Resin choice

with or without chopped strand matt on the back ??
1708 is not the same to all people so what do you call 1708:?:

 

With csm....hate to even ask that question

 

I only had 12-18 mm on the hull floor and tab area. Up the stringer and top was 4-5 soooo do I tape 5 layers of 8 inch 1700 staggered first then add the 4-5 layers of complete glass staggered on top of the tape or run tape on top or do as my yard suggested and run some 1708 with CSM or is there a better way........??
Thanks and hope all is well today!!

 

csm on your 1708 is the better way !!laugh as much as you like the csm glass has no binder and wets out 100% and reinforces the epoxy resin layer between the layers of matt and is a proven fact it is much stronger and far less likely to peel than just matt to matt . its there for a purpose even though others can see it !!

 

No one professionally using epoxy, should be telling you to use CSM, period. CSM is a bulking material and helps weaker resins with bonding issues (inter-laminate or substrate), neither of these issues are problems with epoxy laminates. I'm not sure what Tunnels is talking about, but I'll suspect he's not kept up with this thread.

 

Theres always a logical reasoning behind things to be found

Csm serves a very useful purpose ! and i to used tothink like you did till i saw the merits of using csm between layers ,not only for polyester and vinylester but also used for epoxy's . Yes it has a very slight bulking effect and thats what its attached to the matterial to do just that . The csm used has no binder like i hear so many people grumbling about so wets 100% and like i said its there by the manufacture advice to glass reinforce the potentual resin layer between the layers of fabrics .
Recently i did find all this information explaining the reasoning and i kept a copy that i will have to go searching for . Its completely logical and not there just for the hell of it, its there for a reason . yes i do keep up with things and i do ask reasons why and i do understand the reasoning behind why its done and i totally agree with why its there .
If you want to go through life with blinkers on thats your problem !!

i am always looking for a better way ! always listen to anyone silly ideas and draw my own conclusions , i will never be stuck in a rut and have a narrow way of thinking ! thats the usual signs of a truely professional person , a person that thinks they know it all !!
What i know is because i have done , seem and its works , if i think it is not right i will say so !! and yes i will tread on toes if thats what it takes to open someones eyes .
Its an ever changing world we live in and i am all for change if it is for the better !

 

Found it !!

Took a while to find but i found it
http://www.westsystem.com/ss/chopped-strand-mat-epoxy/
This confirms what i had always believed to be so . If it was written by some one i never heard of i would question IT EVEN FURTHER but i take it west has done some home work on the matter AS THEY ALWAYS DO and in theory they are right AND I FOR ONE COMPLETELY AGREE . resins should be reinforced with glass certinly polyester and vinyl ester and just because some people think epoxy is the best of the 3 resin it to should have glass reinforcing as well .

 

Thanks for the info. I am glad to hear both sides of the issue. I do understand there is more than one way to approach an issue and again THANKS!! but what I gathered from the West site was it could be used but it did not say why one should use it with epoxy. If it is to just build thickness......I am not looking for that alone. I would be fine with a thin layer of anything as long as it was strong I do believe if binders are not disolved it will cause it to be weaker....how much ...not sure as would any other material within the resin. Will CSM cause issues with epoxy, are there stronger materials to use. I am looking to be as strong as a heavy layer of csm/2 layers of heavy woven/heavy layer of CSM.....the rest of the lam is just VE in the stringer area ....12/18mm...again i am here for the same strength AND KNOW NOTHING ABOUT FIBERGLASS AND EPOXY.

The fiberglass strand in mat wets out with epoxy, but the binder holding things together does not dissolve. (It does get put into suspension and is sealed in the cured epoxy.) This undissolved binder causes the wet-out mat to remain a bit stiff compared to wet out with a styrene-based resin. For gently curving or flat projects like cabin soles or plywood decks, mat and epoxy should work fine. The fabric does not wet out perfectly clear with epoxy. Wet-out clarity of mat with epoxy varies somewhat with different suppliers, but none of them wet out as clear as a good 4 oz or 6 oz fiberglass cloth.

 

Just as a add to chopped strand matt can be used to make complete boats and using polyester resin.One company i worked 1986 all there 36 foot boats were 100% chopped strand matt everywhere . Over the course of time i was factory manager i gradually little by little introduced other glass fabrics into the build but only on smaller items .
This is how it had been done for how ever many years and why should we change we never had anu problems !! we are the biggest power boat company in the country and thats how we always do it !!
It didnt take to long because of the narrow mindedness and non progressive habits and ways before they were left in the dust . First reduction in boat sales then reduced staff then they had to start selling off a few big thing and closing buildings to reduce rents wasnt long after they completely closed . Simple really they were not doing any research into what the market wanted !!!.
Change !! without change we stagnate ,without change we donot progress and move forward . if we dont move forward we will get stepped on and eventully left behind !!when the dust settles we look in the mirror and ask what happened ?? and why ?? thy say "but i was the best "!! being the best at anything and not being adaptable to new things and not progressing we become dinosoures .

My point is there is nothing wrong with chopped strand matt !!! glass manufactures have done there home work and will keep doing there home work for ever ,same with resin manufactures they to keep improving products and making improvements and they in turn work together with glass manufactures and look for improvments and keep one step ahead of industry demands !!.
Its no good poo pooing something till you find out the motives and reasoning behind whats been done .
Resin alone is brittle and will shatter just like a chunk of quarts because theres nothing to hold it together !!
,Glass fibres alone are useless by themselves but put the two together and everything changes !!.
Understanding all the materials at your disposal is a mind boggling task the combinations and choices are almost limitless , and just keeping up with some of what there is hard work .

 

Best bet on the mat is run a few test samples and see for yourself with some destructive test, I did several with 17 ounce biax and 6 ounce cloth then added 1-1/2 ounce mat to the mix, The best I liked for all up strength -stiffness was the test with 2 layers of biax with the mat between. The only problem is the mat with binder is a booger to wet out 100% with epoxy and that's working flat no way would I attempt it overhead.
Glad to here tunnels that the 1708 does not have the binder in the mat, wondering if the 1208 is the same?
Tom

 

Wondering if the 1208 is the same? check on line !!!
Understand ! the csm matt you use by its self should be "P" matt has powder binder to hold the fibres in place . "E" matt is the biggest problem its a emussion binder and the problem one .
The matt attached to the back of any of the fabrics you buy has no binder at all and is held with the stitching .
Like i wrote the manufactues have spent lots time and worked with the resin manufactures and have given you what they consider to be the best choice !! The csm weight is really light maybe 125 gram or maybe 225 gram so its light !!
Dont think its a lot and going to take heaps of resin . Make and put two samples together and wet them out you would possible never be able to tell the differance !And if you use peel ply thats even better still .

Know and understand the materials you are using !!!Make a point of finding out why !!!:?:

 

Great info Thanks!!!

 

Some people have the mindset that csm is just crap !! well its not . i been in glassing for long time and i make a point of digging into things that are new and the flavor of the month ,and csm on the back has been round for long long time (1970s we first started to use it ) . its only recently its use is being questioned !! and not to many people know and understand its purpose why its there !!

The boat we are doing i specificly orded fabrics all with a 275 gram csm on the back !!.Its was noticably better to lay and wet out faster and much easyer to roll out 2 layers at a time !! If we had used a fabric and a cm seperately (Using polyester and spraying with a saturater gun )it would have taken twice as long to lay and had to roll out each layer separatly
Boat is 90 feey long !! so we are talking a lot of glass and resin .

 

The link supplied was written by Tom Pawlak, a guy I know and an employee of West System for over 20 years. He simply described what I've previously stated, that binders and sizing used on mat don't affect epoxy and is left in suspension. He didn't address the core issues, except moisture gain, which was about as expected. The core issues with an epoxy laminate, are you're just increasing the resin to fiber ratio and getting nothing of value in return. It's not that you can't build with it, you can and it has been done, but if you want lighter stronger and better resin/fiber ratios, then skip the mat. In other words, if you want to use mat, then just use polyester or vinylester, because these resin have to have the bulking agent and peel strength improvements mat can provide. Again, epoxy doesn't display these issues in normal laminates, so you can save money and effort, not to mention resin by eliminating mat from an epoxy laminate.

It's taken quite a while for the relatively high modulus resins (epoxy) to see enough testing and time trials, to gather enough information about laminate schedules. The same was true of polyester and vinylester resins when they appeared on the scene. In the early days of polyester, they built boats that were literally bullet proof, because they didn't know how thick or how strong the material need to be. I have one of these hulls in the yard and this one ton boat, has 3/4" thick all CSM in it's bottom, tapering to about 1/2" to 3/8" at the rails. At least they tried to keep the weight down by tapering the laminate, but it's still a boat that's 700 - 1,000 pounds heavier then it needs to be. Had they mixed in roving and/or cloth, they could have reduced the weight and maintained the strength and stiffness of the hull shell, plus dramatically reduced the resin/fiber ratio.

The same hull could have been made with epoxy and directional fabrics, with a hull thickness of 1/8" maybe 3/32", still having the same strength and stiffness of the original hull, with a huge savings in material and resin, not to mention effort (unless chopper gun, which is about as easy as it gets). The resulting epoxy laminate would be a fraction of the weight, so the preformance envelop is also dramatically improved.

I don't dislike CSM, I just don't need it in a epoxy layup and would prefer to save weight, improve resin/fiber ratios, while maintaining strength and stiffness. I do use mat occasionally to prevent print through or improve a "blind" bond, but not as a structural material for the most part.

 

So far the sellers online that I have looked at don't specify the mat being stitched "no binder' just that it is compatible with epoxy ect. on the 1208/1708/1808 makes it tough when you haven't used the stuff before.
I have learned the hard way not to assume that it's one way or the other without it being specified,even then you don't know for sure till it's in your hands