Been looking into resins a little more....

[EdBerg]

Just to be clear, you need two sets of rollers, one to wet out the glass and the other, a metal set to work the glass to remove the air bubbles. Both can be washed out with acetone, especially the metal rollers.

As I said before, my metal rollers are 45 years old and easily cleaned. The foam/mohair rollers can also be washed but you have to calculate the cost of the acetone to do so VS the replacement cost of the rollers. Never used mohair, always used a medium map type foam/fiber that is suitable for solvents.

Not sure what you are referring to as the "Pour" method, but if it is what I suspect that you pour the resin straight from the container on to the glass then I would advise against it.

As you said that you have bought a box of 600gsm woven roving, you will have to sandwich the w/roving with a layer of 450 or 600gsm chopped strand mat on either side in one go. When I glass in stringers I use 24oz woven roving with the 2oz(600gsm) CSM either side, don't know what these imperial measurements of the W/roving equate to in metric, but then again I also don't use epoxy.
If you are glassing the stringers in, then make sure that there is a radius on the top of the beams as well as on the bottom where they touch the hull floor. The bottom radius is made with a filler mixed with catalyzed resin till it becomes thick paste. Glass does not like sharp corners.

Lastly if you haven't already discovered it, w/roving does not stretch in the the direction of the fibers, you can twist it diagonally though.

Here is a link to using the metal fiberglass rollers. Although I would laminate the glass slightly differently to what he does it's not too bad a video just that he used way too much resin, just wanted to let you see the metal roller in action.



here is another video



The bottom image are my set of rollers I use, apart from brushes and a smaller paint roller for smaller jobs which I couldn't find, with these I have built everything from 35ft cabin cruisers down to small fiberglass parts, so don't need much more. There are 2 paddle rollers and the 3 threaded rollers I made myself.

Cheers
Ed.

[gazza2006au]

Ed do u suggest using the chopped mat with epoxy? I thought using epoxy and woven roving alone would be fine?

I'll try find the map rollers

[EdBerg]

You would have to confirm that the chopped strand map that you have is compatible with epoxy, (there is a high probability that it will be). Do a small test with epoxy to see if it wets out OK with the metal rollers, but yes in my opinion you should use CSM with the woven roving(W/R).
W/R on its own when you roll it out will contain little pockets of resin where the fibers criss cross each other which weakens the layer when you add a subsequent layer with more pockets of resin, the CSM fibers get forced into that little pocket and reduces the excess resin making it much stronger and also helps it to stick to each subsequent layer you add. (Resin is brittle). In fact I just did a repair on a boat recently that someone had used cloth without CSM between layers to repair a patch, and you could easily pull each layer apart, had to grind the lot out and redo it from scratch. Wasn't happy as it was a crappy job to do and I really, really hate sanding.

The bottom wooden handled rollers are the ones I use the most with the small little one in the middle with a wire handle for smallish fiddly work. The bigger aluminium paddle rollers are for bulk work when I need to roll several layers at once as in a CSM/WR/CSM layer. But be warned those spray the resin every where when you work at speed which works to redistribute the overly resin rich areas to areas that need a bit more resin. How you use those will change as you get experience rolling and using them and also the job you are doing. There is a variation of that type of roller whereby not only it has the grooves running length ways along the roller but also it has circular grooves as well at 90degrees to those. While I can see some benefit to it I haven't had the need to get one.

Usually I coat the area with resin, then give the first CSM layer a resin rich cover, then cover it with W/R layer with resin and then a very light coated CSM layer. Work the 3 layers hard with the Paddle roller, and you can force the resin from the bottom layer to the top of the third layer, using the paint roller to lightly touch up any dry area with slightly more resin, finally finish off with the thicker threaded rod roller.

As I said before I don't use epoxy so don't know the viscosity of the resin you are using but it should be similar to work. You might have to roll each layer if the resin is too thick, but those metal thread rollers are a must to do a good job, especially with W/R as they force the resin in between the tightly packed fiber bundles. They also wash out easily enough with acetone. If for some reason I leave it too late to clean I wait till the resin goes hard and just hit it with a propane torch, followed by a wire brush and good to go again.

At least that is how I do it but there are many ways to skin a cat so to speak and I adapt to the job. But those three types of rollers are the minimum you need to wet out glass. I made mine from threaded rod or a cut off bolt, not sure now is it was about 47 years ago. You should not use the paint roller with resin on its own to laminate, it creates a resin rich but brittle weaker layer. As the saying goes "less is more". Hope I have explained it all correctly.

If you are still having problem with wetting out there are a couple of possibilities, the fibers have been coated with a binder that is only soluble in Poly/Vinyl ester resin. I think that there are two types of binder, a powder type for epoxy which works on most other resins and a styrene based binder for the vinyl/poly resin, and the other possibility is that the cloth/W/R/CSM has absorbed too much moisture from the air.

Personally I think that not using the metal rollers will be your issue.

Double Bias and Triax cloth etc., is a little different in that the bundle of fibers are stitched together rather than coated with a binder, I personally would still generally use a CSM between layers depending on the job. You can also get a 225GSM split fiber CSM as well as a fiberglass tissue but they are expensive and are mainly for mold work or very fine finish.

Cheers
Ed.

[chris69]

Its. all bit weird, i think ED is on the money with the binder theory, how much epoxy are you using for a square meter 450grams should be very wet with 1lt of resin and 200ml of hardner 1.2lts to a lineal meter of 450gram db and id have 27 gram tissue and peel ply over that too.

[gazza2006au]

Awesome Ed thanks heaps for your post i was panning on going 2 layers of woven with epoxy than i thought about glassing the side of the stringer to the floor and than running some double bias over the top as the stringers are 25mm

i will do it your way CSM/WOV/CSM i will have to ask on Monday when i pick up the cloth if its able to be used with epoxy it should be well I'm hopping it will be

i have seen both of those rollers i had the strait roll line roller but i have also seen the other roller online

Ed i think u hit the nail on the head something i never thought about before, When i start glassing in the day my yard is shaded by a gumtree and a huge mulberry tree my grass is still wet and its Winter so there is a little mist around in the air i think as i am bringing the cloth out it may be absorbing the moisture from the air and that maybe why its hard to wet out

Chris i think i found a calculator months ago online that would calculate the cubic inch of a transom once u put in all the dimensions my transom came out to 2 square meters i just mix up the resin and roll with it untill its all wet out i may have kept track in my build thread but i can't remember off the top of my head how much resin i was mixing up

[EdBerg]

No problem, hope it works out for you, don't forget to put a rounded corner on the top of the stringers as glass does not like being bent at 90degress, especially W/R, as it hardens up it will try to go round and will suck air in at the top, and no amount of rolling will remove it. Definitely get the threaded and paddle rollers, will make your job much easier. You could always do a test sample say a couple of 70mm strips over a scrap piece of timber similar to the stringers so you will know what to expect and no surprises if you know what I mean. Epoxy isn't cheap so you don't want to waste too much of it or even worse make a stuff up that you have to remove and redo it.

I don't know how quick glass absorbs moisture but it would be better to keep it in a sealed box till your ready to wet it out. Once wet it shouldn't matter with epoxy as it it moisture resistant unlike the poly resin which will leave a very sticky uncured film if there is too much moisture.

Cheers

Ed.

[gazza2006au]

Ed see the video u linked about the csm with polyester and epoxy see the epoxy side how the resin doest absorb thats how my luck has been with double bias it take a little while to soak in and go translucent

I should be picking up the woven roving on monday i'll do a test when i get some off cuts of the plywood

The local glass supply shop sells both types of csm in rolls $180 what weight should i go with?

[EdBerg]

Gazza, I have sent you a PM.

[tug_tellum]

I agree with Ed. You require powder bound matt for epoxy. Sounds like you and I have had about the same amount of experience Ed. I started in fibreglass when I was 19 and it was going to just pay the bills until a proper job came along. I am now 65 and still waiting for a proper job to come along. I have also had little to do with epoxy. As a member of the Low Tech Bucket and Brush Brigade its not something that is common. More commonly used in high end composites in conjunction with Carbon Fibre and other weird and wonderfull matrix (hows that for a cool word) which there is no point in going into here as it will only confuse the issue at hand.
Ed can you still get 225 Split Strand Mat? I can get 225 Chop strand but not split strand as it hasnt been available for a few years now. I could really use a roll or two if I could lay my hands on a supplier.
Word of advice for anyone repairing/refurbishing a boat,the easiest way is to use Polyster resin and csm with emulsion binder. Woven roving is fine for rigidity where its required ,which is usually in the hull or deck. Rule of thumb is whatever amount of glass you use under woven, use the same amount on top. When I made boats we used to spray the stringers and bearers by gun (continuous roving chopped by the gun and sprayed with the resin) Never have I worked in a shop that used woven on timber bearers or stringers. Some of you guys try to get too techo when there is really no need for it. Spend the time enjoying your boat not working year after year to make it bullet proof.
OK thats my opinion on it all,I stand to be corrected but as I say that is only my opinion.
Cheers
Mick

[EdBerg]

Hi Mick, you are right, pretty much the same history, I got out of fibreglass when I was about 28, except that I keep getting dragged back in every time I get a boat, build one or to make parts or repair them. I loath the stuff now especially when doing repairs, making stuff out of it isn't too bad. Strange about your history with W/R, I have never worked in a place that didn't use W/R over the stringers and I tried really, really hard to avoid working in places that had a chopper gun .

Never had any dealings with Epoxy in all my years so any advice I can give is based on Poly resin and laminating it. I didn't realize 225GSM split strand has been discontinued, rang a couple of places to check for you without success.

[tug_tellum]

Thanks for checking on the 225ssm ,it was worth a try. Hasnt been available for a few years now.
The only boats I was involved with were small stuff 12ft - 18ft in a couple of places and neither of them used woven over stringers or bearers.
I was a gun operator at a few different shops and found it boring as bat $hit spraying all day long. Couldnt care if I never saw another gun again. Cant do really big products without one.
Suppose it wont be long before I retire unless a proper job comes along.
Oh well ,I will keep it up till then.
Mick

[EdBerg]

Hey Gazza, Just an update, I did some ringing around the suppliers for Mick chasing the 225gsm split strand and whilst I was taking to a couple of them I asked about the epoxy and the CSM. I was right, you do need to use the powder bound CSM otherwise with the common styrene binder based CSM, it will appear that it isn't wetting out and looks opaque even using metal rollers to try to wet it out, it will still have trouble binding to the fibres and so it is not recommended unless you use the powder coated glass.

It looks like CSM isn't used much with epoxy because the CSM absorbs way too much epoxy resin for no benefit, and secondly, you apparently can use the woven roving (and most of the stitched cloths) without the CSM in between using Epoxy, just make sure you put a good layer of epoxy on the stringers before you lay your first layer of W/R on top of them, as well as adding a corner fillet of "bog" to the bottom of the stringers where it touches the hull to make a radius there. As I said before, I have never used epoxy before so can't advise you too much on it uses. With the poly/vinyl, then yes, put in the CSM between layers.

Cheers
Ed.

[EdBerg]

Mick, Damn, that is a long time to be doing fibreglass.

[gazza2006au]

Thanks guy's Thanks Ed i will use the two layers of woven roving without the chopped mat, i need to lay down 17 square meters and double that with the WR, with the CSM it was looking at the same cost as using double bias as the mat would eat up all that extra cost on the resin but now u mention i wont need the CSM it should still be reasonably cheap

the epoxy resin is $420 for 24kg, poly is like $200 so its not that big of a leep to go with epoxy

[gazza2006au]

I'm going to take the glass sheet approach where i will wet.out the woven roving on a sheet of glass, lift it up than lay it over the stringer i think this would be an easier aproach that trying to wet out the cloth in position