Inner skin of transom Q's

[drewmitch44]

When glassing how does it go again Mat, roving, mat, roving, mat. In that order??? Im about to get er done and im just curious what the recomended method is. Thanks a lot guys. I know its been talked about before but i couldnt find it with the search function.

mat-roving-mat-roving-mat?????
roving-mat-roving-mat???

Also i have cloth as well but i thought cloth was for finishing stuff like cosmetic kind of things. Thanks a lot guys!!!

 

[rockyrude]

Re: Inner skin of transom Q's

Yep, for strength mat-roving-mat-roving to make the inside reasonably smooth finish with a layer of mat or the grain of the roving will be hard to hide

 

[drewmitch44]

Re: Inner skin of transom Q's

So i should start with mat and end with mat? Is that correct??? And how manny layers????

 

[Bondo]

Re: Inner skin of transom Q's

Ayuh,.....

The Idea with the Mat is to give a Resin Rich layer,+ it goes Under any Rovings or Fabrics.....
If you want to end your lay-up with Mat,...
Go for it,... But it's Not necessary.... It'll just make the surface slightly Smoother....

 

[drewmitch44]

Re: Inner skin of transom Q's

So what is recomended? It dont matter to me how smooth it is. Im going to sand/paint anyways. What is the recomended method? Really i was only going to use the roving around the edges where the transom and the hull bottom and sides meet to give it that needed strength. So my origional plan was to use the mat and then just use the roving like i said on the sides of the wood to join it to the hull and use the mat to sandwitch inbetween the roving. So the middle of the transom would have no roving. Is that a good plan or what should i do?? Thanks for your help on this guys! I really apreciate it!!

 

[ondarvr]

Re: Inner skin of transom Q's

I can't remember if you're using epoxy or polyester (sorry).

while mat will add some strength, it won't add nearly as much as roving, so if you just want to seal the wood, then mat will work fine, if you want to add strength, then use roving also. Yes, mat is the first layer when using polyester and should be used between each layer of roving or cloth. You don't need mat with epoxy.

 

[drewmitch44]

Re: Inner skin of transom Q's

any other sudjestions? im putting mat on now.

 

[BillP]

Re: Inner skin of transom Q's

It doesn't matter which one you end up with but start with mat and use it between woven. Mat has totally different structural properties than woven. It adds stiffness and strength that woven can't give without heavier layups and higher weight. Mat's often overstated "weakness" in tensile strength (compared to woven roven) is greatly offset with it's (random fiber) stiffness. Lb for Lb, laminates of only woven are way more flexible than those layups used with mat. Mat and roven are an "engineered system" to be used with each other no matter what resin it is...that's why every production boat on the planet uses laminations of mat with woven.

Do you want to test it in person and remove all doubt? Laminate two 12"x36" panels. One with two layers of 1.5 oz mat... the other with one layer of 24oz woven roven. The weights are close (27 oz mat compared to 24 oz woven) enough to show how it works. It doesn't matter what resin is used. When cured, put one end in a vice or workbench and start destructive torturing and bending etc. The mat will be stiffer than the woven by a large margin. The mat will also surprise you how strong it really is...compared to perceptions about it being so weak.

bp

 

[ondarvr]

Re: Inner skin of transom Q's

Mat does have some strength and many other desirable characteristics, but don't confuse stiffness with strength. Mat is engineered out of any laminated that it can be, because the same strength can be had with much lower weight when it's eliminated. One big reason for using mat, is for a good surface profile, when woven or stitched products are used too near the surface they tend to print through and can easily be seen, mat can reduce or or help eliminate the print. They're also used to bulk up a laminate so it will be stiffer, frequently the flex is perceived as weakness by the consumer, so mat, or another type of stiffening product is used.

In hand lamination mat is important in keeping the layers of woven or stitched glass bonded to one another.

 

[Coors]

Re: Inner skin of transom Q's

If you use epoxy, this constant conversation will go away.

 

[erikgreen]

Re: Inner skin of transom Q's

Use epoxy and biaxial-biaxial-biaxial. Less work, stronger than mat/poly, and fewer headaches keeping it from unraveling

 

[ondarvr]

Re: Inner skin of transom Q's

If he's using polyester and has already started, it's a little late to switch.

 

[BillP]

Re: Inner skin of transom Q's

If you use epoxy, this constant conversation will go away.

What is "this constant conversation" and how does epoxy make it "go away"?

bp

 

[ondarvr]

Re: Inner skin of transom Q's

I think the "constant conversation" works out well, I learn a great deal from the exchanges. Plus it gives a much deeper look into what these (all) products will and won't do, this hopefully gives each person enough information to choose the products and methods that will fit into their budget and still achieve their goals. Many times there are several "right" answers or options, although not everyone agrees (which is fine) which one may be the best, the pros and cons of each method get discussed.

 

[BillP]

Re: Inner skin of transom Q's

Mat does have some strength and many other desirable characteristics, but don't confuse stiffness with strength. Mat is engineered out of any laminated that it can be, because the same strength can be had with much lower weight when it's eliminated. One big reason for using mat, is for a good surface profile, when woven or stitched products are used too near the surface they tend to print through and can easily be seen, mat can reduce or or help eliminate the print. They're also used to bulk up a laminate so it will be stiffer, frequently the flex is perceived as weakness by the consumer, so mat, or another type of stiffening product is used.

In hand lamination mat is important in keeping the layers of woven or stitched glass bonded to one another.

I'm listening but anyone confused about mat use should do a few test panels with and without mat to understand why its used in 99.99% of all glass products that need structure...with polyester or epoxy. The only alternative (for best engineering, lowest cost, best weight, least labor) to eliminate mat is to angle woven plys like biaxial but it's labor intensive and uses more materials to get the same stiffness. There's way more to mat than than preventing print though and woven ply peel. Disclaimer...there are always exceptions.

bp