Balsa experiment, It’s only been one week...

**powerabout** · 06-08-2022, 10:39 PM

balsa
foam
balsa
foam
balsa
foam

vinylester also over 50 years old.
invented for the chemical industry for pipes and tanks surely that was a clue for people that build boats to put in the water?

**Instigator** · 06-09-2022, 05:36 AM

We used vinylester building the sport fish boats when I was in Fla.
I know it’s better than poly but I never saw any difference in what we did.

A bilge w/water n oil on it for 20 yrs maybe???

Im a tight wad so I look at how cheaply I can build it w/o breaking it and that’s how I do it.

Ive done enough shade tree tests to convince me enough to have no second thoughts.

When I recorded my Vector a 100 yrs ago I read everything there was.
But when we’re comparing one method to another done improperly……, what have we learned?

Hydrostream sucked at balsa core so we use foam, that’s 50% more expensive?
Vinylester instead of poly for the same reason??

Not counting that Stream, Ive owned three balsa cored boats, Checkmates that I cut into, that had zero delam issues.

A ‘1969 16’ that sat outside, uncovered its entire life.
Zero delam!

My ‘87 25’ Convincor that I have now, I’ve cut into transom, hull, stringers, floor, deck (side and front) and bulkheads and had zero issues.
Some was plywood but my theory is, good lamination is good lamination.

Only issue I found was in the sun lounge, where the pad was bolted to/through it.
The factory must have had fourty 1/4” bolts/holes, holding it on!

I had to repair some of that core around the bolt holes where it doesn’t look like they were treated.
Balsas fault???

So what needs improved??

To save 5% weight? Already lighter than most.
Add 10% strength? Already survived 35 yrs.

To do it to do it, or to race it…., I get it.

I took a scrap off a 1 1/2” thick transom I made from two pcs of 3/4” ext ply, laminated together w/2 layers of 2 Oz mat w/poly resin and threw it in my yard.
When we lived in Fla.

Made sure it was where it go sun, rain etc.
Last I checked, it had been there 2 or 3 yrs and showed no signs of delam!
And that’s bottom of the barrel material!

I guess my theory has always been, and I think validated, method is way more important than material.

Kinda back to the old Bass and Wallaye mag story where two biggest builders of the day, one w/balsa, one w/NO WOOD agreed that done correctly, it’s all marketing.

Carry on ��

Originally Posted by powerabout

balsa
foam
balsa
foam
balsa
foam

vinylester also over 50 years old.
invented for the chemical industry for pipes and tanks surely that was a clue for people that build boats to put in the water?

**LakeFever** · 06-09-2022, 06:06 AM

As a newb after working with both i prefer the vinylester for a few reasons. The number one reason is it adheres much better. Number two is the secondary bonding window is at least a week if not two where poly has to be sanded soon as its kicked for another lay. Number three is it definitely is water proof, im seeing zero degradation in these water tests where the poly is certainly breaking down.

my thoughts on materials are this; if its just a repair or a build for something your going to have a while and move on from? Then instigator im with you 100% use the cheapest materials that will get the job done properly. But if the goal is to hang onto it for perhaps life? Then buy the best materials possible. Considering the cost difference on a small boat would a coupla three grand its not such that its a life altering expense.

**XstreamVking** · 06-09-2022, 07:10 AM

Foam, vinyl, and 1708 for me.

**LakeFever** · 06-09-2022, 08:47 AM

My hull came with loads of new balsa core so i used it. If i was buying new id probably have gone with foam mostly for ease of use now that i have worked with balsa it was messy and i did have to use a lot more resin to bond and seal it so that puts the cost advantage closer.

I will be very surprised if any issues come up with mine the way i laid it in with corebond after two coats of poly on the core then two more of vinyester on top of the balsa after bedding and faring and then two layers of vinyl 1708 over the core before laying stringers and then the pad area using fat tabs first then one piece of 1708 up/across/up the stringers over the pad so there is plenty of protection. I didnt gel it either so i can keep an eye on it over time.

**FUJIMO** · 06-09-2022, 03:39 PM

Originally Posted by XstreamVking

Foam, vinyl, and 1708 for me.

...

**powerabout** · 06-09-2022, 07:52 PM

vinylester is not only waterproof its stronger and stiffer than poly plus has a chemical bond when its repaired on itself and over poly

**FUJIMO** · 06-11-2022, 02:57 PM

...vinylester is much superior to general purpose(gp) polyester resin, in many ways. its barcol rating will surprise you if you ever test/check it's surface hardness, even after its fully cured. if you are used to only using gp resin, its a different world, that will have you shaking your head. its secondary bonding characteristics are just one of its many advantages...

**FUJIMO** · 06-11-2022, 03:18 PM

...this is what your typical barcol hardness tester looks like. its not rocket science. it basically is just a sharp pin, that, when you push down on the tool, presses into the top of the surface of your fiberglass project & gives you a reading of hardness on the dial indicator. regular cured gp resin is in the 60 to 90 range. cured vinylester is less...is softer...