i need help or suggestions on how to straighten an old bamboo rod prior to or part of rebuilding

Sam,
I am a little surprised that you have not gotten an answer from a bamboo rod builder.
I think that it is done by applying a relatively low heat and then bending the rod against the curve while it is hot but that is just something that I have read somewhere. I have not done it myself. There are several web sites for the bamboo rod builders and users. I will bet that if you do a web search you will easily fine one and if you ask your question on one of those sites you will get someone who knows what they are talking about and will help you.

Sam; Emory is correct. Heat is used in conjunction with pressure to bend the blank back to being straight.Be careful with the application of heat.. too much can scorch (and thereby weaken) a rod. I'd suggest you stay away from flame..a heat gun if you have one works great; the blank can be heated over a stove burner; a hair dryer might get the blank hot enough..never tried that myself. Essentially, just rotate the crooked section of the blank in your heat source. When it's warm enough , it'll "melt", or soften slightly. Press with your thumbs against the bend to straighten.Proceed slowly and carefully;this takes a little practice. Barry.

Sam;
I use an variable temp heat gun to straighten nodes and blanks, the smaller the area I'm trying to straighten, the lower the temp. I have the gun, so that's what I use, but there are many possibilities. Any heat source will work, you just have to be very careful not to scorch or burn the bamboo. As an alternative, you could use an electric stove, or a gas stove with a diffuser on the burner, alcohol lamp, toaster or hair dryer, tho hair dryers generally don't get very hot. Heat the bamboo bare handed, no gloves, if you can't hold it, it's too hot. Heat while rotating the rod and keeping tra k of which way you want to bend it untiil it "gives" , then counter bend it and remove from the heat, blowing on it will hasten the cooling process, sight and repeat as necessary. hope this helps
john

Steam is the method I use. Remove the guides, suspend over boiling water and roll on a counter top. If the bend is slight you can roll it over the spout of a teapot --- worked for decades.

thanks a lot, i bought a variable temp heat gun and it works like a charm