Hey all,

Sorry if the question is a bit confusing but as I'm working on the 1/144 Trumpeter Seawolf sub I was wondering if anyone knows how I could make the hulls a bit more rigid/solid to aid in the filling and sanding of the seams. What is mean is that after dry-fitting both hulls together there seems to be a lot of 'flex' on the join lines and I'm concerned that these may crack if pressure is placed on them during the gluing and filling/sanding stage. Is there a method you all submarine builders use to have some rigidity inside the joined hulls so as to make the assembly somewhat solid? On the Trumpy Seawolf the hull itself is almost 2 feet long so I need something inside, I think, to strengthen these joins.

I've heard some use foam or bracing inside the hulls but a bit more info on this or any other method will be appreciated.

Rob

Rob,
I'm building a 1/72 Gato so I know what you mean with wanting the large hull a little more ridged. I used Spray Insulated Foam. The same type you would use to fill in gaps in window frames and such. I used the "3M" brand, low expansion. This gave me much more sterength in the hull with out adding alot of weight.

Thanks much for the prompt reply, Frank. Another question re. using foam. How did you add the foam to the inside of the hull (after having joined them I assume)? Did you cut a piece of the hull somehow after joining and then added the foam? Sorry but I've never seen the Gato (and don't normally build ships/subs) so I don't know how you may have tackle this....

Thanks again,

Rob

Rob, not sure how Frank did it ( I have the Gato in the stash ) but be very carfull with the foam spray. It is STICKY as all heck and hard to get off your hands or cloths, personal experiance .One good thing about using the foam. Your sub will never sink.

Look for the newer water clean up expanding foam, as the other stuff is almost impossible to remove from any surfaces you don't want it on, like skin, clothes, gloves etc.

It's been used by vacform aircraft modelers for a long time. (You use to buy a kit, mixing the two chemicals together like 5 minute epoxy, pour it into each fuselage half, and let it foam up and expand and cure over night, then trim after curing) I would imagine its still the same principle, (except it now comes in an aerosol can) run a bead along each sides inner seam, let it expand and cure, then trim the excess back to the plastic hull half, using a long sharp knife or saw blade and maybe a little sanding block. You'll probably loose the little alignment pips, but no big deal, as the parts are now really strong enough to resist flexing and mis-alignment when gluing together. I'd go slow and easy assembling the hull halves, and watch out for excess liquid cement seeping into the inner hull as it will probably dissolve the foam it contacts.

I had joined the hull of my Gato, On the hull, the portion covered by the deck, I drilled some holes and sprayed the foam in through the holes. I used low expasion foam so I wouldn't run the chance of cracking the seal.

Thanks a lot gents for the info. I'll be looking to get the water clean-up one as Dave suggested as it seems easier to work with. I guess I'll glue the hulls first and then will use the foam to strengthen the seams. I'll have to cut an opening on both ends of the hulls though as if I don't, once I glue the hulls, the inside space will be sealed by the plastic bulkheads at their ends. You all touched on this a bit but just to confirm, should I try to fill the entire empty space inside the hulls or just make sure I have enough to cover the joins?

Thanks again all for the great help!

Rob

I just joined the two halves of my 1/72 Gato tonight, and the two internal braces supplied in the kit seem more than adequate. It seems that two or three properly shaped discs of .040 styrene would do, with a lot less cost.

ETA: Oops, I just realised how old this thread is.

The inability to sink isn't generally seen as a positive quality in submarines

No problem there Robert!! Thanks for the pointer. I did ultimately use the foam on my sub (got a build log here.

I'll probably use braces if I do another sub as the foam, although okay, did not really yield the results I was after.

Rob