woking with mat and roving

[wiz]

i have a 15' x 2.5' sheet of .75oz mat and 18oz. roving to put on the sides(inside) from just behind bow to transom of my project, thats the 15'. The 2.5' goes from floor up sides and over the railing to outside. When i lay out mat and apply resin do i need to use my bubble roller to get bubbles out before i put the roving into place wet out and roll bubbles OR can i wet mat, put roving on, wet roving out, then use bubble roller on both at same time? I'm using poly resin and am doing it solo.

Anybody want to offer any tips on doing such a big area?

 

[sdunt]

Re: woking with mat and roving

Yes, do jell time tests on that resin BEFORE you start using it.. You want a nice slow set. Based on materials I have used in the past I would suggest US Composites B-440 resin. http://www.uscomposites.com/polyesters.html

And, yes I would roll out each layer separately with the fiberglass roller, that does a lot faster than you think. I would probably let the resin start to setup - jell quite a bit before I installed the next layer. So long as you use UN waxed (not a 'finishing' resin) then your 2nd layer will bond nicely without the need to sand between layers.

You might also use the 'wet' method of putting on the mat. apply a layer of resin to, what are we covering by the way?, then put the matting into the resin. DOB on more resin, if you try to brush more resin on to matting it will come apart and bunch up. Roll out the mat as you work from one end of the boat to another. Then go back after the mat layer has started to jell and put on a 2nd layer of resin and lay the roven into that. Then you can brush or roll on more resin.

You can actually do all of this work with UN waxed resin and come back tomorrow and brush or roll on a layer of Waxed finishing resin.

Please read about the disaster I had with resin, and test this before you start on the boat..

http://www.shareaproject.com/pages/imageDetail,p,148,i,4049,00.html

 

[wiz]

Re: woking with mat and roving

Thanks sdunt,

This is what i am covering "sides(inside) from just behind bow to transom of my project, thats the 15'. The 2.5' goes from floor up sides and over the railing to outside". In all a 15'x2.5' section

I thought the pupose of using mat with roving is to put roving onto not-yet-gelled mat so that the mat would fill in behind the roving's weave giving more bondage for the roving?

could i use a roller designed for epoxy to roll on poly resin to the mat or would that pick up to much strands and make a huge mess? THis a huge vertical section not like a floor so getting resin to mat in proper time is a huge concern.

 

[sdunt]

Re: woking with mat and roving

Mat is actually used to fill in the weave of roving or cloth. A vertical surface is the PERFECT place to use the 'wet' method where you can put 1/2 of the resin on before you have to try and force resin into the matting.

Yes, an epoxy like roller would be good. I have not used one on mat, so I don't know if it will pick up fibers as it goes along or not. You need to see what works. Have both available, roller and brushes.

I stock up on these when Harbor Freight has a sale, like now: http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=4182

This is 36 brushes for 9 dollars. You can print the sale price page off the internet and take it in to a harbor store and they will give you the internet price.

I know that getting resin on to vertical surfaces is a pain.. I did the inside of my transom.. Its kind of a scoop and carry the resin over with a brush in conjunction with, in some cases, pouring resin on the surface. Again slow(er) set time resin.

Also that fiberglass roller does the job of compacting all of the fibers together for a complete bond. Its interesting to watch factories where they use 'chopper guns' where they are literally spraying on chopped fibers mixed with resin and catalyst on a mold for a boat. And the worker STILL roll out the entire surface with fiberglass rollers.