How thick is your hull really ??

[tunnels]

I do appreciate the lesson in glass you are giving me ( which obviously I need ). Given my particular Attachment 361393situation, I would assume that you would recommend something like DBM 1708.

+/- 45degree
Contains double bias(17oz) stitched at 45degrees along with one layer of 3/4oz mat.
Thickness: 0.044"
yes that's right !



http://vectorply.com/stitch-bonded-reinforcements/ read this !!!

[dwilfong]

Mat will not work if you use epoxy. It has a coating on it for esters only.

[tunnels]

Mat will not work if you use epoxy. It has a coating on it for esters only.

The older csm had a binder coating yes but the newer doesn't have that's why its stitched onto the fabric ! Your manufactures have not been sitting twiddling there thumbs they should have changed by now !
Here in china they saw this problem long time ago and sorted it ! that's why It pays to do samples of things before you totally commit to any project these days , things keep changing and the suppliers are sometimes slow to catch on and don't realize what's happening or why in some cases ! plus they want to get rid of there old stocks !

[One Oldman]

U.S. Composites claims all their CSM is completely compatible with their epoxy.

[dwilfong]

http://www.uscomposites.com/specialty.html
Here is where I got mine from. It was very high quality and laid down smooth as glass.
The mat on there's is compatible with epoxy I see.
The small sheet I got from Fiberglass Florida was CRAP..............
Only used it to mount the brackets to hold stuff to the inside if the hull.
But there epoxy was killer and cheep..................
The mat will soak up lots of epoxy and don't think it will give that much of a advantage on a small light weight hull.
Two layers of DB170 would use less epoxy and give much more support. If you really think is needed?
The lay up using a complete sheet from front to back will give a better matrix to spread the load out over the hull.
Broken sheets will not react the same.
Remember there is no strength in the epoxy. The glass weave is what makes it strong.
Mat will build thickness but it will not add to the matrix the same as a DB weave in transferring the load.
Thicker is not always better when adding to a existing hull.
Same as core thickness. If the weave used is a quality product. Thinner core will work just as good as a thick core.
Adding more core to cover the complete hull will do more than a thick core that is smaller.
The load will be spread out more.
If the core is covered in small patches the load will not transfer across the whole boat. The transitions also have to be filled good with fillet at the ends.
It is like a sheet if the transitions are to short and abrupt it will pop the sheet as it tries to straighten out from the load.
You have to think about how the load is pulling on the sheet when you do the layup.
Basically you want the top sheet as flat as you can get it when you lay it up. The inside of the hull needs to be as flat as you can get it also.
More to it than just making it thick. That is just a band aid to a poor design.
But if weight is no concern than LAY IT ON THICK.......................

[tunnels]

U.S. Composites claims all their CSM is completely compatible with their epoxy.

Getting information from suppliers is like getting blood from a stone and UNLESS YOU ASK A SPECIFIC QUESTION they will never volunteer any information .
On big projects here I deal with a composite broker they know everything!! where to get the best materials , who makes what I require, what size and width that is needed to help eliminate joins to a minimum in some cases have been able to get specially run fabrics ,always to the latest specifications ! these people are very clever and extremely helpful and when the shipment arrives in the factory they are there onsite to open and personally check everything is 100% ok !
That's what I call service !

[powerabout]

Tunnels, if you use all uni is there any need for csm?

[tunnels]

Tunnels, if you use all uni is there any need for csm?

Didn't you read the post with the actual hull laminate written I posted ??
In there you can see how a combination if csm and just 2 different fabrics are used and what they are used for !! its really simple and really strong ! its used for boats 5 meters and upwards to 48 foot with just minor changes once you get into the 30 foot plus size !
And yes there is a need to use csm in the right places !! and yes you can build boats out of uni glass ! what do you think stitch fabrics are made from??layers of uni run in all directions to make the fabric you choose !

[tunnels]

In all my time being in composites if there were new materials I had never seen or used I would cut off a small length about a foot long and then dissect it bit by bit to find out what it was , how it was made, what were the filament's that were used ,what was holding it together and then the weights of each various layers!. Then id ask questions where was it ,what are its uses, how is it best used ,why do the layers run in different directions ,and why are some layers different weights to others in the same fabric ? why ? Some fabrics look almost Identical to other but behave quite differently some wet out quickly while others are slow to wet ! Why ??
If you don't ask questions and find answers then you have to find someone that cam give you that information !
Its the same with equipment that gets used such and saturator guns and chopped guns and gel coat spray units you need to know every last nut and bolt and what its for and how it works , I have taken old pressure pots that I was told were terrible things and stripped , added another pressure regulator and completely changed what it could do . Guys used to shake there heads and walk away ! when there's a stoppage you need to know instinctively what cause it where to find the problem and fix it in just a few minutes and carry on like nothing had happened !
Same with resins and gel coats you need to be able to look at a problem and know immediately what caused it even to the person that caused the problem !.workers are creatures of habit and keep doing then same things over and over and changing peoples work habits is not easy believe me !

[One Oldman]

Mr Tunnels, Our discussion and your link has caused me to reconsider my layup. I will now use DBM1708 in tabbing structural components, transom, step, sole plates, stringers, knees, and deck. I used mostly DBM1708 on my Bullet build and was just looking for something a little easier to work with, with the light woven. Given that my stringers will be no more than 10" apart and much closer in the V portion, do you think 1 layer of 1708 will be sufficient to tie in a properly bedded and filleted stringer? I do not intend to fully wrap stingers but I do not have my composite board in hand. I'll decide that when I see what I think of the composite. I still plan on using some of the light woven in places but will add some 3/4oz CSM in most. All your help has been much appreciated!

[tunnels]

Mr Tunnels, Our discussion and your link has caused me to reconsider my layup. I will now use DBM1708 in tabbing structural components, transom, step, sole plates, stringers, knees, and deck. I used mostly DBM1708 on my Bullet build and was just looking for something a little easier to work with, with the light woven. Given that my stringers will be no more than 10" apart and much closer in the V portion, do you think 1 layer of 1708 will be sufficient to tie in a properly bedded and filleted stringer? I do not intend to fully wrap stingers but I do not have my composite board in hand. I'll decide that when I see what I think of the composite. I still plan on using some of the light woven in places but will add some 3/4oz CSM in most. All your help has been much appreciated!

Ok tell me the actual size of the stringers you are making !! how high are they and thickness and do you anticipate glassing completely over the tip ?

When you say light woven what weight is it ! 3/4 oz csm is only good for putting between layers of heavier glass roving's and the like that's all

I await you next post !!