willy Posted September 20, 2007 Report Share Posted September 20, 2007 (edited) Hello to everyone. Im lucky enough to have been given a stunning 1/4" bookmatched flamed maple top. I really want to get on and joint the two halfs together, the problem is both halfs are bent. Looking at the endgrain i can see a nasty radius across the timber. This is work in progress so i hope ive posted in the right place. What should i do to flatten them ? Iron and steam i guess ?... im a little scared of splitting the wood. I have them clamped flat at the moment, to stop them getting worse. Please help me. Edited September 20, 2007 by willy Quote Link to comment Share on other sites More sharing options...
Supernova9 Posted September 20, 2007 Report Share Posted September 20, 2007 Hello to everyone. Im lucky enough to have been given a stunning 1/4" bookmatched flamed maple top. I really want to get on and joint the two halfs together, the problem is both halfs are bent. Looking at the endgrain i can see a nasty radius across the timber. This is work in progress so i hope ive posted in the right place. What should i do to flatten them ? Iron and steam i guess ?... im a little scared of splitting the wood. I have them clamped flat at the moment, to stop them getting worse. Please help me. How far from flat are they? From your description, it sounds like the pieces are cupped along their length. If you lay it flat, how much space is under the pieces at their highest point? Quote Link to comment Share on other sites More sharing options...
willy Posted September 20, 2007 Author Report Share Posted September 20, 2007 Thanks for your reply. I would say about 8- 10mm, please tell me that it will be easy ! Thanks again. Quote Link to comment Share on other sites More sharing options...
RGman Posted September 20, 2007 Report Share Posted September 20, 2007 Thats a fair amount of cupping, the most i have seen from a top is probably 2mm, but the tops i have collected are all close to quarter sawn, sounds like yours are flat sawn. I have no experience in flattening timber with large cupping, your top is only 1/4" thick so i guess you can't thickness it either. I guess you could try and keep it flat by stickering the two pieces and weighting and leaving them to dry some more? Quote Link to comment Share on other sites More sharing options...
willy Posted September 21, 2007 Author Report Share Posted September 21, 2007 Hi RGman, yes its quite bad and im sure its not going to be possible to joint them in their state. I clamped them flat a few days ago, i did have a sneakie look to see if they were any better but they are still the same. Ive only got a few weeks then ive got to make a decision whether or not its usable. Im going to try and iron them in a week or so, if its possible to iron them over a arm rest then (FINGERS CROSSED) it will also work for flattening. Quote Link to comment Share on other sites More sharing options...
Mattia Posted September 21, 2007 Report Share Posted September 21, 2007 Bit of water (concave side), bit of weight, if that don't work, add a bit of heat. Quote Link to comment Share on other sites More sharing options...
Geo Posted September 21, 2007 Report Share Posted September 21, 2007 I clamped them flat a few days ago, i did have a sneakie look to see if they were any better but they are still the same. I think you need to allow air to circulate on the surfaces of the boards. This is what "stickering" means--placing spacers between the boards but still keeping them "flat" with pressure. Quote Link to comment Share on other sites More sharing options...
fryovanni Posted September 22, 2007 Report Share Posted September 22, 2007 Mattia is right. If you have an issue with imbalance in drying(things like allowing air to one face and not the other cause this problem, as well as fresh cutting of wood that is not fully dried). Spritzing a small amount of water on the cupped side(it is cupped due to that side shrinking quicker than the opposite face) can bring it a little closer to being equally moist. Then you can place sticks(sticker) the wood more easily. Applying a bit of weight to the sticks(Note; Don't cover any face of the wood with the weighting material) can help keep things flat during drying. A small fan to help keep air flowing is also a handy way to gently speed up and evenly dry the wood. If the wood is dry and this imbalance is not the issue, and you want to try to use heat. You have to be able to get wood up around 300 degrees, evenly, on a flat surface, then clamp or weight while it cools. The best method for doing this(and only method I have ever used with success) is using heat blankets. It is really hard to get wood up to this temperature evenly, and the thicker the wood the harder it is do(if you honestly want to have it take and hold a new shape). A steam box, or possibly even a heat lamp box may be able to be fabricated and insulated in such a way to generate even heating if you don't want to sink about $100 into heating blankets. A couple 36"long x 6" wide heating blankets can open a lot of avenues for wood bending(archtops, bent side semi's , acoustic flat tops, and such.., not to mention contours) so it can be a good investment. Peace,Rich Quote Link to comment Share on other sites More sharing options...
willy Posted September 22, 2007 Author Report Share Posted September 22, 2007 Thanks for making it so clear what to do. Ive weighted them down with sticks for now and will leave them for a week or so. I use a local joiners when i need to joint large planks and last time i was in their workshop i was shown a medium sized steam tunnel that i could use if i really need too. Thanks again you lot, i knew you would sort me out ! I will post up my progress with my guitar soon. Quote Link to comment Share on other sites More sharing options...
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