backing

[BOWMAN53]

its 1 1/2 at the fades by the handle and 1/2" at the tips.

[sleek]

You have the meat needed. Chop those tips off if you want a D style bow to make the bow 68 inches, retiller slightly to make the tips not so stiff and then weigh it. If you are not happy then, recurve it if you have the means. If not I wouldnt go any shorter than 66 inches long for sure. If that doesnt do it, add sinew as fishfinder said, and recurve it and you will get allot of weight from it then!

[DarkSoul]

No f!b€rgl@$$ please!

What wood is the bow?
Is it already finished (if yes, what did you use for finish)?

You could also just start a new bow...raising the drawweight ten pounds is a lot and often requires almost as much work as starting a new bow.
Otherwise, you could glue down a lamination on the back. A strip of hickory/ash/white oak/elm would work good.
You could also glue down a fiber backing. Cloth or raw hide will not add a lot of drawweight, but a thick fiber backing such as raw flax or hemp fiber has been recommened by Tim Baker.

[k-hat]

The time you're going to spend getting weight up to 10 pounds is time you could be making a bow intentionally 10 pounds heavier.  Anything you do (other than sinew) is going to add stress to the bow and 10 pounds in weight gain may not all translate to kinetic energy (eg: shortening and flipping tips will cause additional set, etc).   BTW, adding 10 pounds to a  25# bow is HUGE change... almost 50% of current weight!!   
I did what you're trying on my second bow and wound up with an overstressed, fretted, and splintered bow that was otherwise fine before i decided not to leave well enough alone.  Not saying it has to happen that way, but it easily can.

I guess it depends on your purpose.  You want a 10# heavier bow..... make one!!!   you want to experiment on a stave you don't mind potentially messing up... then experiment to learn how not to mess up using these other methods (sinew, backing, etc). 

My 3 cents worth

[BOWMAN53]

I think I might just back it with a paper bag just for a lil protection.  Ill build my next bow a lot better.

Right now I am 2 out 4 in my early bow making career

[bubby]

ya know a young'in or a woman might really like a nice 25# bow, give her away and build a heavyer bow, that's what i'd do, Bub

[mikekeswick]

AS already suggested forget trying to raise the weight by 10#....for lots of reasons
Start a new one and give it away if you don't like it.
Best bet is buy the Traditional Bowyers Bible volume 1 and reading the chapter about tillering over and over again!
Good luck.

[BOWMAN53]

Well I can even get why wife to come out a shoot a bow one time so I can't give it to her.  I don't trust my lil bro with one just yet and my oldest daughter is a lefty and I cut a shelf for a righty. So I think ill just keep it as a reminder.

[fishfinder401]

this is coming from someone who enjoys shooting bows around 140lbs..... shooting a bow that weight can still be fun, just different