabric.I've used fiberglass cloth and mat for auto body repairs, but never for the boat building applications like these.

 

[Jim Dodd]

I wet out the first layer, and when it cures enough, that I can put the second layer on, I do, and apply resin.
This probably adds more resin, than wetting both layers at one time, but I won't swear to it !

Time to build a canoe Wgiles ! You have a big advantage over others that have never handled resin !
I know that was My biggest fear the first time !

You can do it !

Jim

 

[Holmes375]

I tried wetting out both the main layer and the outer football patch together one. I do a seal coat thus figured I wouldn't have a resin starvation issue doing this. And it was my 4th build which meant I was an expert

It was a big S&G canoe so I made my first batch a little larger - 8 oz - than I usually work with. Poured out a nice S trail, took up the squeegee and.... yup, you guessed it. Kinda like that old Paul Simon song, "Slip slidin' away."

I quickly realized the folly of my brightness and we carefully lifted the football patch off the hull and draped it over a couple clotheslines so I could salvage what cloth I might later. Straightened the main layer out and finished the wet out. My two helpers - the owners of the yet to be completed canoe - looked at each other with some trepidation. Fortunately, I had plenty of cloth on hand and they felt much better later on when we added the patch after the main layer had gone tack free.

I know some builders can do two layers at once but its apparently beyond my skill set

 

[Alan Gage]

I've never had a problem doing two layers at once as long as the partial layer is buried. Never tried both at the same time with the partial on top. When the partial is buried make sure all the wrinkles are out of it because you can't smooth the bottom layer through the top layer. A couple times I've had to lift the top layer so I could get to the bottom layer to get rid of a wrinkle or two.

Alan

 

[wgiles]

The possibility of building a canoe sometime in the future is very real, but it will take a long time to assimilate all of the knowledge and experience presented here. My own experience is that I can read and watch forever, but I only really start to learn when I start doing. I would be best served by taking on some smaller projects first. I need to get some of the materials so that I can experience the feel and properties first hand.

 

[Alan Gage]

The possibility of building a canoe sometime in the future is very real, but it will take a long time to assimilate all of the knowledge and experience presented here. My own experience is that I can read and watch forever, but I only really start to learn when I start doing.

I'm the same way.

I would be best served by taking on some smaller projects first. I need to get some of the materials so that I can experience the feel and properties first hand.

I say just jump in and do it. It's not really that hard. People with zero experience (me, for instance) build wood boats all the time and they come out fine. The worst part is there are multiple ways to do each step and without experience (and many times even with a little experience) it's hard to know which way to go about each step: square edge or bead and cove? stems or stemless? single or double layer of cloth? what weight of cloth? gunwale material? gunwale profile and thickness? screwed or glued gunwales? hang the seats from the gunwales to cleats glued to the hull? decks or no decks? float tanks or no tanks?

But the best part is there are multiple ways to do each step and no matter which combination you choose it will turn out fine.

Alan

 

[Jim Dodd]

For those that have never used S-glass, here is a close up pic of it on the inside of one of my strippers.
This again is close up, from a bit of a distance, it's not so apparent.

Jim