Straightening Warped T39 Panels

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wespaul
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Straightening Warped T39 Panels

#1 Post by wespaul »

If I have a panel or 2 (or 3) that I have already cut for my T39 that are curved (warped), can I use the wet cloth and steam iron trick on the concave side to straighten them a bit? Funny, those plywood sheets were straight, but the panels warped once cut from the sheet. Straighter panels would be a lot easier to screw and glue in place. Thanks.

DaveK
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#2 Post by DaveK »

What panels? With all the bracing in a T39, you'll probably be able to pull them back to flat as you nail or screw them in place.

wespaul
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#3 Post by wespaul »

All of the panels are less than straight. If I put one edge of the panel where it should be and square up the edge, the other end may deviate as much as a quarter inch from where it should land. So you think it best to try to pull them straight as it goes together? This plywood is pretty stiff - it might take a bit of force.

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Bill Fitzmaurice
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#4 Post by Bill Fitzmaurice »

wespaul wrote:This plywood is pretty stiff - it might take a bit of force.
If you follow the instructions in the plans and use the guideboard method of jointing it's a non-issue.

gdougherty
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#5 Post by gdougherty »

Bill Fitzmaurice wrote:
wespaul wrote:This plywood is pretty stiff - it might take a bit of force.
If you follow the instructions in the plans and use the guideboard method of jointing it's a non-issue.
+1 As long as all the cut edges were straight, the horn path will square up the driver end of the cab and the sides will come into square as well when you assemble them. That's why you measure the bracing up against the side, a few screws or some pressure and brads will tack it all together. Make sure all the path corners are straight from side to side and it all works out. I had the same sort of deal with my most recent OT12 build. Small warps in the large panels but it all came square upon assembly. Use a large square and just make sure they're in line.

wespaul
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#6 Post by wespaul »

OK - I'm sure it will become clearer as I actually begin to joint the panels. I won't have the drivers until late next week, anyway. Thanks!

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DJPhatman
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#7 Post by DJPhatman »

wespaul wrote:I won't have the drivers until late next week, anyway.
So how did you fit the driver to the baffle? Without the driver on hand, there is no way to insure that the driver fits the H-nuts or T-nuts, whichever you used. Even with one side off the T39, it is still very very difficult to get them installed correctly.

BTW, there is even differences between individual drivers. I suggest you fit a driver to a baffle, and use that same driver in that baffle spot.

(edit for spelling)
Last edited by DJPhatman on Sun Mar 16, 2008 7:48 pm, edited 1 time in total.
I know money often seals the deal, but seriously, quality is an investment, not an expense... Grant Bunter
Accept the fact that airtight and well-braced are more important than pretty on the inside. Bill Fitzmaurice

wespaul
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#8 Post by wespaul »

DJPhatman wrote:
wespaul wrote:I won't have the drivers until late next week, anyway.
So how did you fit the driver to the baffle? Without the driver on hand, there is no way to insure that the driver fits the H-nuts or T-nuts, whichever you used. Even with one side off the T39, it is still very very difficult to get them installed correctly.

BTW, there is even differences between individual drivers. I suggest you fir a driver to a baffle, and use that same driver in that baffle spot.
I haven't put anything together yet except for the top to the side. I am dry-fitting all my parts to see how they fit the lines I traced.

I'll heed your suggestion on mounting the drivers on the side of the baffle I fit them on before jointing the baffle panel in, and thanks for the warning.

bluemark0
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Re: Straightening Warped T39 Panels

#9 Post by bluemark0 »

i know this is an old post but hey. some years ago i made a load of checking fixtures that needed to be flat within 0.004" the ply wasnt too good. the solution was to cut grooves in the ply going through all but the last 1 or 2 laminations cut in both directions of the board about 4-6" apart. the grooves were then filled with epoxy resin and the base screwed on. should work to get badly warped panels flat without having to put anything under stress and using pu instead of epoxy.

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