Fixing a warped [plastic] hull - 1/700 HobbyBoss LHD

[spejic]

The hull proved in my 1/700 HobbyBoss USS Boxer kit was twisted and bowed up in the center quite a bit - about 2mm. I thought the hot water method would be the best way to fix it, although I've never tried it before. I bought a metal pan with a flat bottom large enough to hold the part. First I tried soaking the part in not-quite boiling water, not quite fully submerged, and weighed with wooden blocks which were removed once the water cooled. That removed the twist, but it made the bowing even worse. Not wanting to abandon an expensive kit, I kept trying, upping the temperature each time. The fourth try - with water at a rolling boil, the weight increased by a soup can, and the weight kept on overnight - finally removed the bowing.

But it caused a new problem: the sides were now wrinkled along their lengths.



In fact, it was so bad none of those boxes installed internally could fit flush, and you can see they are pointing all over the place. The flight deck is thin, and its gluing edge too small to fix it. So I cut a slice of very thick 3/32in plastic sheet to the right size and glued it in a bit at a time using velcro straps to hold the hull against the form.



I had to cut out holes for the indented elevator sections, but fixing the sides close to the elevators didn't fix the elevator sections themselves - they were still bent in. I had to force the elevator sections out with 3/32 thick plastic shims.



And now it looks like it should and the flight deck fits. Hopefully this example will help other modelers.

[Steve]

The hull proved in my 1/700 HobbyBoss USS Boxer kit was twisted and bowed up in the center quite a bit - about 2mm. I thought the hot water method would be the best way to fix it, although I've never tried it before. I bought a metal pan with a flat bottom large enough to hold the part. First I tried soaking the part in not-quite boiling water, not quite fully submerged, and weighed with wooden blocks which were removed once the water cooled. That removed the twist, but it made the bowing even worse. Not wanting to abandon an expensive kit, I kept trying, upping the temperature each time. The fourth try - with water at a rolling boil, the weight increased by a soup can, and the weight kept on overnight - finally removed the bowing.

But it caused a new problem: the sides were now wrinkled along their lengths.



In fact, it was so bad none of those boxes installed internally could fit flush, and you can see they are pointing all over the place. The flight deck is thin, and its gluing edge too small to fix it. So I cut a slice of very thick 3/32in plastic sheet to the right size and glued it in a bit at a time using velcro straps to hold the hull against the form.



I had to cut out holes for the indented elevator sections, but fixing the sides close to the elevators didn't fix the elevator sections themselves - they were still bent in. I had to force the elevator sections out with 3/32 thick plastic shims.



And now it looks like it should and the flight deck fits. Hopefully this example will help other modelers.

Excellent post with terrific results. Many would have just written off this hull. Having done a number of hot water hull corrections on 700 scale hulls but none this complicated I can offer the following. First clamp the the hull to a piece of aluminum angle stock (flat stock if wide enough angle stock can not be found). The assembly should be set above the bottom of the pan being heated to avoid direct contact with the heated surface. As a first pass try with the hull submerged only to the depth of the twisted basic hull structure and avoid clamp contact with hull side or deck structures. I have also quenched the assembly in cold water, still clamped, to set the plastic. Smaller ships have been problematic with hogging and sagging the common issue. A twin kit Fujimi IJN DD kit had one ok and one hogged - both in the same plastic bag.

[Dan K]

Agreed, a very, very impressive fix.