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| Why alum. and not wood dowels? http://luthiersforum.com/forum/viewtopic.php?f=10101&t=36399 |
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| Author: | Chuck [ Sun May 06, 2012 3:17 am ] |
| Post subject: | Why alum. and not wood dowels? |
Today I made a mold for my side bender. As I was fitting the round aluminum 6 inch rods into the the sides of the mold it occured to me why wouldn't it work if a person just used round wood dowels to span the 6 inches and just glued them in? Also,why do the 6 inch aluminum dowels need to just meet at the edge of the mold? I understand why they can not protrude beyond the edge as you might get a hump when the slats and wood are put over it but what would be wrong it the rods were about an eigth inch from the edge on the inside of the edge. Chuck |
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| Author: | ChuckB [ Sun May 06, 2012 5:38 am ] |
| Post subject: | Re: Why alum. and not wood dowels? |
Chuck, the rods meet at the top edge to maintain the side shape across the width, and to eliminate buckling. Wooden dowels will work, I have a number of forms that I built using 1 1/4" dowels and they work just fine. Chuck |
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| Author: | Chuck [ Sun May 06, 2012 12:25 pm ] |
| Post subject: | Re: Why alum. and not wood dowels? |
Thanks you guys. After I made it I figured aluminum cross rods were for support but I hadn't thought about wrinkling problem. Then as I looked at it I thought why couldn't I use 1/4 inch dowels and the only reason I could come up with was I could use the aluminum over and over for different molds. Then, being a little slow, I thought well I could do the same thing with the wood dowels. However, it made sense to me that if I were making the molds with 1/4 wood dowels I would just glue them in. I am using the light bulbs for now but I plan to buy a blanket after I have a few bends under my belt. Then I most likely will build the molds solid as I think there would be less chance of anything going wrong. However, I might be wrong on that one also. So much to learn and so little time. Just taking baby steps and don't mind if I have to do something over a few times to get it right. Chuck |
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| Author: | Daniel Minard [ Sun May 06, 2012 12:26 pm ] |
| Post subject: | Re: Why alum. and not wood dowels? |
I use 1/2" hardwood dowels in my bender molds now. They work just fine. No need to glue them in. One set will service all of your molds & the molds will be much easier to store if not glued to the dowels. When still using light bulbs to heat the bender, I used 1/2" copper pipe. Scraps from a plumber friend. Free, my favourite price! |
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| Author: | Chuck [ Sun May 06, 2012 12:39 pm ] |
| Post subject: | Re: Why alum. and not wood dowels? |
Daniel Minard wrote: I use 1/2" hardwood dowels in my bender molds now. They work just fine. No need to glue them in. One set will service all of your molds & the molds will be much easier to store if not glued to the dowels. When still using light bulbs to heat the bender, I used 1/2" copper pipe. Scraps from a plumber friend. Free, my favourite price! Are you placing the 1/2 dowels so that the side of the dowels just match the edge of the top side of the plywood? Chuck |
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| Author: | ChuckB [ Sun May 06, 2012 1:06 pm ] |
| Post subject: | Re: Why alum. and not wood dowels? |
Chuck, please reread my post. I use 1.25 inch dowels (mostly cut off from old broom handles), not 1/4". I would not recommend 1/4" dowels or any wood dowels if using light bulbs. Chuck |
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| Author: | Joe Beaver [ Sun May 06, 2012 2:51 pm ] |
| Post subject: | Re: Why alum. and not wood dowels? |
One thing to keep in mind is the mold can get hot. Hot enough to soften the glue of glued in dowels so I would just put a screw in them and call it good. |
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| Author: | Joe Sallis [ Mon May 07, 2012 2:33 pm ] |
| Post subject: | Re: Why alum. and not wood dowels? |
I use mild steel rod. Much cheaper than alu and dosen't burn. |
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| Author: | Daniel Minard [ Tue May 08, 2012 12:29 am ] |
| Post subject: | Re: Why alum. and not wood dowels? |
Hey Chuck; I drill the holes so they just barely blow out the plywood (or MDF) at the edge of the mold. On a big jumbo mold, I use 12 dowels. The parlour mold has 9. All the rest use ten. Seems to be plenty tough enough to do the job. |
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| Author: | Chuck [ Tue May 08, 2012 8:10 am ] |
| Post subject: | Re: Why alum. and not wood dowels? |
Daniel Minard wrote: Hey Chuck; I drill the holes so they just barely blow out the plywood (or MDF) at the edge of the mold. On a big jumbo mold, I use 12 dowels. The parlour mold has 9. All the rest use ten. Seems to be plenty tough enough to do the job. My mold is for an L-OO and I used 9 al. rods and put them in like you did on the edge. I did have to drill a couple twice as when I finished them there was a hump when I put in the rods and I knew that wouldn't work. So I moved the drill hole over about 3/4 of an inch and drilled another. I may go back and fill in the holes that are not right with wooden dowels and sand them down so there is no high spots. Chuck |
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