Polyester fabric

[Walter Thom]

I would like to use the polyester fabric rather than fiberglass because of the ease of application and draping capabilities of polyester. So, do I use the same resin for polyester fabric as one would use for fiberglass? I know that it drinks up a lot more resin, I am OK with that. That's it. A simple question and hopefully a simple answer.
Thanks
Walter Thom

[joe2700]

I would like to use the polyester fabric rather than fiberglass because of the ease of application and draping capabilities of polyester. So, do I use the same resin for polyester fabric as one would use for fiberglass? I know that it drinks up a lot more resin, I am OK with that. That's it. A simple question and hopefully a simple answer.
Thanks
Walter Thom

While polyester resin instead of epoxy is common in boatbuilding(but not for the boats built here) I have never heard of using polyester fabric as an alternative to fiberglass in structural applications such as boat building. Can't find anything while searching either, but because polyester resin is so common it's not easy to search for. Can you link to some information about this technique or the particular fabric you want to use? The manufacturer should be telling you what resin to use and giving the mechanical properties of that finished composite.

My gut is that you can't do this in a structural application, but I'm open to learning something new. The closest I've seen is using fabric stretched over a frame and cured with resin to make a hard shell which is then fiberglassed over for strength.

[OneWayTraffic]

Essentially no you can not use a different fabric. Some people use xynole for sheathing and abrasion resistance in a wood boat but it can in no way replace glass for structural integrity. It has superior performance against abrasion but almost no performance in holding your boat together.

If you were to use a Xynole you would need to completely reengineer the boat. I’d guess at least twice the hull thickness, which then would not bend so you’d need to cold mould. Then there’s the stringers etc, which would still need to be glassed in.

The good news is that you can drape biaxial cloth just fine. It’s woven that wrinkles.

[TomW1]

I would like to use the polyester fabric rather than fiberglass because of the ease of application and draping capabilities of polyester. So, do I use the same resin for polyester fabric as one would use for fiberglass? I know that it drinks up a lot more resin, I am OK with that. That's it. A simple question and hopefully a simple answer.
Thanks
Walter Thom

I believe. that if you use polyester cloth you need to use polyester resins neither are sold here. I do not know why you believe that polyester drapes easier than fiberglass but you will need more layers of polyester than one layer of 12oz fiberglass.

Tom

[BarraMan]

I would like to use the polyester fabric rather than fiberglass because of the ease of application and draping capabilities of polyester. So, do I use the same resin for polyester fabric as one would use for fiberglass? I know that it drinks up a lot more resin, I am OK with that. That's it. A simple question and hopefully a simple answer.
Thanks
Walter Thom

Why?

[Evan_Gatehouse]

No you can't do this. Resin doesn't stick to polyester fabric. It's also very flexible compared to fiberglass. It has no structural properties.

[OneWayTraffic]

No you can't do this. Resin doesn't stick to polyester fabric. It's also very flexible compared to fiberglass. It has no structural properties.

Xynole is polyester I thought? Do they treat it for resin to bond. I've never used the stuff, though apparently it's good for its purpose, which is not holding a boat together.

[Walter Thom]

OK,
It looks like I am not going to use polyester fabric and will do the fiberglass. This is my first motor boat build after 70 years of floundering my way along. I have built a couple of skin on frame kayaks. It will be a Inlet Runner 18 by Dix design. He recommends a 12oz biaxial fiberglass fabric.

I am putting the items on his material list together so I have an idea how much of an investment this will be. I have priced out most of the items so far but, there is a solvent for cleaning on the list... I don't know what I am to be cleaning with this and/or what type of cleaner is to be used. I would like to avoid pestering him for these types of questions which is why I am seeking answers here on the boat builders forum.

One thing that isn't on the list is gel-coat or paint. So that's another question. Paint or gel-coat, which one is best or are they both just fine? I have seen gel-coat crack with age and I would prefer not to go that route for the ease of future touch ups and maintenance... I'm sure there will be more questions along the way.
Thanks
Wally

[Jaysen]

If you are using epoxy you need paint.
If poly or vinyl ester then gel or paint.

If you go gel, match it to the base… so vinyl ester gel or poly ester gel. A good ester supply company can help with that.

Cleaner should be alcohol for general wipe down post sanding or surfaces before fully cure is achieved. Acetone for tool clean up or material destruction. Acetone on uncured surfaces is bad.

If you are using ester, styrene for a thinning agent. There is no thinning agent for epoxy.

MEK (not MEKp) can be used for some clean up but I find acetone is easier to obtain and stays usable longer. I keep some mason jars for tool soak and a “lab bottle” for directed spray.

[joe2700]

For working with epoxy I find denatured alcohol to be cheaper, less toxic, and just as effective as acetone for almost everything. There are almost no tools I try to save, just buy disposable things from the start in bulk. You'll spend more in solvent trying to reuse something. So alcohol for everything until prep for paint, at which point I use the paint company's expensive cleaning solvent of choice. Buy it by the gallon and if you use it very freely as I do you'll spend a couple hundred on it over the entire project at $20 a gallon. You could be less wasteful with it if desired.

Also buy an entire case of gloves and of towels. I like scott rags in a box, the white ones not the blue shop towels. They are the only disposable ones that don't start to fall apart on me leaving bits behind on the project.

I wouldn't consider gel coat personally. Gel coat is great when applied directly to a mold as you get a chemical bond to composite applied afterwards and a finished surface as soon as you pop it out of the mold. Applying it at the end you don't get any of those benefits, I'd just use paint. Paint can be several hundred to several thousand dollars depending on what direction you choose to go with it.


Things to buy in bulk to save money:
-gloves
-rags
-mixing cups(check for accuracy)
-stir sticks
-chip brushes
-painters tape