Tabbing stringer with ridgid foam instead of peanut butter

[Freezebrand44]

So I've decided to do a partial stringer and deck replacement my self. I've read a lot of comments on here, I've watched most of Frisco boaters stringer videos....I am wondering, ( I might be clueless), when I put the stringer in with the PL adhesive, if a piece of 1" x 1" ridgid foam, cut on a 45 degree, placed in the PL, at the base of the stringer, would be an acceptable option for tabbing in the stringer, rather than mixing and using peanut butter....??

 

[jbcurt00]

No.

Some PL isnt foam friendly

PL takes forever to adequately, if ever used as you describe, to cure, which effects the adhesion of polyester resin as the PL off-gases

 

[Freezebrand44]

Thanks....this isn't my are of expertise, definitely uncharted waters... I wasn't sure if the peanut butter was simply there to make the corner more curved for the glass to transition to the hull, or if it's part of the structural strength of the stringer. It doesn't sound like PL adhesive is real user friendly.

 

[gm280]

If I were you, I would certainly follow the typical procedures for installing all stringers and bulkheads and ever transoms. Look at it this way, this is probably the first and last time you will ever be rebuilding this boat. So do the absolute best method of repairs that are proven so you will end up with a sound solid hull. Then you will know that your boat will be around as long as you want it. Short-cuts are always asking for problems down the road. Spend the time and money to do it right, and you won't be doing it again! JMHO

 

[Freezebrand44]

Agree I definitely want it to be right, and last. My expertise is more the mechanical, motor swaps, rebuilds....this is the first time I've had to go below deck... there lots of info around for the how, but not much for the why, and yeah I was probably trying to figure a way to cut down the steps, (and time), but I definitely dont want to cut corners on the quality of the repair....a lot of info out there for using "peanut butter" at the base of the stringer, but not much on the why to use it...
thanks for the info.

 

[gm280]

PB is a thickened method of polyester resin used to make fillets in corners. And the reason for fillets is to give the stringers and bulkhead a lot of strength while making a rounded area for further 1708 fiberglass material to be used and smoothed out easier. It is the cheapest method to give such strength while being the least costly.

Most use polyester resin with cabosil powder to thicken the resin. It is a very very light weight thickening agent that works great in doing such fillets using a "pastry bag" type way to help apply it to the corner areas. And some even use a spoon to help form those fillets as well.

If you need any further help, just ask. There are tons of quality type help on these forums to assist you.

 

[fibersport]

I like your thinking. In my opinion, the fillet formed by using thickened resin is there to help prevent stress risers and nothing more, it really doesn't add any strength. Think about it, you are supposed to raise the stringer off the hull about 1/8" to prevent the stringer from causing a hard spot on the hull skin. Then everyone thickens up their resin to form nice fillets, however resin by itself is not strong, it's the glass mat that adds strength. I would bet that there are many boats out there today with foam core engine stringers, again because the glass is what makes them strong, not the core material. Your original question about using foam to make the fillets is very logical and a novel approach. I have been planning on the method to rebuild my Century Cardel, it will involve gluing the stringers to the hull with 1/8" spacers, then forming the fillets with waterproof kittyhair type filler - although your thought of foam might make me change my plans as long as the foam is not eaten up by resin. For the glue, I think I will use either 3M 5200 or Loctite PL. I will put in some material as a fillet and then a layer or two of glass mat.

 

[Freezebrand44]

Well thank you for letting me know that my thought process was ok.. I wasn't sure about the strength being from the peanut butter. I got the idea from a video of a foam product, that you glass onto an angled section of the hull...to allow your stringer to be applied to a flat surface rather than angled one. And yeah not sure if resin and foam are friends, maybe certain kinds. But my whole thought was based on the stringer being held up off the hull.... thanks for the input, at this point I'm still doing demo, so decision will be made later....
this boat is an 86 searay, after researching, the floor and stringers were bad when I bought it. The floor patch over the gas tank, (factory), big cause... the carpeted plywood ski locker lid was also a big cause...all, bad design. I have gotten a water tight ski locker hatch to go back, and the floor over the tank will be fully covered, from side to side of the boat... and I'm going to add extra bulk heads, for added support for the floor....
thanks agafor the info.

 

[gm280]

Something to understand. There will always be multiple ways to do most everything. We offer opinions and usually those opinions follow the most used ideas. However, that certainly doesn't mean that is the only way to do things. Your job is to select the idea that best suits your needs. And since it is your project, it is your option which one you follow. And that is how these forums work. So you can try anything you wish and if it works, great, and if it doesn't...well that is your issue as well! Just understand that everything you read is merely opinions backed by typical ways to do something...but new ideas can accomplish the same results too!

 

[Freezebrand44]

I totally appreciate all the info and opinions on this forum. I am just starting out down this dirty, dirty road....and I'm definitely looking at the best way to get this done....my nature, is always to look for a quicker way, not necessarily a cheaper way, but quicker....I'm a contractor, and time and labor is always the thing I'm trying diminish, but never quality. Again I appreciate the knowledge shared here, because I have zero knowledge below the floor of a boat... please don't hold it against me for trying to find a faster way to getter done...