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Building Tips and technical articles. => Paint and finishing => Topic started by: John Tomlin on February 28, 2021, 10:59:03 AM
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I have a Veco Chief that has the wing covered in silk. It has been sitting for numerous years. The wing has a slight warp in the trailing edge. I put a coat of clear dope and clamped it to the work bench. After a couple of days I took it off and it was straight as an arrow. Let it sit for a week or two and she is still straight as an arrow. Applied a coat of talc and dope to whole wing and allowed to dry. Warp came back. I need another coat of talc and dope. I could put a final coat of clear and clamp it to the bench but afraid when I shoot the silver base coat, the warp will come back. Will be using Klass Kote as color coat and clear. Nitrate was used to adhere the silk and butyrate was used for filler coats. Any ideas on how to keep the warp from coming back?
John
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I have a Veco Chief that has the wing covered in silk. It has been sitting for numerous years. The wing has a slight warp in the trailing edge. I put a coat of clear dope and clamped it to the work bench. After a couple of days I took it off and it was straight as an arrow. Let it sit for a week or two and she is still straight as an arrow. Applied a coat of talc and dope to whole wing and allowed to dry. Warp came back. I need another coat of talc and dope. I could put a final coat of clear and clamp it to the bench but afraid when I shoot the silver base coat, the warp will come back. Will be using Klass Kote as color coat and clear. Nitrate was used to adhere the silk and butyrate was used for filler coats. Any ideas on how to keep the warp from coming back?
John
The type of structure used for the Chief is very prone to warping. I am guessing that your warp is due to internal tension in the structure that allows it to "warp" when the covering tension is eased. Chances are that it will keep coming back so I would just finish it then clamp it down on the final coat. You can relax the tension w/o covering using steam and heat but I suspect that ship has already sailed.
Ken
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Thanks Ken. I think I might try blocking up one end when I apply the final coat of dope so it will warp the other way slightly and then when the silver relaxes it, it may be right. Worth a try.
John
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If you get it back straight again, let it gas off as much as possible and then continue from that point on with non-tautening dope until you are finished with the build us. For the silver and colors, all SIG color dope is based with their non-tautening Lite Coat dope. Just a suggestion.
Type at you later,
Dan McEntee
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O.K. so I put a popsicle stick under the side that was bowed and clamped it down and doped it. So far it has been a week or so and she is still straight. Will spray lite silver coat so as not to cause it to warp. KlassKote should not cause warpage. Thanks guys.
John
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John,
I was fighting a bad twist in a newly covered wing. I tried heat from a heat gun, jugged it up and it did not work. Finally I went back the the age old method of steam from a kettle. This was desperation move that I really didn't have much hope for but I tried it anyway. Damn, if it didn't work. There is something about steam getting the heat deep into the wood that works (I don't think any of the moisture gets through the dope, just gets the the heat in). I would try the steam to get a more permeant set and prevent the dope from relaxing and re-warping once the ship sits in the sun.
Best, DennisT