Caulk for RC hull?? RADIO

[Ian_Grant]

Hi members,

 

I'm making a model for RC operation on the water. I skinned it in plywood with all joints on framing; I don't want to f/g the outside.  I do plan to spar varnish before scuffing and painting.

 

There are outer wales and a few trim pieces to apply to the outer hull. I don't want cracks to show along the their edges. If it was room trim, I'd use painter's caulk then paint over. Can I use this for a hull which will see water?  Is there something better?

[bluenose2]

Hello Les here. As a painter I get what your talking about. Dap. This product is not rated for this application. If you must, use a solvent based product that is used for exterior siding. Mulco is one. Just be aware that you can't cut the tip fine enough to apply to a very small bead. I would Google " marine caulking" and see what comes up.

[Ian_Grant]

Thank you.  🤙

[David W]

I can fully understand not wanting to fiberglass a model but maybe just a coat or two of FINISHING resin, polyester comes to mind. I'm (slowly) building an Amati Fifie for R/C useand in the same dilemma 'glass or just a couple coats of resin then paint. I've' already sealed the inside with spar varnish plus paint but not fully comfortable with the outer skin/planking only spar varnished. This or similar is what I'm looking at using:https://www.amazon.com/dp/B00PZ1CU1G/?coliid=I1GHA86B7RTVXO&colid=2GHV6Y2C7OD8R&psc=1&ref_=lv_ov_lig_dp_it

Edited April 26, 2023 by David W

[Ian_Grant]

1 hour ago, David W said:

I can fully understand not wanting to fiberglass a model but maybe just a coat or two of FINISHING resin, polyester comes to mind. I'm (slowly) building an Amati Fifie for R/C useand in the same dilemma 'glass or just a couple coats of resin then paint. I've' already sealed the inside with spar varnish plus paint but not fully comfortable with the outer skin/planking only spar varnished. This or similar is what I'm looking at using:https://www.amazon.com/dp/B00PZ1CU1G/?coliid=I1GHA86B7RTVXO&colid=2GHV6Y2C7OD8R&psc=1&ref_=lv_ov_lig_dp_it

Hi David; thanks for the reply. Yes, it is something to ponder. I thought about cloth and resin over the smooth hull before applying walesetc; on the other hand this is a made-up hull (ie, there were no plans available) and my hull displacement calculations and estimated total weight were a little uncertain so I'm trying to keep weight down. In my case, the skin is all 1/32" plywood with joints over framing members; if it was planked I'd definitely use cloth and resin on the exterior, and resin on the interior.

 

I hadn't heard of TotalBoat before, I've always used West System which as far as I know only has one type of resin. Thanks for the reference; I will read up on TB's resin varieties. I notice that the finishing resin has wax in it but they say it can be painted; that's a little unusual.

 

Will post later and report on whatever I end up doing.

[David W]

Ian, there is another finishing (sanding) resin that's often sold in hobby shops that I've also considered and since I was late on my way to the dentist as I wrote the last, just plain forgot. Take a look at this as well. It has been out of stock recently but looks like AMAZON US at least, has it again: https://www.amazon.com/Pacer-Technology-Zap-Finishing-Adhesives/dp/B0006O8ESK?th=1