Parts for a bender

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Kevin Sjostrand
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Joined: Sat Feb 09, 2008 8:06 pm
Location: Visalia, CA

Parts for a bender

Post by Kevin Sjostrand »

Since most of the bending is done within around 2" of each end of a side, can someone tell me if 25" metal slats would be long enough to work when bending sides? Seems they would support that part of the wood that is being bent.
I ask as I see that much of the shim stock available (spring steel) comes in 25" lengths, and SS stock in either 50" or 60" rolls (which would yield 30" pieces - better yet I'm sure).
What do you guys know or think about this?
Also, what if the heat blanket is only 30" long...adequate or not?

Kevin
tippie53
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Re: Parts for a bender

Post by tippie53 »

what happens is the exposed part will dry off faster during bending causing cupping. most of the time this is in the block areas and once in a while the sides will split from the uneven drying . My best advice is to say that sometimes saving pennies costs more dollars .
Also shim stock is not a tempered stainless and will bend pretty easy . Yes I do sell slats and it is a tempered stainless . Just my 2 cents
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
Kevin Sjostrand
Posts: 3712
Joined: Sat Feb 09, 2008 8:06 pm
Location: Visalia, CA

Re: Parts for a bender

Post by Kevin Sjostrand »

Thanks John, I know you do, and the price is a very good price. Your $.02 is worth $$$$$ to many of us and we appreciate your experience and expertise!
I see you also sell spring steel slats. Other than these can rust, and transfer color to the wood, would you say they work better than the stainless?
I only want to save pennies where it doesn't affect the process, quality, ease of use, etc.
I would purchase your bending machine in a heart beat if I had the cash. I am looking at building one a might look to you for some parts.

Kevin
tippie53
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Re: Parts for a bender

Post by tippie53 »

I prefer the stainless . Not only won't it rust it won't stain. 30 inch blanket will do the job on most guitars . I started with a 30 and now use mostly 32 inch. The 36 started most likely as that was the standard sized blanket at the time. I am actually a distributor of the heat blankets for pro therm and got them to make the smaller sized ones .
If I had to say , you can get away with 30 blanket and slat but that would limit you to non cutaway and only standard shapes. Most guitar sides are just under 30 inch. The cutaway I make is longer as I joint the upper of the guitar on the cutaway rise on the front of the neck block.
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
kencierp

Re: Parts for a bender

Post by kencierp »

All our benders with the exception of the OM cutaway use aluminum for slats and profile form skin (we only have an outer loose slat) .023" +/- MacMaster Carr, Speedy Metals, Home Depot, Lowe's and all other heat transfer components are also aluminum. For the cut bender and its very tight curves we use .007" stainless steel shim stock.
Kevin Sjostrand
Posts: 3712
Joined: Sat Feb 09, 2008 8:06 pm
Location: Visalia, CA

Re: Parts for a bender

Post by Kevin Sjostrand »

Another two part question:
I see most of the molds for benders are constructed of plywood and some type of metal pipe or slats for separators. I assume this design came from the need to have a open mold design that the heat from light bulbs could get to the side being bent. If one is going to use a heating blanket, I would think this design would not be necessary, and either a solid mold, or, perhaps a three section plywood mold; one down the center would work as well or better?
If the mold was made this way, or solid, would that metal support bar at the waist area for bending be necessary?

Kevin
kencierp

Re: Parts for a bender

Post by kencierp »

You may get away with not having a waist support bar/system if bending "D"s --- but you can just about guarantee a snap will occur with a tight waist style at some point. The LMII bender, I believe is a three section form -- a solid form will work with a blanket.
tippie53
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Re: Parts for a bender

Post by tippie53 »

I find that the waist bar is not for support but location of the waist cawl to the ram. Here is where stainless slats are better than aluminum , they support all curved areas much better . We at blues creek found that standard shim stock is not tempered stainless. We do use a tempered stainless as it will last about forever and shouldn't kink.
As for a solid form , they work well with blankets . A solid form can be covered in aluminum as here it is a heat shield and the form supports that well.
I don't recommend using a blanket against the wood as this can raise the grain in the wood to the pattern of the heat elements in the blanket This can leave a signature when you are finishing . Use a slat to dissipate the heat to the wood .
This year I have bent 250 side sets to date . The process is simple , let the heat get into the wood and bend. At the same time , don't wait too long. I am done the actual bend process in under 4 minutes .
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
Kevin Sjostrand
Posts: 3712
Joined: Sat Feb 09, 2008 8:06 pm
Location: Visalia, CA

Re: Parts for a bender

Post by Kevin Sjostrand »

I like the idea of a solid mold, al bet it will be much heavier, but I have a roll of stainless steel foil that would work great for covering the wood surface. I was going to just get some steel conduit for the pipe separators ( I know, galvanized, but it will eventually burn off) and that is pretty inexpensive to by, plus the mold is much lighter weight.

So with a solid mold, I could use just one slat over the top of the blanket and side, correct?

Kevin
SKBarbour
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Joined: Fri Oct 01, 2010 5:19 pm
Location: Glen Burnie Md

Re: Parts for a bender

Post by SKBarbour »

I like the idea of the molds using the pipe as supports. I made a solid mold during the last build to bend some binding and it was kind of a mess profiling all the sections. With the other mold you only need two sides which means alot less mess and time. But I guess the solid mold may hold up longer.
kyle
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