Advice on a layup schedule.

[mogfisher]

Hey folks. It's almost time to lay the transom and I need help with the layup. I have questions about 2 parts of my restoration. The transom and the stringers.

The transom will be the 1.5" ply adhered to the outer skin with 2 pieces of half inch on either side. All gaps and edges will be filled with a mix of resin/cabosil,milled fibers. I have on hand a huge roll of woven roving, and tons of 2 oz mat. I planned to put 1 coat of mat down over the whole transom/side panel area. Then a layer of woven over that. Then, after I put the flooring and knee braces in, another layer of or two of 2 oz mat over the whole shebang. Originally the fiberglass was not that thick on the inner skin, but did appear to have some woven cloth in it.

The other question is about the stringers. My boat does not have wooden stringers. I has large foam filled fiberglass stringers. I had to cut the top off of them because the foam is wet. I plan to fill them with foam, cut the foam flat accross the top and glass them back up. The glass is somewhat thick. Almost 1/4" in some spots and it does have cloth and mat (or chopper gun). I am wondering if the woven roving I have is going to have trouble with the corners here. Should I get a lower weight cloth? I was hoping to do 1 layer of 2 oz, a layer of woven, and 2 layers of 2 oz here too. Unless you guys think I'll have issues with the woven over the stringers. The edges are quite rounded but it's still a 90 degree turn. The roll of roving I have is approx 1 foot wide and about 1.5 feet in diameter so I have a lot of it and it was free so I'd like to use it. I really appreciate the feedback! Heres some pics.

 

[bigredinohio]

Re: Advice on a layup schedule.

What size boat is this and size motor you plan to run and are you using polyester or epoxy resin? Alsoi, it's advisable that you layer csm between the layers of WR.

For the transom, I would glue the wood in place. Then fill and fillet (filling an edge to make it round) with your PB (peanut butter or thickened resin), then tab those areas to reinforce those joints. After that, add no less then two layers of woven roven. Depending on the size boat and motor, I would even consider going a third. Be sure to sandwich with csm to all a smooth surface for the WR to bond to and extend each layer past the previous.

For your stringers, you could make a jig of sorts or use clamps to help hold or mold the thick glass in place. I wetted out my fiberglass, laid in place then covered it with wax paper to prevent sticking then applied clamps on a 2x4 to make a nice 90 degree angle with 18 oz. WR and 1.5 CSM on my splashwell. It worked fairly nice. You might want to fabricate the stringers then glue and tab then in place afterwards instead of trying to do it in one shot.

Hope this is helpful.

 

[mogfisher]

Re: Advice on a layup schedule.

Thanks. That does help. Its an 18 foot bass boat rated for a 150 hp motor and that's what will be going on there. I am using poly resin.

That sure sounds like a lot of glass on the inside of the transom! I'm imagining how thick that will end up being and I'm guessing it will be twice as thick as it was from the factory. I guess it's better to overbuild than underbuild though, right?

Did you build the molds because you had an issue with sharp bends? Maybe the only way I'll find out is to try it.

I have another question. I see many people wet out the glass and then put it in. I've only worked with csm before and always did fine just wetting the surface, placing the csm, and then applying resin to the outside. Is this not possible with woven? What is the reason for wetting the glass first? There must be a reason if so many of you guys do it.

 

[ondarvr]

Re: Advice on a layup schedule.

Don't use more mat than needed, it adds less strength and much more weight than roving.

use a mat, roving, mat, roving, layup, mat as the top layer may give better cosmetics at times, but doesn't do much more than that.

There is no need to wet out the glass and then put it in place, just wet it out in place. There are times when it needs to be done though.

As for the radius, it just depends on how tight it is, try it and see, it may be fine.

 

[mogfisher]

Re: Advice on a layup schedule.

Awesome. Thanks! A couple more questions.

I should treat the mat/roving as 1 "layer" correct? By that I mean when extending the top layer over the previous I don't want to extend the roving past the mat.

Also, is csm enough for my floors and such? I had planned 1 layer of mat on the underside of the flooring before putting it down and then probly 2 layers on top. Sound like a good plan? I obviously have enough roving to put on the floor but seems like overkill to me. Am I correct?

Thanks again for the help. I wouldnt even attempt this without this forum.

 

[ondarvr]

Re: Advice on a layup schedule.

Correct, the roving shouldn't extend past the mat, but you don't need to limit yourself to just a single layer of mat and roving at a time. Depending on the resin, ambient temp, size of the lay up, your skill, etc, you can double that and get done much quicker.


For the bottom one mat is fine, I might go a little thicker on the top side, a mat and a light cloth works well, its durable and smooth. A mat and roving works, but the surface will have a roving pattern. Both of these will be lighter and stronger than 2 mat, two mat will still work though.

 

[bigredinohio]

Re: Advice on a layup schedule.

....

 

[NSBCraig]

Re: Advice on a layup schedule.

Throw that rovin in the trash and buy some biaxial.

2 layers on the transom and it will loads stronger ten it ever was.

 

[erikgreen]

Re: Advice on a layup schedule.

Depends on a lot... the weight and direction of the biax, how it's applied, etc.

Since he's already got roving, that's just fine for this. More boats have been made with mat/roving layers than any other cloth...

I did my boat with epoxy and biax, but then I like overkill...

 

[mogfisher]

Re: Advice on a layup schedule.

That may be good advice, but lets not forget that this is an old tracker boat here. Maybe if I was redoing a high end boat with a huge motor I would spend some more dough on the materials like epoxy and biax.

 

[mogfisher]

Re: Advice on a layup schedule.

I just discovered my woven roving is 18 oz. I really wasn't sure what it was but one of the rolls is new and had a tag on the end of it. I think there is also a roll of something a bit heavier back there but it may be the same. I also came across a roll of what I'm thinking some of you refer to as "finishing veil". Its a 4 foot wide roll of the stuff that you buy at auto zone in the little packets. Maybe that will give me a nice finish on the last layer of roving instead of mat and save some weight? Any good use for the chopper gun and the huge roll of gun roving? LOL. I was thinking that I could chop some strands up (it makes about 1" strands) and add it to the mix when I do my fillets? Too course? It looks like you can change the strand lenght by adding blades to this gun. I don't know. Probably not worth it though when milled fibers are so cheap.

 

[mogfisher]

Re: Advice on a layup schedule.

OK. Just one last question and I think I've got what I need to get started. For the woven layers on top of mat, obviously there will be multiple pieces. Should the pieces overlap or butt against each other? Obviously I would stagger any seams on the next layer, but I'm guessing the need for mat in between layers of woven is to fill the large gaps left by the woven. That would make me think that I would butt my pieces of woven against each other instead of overlap them. Correct?

 

[mogfisher]

Re: Advice on a layup schedule.

anyone? Please. Thanks!

 

[Mark42]

Re: Advice on a layup schedule.

If the layup is many layers, butt ends are OK, if staggered. If the layup is only two or three layers, I would overlap, and stagger. If the layup is not a finished area, then raised areas from overlap is not an issue, like the inside of the transom and the stringers.

Regarding the roven following the curve of the stringer, be sure to have a disposable hair brush sitting in a jar of alcohol to go back and press the glass down as the resin kicks. I have read where some members have used a staple gun to pull the glass tight to the radious while it kicks. Never tried it, but apparently it works. Not sure how it will work with your foam/glass stringers.

A lot of repairs involve using your ingenuity to make the job easier. Let us know what you come up with.

 

[mogfisher]

Re: Advice on a layup schedule.

Awesome. Thank you. I also ordered a roll of 6" 1708 biax tape for the seams and joints today. That should help stiffen it up a bit too. Cant wait to get started! Thanks everyone! I'll post up some pics when it's done.

 

[Fisherball]

Re: Advice on a layup schedule.

I'll be looking at this in a few months when I tear mine apart.