1968 Larson rebuild

[bp1313]

Re: 1968 Larson rebuild

more pics from the same place as the last post:

 

[bp1313]

Re: 1968 Larson rebuild

There has to be some feedback out there... Let me know if I need to post specific pics or explain anything I ended up doing. I'd like this boat to last awhile (mostly because I underestimated the $$ involved so I wanna make sure what i'm doing is alright.

Gracias!

 

[Woodonglass]

Re: 1968 Larson rebuild

What did you put over the Transom? Did you tab it to the bottom and sides of the hull with mat and cloth? CSM does NOT have any structural strength and will not be adequate for holding the transom in place. Did you fillet the sides of the transom? What did you Bed the Stringers to the hull with?

 

[petertay]

Re: 1968 Larson rebuild

Hello bp1313. Thank your for sharing your project. I am doing the same project on the same boat, and as I've never done such, am very interested in following your progress and studying the pics.
WOG reminds us that CSM is not particularly structural. I wonder, then, why we use it?

 

[coolbri70]

Re: 1968 Larson rebuild

do you plan on adding foam? your stringers look heavy, adding a bilge?

 

[jbcurt00]

Re: 1968 Larson rebuild

WOG reminds us that CSM is not particularly structural. I wonder, then, why we use it?

Previously, it was recommended to use CSM 1st in a layup schedule to create a resin rich layer to prevent the 1708 layer from being starved of resin in the layups, and not getting an adequate bond w/ it's substrate. Treating the CSM as a 'primer' for the finish coat 'paint' layers of 1708. Ensure good adhesion & coverage. All that ^^^ is using 1.5oz CSM.

1708 does have 3/4oz of CSM stitched to the back. Some (many/most?) consider that 3/4oz CSM to be insufficient for the 1708 to create it's own resin rich bonding layer. There has been some suggestion that in certain applications & situations the CSM stitched to the back of 1708 IS sufficient, and some no longer use the 1.5oz CSM as a bonding layer.

WOG's 'original' stringer, transom & deck layup schedule graphics in his signature line, has been revised recently (Feb 2013 I think) & now reflects that the 1708's 3/4oz CSM backing is sufficient on the stringers.

Some of those no longer using CSM are also skipping it because it can be difficult to work w/ once it gets wetted out w/ resin, AND they think it offers little additional strength & benefits, I think Friscoboater falls in this group.

Many factors can be used in determining what's the best layup schedule & materials to be used in each situation & boat differently:

the underlying fiberglass is thin or thick, well ground smooth (but w/ a keyed tooth for the new glass & resin to 'grab'), has a lot or a little weave print thru of factory woven roving used to create the hull, is it a structural application, or not

And other factors.

None of what is done in 1 rebuild is guaranteed to be done or done similarly in another. You need to educate yourself and decide how YOU think is best to rebuild YOUR boat.

Currently, I'd err on the side of a slightly more expensive, slightly more involved, slightly heavier layup in most applications, and use the CSM/1708/CSM/1708 layup schedule. Those are the downsides to using CSM.

As a novice fiberglasser, the risk of having an insufficient bond using just 1708, skipping the CSM layers, is enough to have me to continue to suggest using CSM 1st & will on my project. This is not to suggest WOG or the graphic linked in his signature is inaccurate or shouldn't be followed.

 

[bp1313]

Re: 1968 Larson rebuild

Sweet! love the fact that I know some peeps are looking at the thread Thank you for the feedback.

WOG - the transom is tabbed in with two layers of 1708 so far. I've already tabbed the stringers to the transom...so those areas have 4 layers at least. I'm going to hit the transom one more time with a full layer of some biax mat that my buddy has. (I think it may be 1708) I'll post the pics when I have them. I bedded the stringers in with peanut butter...lots of it. I filleted the transom and the stringers. The stringers were coated with CSM prior to putting them in the boat...and they've been tabbed in with two layers of 1708 since. I'm really wondering if I need bulkheads...?

Peter - I can't wait to see some pics of what you're doing. These boats have a little bit different set-up from the factory from what I've seen on the forums. I chose to rip all of it out and redo it differently. I'm interested in what you decide based on what you find below deck

Coolbri - I'll be adding foam under the deck starboard and port. I'll leave the bilge up the middle and also have a bilge pump in the back. The stringers were only 3/4 inch planks.. but they are coated with some glass at this point. They're tabbed with two layers of 1708 and are... in my opinion.. solid as ****. I'll probably hit them with another, but I'm winging it

As for the glass discussion... CSM is not what I use for tabbing or any curves. I'm treating it mostly as a waterproofing step and using fabric for anything that needs strength. I do agree with the idea of getting it underneath something like 1708 for adhesion and wet out, but my brother got me doing something with the 1708 that seems to be working nicely. Once all my 1708 is pre-cut and ready... we wet out the back of it liberally and let it soak for a minute before putting it in place. (figured that out on the 2nd stringer and found it worked much nicer) I won't have to grind and touch up the 2nd one. We apply resin to the area we'll be laying it with a roller first... but the glass is totally wet when I put it in place and it looks really good.

What about bulkheads? I'll have 2 solid stringers with 3/4 inch deck on top and It's not going to move much once it's got all the glass on it. Maybe some underneath where the seats will go? I'm going to use the expanding foam... so that will help rigidity to a point. It's got a 70hp motor and its 16ft so I don't wanna go overboard... but I want it to be safe and last. There weren't any bulkheads in the boat as it was from the factory..do I need them now?

If I'm not putting bulkheads in... I might be able to have the deck mounted and tabbed in within 2 weeks. A really warm Easter weekend has the family wondering if I'll be able to get the awful looking think I call a boat done by this summer Would be nice to get her in the water soon.... I'll mull it over based on feedback and my gut and go from there.

Hope you're all well. Thank you for giving feedback and asking questions.

 

[Woodonglass]

Re: 1968 Larson rebuild

As long as you're using 1708 or some other cloth that HAS the CSM stitched to it then you should be fine. But...You cannot use fiberglass cloth without CSM. Not all Cloth comes with CSM sitched to it. Just want to make that clear for any other readers of this thread. When using Polyester Resin you must always have a first layer of CSM prior to the application of Cloth to get proper adhesion.

 

[bp1313]

Re: 1968 Larson rebuild

Thanks WOG. What do you think about bulkheads? I kinda feel like i'd be justifying cutting a corner in cost and labor to not put some in. But I do truly wonder if I need them...

 

[Woodonglass]

Re: 1968 Larson rebuild

My 61' is very similar and she doesn't have any. I think you'll be fine without em.

 

[petertay]

Re: 1968 Larson rebuild

Thanks to WOG for that clarification about the necessity of CSM. I have spent hours here, reading up on the projects and how they were done, but somehow missed that requirement of CSM. -- Peter

 

[bp1313]

Re: 1968 Larson rebuild

Confirmation backed by experience is a good thing Thanks WOG for providing that.

No bulkheads then. Covered the transom in one last layer of 1708 tonight. I think the deck will start getting put down this week. I'll keep you posted.

Thank you for all the advice!

 

[bp1313]

Re: 1968 Larson rebuild

Go the deck boards installed in the last week. The bottoms of the boards have a layer of CSM on them for waterproofing. Lots and lots of PB was used around the edge and also on top of the stringers. I ended up putting a few screws in to suck it all down. I may take them out later, but I haven't decided yet. After I let them set in... I ground the edges for a fresh surface (cause yeah..I'm using waxed resin) and used more PB for a nice fillet. I've tabbed the rear board to the sides of the hull and the transom and laid two layers of CSM over it. I'm not going any further with the top coat yet because the pour foam is being delivered and I want to avoid cutting through the glass on the deck.

I ordered the two gallon pour foam kit (8 cubic ft) and I hope that's enough. I guess we'll see. I'm going to do a good sanding tomorrow so that the only thing left to do in the rear of the boat is cover it with durabak. I wanted to get that part done so that there's no serious work to do back there because it would be much harder once the splashwell is back in place. I'll get some pictures of where I'm at tomorrow and post them.

 

[bp1313]

Re: 1968 Larson rebuild

Got the pour foam in the mail now. I should be getting a few more packages this week as well (vinyl, durabak, and the primer for the topside coat.) Here's some pictures of the progress up to this point.



Here's the stringers where they meet the transom. They were wrapped in CSM first, and that's the first of two layers of 1708.



The rear deck board got installed. Here's a look down into the cutout into the bilge.



Here's a look at the port side tabbing. One layer of 1708





here's a look back at the first deck board that got mounted. You can see the color change because the rear board is covered with 2 layers of CSM that cured the night before.



So.... My brother text me and said he had begun putting the splash well back in. I'll get some pics of that as soon as I can. Next step is pouring the foam, and then I'll glass the whole deck in. I've got a question about the foam... I ordered a two gallon kit that is supposed to be 8 cu ft of foam. Looking at this picture... any guesses as to the volume I'll actually need to fill both cavities on the sides of the stringers?



stringers are 6in deep at the transom. Deepest they get is 11 inches under the front seats. They're 11' 6" long. I know that's tough to go on..but I'll take guesses really. I'm questioning if 8cu ft will do it and really don't want to order more foam. Any arguments against using packing peanuts in the foam like chocolate chips in cookie dough?

I'm not counting on a huge amount of support from the foam...but it will help. If peanuts would be okay... any thoughts on the best way to make sure they were as evenly distributed in the foam as possible? Let me know what you think and thanks for looking.

 

[avpaulb]

Re: 1968 Larson rebuild

in all likelyhood peanuts will completely melt in your foam mix, just like they would in acetone. They also have virtually no density... mostly air. They melt into nothing. Try melting as many as you can into a capfull of acetone and you will see. Not a good idea.

 

[avpaulb]

Re: 1968 Larson rebuild

you need 16 cubic to amply fill this boat

 

[kfa4303]

Re: 1968 Larson rebuild

+1 No peanuts. Use Pink/blue closed cell insulation foam board from Lowes/HD and cut it to fit. Then fill any voids with foam. You could even use seal plastic bottles, but the peanuts will probably "melt" as avpaulb stated.

 

[jigngrub]

Re: 1968 Larson rebuild

I'm guessing you're going to use the Durabak for the deck?

I'm not sure how particular you're going to be about the appearance of this product, but I seen some recent builds that have used this product... and while they don't look bad, they do look like they could've used more prep work.

I personally would fair everything out I was going to apply it to and then sand for a smooth finish, then apply the Durabak for a nice smooth and clean looking installation.

 

[bp1313]

Re: 1968 Larson rebuild

Thank you very much!

Scratched the peanut idea. I'm going to go with the foam insulation board as recommended. Going to be leaving right after this to go grab some.

As for the durabak... I agree with you jigngrub. My buddy's boat has the durabak coating on the deck. It looks like he did a decent prep job on it because it turned out pretty nice. It does show the imperfections underneath though. I can only hope to fair, sand, and have it turn out as nice as possible. I'll take some close-ups under good lighting after it's all painted on .

Got my vinyl yesterday and I'll have to send it back. Probably my fault in ordering... but it's not what I expected. I got the fabric type when I was hoping for the fake leather look. I'll be coating the side boards with it and need it to be washable.

If I'm lucky and have the time... I'll have the foam in and the deck completely glassed by the end of the day today. Pics to come

 

[bp1313]

Re: 1968 Larson rebuild

Good evening peeps!

Lots of work done as of late. I'm really pushing to be able to get some use out of her before summer is over. Here's the latest pics:

Cut the pads for the pedestal seats and glassed them in.



After both seat pads were down and glassed... a whole bunch of sanding took place. Here's just prior to cleaning the whole deck with Xylene prior to durabak installation.



And here's what the durabak looks like. I went with dark grey over the light.



Sprayed on the first layer of primer. I got a cheap spray gun from HF and it seemed to work pretty well.