Some of the coolest things seem so simple

[Lee Robinson .]

Sunset,

Do you use an air hose system? You didn't say what you are using now. While you didn't directly mention that the air hose system actually increases pressure when heated, I believe you are referring to that based upon what other option is left that could increase pressure once everything is warmed up?

I have opened my hot box on my personal bows during glue up to see how things were going and have checked the air pressure...because I know heat causes air to expand and I was curious as to how much pressure was gained by the heating of the air hose. I don't remember how much it changed exactly, but if memory serves me correctly the pressure didn't increase as much as I expected it to. I do like the fact that it doesn't reduce pressure though.

[Nate Steen .]

Lee,

the air pressure system doesn't increase pressure much because the hose is trapped and can't expand much which is good, because pressure isn't reduced.  I use a type of metal spring clamp form, which keeps pressure continually adjusting as components heat up and get soft, the springs clamp down more...essentially the same result as the air hose system....

[Lee Robinson .]

According to this link...   http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=73  

A "general rule of thumb" as they put it is for every 10 degrees F change in temp, the psi is altered by only 1 psi. I am sure that isn't an exact correlation, but if it is relatively close that rule would be very simple and convenient to use.

So, if I inflate to 100 psi at 80 degrees...and then "cook" at 160, then the pressure in the hose would increase 8 psi...making it 108 psi total when at 160 degrees.

As I said, I don't remember exactly how much change I saw, but I would say it was probably pretty close to that "rule."

[Apex Predator]

Lee,

I am very convinced that your system works for you and your fine bows.  I only wanted to share that the rubber band method can, and does work extremely well for the "hobby" bowyer.  I have thought of changing my methods to make things quicker and easier, but always balk at the idea.  I'm not a "production" type bowyer, and never will be.  Personally, I like to build them one at a time, where no two are the same.  The design characteristics are the same for a given model, but I won't build bows in a "quicker and easier" fashion.  As a result, I will never be a "big time" bowyer, as I prefer the simpler "hands on" approach to each step.  There are many steps that a bowyer can take to save time, and they are not bad, just not for me.

The pressure strip is key in the rubber band type form.  I start with a piece of aluminum that I can bend to conform to the fades of the chosen riser, which is either 1/16" or 1/8", depending on the model.  I glue rubber to the bottom and a piece of pvc lattice to the top to make sure the epoxy is forced out from the center to the edges.  With a pressure strip the full width of your lams, it has a tendancy to bow up in the middle.  The narrower lattice prevents this.  Here is an example of my pressure strips.

 

 

 

To make money in bowyering, you have to streamline the process.  I will probably never make money in this endeavor!     The guys making money selling bows, are not making much, cause it's still a "labor of love"!  

[Str8Arrow]

Where do you get the rubber for that type of form? I like the concept, but can't think of where the rubber might come from.

[Apex Predator]

I get mine for free at the local bicycle shop.  They throw out all the ones they replace.  Nothing wrong with them, usually, except a pin hole, which will not affect them for what you need them for.  I cut them into length-wise strips.  On a fat one I may get three strips, but normally only two.  I like them to be around 1 1/4-1 1/2".

[Lee Robinson .]

As mentioned, my two piece high pressure form weighs about 100# reinforced like it is, so it isn't used for convenience. I use it on my protege longbows though because cumbersome or not...it offers me a great deal of precision and quality and it works perfectly for me.

That said, I would like to use the rubberband system on my "youth bow" form, so your tips on the pressure strip are much appreciated. When I do a second attempt, I am certain those tips will help. They make a lot of sense. Thanks. I will keep you posted...unfortunately it may be a while before I have time to make another personal bow (for the family), as I need to first take care of some custom orders from some much appreciated customers.

[Lee Robinson .]

Marty,

Is the rubber on your aluminum pressure strip inner tube rubber also, or is it some other type? It looks thicker. I am sure those tips will help me make my son a better bow without going through the trouble of making a high pressure form for his bow's layout. I will post some pictures of my heavy form if you like. It isn't near as simple, but it does work great. Maybe you will see something you can use should you ever decide to go that route.

[OkKeith]

Marty,

Your form looks really similar to the one I have put together.

I understand that the pressure strip is the key to the "rubber band" method. Where is it you get the aluminum and stick-on rubber?

Do you buy a whole 4X8 sheet of the lattice and take it apart to get those pieces?

I hope you truly beileve that "Imitation is the purest form of flattery" because I am TOTALLY swipeing your glue-up process. I'm never gonna be any competition in the bow market. I just hope mine turn out half as good looking as yours.

OkKeith

[Apex Predator]

The aluminum,lattice, and rubber can be found at Lowe's.  The lattice can be bought in singe strips in the trim molding section.  The rubber comes in 4' lengths, is about 5-6" wide and is used in tile flooring jobs.  I can't remember what it's purpose is but you can find it if you look.

[stringstretcher]

Apex, you just answered the question I have been trying to get at about the "mound" on top. Makes perfect sense to me.  My for will be make just like yours and I am sure it will be all I need.  Just one question.  On the bottom of your form, do you also use a pressure strip with rubber of just glue down directly to the form?

[Apex Predator]

Mine have an aluminum strip glued straight to the form, which averages out any imperfections in the surface of the form.  On top of the aluminum I add another piece of hard rubber.

[Lee Robinson .]

On top of both of my forms (my protege longbow form and my youth bow), I used a piece of formica for the same reason Marrty uses the aluminum/rubber. On my high pressure form I don't use rubber, but I wouldn't object to using a thin piece on the belly side (which wouldn't be on the form). I fear any loss of precision (I believe I am within micrometer accuracy and balance on my form's limbs). I spent a LOT of time and measurements putting extreme precision into my form. I try to keep that as smooth as possible to as I don't like that idea of anything reducing the precision I put into creating my desired profile. I also have a fear that heat strips cause a loss of precision on the form and don't use them for that reason (I use an oven)...but that may be ureasonable on my part. The heat strips are convenient and quick, but I can't help but wonder how "flat" (consistent and even) they are under pressure.  That is why I wax my form every time I use it...I want my bows to have a perfect surface.

[OkKeith]

Thanks for all the help guys!

I have learned quite a bit from these posts.

OkKeith

[EL Mejor]

NICE,,,LOOKS GOOD,,,

[bowfanatik]

Hi , this is old topic. New for me      
i have two options

first options is
   

second options is
       

I want to make bows, but as a hobby. I do not care no more than that. But I'd like to do it well and in the best way, I'm aware that there are many ways and that no one is wrong. But I'd do it in a way that has the least bad side. So I would like to hear advice