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Fiberglass

Posted: Wed Feb 17, 2021 7:48 pm
by Chris L
Jacques put a good writing out describing differences in fiberglass and when and where they are used. I’m still a bit green with this stuff. He said never use CSM I take it that means CSM by itself. But 1708 has CSM backing? Correct? or is there a 1708 without CSM backing? I’m thinking if it has CSM at all it has the binder that don’t work well with Epoxy. I’m probably wrong but correct me.

Re: Fiberglass

Posted: Wed Feb 17, 2021 9:36 pm
by fallguy1000
The topic was locked. But I will at least fill in a few blanks.

1208 and 1708 are mat backed stitched fabrics.

They can be used with epoxy. The csm portion of the fabrics are typically fashioned with a binder that breaks down in ester. The epoxy does not break it down, but does not need to for adhesion.

They come with a significant weight penalty. 8 ounces per sqft or 7.2 ounces per yard, so 1208 is a 19.2 ounce cloth and 1708 is a 24.2 ounce cloth. Of course, the weight penalty doubles with resin, so 14.4 ounces per yard is the real penalty.

But, there is a value in these fabrics. Most of the value needs thorough cost/benefit analysis.

The major benefit is the csm backed fabrics can be wetted and moved to the boat. And you can apply them on ceilings or walls or upside down and they do not deform as easily (but will). You can wet them on a table and roll them up and lay hundreds of feet of the stuff in an hour. And the work is neater.

Very few of the Merten's designed boats would need csm backed fabrics, if any, as I understand it.

My boat used csm backed fabrics in several places. All my tabbing used them. This allowed me to wetout tapes in 3 pound or 10 pound batches and move them to the boat on a cardboard. The weight penalty is several hundred pounds which equates to 150 pounds of resin or about 17 gallons excess epoxy. I regret using 1708 and believe 1208 tapes would have saved me 5 ounces per yard or maybe a 200 pound penalty or 11 gallons epoxy or so.

Bottom line. Csm backed fabrics have a place in boat building, but fair to say very little in the Merten's designs.

Further, csm can be used if you simply want to create a mould or something nonstructural like a lid. However, they make damned heavy components and there are much better options. Csm makes a handy hole patching material; the fabric can be laid in a hole and smaller and smaller bits of the stuff can fill the hole to near flat.

Hope it helps.

Re: Fiberglass

Posted: Thu Feb 18, 2021 2:34 am
by Fuzz
I will add a couple of things. Pound for pound fibreglass is a very flexible material. 1208 and 1708 and other materials with a mat backing build bulk more quickly. Fibreglass will reach the needed strength long before it reaches the needed stiffness. So you can make a thicker laminate of all glass or you can use some form of core to get the needed stiffness. Wood is very stiff pound for pound but if used it needs epoxy to be used with it or you will get water ingress. Some other cores can be used with epoxy or poly. CSM is made for poly and the binder will break down so it becomes almost like cold honey and that makes it easy to shape and fill. 12 oz biax is very easy to work with and is what is called for in most of the plans here. The BOM for each plan tells you what to use. Fallguy is building a foam core boat where epoxy is needed. Also because the foam is not as stiff as wood he needs heavier glass laminates. And for puncture resistance.

Re: Fiberglass

Posted: Thu Feb 18, 2021 4:41 am
by OneWayTraffic
I'll add a few things as well.

CSM has a couple of other benefits that don't really apply to these boats:
It provides better interlaminar bonding between layers of woven roving. CSM is resin rich and the squishy nature of this provides a good bonding surface between layers of roving. This matters for polyester, but not for epoxy. I learned this when trying to remove glass laid in epoxy from my boat. It was not easy!
CSM has equal strength in all directions on the plane in which it's laid. It's even stronger than biaxial glass laid in epoxy if the load is not aligned with the fibres.

In these boats strength is provided by both the wood and the glass. The layers cover 0/45/90/135 degrees providing strength in all directions. The designer anticipates the direction of loads and fibres are laid to carry the loads. Stringers and frames provide global strength. Since the glass is laid on a core material that provides both strength and resistance to penetration, thin layers are fine. In small foam core boats the skins need to be much thicker than required for either stiffness or strength just to prevent penetration from impacts. Or thin skins used and the risk of damage accepted.

In short using CSM will add a little strength, a fair bit of stiffness (but less than using a thicker core at the same weight) and a lot of weight and cost. If that trade of is ok to you, use it. In some boats it's an option.

Re: Fiberglass

Posted: Thu Feb 18, 2021 9:14 am
by fallguy1000
Fuzz wrote: Thu Feb 18, 2021 2:34 am I will add a couple of things. Pound for pound fibreglass is a very flexible material. 1208 and 1708 and other materials with a mat backing build bulk more quickly. Fibreglass will reach the needed strength long before it reaches the needed stiffness. So you can make a thicker laminate of all glass or you can use some form of core to get the needed stiffness. Wood is very stiff pound for pound but if used it needs epoxy to be used with it or you will get water ingress. Some other cores can be used with epoxy or poly. CSM is made for poly and the binder will break down so it becomes almost like cold honey and that makes it easy to shape and fill. 12 oz biax is very easy to work with and is what is called for in most of the plans here. The BOM for each plan tells you what to use. Fallguy is building a foam core boat where epoxy is needed. Also because the foam is not as stiff as wood he needs heavier glass laminates. And for puncture resistance.
A great point on the stiffness. To be clear, my build only uses stitched glass due to the foam. The only place we used csm backed materials was to make the beam sockets where stiffness was needed and to laminate them into the hull because it is seriously difficult upside down and vertical lamination work. I still threw a couple pieces in the bin that got misshapen. But I want folks to know, the boat does not use CSM much except for tabbing and the beam areas. The primary hull laminate is triaxial glass and we used 1700 and 1200 quite a lot as well when the triax was too much. I apologize if I seem to detract. Bottom line foam does not require csm either.

Re: Fiberglass

Posted: Thu Feb 18, 2021 3:04 pm
by cape_fisherman
Chris L wrote: Wed Feb 17, 2021 7:48 pm... is there a 1708 without CSM backing? I’m thinking if it has CSM at all it has the binder that don’t work well with Epoxy.
You don't have to worry about binders/epoxy with the 08s because they are stitched and have no binder. But to answer the first question, 1700 is the glass without any CSM at all. This is the route I would go...especially with epoxy. The CSM will soak up extra resin, and it doesn't add much in the way of strength. 1700 is all you need with epoxy.

Re: Fiberglass

Posted: Fri Feb 19, 2021 12:42 am
by TomW1
Chris L the 1708 sold here does not have CSM. It is designed to work with epoxy exclusively. !708 is basically used to build thickness and/or protection, the XF20 is a good example. If you are only using fiberglass for strength use 1700 no need for the mat. Your bill of materials should dictate which you need to use.

Tom

Re: Fiberglass

Posted: Fri Feb 19, 2021 1:27 am
by fallguy1000
TomW1 wrote: Fri Feb 19, 2021 12:42 am Chris L the 1708 sold here does not have CSM. It is designed to work with epoxy exclusively. !708 is basically used to build thickness and/or protection, the XF20 is a good example. If you are only using fiberglass for strength use 1700 no need for the mat. Your bill of materials should dictate which you need to use.

Tom
All 1708 has csm. And all csm uses a binder to keep it from falling apart. If you can point me to a tds on 1708 for epoxy; that'd be something new to me.

Hard to say this without a tone. Apologies in advance.

Re: Fiberglass

Posted: Fri Feb 19, 2021 5:57 pm
by TomW1
fallguy1000 wrote: Fri Feb 19, 2021 1:27 am
TomW1 wrote: Fri Feb 19, 2021 12:42 am Chris L the 1708 sold here does not have CSM. It is designed to work with epoxy exclusively. !708 is basically used to build thickness and/or protection, the XF20 is a good example. If you are only using fiberglass for strength use 1700 no need for the mat. Your bill of materials should dictate which you need to use.

Tom
All 1708 has csm. And all csm uses a binder to keep it from falling apart. If you can point me to a tds on 1708 for epoxy; that'd be something new to me.

Hard to say this without a tone. Apologies in advance.
Why would Jeff buy a product with Clorosulfonated Polyethelene(CSM) when he knows it would not work with epoxy. Why don't you call him and talk to him. I have done some research and some 1708 is stitched on and it does not use CSM. Thus epoxy is fully compatible with it. Otherwise as far as my research is concerned CSM is not compatible with epoxy. So take it for what you want, no apology needed.

Re: Fiberglass

Posted: Fri Feb 19, 2021 7:41 pm
by fallguy1000
TomW1 wrote: Fri Feb 19, 2021 5:57 pm
fallguy1000 wrote: Fri Feb 19, 2021 1:27 am
TomW1 wrote: Fri Feb 19, 2021 12:42 am Chris L the 1708 sold here does not have CSM. It is designed to work with epoxy exclusively. !708 is basically used to build thickness and/or protection, the XF20 is a good example. If you are only using fiberglass for strength use 1700 no need for the mat. Your bill of materials should dictate which you need to use.

Tom
All 1708 has csm. And all csm uses a binder to keep it from falling apart. If you can point me to a tds on 1708 for epoxy; that'd be something new to me.

Hard to say this without a tone. Apologies in advance.
Why would Jeff buy a product with Clorosulfonated Polyethelene(CSM) when he knows it would not work with epoxy. Why don't you call him and talk to him. I have done some research and some 1708 is stitched on and it does not use CSM. Thus epoxy is fully compatible with it. Otherwise as far as my research is concerned CSM is not compatible with epoxy. So take it for what you want, no apology needed.
Tom-the bond strength of epoxy doesn't care if there is a binder.

Csm in the fiberglass world is Chopped Strand Mat.

Re: Fiberglass

Posted: Fri Feb 19, 2021 9:50 pm
by cape_fisherman
I believe there is a simple misunderstanding. If y'all could calm down & research a tad more, you're 'argument' wouldn't be needed.

CSM, as a stand alone product, typically has styrene binders that dissolve when polyester or vinylester resins are applied. It basically 'melts' apart and conforms to what you're applying it to...sort of. Epoxy will not dissolve the styrene binder and makes it sort of useless. HOWEVER, there IS a CSM product available that has a powder binder instead of the more common styrene binder. The powder binder IS compatible with epoxy.

Now on to 1708 (and 1208 for that matter). The 08s do indeed have CSM attached to one side. They do. That's what the "08" is...CSM. With that said, the 08s DO NOT have any binders because they are stitched. They are held together with the stitching, and binders are not needed. Because of this, the 08s are compatible with epoxy, poly, and vinylester.

1700(1200) is the product that does not include CSM...and typically a better choice when using epoxy.

Re: Fiberglass

Posted: Fri Feb 19, 2021 11:15 pm
by TomW1
Thanks cape fisherman. I agree no more comments from me.

Re: Fiberglass

Posted: Fri Feb 19, 2021 11:22 pm
by fallguy1000
No attempt to argue cf. I even apologized in advance for my tone AND asked for edification.

The other thing I did wrong here was the math. The stuff is 0.75 oz per square foot or 6.75 ounces per square yard. I am not sure why they use the 08 numbering. I tend to treat the 8 as 8 ounces in my pea brain.

I have used actual csm with epoxy. The epoxy does not need to break down the binders for certain applications. For other applications; the binder breaking allows for greater movement of the glass and is essential.

If one scours the interwebs for details on how 1708 is made; it is rather hard to find. There is some way the chopped strand mat is held together to end up attached to the db. I will see if it is stitched. I never noticed stitching thru and thru.

I have used some 1708 that is rather stiff and makes funny noises. It is either a coating applied to the entire fabric or something used to hold the mat portion together. Not sure which. And it is not all the time.

All trying to be straight is all.

I used veil on two of the Skoota hull panels. It was csm. Epoxy does not care. The veil layer did not accomplish my wishes. I have a whole roll of it if anyone knows wjat to do with it! It was like $450. I used maybe 70 feet of ?100 or 200 yards.

Re: Fiberglass

Posted: Sat Feb 20, 2021 11:52 am
by cape_fisherman
See below ... ...

Re: Fiberglass

Posted: Sat Feb 20, 2021 11:55 am
by cape_fisherman
Not sure how easy, or difficult, the stitching is to see here...

Image

Image

Re: Fiberglass

Posted: Sat Feb 20, 2021 3:19 pm
by piperdown
^^^^ That's the stuff Tom (thb) sent me to help build thickness for the rocker I had. It's stitched like that. And it takes a TON of epoxy to wet out!

Re: Fiberglass

Posted: Sat Feb 20, 2021 3:45 pm
by fallguy1000
Maybe they spray a bit of binder to hold it until stitched and that is the scrunching noise I hear.

Re: Fiberglass

Posted: Sat Feb 20, 2021 6:39 pm
by cape_fisherman
piperdown wrote: Sat Feb 20, 2021 3:19 pm And it takes a TON of epoxy to wet out!
Which is why builders I know don't use it. Takes twice the amount of epoxy for not even half the amount of strength. A friend of mine that builds custom sportfishers out of wood & epoxy doesn't have a single yard of 1708 in his shop. He's a 1700 guy through & through.

Re: Fiberglass

Posted: Tue Feb 23, 2021 3:30 pm
by jacquesmm
There may be a problem with terminology here. In this discussion, CSM stands for Chopped Strand Mat not that Chloro something stuff.
CSM is normally the chopped fiber that comes out of a chop gun used in fiberglass boat production but it also exist as a fabric in which all those glass strands are kept together with a binder. Some people call the fabric version, it is correct if you want but many more just call it mat.
The binder can be of different types and yes, some are very stiff.
1208, 1708 etc. are made with mat stitched to the biaxial.
I very rarely specify it because as Fallguy writes, it soaks up resin without adding much strength. However, when a laminate is sufficiently strong but not stiff enough, I need to increase that stiffness by making it thicker and that is where 1708 comes into play. It is cheap and bulky, it makes that panel stiffer.
The 1708 sold by Jeff, is compatible with epoxy.

Re: Fiberglass

Posted: Sat Feb 27, 2021 2:13 pm
by Evan_Gatehouse
1708 = 17 oz biaxial + 8 oz CSM stitched together. That's the definition of the stuff. It always have CSM.

Most 1708 has a binder compatible with epoxy these days.

Re: XF20

Posted: Wed Mar 03, 2021 1:43 pm
by Chris L
Ok I’m sure I have over thought this beyond normalcy but trying to cut to the chase. The original plan I purchased is no longer the best way to build boat. The new version is the heavy duty, which is a different and a lot more material for building. That being said my panels have already been cut if we continue on building like the old way but just using the updated lamination schedule will that present any problems. Example: should we use butt blocks for bottom of boat panels or glass splices? In their original plans it was but block preferred now it’s optional. The new plans call for 1708 on the bottom up 6 inches of the waterline then it’s optional if or what you want to use for the rest of the sides or shear. I guess to simplify if I layup the 1708 glass I would rather do the bottom and all the sides in 1708. From that point what weight glass would be best for the inside hull, stringers etc. I want to do a raised deck so I was just going to cut solid frames in the dimensions of the new plan and place them in location based on the build sheet. I know BBC offers kits etc but all I need is glass. Any insight on other builds or what they used. All new to me, eventually I will figure it out. I just started questioning when original plan said 1708 inside and out and new plan has different approach. Thanks

Re: Fiberglass

Posted: Wed Mar 03, 2021 3:04 pm
by Chris L
Sorry didn’t realize this last post posted to this fiberglass forum.

Re: Fiberglass

Posted: Thu Mar 04, 2021 4:31 am
by OneWayTraffic
I wouldn't sweat it. Use 1708 if you have otherwise two layers of 12oz biax will have equivalent stiffness and better strength.

Re: Fiberglass

Posted: Thu Mar 04, 2021 11:00 am
by jacquesmm
Correct. Use the new specs. The hull panels are exactly the same. I added a sole but it is optional. I also made the transom from several layers of plywood instead of one layer plus a 2 by 8. Same for the stringers and frames: it's all plywood now. You can combine the two versions but I would keep it simple and build according to the new specs.