1968 Saftmate - Stringer Work and Question

Smell is pretty bad for working in your garage is all.

 

Yes i used poly in 97 on this boat

 

So did a little grinding to remind myself of the mess this makes. Can I get away with just roughing up the woven tapping or do I need to grind off?

 

You don’t need to grind it off if it’s in good shape and securely bonded in place. Many times the stringers are glassed in so poorly that it all needs to be removed though.

For a good bond you need to thoroughly grind the surface, 100% of it.

 

^
+

I would make sure also to use thixo on all of it to avoid lotsa air on the new stuff. I am repeating myself, but it is best.

 

Using thixo putty will reduce the strength of the bond, only on rare occasions should any type of putty be applied first if strength is a concern.

 

Thanks all. Can i leave the lip of existing floor and epoxy putty the new floor to this with 1708 tabbing extending over this joint? The wood is in good shape (rot was not reason for opening up floor).

 

Which type of resin do you plan to use for the rest of it? Either type will work.

It’s best to stick with one resin type when doing a rebuild.

Yes you can bed the floor in putty, or any good adhesive, then tab it in place.

 

Was planning to use epoxy resin just because i like the idea of overkill. Could i use some construction adhesive to bond the new floor to old or make putty from epoxy?

 

Putty vs air?

 

There shouldn’t be any air, all surfaces need to be sanded smooth, there shouldn’t be any depressions large enough to not be able to glass into.

Putty is resin with fillers, it’s weaker than than the glass layup, using it as the first layer limits your bond strength to that of the resin itself. You can add glass fibers, but short ones don’t add much strength, and longer ones are harder to work with. Plus the resin to fiber ratio is still high, you want less resin for strength.

If someone is looking for the best properties possible you don’t use it.

In a radius it helps to keep a uniform radius with less air, but the putty can be the weak link there too.

 

I should clarify it a little.
The bond is the same, it’s the resin rich layer of putty that can fail.

 

Thanks

 

Hey all. So what design change should i make to this stringer system if any? Adding 2 or so of these floor supports shown above isnt likely to stiffen the stringer system? Middle picture above.

thanks

 

Always look at what was originally done, then see if it failed in some way.

If everything survived the first 40+ years of the original build, other than rotten wood, then making upgrades or changes in the design or materials doesn’t really pay off.

Doing a better job, as in better attention to detail, does pay off. This increases every aspect of the build at no additional cost.

You can add or improve stringers, bulkheads, supports, bracing, materials, etc, but if it didn’t fail before.....