Busted KV-1
12-23-2009, 03:29 PM
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Busted KV-1
Lesson learned:
Today I began installation of 3:1 gearboxes in my HL KV-1. It was the first time I opened up the KV-1, so I started unscrewing all the screws in the bottom of the lower hull. There were 6 medium plated screws and 4 small black screws. Turns out 2 of the black screws hold down the smoker, and the other 2 black screws hold down the speaker. Well when all these screws were out, the back end between the lower and upper hull was still being held together by something. I saw some residue of glue from an over zealous assembler and assumed that was the problem. I used my flat exacto blade to cut through these areas and started prying. Big mistake! All at once one side popped and I could see I had broken one of the tabs that were still holding the upper and lower hull together. Turns out there were two more small black screws going through the side of the hull near the drive sprocket, one on each side. The picture attached show the tabs in question.
Question:
I want to repair the broken tab and would like some input.
First) Are HL tanks made of ABS?
Second) If so what' the best glue?
Third) Looking at the busted piece, if I glue it without reinforcement it probably won't survive long. Should I try to find some plastic sheet stock to form a doubler/splint to form a lap joint over the broken joint?
Thanks for any recommendations
Today I began installation of 3:1 gearboxes in my HL KV-1. It was the first time I opened up the KV-1, so I started unscrewing all the screws in the bottom of the lower hull. There were 6 medium plated screws and 4 small black screws. Turns out 2 of the black screws hold down the smoker, and the other 2 black screws hold down the speaker. Well when all these screws were out, the back end between the lower and upper hull was still being held together by something. I saw some residue of glue from an over zealous assembler and assumed that was the problem. I used my flat exacto blade to cut through these areas and started prying. Big mistake! All at once one side popped and I could see I had broken one of the tabs that were still holding the upper and lower hull together. Turns out there were two more small black screws going through the side of the hull near the drive sprocket, one on each side. The picture attached show the tabs in question.
Question:
I want to repair the broken tab and would like some input.
First) Are HL tanks made of ABS?
Second) If so what' the best glue?
Third) Looking at the busted piece, if I glue it without reinforcement it probably won't survive long. Should I try to find some plastic sheet stock to form a doubler/splint to form a lap joint over the broken joint?
Thanks for any recommendations
12-23-2009, 03:48 PM
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RE: Busted KV-1
My KV-1 came with one of those tabs broken off free of charge. I used a Dremel tool to grind the inside of the hull flat and fabricated a tab from plywood. I may have used Duco cement to install it, i forget right now.
Anyway, the rest is easy, assemble the tank, mark the tab for the screw hole, drillundersize, then assemble. No problem.
Anyway, the rest is easy, assemble the tank, mark the tab for the screw hole, drillundersize, then assemble. No problem.
12-23-2009, 06:33 PM
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RE: Busted KV-1
If it were me, and I planned on doing some "bodywork"/paint anyways...
I'd fabricate a piece out of Aluminum or steel. Looks like it could be "square" stock, fancy cuts not necessary.
I'd grind all the plastic off that WAS part of the piece. Mark either side with a permanent marker/light cuts before doing so, to give you a relative point after it's gone.
Assuming the upper portion is on the visible portion of the hull, I'd put a countersunk screw in through the top portion, and one through the lower portion (again, looks like one would protrude through the upper hull above the fender, one below), "bolt" the piece in with a loc-tited nut, and epoxy/bondo/whatever the screw heads over, and paint it.
Did similar with the plastic hull sides on the Asiatam PzIII metal lower hull, that had exposed phillips head screws. Epoxied over them, sanded smooth, and will paint over. Can't tell they were ever there from the outside.
I'd fabricate a piece out of Aluminum or steel. Looks like it could be "square" stock, fancy cuts not necessary.
I'd grind all the plastic off that WAS part of the piece. Mark either side with a permanent marker/light cuts before doing so, to give you a relative point after it's gone.
Assuming the upper portion is on the visible portion of the hull, I'd put a countersunk screw in through the top portion, and one through the lower portion (again, looks like one would protrude through the upper hull above the fender, one below), "bolt" the piece in with a loc-tited nut, and epoxy/bondo/whatever the screw heads over, and paint it.
Did similar with the plastic hull sides on the Asiatam PzIII metal lower hull, that had exposed phillips head screws. Epoxied over them, sanded smooth, and will paint over. Can't tell they were ever there from the outside.
12-24-2009, 08:18 AM
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RE: Busted KV-1
Frank,
I would most definitly use a splint. I would first build the sides even with some plastic strip to have a level surface across the tab. Then build the splint the full width and length of the tab. You could use either regular plastic glue or super glue, just make sure to clamp it until fully dried. You could also use a piece of thin sheet brass for the splint, super glue it and when dry, drill some holes for micro screws and screw them in for additional support. I guess it depends on how much stress the tab is under when the tank is assembled ( I don't own a KV-1. I want one though). Hope this helps.
Jim
PS Another point here is that when I take apart a tank for the first time, I check here to see how. If you don't find a thread, just post your question. 1Sgt
I would most definitly use a splint. I would first build the sides even with some plastic strip to have a level surface across the tab. Then build the splint the full width and length of the tab. You could use either regular plastic glue or super glue, just make sure to clamp it until fully dried. You could also use a piece of thin sheet brass for the splint, super glue it and when dry, drill some holes for micro screws and screw them in for additional support. I guess it depends on how much stress the tab is under when the tank is assembled ( I don't own a KV-1. I want one though). Hope this helps.
Jim
PS Another point here is that when I take apart a tank for the first time, I check here to see how. If you don't find a thread, just post your question. 1Sgt
12-24-2009, 09:24 AM
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RE: Busted KV-1
Mine was broken the same way i used an aluminum plate under the gearboxes to stiffen the mounts and it does not seem to need those screws anyway.
12-24-2009, 02:30 PM
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RE: Busted KV-1
ORIGINAL: fsciorelli
Lesson learned:
Today I began installation of 3:1 gearboxes in my HL KV-1. It was the first time I opened up the KV-1, so I started unscrewing all the screws in the bottom of the lower hull. There were 6 medium plated screws and 4 small black screws. Turns out 2 of the black screws hold down the smoker, and the other 2 black screws hold down the speaker. Well when all these screws were out, the back end between the lower and upper hull was still being held together by something. I saw some residue of glue from an over zealous assembler and assumed that was the problem. I used my flat exacto blade to cut through these areas and started prying. Big mistake! All at once one side popped and I could see I had broken one of the tabs that were still holding the upper and lower hull together. Turns out there were two more small black screws going through the side of the hull near the drive sprocket, one on each side. The picture attached show the tabs in question.
Question:
I want to repair the broken tab and would like some input.
First) Are HL tanks made of ABS?
Second) If so what' the best glue?
Third) Looking at the busted piece, if I glue it without reinforcement it probably won't survive long. Should I try to find some plastic sheet stock to form a doubler/splint to form a lap joint over the broken joint?
Thanks for any recommendations
Lesson learned:
Today I began installation of 3:1 gearboxes in my HL KV-1. It was the first time I opened up the KV-1, so I started unscrewing all the screws in the bottom of the lower hull. There were 6 medium plated screws and 4 small black screws. Turns out 2 of the black screws hold down the smoker, and the other 2 black screws hold down the speaker. Well when all these screws were out, the back end between the lower and upper hull was still being held together by something. I saw some residue of glue from an over zealous assembler and assumed that was the problem. I used my flat exacto blade to cut through these areas and started prying. Big mistake! All at once one side popped and I could see I had broken one of the tabs that were still holding the upper and lower hull together. Turns out there were two more small black screws going through the side of the hull near the drive sprocket, one on each side. The picture attached show the tabs in question.
Question:
I want to repair the broken tab and would like some input.
First) Are HL tanks made of ABS?
Second) If so what' the best glue?
Third) Looking at the busted piece, if I glue it without reinforcement it probably won't survive long. Should I try to find some plastic sheet stock to form a doubler/splint to form a lap joint over the broken joint?
Thanks for any recommendations
Thanks everyone for the input. After considering all the recommendations and some research on my own I ended up ordering some 3/8" x 1/8" ABS rectangular rod and Bondene solvent cement from Plastistruct. I'm going to remove the remaining portion of the tab from the upper hull and replace it the new abs material, perhaps even doubled up by cementing two pieces together. The Bondene cement is intended for gluing like plastics together (ABS-ABS, styrene-styrene, etc). Then I'll drill a new pilot hole and reassemble. Check out the Plastistruct website. They have a downloadable catalog with a lot of good technical info.
Last thing is I appreciate all the input. I try to look at all info objectively and make the best choice. THere is not such a thing as too much info. Ultimately I get to decide the course I want to take. One other RC tank website I frequent has a very micromanaging moderator who wants to judge every comment and bit of info for public consumption and is consistently trying to influence any and all communication. The result is very few people post and very little info is available. I'm glad this is not the case on this forum
