epoxy

[rjdubiel]

has anyone used this mrfiberglass.com epoxy? he says, "Mr Fiberglass now has an epoxy under the Mr Fiberglass name. It is a high quality product and handles just like the WEST SYSTEM epoxy many of you are familiar with. It comes in many sizes and 3 cure rates. Please refer to the descriptions below as to pricing and working times & temperatures. If you have concerns regarding selection, feel free to call or email me. The pumps are recommended as they make dispensing much easier."

i have emailed him and waiting for a reply. just wondering if anyone has used this or know anything about it.

thanks
RJ

[stokernick]

nope,but why not WEST's?

[rjdubiel]

$$$$ still exploring all different kinds of resin. i get my mind made up then talk myself into changint it. wests is about 450.00 for 5 gal, this mr fiberglass epoxy is 230.00 and 5 gals of poly is 100-150 depending on what kind.

i am not saying i am on a low budget build, but all the $$ saved can be put to good use on a motor for next year.

[Techno]

On the west system the pumps are ratioed, meaning one pump of hardener to one pump of resin.
I bought some other stuff once-and it had 'pumps'. They were not ratioed so you had to pump 5 or whatever of the resin for one of the hardener. This don't seem like a big deal but its much simpler counting one and one, two and two. Than it is doing 3 & 15.
That and if you want small quantities your small quantity is several pump capacities rather than a single.
I only mention it since this is biggest reason I like west system and then someone says they have pumps too.

[hsbob]

dont trust the pumps. epoxy needs to be real close to the ratios. not like polyesters. i'll eithe weigh or use measurements. to much cat will weaken the resin, not enough and it wont cure.

[rjdubiel]

alot of mat fiberglass material says its for poly use only, or that epoxy will not break down the binder is this true? i think i have seen mat that said it was for epoxy use.
thanks
RJ

[jphii]

Go to www.jgreer.com

[FX10 Superboats]

$$$$ still exploring all different kinds of resin. i get my mind made up then talk myself into changint it. wests is about 450.00 for 5 gal, this mr fiberglass epoxy is 230.00 and 5 gals of poly is 100-150 depending on what kind.

i am not saying i am on a low budget build, but all the $$ saved can be put to good use on a motor for next year.

Why not go with Vinylester ???? Same benifits as epoxy, but easy to work with like polyester. Plus the $$$ factor. Vinylester is around $ 39.50 a gal. or $ 155.00 for 5 gal. A no brainer.
Here's a link for you.
http://www.uscomposites.com/polyesters.html

Just scrool down to Vinylester resin

[Riverman]

alot of mat fiberglass material says its for poly use only, or that epoxy will not break down the binder is this true? i think i have seen mat that said it was for epoxy use.
thanks
RJ

Yes it is true. Regular mat has binders that are soluble in styrene.

[Liqui-Fly]

Chopped strand mat & epoxy

By Tom Pawlak

Chopped strand mat, in fabric form, is sold on the roll and in small folded packages. It is made up of 1"-2" long fiberglass strands that are randomly oriented and typically held together with a styrene-soluble binder that acts like glue connecting the fibers. The binder is designed to dissolve upon contact with styrene in polyester resin or vinylester resin. Once dissolved, the fabric softens, allowing it to drape around curved shapes. It comes in a variety of weights between .75 oz to 3 oz per square foot. The most popular weights are .75 oz and 1.5 oz.

In the US, chopped strand mat is nearly always sold or specified in ounces per square foot. This is different than fiberglass cloth and fiberglass fabrics with oriented fiber layers (including woven cloth, stitched biaxial & triaxial fabrics, and the like). These are designated in ounces per square yard. When mat is attached to any of these fabrics (as in fabmat or biaxial with mat), the combined fabric is often called out in fabric weight. An example of this is our 738 Biaxial Fabric, which is a 1508 biaxial fabric with mat. This means 15 oz per sq yard of biaxial fabric plus an attached 0.8 oz per sq foot layer of mat.

The big question

Can WEST SYSTEM® epoxy be used to wet out chopped strand mat? The answer is yes. 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.

The texture of the chopped strand mat is quite rough given its random fibers (many of which come loose when epoxy is applied). Mat requires a number of coats of epoxy to fill the profile at the surface. 879 Release Fabric can be applied over the freshly wet-out mat to compress the fibers and minimize the need for many of the buildup coats. Using release fabric in this way will result in a much smoother surface, and if you are going to allow the epoxy to cure before continuing, the surface is ready for buildup coats of epoxy or fairing putty after the release fabric is removed.

4 mil plastic sheeting can also be used over the still uncured epoxy and mat to compress the fibers. Trapped air bubbles can be removed by piercing or slitting the plastic over the bubble before the epoxy begins to cure. If the plastic was clean when it was applied, you can pull the plastic after the epoxy cures to a hard gel and apply epoxy fairing putty or buildup coats of epoxy later the same day. If you allow the epoxy to cure hard before pulling the plastic, be sure to sand the surface completely dull before applying more epoxy.

When choosing chopped strand mat to be used with epoxy, look for mat that is soft and pliable. Some forms are quite stiff and may cause problems wetting out with epoxy. Stiff mat is often older stock and the fibers may take more time to wet out with epoxy.

Stitched mat

There are chopped strand mats produced without binder that work extremely well with epoxy. These products are referred to as stitched mats. The random oriented strands are held together with light stitching, which runs parallel to the length of the roll and is spaced about 3/16" to 1/4" apart over the width of the roll. The stitching eliminates the need for binders. These products tend to wet out a bit faster with epoxy and become more flexible on average than generic chopped strand mats.

These stitched mats are suitable for use above and below the waterline for marine applications. Roll mat, the type held together with binder (not stitched), is used by some of our customers for new construction and repair for below water applications, but we have had some reservations on this if the boat stays in the water.

Testing in warm/moist conditions

To see if our concerns were justified, we compared samples of generic chopped strand mat (wet out with WEST SYSTEM 105 Resin and 206 Hardener) against samples made with our Episize™ fiberglass fabrics (wet out with 105/206) in moisture uptake testing under warm/moist conditions. The test environment was a room we affectionately refer to as "The Amazon Room". This room is maintained at 100°F and 100% relative humidity, jungle-like conditions. All of the samples were accurately weighed on a gram scale before entering the chamber. Each specimen was weighed periodically until no additional weight gain was observed. The samples made with generic roll mat and epoxy experienced an average 2.3% weight gain over a two-month period. The Episize fiberglass/epoxy samples gained weight at a slightly lower percentage of 1.9%.

Wet-out chopped strand mat and woven fabric test samples are prepared for moisture uptake testing.


Visually all of the fiberglass/epoxy samples "whited-out" or became slightly more opaque during the test. We were not concerned about this because there were no obvious differences in appearance between samples made with our Episize™ fiberglass and samples made with generic chopped strand mat. Our test included three specimens of chopped strand mat, two different sources of 1.5 oz and one 3 oz. One of the samples was made with generic mat found on the fiberglass rack in our shop, and the other two were purchased from Composite Structures Technology in Tehachapi, California. (661-822-4162)

Conclusion

Chopped strand mat can be used effectively with WEST SYSTEM epoxy for a variety of marine projects. Based on the results of our moisture uptake testing, we would feel comfortable using the mats that we tested for below the waterline applications including hulls that stay in the water for extended periods. Like any fiberglass applied to surfaces that will be used below the waterline, barrier coats of epoxy are necessary over the fabric to provide the moisture barrier required for long-term protection.

Epoxyworks 21 / Summer 2003

[mr_velocity]

Why would anyone what to use chop strand mat. Its weak and heavy compared to other materials. Do it right and use a double bias cloth (45x45), if you need thinkness use a good core. Doing it right and cheap usually don't go together.

BTW, talked to Peter a skater, they tried cloth backed with strand mat (1708) and had failures between those layers. Based on what Peter found in real world performance conditions I wouldn't use it with epoxy.

[tunnels]

Why would anyone what to use chop strand mat. Its weak and heavy compared to other materials. Do it right and use a double bias cloth (45x45), if you need thinkness use a good core. Doing it right and cheap usually don't go together.

BTW, talked to Peter a skater, they tried cloth backed with strand mat (1708) and had failures between those layers. Based on what Peter found in real world performance conditions I wouldn't use it with epoxy.

There is a lot to think about at stake here !
Csm is not for use with epoxy !!
and only minimal amounts of csm should be used with Yinylester !!
Yes vinylester is much easyer to use ,has almost the same strenghts as Epoxy , but do your home work as to whitch one is best for you . Carefully think about the glass thing to !.
Stitched cloths and the like use less resin for the same glass weight than woven but there shear strengths are quite differant .
Csm can use up to 1.5 to 1.75 or even heigher x the amount of resin to glass just to wet it out .
Cloths can be down to 1 to 1 if you are carefull . Check out what glass is best for your situation .
Doing it right is the cheapest option as you do it once and dont have to do it again .

[sho305]

I had a hunk of heavy (well, not huge but heavy for what I needed) old csm I used on my transom. I laid it on the inside over the wood to the sides. It had heavy 1/4"+ thick glass about 2" or more around the edge of the wood and so thin in the center it all fell out with the rotten wood. So I fit the wood into the old edge and laid this on there, then some cloth around the edges and at bolt areas just to make sure. After about a minute it turned so clear I could not see the glass, could still see the grain of the new ply easily. The mat was about 1/8" thick dry and could not see through it. This stuff was from near 20 yr ago when I was repairing some vettes. So it had more on it than before, that was good enough for that. But if I did a nicer boat I doubt I would use hardly any mat.

There are other epoxies, this one was recommended by a guy that made his own race boat. http://www.fgci.com/ I like the wests a lot, but I think there is more need for it in a repair like my transom than when you do a large area like a recore with much, much more bonding area. My transom only has limited places to bond to the old so I used epoxy. It is likely I would use it to core with too though just maybe a cheaper but recommended brand if cost was an issue.

Here is best pick I can find, not sure if I was done yet but that is the heavy mat on there. Took a little to get it around those corners. Just worked it with gloves on and it went. It looks dirty but all that white was ground with 24 grit or so.

[tunnels]

has anyone used this mrfiberglass.com epoxy? he says, "Mr Fiberglass now has an epoxy under the Mr Fiberglass name. It is a high quality product and handles just like the WEST SYSTEM epoxy many of you are familiar with. It comes in many sizes and 3 cure rates. Please refer to the descriptions below as to pricing and working times & temperatures. If you have concerns regarding selection, feel free to call or email me. The pumps are recommended as they make dispensing much easier."

i have emailed him and waiting for a reply. just wondering if anyone has used this or know anything about it.

thanks
RJ

Cure or gel ?? Dont get confused with these two . Its will gel or go hard but not cure for days if the tempature is to low . To make resin cure to its potentual hardness it needs heat to cook it so to speak . Check as to the time and the temprature to achieve the proper cure something like = Like 24 hours at 25 degrees C, can make a huge differance to the articals performance / hardness . "This applies to all resins" with no exception !! .

[tunnels]

There is a lot to think about at stake here !
Csm is not for use with epoxy !!
and only minimal amounts of csm should be used with Yinylester !!
Yes vinylester is much easyer to use ,has almost the same strenghts as Epoxy , but do your home work as to whitch one is best for you . Carefully think about the glass thing to !.
Stitched cloths and the like use less resin for the same glass weight than woven but there shear strengths are quite differant .
Csm can use up to 1.5 to 1.75 or even heigher x the amount of resin to glass just to wet it out .
Cloths can be down to 1 to 1 if you are carefull . Check out what glass is best for your situation .
Doing it right is the cheapest option as you do it once and dont have to do it again .

An up date on the CSM thing .
There are 2 types of csm mats .
E matt has emoltion binder that is sprayed on the choppie matt as it is being made to hold it all together then heated up to evaporate the moisture out of the binder , whats left does not break down if you use epoxy resin ,but it is soluble in polyester and vinylester , as long as it is not a fast gelling brew of resin you are using . So the eventual strenght factor is lower .
P matt has a powder binder this is a powdered resin product sprinked over the choppie as its being made then baked at a high temprature to melt the powder and stick the glass strands together , then Yes you can use Csm with epoxy and the strength with any of the 3 resins systems ( polyester , vinylester and epoxy) is slightly higher .
Its also recomended to use p matt against the gel coat if the boat is kept in the water for long periods to help guard against the pox!! and it can help with print through from the glass matt pattern behind the gel coat.
P matt wets out quicker than e matt ,it is slightly harder to lay around sharp corners than e matt.
The wee bundles of glass fibre strands are saturated out much much better and so the strenght is higher .
Just something else to take into cosideration when you go to the glass shopto buy you glass etc .