1708 Biaxial +/- 45 vs Woven Roving

[DeepBlue2010]

Hi

I am planning to enforce the inner side of my hull in the bow area with FB. My original plan was

One layer of ....
1.5 OZ mat
18 OZ Woven Roving
1.5 OZ mat
6 OZ cloth for a smooth finish

But I read here in the forum that 1708 +/- 45 Biaxial will also do the job with the same strength if not better. The schedule will look like this

One layer of ....
1708
6 OZ cloth for a smooth finish

Is it true that the two schedules are equivalent strength wise?

I am not clear if both fabrics can be used in place of each other or each has its own use. I would appreciate if some of the experts here can shed some light.


Boat : 1994 Bayliner 2252 cuddy

Resin: Vinyl Ester (US Composites)

Thanks

 

[Woodonglass]

Re: 1708 Biaxial +/- 45 vs Woven Roving

In my opinion they are pretty close to being the same and using the 1708 will save you some resin. You don't say what your project really is though.

Got any pics?

 

[BWT]

Re: 1708 Biaxial +/- 45 vs Woven Roving

the two glass schedules are comparable. Actual weight comparisons your first layup totals 27oz of glass; option #2 totals roughly 24. Given the directional layout of the 1708, although a little lighter will result in a little stiffer laminate. Personally I would do schedule #2 with one exception; add a layer of CSM between the 1708 and the cloth. I typically use a layer of CSM between two different types of glass just to ensure a good bond. Hope this helps!

 

[DeepBlue2010]

Re: 1708 Biaxial +/- 45 vs Woven Roving

Thank you both for taking the time to answer my question. It sure helps. WoodOnGlass, you are right about the project & pictures. I think I need to get out of the denial phase and start a project thread.

 

[ondarvr]

Re: 1708 Biaxial +/- 45 vs Woven Roving

Why do you feel the bow area needs to be reinforced?

 

[DeepBlue2010]

Re: 1708 Biaxial +/- 45 vs Woven Roving

Ondarve, great question. My cabin was originally covered with this ugly fabric known among Bayliner owners as monkey/mouse fur from top to sides. I am planning on painting or gel coating the sides and install the fabric - the same fabric unfortunately - only on the ceiling of the cabin and down until the connection line between the cap and the hull. I prepared the surface by removing the glue and belt sand with 80 grit. The amount of glass the belt sander shaved out worries me a little. I am worried that I might overdone it or sanded more that I should have. Honestly I don't believe I did since I still see the same exact patterns of woven with the tops smoothed out and overlapping lines are gone. But I am still concerned and just want to make sure.


Do you anticipate any problems with reinforcing this area?

If you have any advise regarding the plan or the FG schedule, it would be truly appreciated.

 

[ondarvr]

Re: 1708 Biaxial +/- 45 vs Woven Roving

If you removed enough glass, then it may be necessary to replace some of it, but even if you did remove some, a belt sander wouldn't have removed the amount you plan to put back on.

One layer of mat and one layer of roving would be more than enough unless you really got carried away while sanding. Even a single layer of mat would probably get the job done.

If you really think you need to do this, just use a single layer of mat and a single layer of cloth if you want the surface smooth.

 

[DeepBlue2010]

Re: 1708 Biaxial +/- 45 vs Woven Roving

Thanks Ondarvr , I appreciate your feedback on this issue.

One more question; I read in Jay's thread "Here I go again" post #877 last paragraph an advice to finish Woven with CSM to avoid cutting through the strands when sanding for smooth surface at the end.

Is sanding Woven smooth - which means all the high strands were sanded out - compromises the structural integrity of the fabric/glass?

 

[ondarvr]

Re: 1708 Biaxial +/- 45 vs Woven Roving

If you plan to have a smooth surface, then using a layer of mat to sand on is better than sanding on the roving.