Fiberglass - Can I build with this type?

P

Paul Tychsen

Active member
Gents- Recently found a source for large pieces of scrap fiberglass cloth.

As I have only built one boat (1-man layout) and used 10oz biaxial cloth for it, I'm not sure how this type of fiberglass would lay down. The glass that I'm used to using is the neatly woven type (apologies for the non-technical verbiage).

It appears similar to the fiberglass that my MLB ZT is made out of, as is my 4-rivers. Perhaps this type of fiberglass works best in a mold, versus laying it over wood.

This is listed as 1.5oz (that seems very light to me as compared to 10oz that I used for my layout).

Questions I'm hoping to get answered:
1) Is this a suitable type of fiberglass to build with?
2) Can this type of cloth be laid over wood?
3) Does this type of glass suck up WAY more resin than the neatly woven stuff?

Pictures are below:

[inline glass1.jpg]

[inline glass2.jpg]

And a picture of the material after it's been coated with resin and a top and bottom additional layer of thin fiberglass veiling.

[inline glass3.jpg]

View attachment glass1.JPG
View attachment glass2.JPG
View attachment glass3.JPG
 
Paul,
The material you have there is 1.5 oz. CSM (Chopped Strand Mat). If you are using Polyester resin...this is what you want as your first layer onto wood or into a mold. We then follow that with either a regular cloth or (preferably) Knytex 1708 which is a biaxial cloth (45/45)(sewn) with 3/4 oz. CSM attached to the underside.

If you are using Epoxy, you do NOT want to use CSM. You would want to use Cloth exclusively.

When using Polyester Resin, the reason for the CSM is as a "bulk" layer to hold resin to develop the heat necessary for a good cure as well as a good bond. It also contours well because the Polyester Resin is designed (due to the styrene) to partially dissolve the CSM and make it easy to "mush"/roll into contours.

What resin are you using?
Lou
 
God I hated that stuff!!!!! Once upon a time I used to make fiberglass truck bodies. I just hated CSM.. always would end up coming appart on me...
 
God I hated that stuff!!!!! Once upon a time I used to make fiberglass truck bodies. I just hated CSM.. always would end up coming appart on me...
Click to expand...

It's all in how you use it. If using 1.5 oz. CSM, wet out the surface and then put the CSM down and roll it out. If using 2 oz. , do the same unless you have small areas, then you can pre-wet and lay it down and then roll. We use a lot of the 3 oz. CSM and we lay it on a table, pre-wet it and then pick it up and set it down on the surface....as long as it's not too big of an area and you don't want to wet it out toooooo much.
It takes some time to learn to make it work for you.
Lou
 
For the layout I used West Systems Boaters Resin - I have a Marine General 3 miles from my house and got the resin on sale for $30 a gallon.

Lou - would I HAVE to add a layer of the biaxial cloth over the top of the CSM? Ideally I would be able to exclusively use CSM - then I wouldn't have to buy the woven cloth.....Thoughts?

Thanks-
Paul
 
For the layout I used West Systems Boaters Resin - I have a Marine General 3 miles from my house and got the resin on sale for $30 a gallon.

Lou - would I HAVE to add a layer of the biaxial cloth over the top of the CSM? Ideally I would be able to exclusively use CSM - then I wouldn't have to buy the woven cloth.....Thoughts?

Thanks-
Paul
Click to expand...

Paul,
First thing...are you using an epoxy resin or a polyester resin?
Lou
 
Sorry - just realized I left that info out. I am using Polyester Resin.

Thanks-
Click to expand...

Paul,
Yes, Polyester Resin is what you want with the CSM.
Yes, you "could" do the laminating with only the CSM but you will end up with a very rough/bumpy surface which would require a lot of sanding if you want it to be smooth.
I would recommend using the CSM and then follow with some cloth (i.e. 8oz., 10oz., or 12oz. and squeegee that into the CSM and you'll get a nicer surface. 1708 will give you a nice surface also but you'll end up with a bit more bulk.
Holler with more questions.
Lou
 
Paul,

the question is what finish do you want for the boat and how long do you plan on using this one? Cloth will make is nicer if used over the CSM, but if all you are doing is adding some resin and CSM to make it water proof and the wood of the boat is the main source of strength, well then NO further cloth is needed. BUT, it will be rougher than with glass over it.

Just don't use epoxy with it, they make special Mat for use with epoxy.
 
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