Best fiberglass for stringers?

[Truefire]

Hey guys, what is the best type of fiberglass make for overlayment of stringers after they are installed.

• woven roving
• fiberglass cloth
• fiberglass mat

I also understand that they all come in various weights and widths. I would like to know what would be the best advisable configuration in reference to type and weight combination for the overlayment of stringers being installed in a 17' glasstream bass boat hull.

All advise, help and concerns voiced are greatly appreciated.

Chris Harrell

 

[redfury]

Re: Best fiberglass for stringers?

What was there originally? My boat ( 75 glastron ) had heavy CSM over the entire stringer system except where the cross braces where. I think it is really going to depend on the individual boat manufacturer as to what they used, I'd stick with the same.

CSM is going to be the easiest to work with if you build it up in layers as it can conform to curves easier than a weave.

Your best bet for strength would be to use 3 layers of a thinner cloth/mat than trying to do it in one big lay up. The thinner material is easier to work with as far as making the corners, and once layed up will be as strong if not stronger than a thicker single layer.

Your choice though.

 

[danond]

Re: Best fiberglass for stringers?

Original doesn't matter, really. You can always go stronger. The most fun/quickest building glass, in my opinion, is biaxial/1708. 17 ounces of woven with 8 ounces of mat stitched to it. 2 layers of that with epoxy on any stringer and it'll be good to go.

 

[Truefire]

Re: Best fiberglass for stringers?

Original doesn't matter, really. You can always go stronger. The most fun/quickest building glass, in my opinion, is biaxial/1708. 17 ounces of woven with 8 ounces of mat stitched to it. 2 layers of that with epoxy on any stringer and it'll be good to go.

Where is good place to find such material -biaxial 1708 woven.

Now in regards to the mat, are you talking about a thin type unidirectional weave of fiberglass or a plain weave mat.. I suppose the type in thought is able to bend in a radiius with ease, correct?

Should i produce a fillet on both sides of these new stringers replaced or should i utilize the mat to bend those 90 degree corners out to the point that the woven roving will bond well to the mat and seal all air gaps.

Thanks for all of your help.

chris

 

[danond]

Re: Best fiberglass for stringers?

You can order online, or you can find just about any local fiberglass place and they can sell it to you.

Mat is otherwise known as CSM or Chopped Strand Mat. The fiberglass is chopped up and woven in all directions - it looks like a mess and is typically pretty thick. It's typically used to bond and to build - i.e. stick stuff together. 1708 is excellent for strength in all directions and provides a nice, smooth surface for painting/sanding. 1708 is also easier to "wet out" or soak with resin than CSM since it doesn't gob up the brush or pull apart.

1708/biaxial will have a layer of woven glass on top (woven in 2 directions), and a layer of CSM stitched to the back. Do some googling and you'll see what I'm talking about.

As far as fillets go - just bed the stringer in thickened epoxy/resin (I use talc as a thickener), then blob some of that along the corner. You don't have to be perfect with fillets - just make sure there's something there to stick the glass to (no air). Some people rip tufts of CSM and stick it in the corner, then pour resin mix onto it as a fillet. To each his own.

1708 will turn corners without much hassle, but it doesn't like to go over the top of a typical stringer. I ran 1708 to the top of my stringers then topped them with CSM.

 

[Truefire]

Re: Best fiberglass for stringers?

Danond, thanks a great deal for laying it out in laymen terms and for helping me so that i may not have to take another course through the school of hard knocks and discouragements. That tidbit just taught me some stuff and i want to thank you, i see exactly what you are saying.

Thanks, Chris

I will certainly look in to that and will consider taking chopped strand mat over the top of my stringers.

 

[ondarvr]

Re: Best fiberglass for stringers?

Read the sticky at the top of the page and it will answer many of your questions about glass, with pictures too.

 

[Robert D]

Re: Best fiberglass for stringers?

Bass boat.....is this one of those 90 mph bass boats? How much HP you running? Now is the time to go for overkill and make those stringers better than factory, if you're running serious horsepower.

Note: I'm glad I don't have one of those 'go-fast' bass boats. I'd be having too much fun and wouldn't get any fishing in!

 

[ondarvr]

Re: Best fiberglass for stringers?

Since the wood is rotten I'm sure the boat is rather old, this means the layup on the stringers didn't fail due to lack of strength in all those years, so making them stronger than stock won't really be of much value. I'm not saying its bad, it just won't be needed for it to hold up for another 30 years with the same type of use. At most the layup was a couple layers of 1.5 oz mat and a couple layers of 24 oz roving (mat-roving-mat-roving), but it was probobly half that. Using 1708 or mat and roving will be fine and you won't see any difference in the final product, so just get what fits your budget.

stay away from cloth if you're using polyester, its of little value.

 

[Bob_VT]

Re: Best fiberglass for stringers?

Hey guys, what is the best type of fiberglass make for overlayment of stringers after they are installed.

• woven roving
• fiberglass cloth
• fiberglass mat

I also understand that they all come in various weights and widths. I would like to know what would be the best advisable configuration in reference to type and weight combination for the overlayment of stringers being installed in a 17' glasstream bass boat hull.

All advise, help and concerns voiced are greatly appreciated.

Chris Harrell

This is a bit "off topic" but, important food for thought. If your old structure has been removed from the hull and it was rotted...... make sure you do not attach the new stringers to a hull that has devleoped a "hooK". You need to remember that the hull shape can change if not properly supported and if assembled that way will lead to some future undesired characteristics.

Just a simple word of warning to keep in the back of your head. Good luck

 

[chrishayes]

Re: Best fiberglass for stringers?

how does one know if there is a hook?

 

[danond]

Re: Best fiberglass for stringers?

Since there's no original mold to compare it to you'd need to make sure it's supported and measured before you start, and supported/measured/sighted along the way.

For example - don't take it off the trailer and lay it on the ground on its side, then replace the stringers. You'll have a bent boat when you're done.

 

[chrishayes]

Re: Best fiberglass for stringers?

cool, I feared some issues would come about due to the fact that I removed the cap and took out what was left of the stringers so now the boat is bare just a shell. I did take measurements and fortunately I did not take it off the trailer. Hope all is well. Thanks for the answer. No hijack meant.

 

[Yacht Dr.]

Re: Best fiberglass for stringers?

Woven..

YD..

 

[Truefire]

Re: Best fiberglass for stringers?

This is a bit "off topic" but, important food for thought. If your old structure has been removed from the hull and it was rotted...... make sure you do not attach the new stringers to a hull that has devleoped a "hooK". You need to remember that the hull shape can change if not properly supported and if assembled that way will lead to some future undesired characteristics.

Just a simple word of warning to keep in the back of your head. Good luck

Glad you mentioned that, i have thought about that and have taken my two halves apart. I am gonna make a frame to sit the bottom hull in so that it doesn't develop any type of hook, i had thought about that, not the terminology exactly but understood that it could pull the boat's hull out of it's original design working on the 'ground' so to speak.

I have removed some of the stringer from one side of the boat and planned on replacing the stringer and the hull reinforcing strip on that one side prior to getting involved in the other side of the hull.

I do however need to go ahead and build a support system to sit the boat hull on or at the least purchase my drive on boat trailer a little early to place it on to give the hull some sort of rigidity prior to the rebuild. This boat was picked up and brought to my house on my utility trailer so that is why it is on the ground for now. I don't have a big enough shop to suffice for placing the boat inside of, i know, cheesey way to work, but what can i say. It is gonna be a project that is all i can say at this point.

Thanks, shoot me with advice, if need be...

chris

 

[Truefire]

Re: Best fiberglass for stringers?

Bass boat.....is this one of those 90 mph bass boats? How much HP you running? Now is the time to go for overkill and make those stringers better than factory, if you're running serious horsepower.

Note: I'm glad I don't have one of those 'go-fast' bass boats. I'd be having too much fun and wouldn't get any fishing in!

Robert i appreciate your thoughts, yes it will probably run in the arena of approximately 60-70 mph range when it is weigthed with the complete array of motor, seats, decking, attachments, seats, live well and such.. so i am certainly doing my research and trying to pick the brains of those that are better learned than myself in the arena of boat engineering and the science of fiberglassing. I know i must put forth the extra time in research before the restore to make it right, and i am willing to do just that, i am concerned a little bit at this point about the monies that may be conclusively involved in the project's entirety. Wow...

I'll get it right, but no it will not run 90 but more in the range of 60-70 with a properly maintained 150 hp motor fitted.

Take care, chris

 

[Truefire]

Re: Best fiberglass for stringers?

This is a bit "off topic" but, important food for thought. If your old structure has been removed from the hull and it was rotted...... make sure you do not attach the new stringers to a hull that has devleoped a "hooK". You need to remember that the hull shape can change if not properly supported and if assembled that way will lead to some future undesired characteristics.

Just a simple word of warning to keep in the back of your head. Good luck

Bob, also do you think that i could provide the hull with the rigidity that it needs to maintain it's original shape if i sat it on an properly sized drive on boat trailer and worked on one side at a time???? I have thought about the manner in which OOPs actually screwed 2x4"s directly to the hull along it's longitudanal axis to maintain his hull's shape. That could be an option and remove them and simply patch the screwholes thoroughly. ???Any thoughts...

Chris H.

 

[legoman67]

Re: Best fiberglass for stringers?

I used CSM and 1708 for my transom, it saves a lot of time over the conventional mat-roven-mat-roven....

the average boat trailer will not give the support required to rip out all the stringers at once. You will need to make wood braces that hug the hull in its current form, and extend up the sides. the other method is to do the stringers one at a time, rip one out, grind out the glass, install new one, glass it, move on.. it takes longer, but may work better if you dont have the facilities to make a proper structure to hold the boat.

 

[Truefire]

Re: Best fiberglass for stringers?

Legoman, thanks for your input and advice i really do appreciate it and was considering performing the hull redo in that manner one stringer at a time. Thanks for confirming my thoughts regarding this manner, i gladly accept any ideas, advice and constructive criticism you guys here on the discussion board give me.

I respect the knowledge and understanding so many of you up here possess in the arena of boatbuilding and being this is my first restore, well i try to remain teachable amidst my type A personality.

Thanks, Chris