spar urethane sealing inside wood hydro

[maximus44]

I am at the stage of sealing inside of wood hydro for my first wood boat kit. And was wondering if Helmsman spar urethane would be adequate for sealing inside? Instead of using the usual heavier epoxy method. If it is not, can you tell me why?

Also should I fiberglass the bottom of the hull?

thanks, matt

[785boats]

Hi Matt.
The first question that comes to mind is how did you glue all the frames together & skins on? With medium CA glue, or epoxy?
If you used epoxy along the full length of all the joins, then the urethane will be fine.
If you Used Medium CA, which is my preferred method, then I would use the Epoxy resin. This creeps into all the spaces between the surfaces where the CA has missed, and really strengthens the whole structure. Urethane won't add the extra strength.

Is this an ML Boatworks Kit?

Cheers.
Paul.

[maximus44]

thankyou for replying. that makes sense now why I should use epoxy for coating since it was built with maxi-cure thick ca. I used this as it is marketed for bonding plywood etc. The kit is the old Dumas 36" miss unlimited that I got cheap to get my feet wet with boat building. It is built using crappy die cut 1/8 ply and mahogany deck. Know I know why there are no build threads here on it.
After finishing this it will be a joy to build a lasercut ML kit not sure which one I want yet or size but don't really want to have to run an expensive 10s HV setup like on the 1/8 sizes.
Any insight on fiberglass the bottom of hull or not?
-matt

[785boats]

So yes, I would use an Epoxy finishing resin to seal. Brush it well into all the joints.

I generally fiberglass the area where the batteries are fitted, making sure it turns up the tub walls about 25mm. And then just along the join of the tub walls & the floor with some 50mm fiberglass tape.
But many people fiberglass the whole tub floor. Your choice really.

As for a future kit. The ML Boatworks sports hydros are great kits.

But also check with 'Shooter' on this forum. He also cuts & sells a great Sports Hydro kit. The Black Pearl.

Here's the one I built. But there are many other builds here to use as a reference too.
https://forums.offshoreelectrics.com...dro&highlight=

[Fluid]

....After finishing this it will be a joy to build a lasercut ML kit not sure which one I want yet or size but don't really want to have to run an expensive 10s HV setup like on the 1/8 sizes. Any insight on fiberglass the bottom of hull or not?

If you like the size of the Dumas boat, then I'd suggest trying an ML GSX380v@ Sport Hydro. There were several in my old club and they performed very well on 6S power. Worked great on windy ponds too. Most used 6S2P and 40x92/1250 Kv motors. Plenty fast and handled great. And a MUCH better kit that that crappy Dumas - I know, I built various Dumas kits in the 1970 and 1980s.


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