#1
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Heating frets for removal
Why?
I get that it's done to loosen any glue that might be in there so that's why I do it but if I determine there is no glue used then I carry on without heating. I brought this up in a conversation the other day where it was proposed that heating up a fret expands it and would make it actually more difficult to remove. I suppose heating it then letting it cool might push some of the fibers in the slot apart and make removal easier. |
#2
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I use a Weller 80-watt stained glass soldering iron with a simple groove filed in the tip to balance it on top of the fret.
I don’t try to remove a fret without heating it, and I clean the soldering iron tip frequently to get good heat transfer. I want the fret to get hot. I don't take the iron off the fret untill I've actually started to lift it oput of th slot. Heated, the fret lubricates its path out of the slot by searing the wood surface of the fret slot a little, releasing natural oils and such.
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Cheers, Frank Ford |
#3
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I read your page on your site about that Frank and perhaps I missed the bit about releasing the oils but I had thought about that too. I like the little jig you made for the heat too.
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#4
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I heat unglued frets to reduce chipping. Ebony boards are more prone to chipping than rosewood.
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#5
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Quote:
Heat expands metal be that ferrous of non ferrous eg nickle silver, however the expanision is something like 2.5mm on a 2000mm length of material, so its really a non relevant. I have not actually calculated it out, but my days of non destructive testing for the Fda and Casa, we did calculate it out for aluminiums etc as we had to inspect aircraft for stress cracking in the wing sections which were made from aluminium. Like yourself, once I know it does not have glue I dont use heat to pull the frets. As far as heating the wood, I have two scenarios for and against. Scenario 1 against... Heat expands the wood, that expansion of wood is counteractive to pulling IMO as well, as the neck is not heated, just localised area at the fret, so in theory more compression is being applied to the side of the fret itself as well from the localised expansion Scenario 2 for..... Heat expands the wood, in doing so it weakens the glue bonds within the wood itself, like bending wood with steam, this weakened structure can allow a fret barb to be withdrawn without tearing the wood, with the localised growth of the wood as well from heat the side compression on the fret may actually assist in removal by the fact its being squeezed out. As you can see, I too have given this thought over the years Steve
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Cole Clark Fat Lady Gretsch Electromatic Martin CEO7 Maton Messiah Taylor 814CE |
#6
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Thermal expansion of wood is negligible. My take is based on experience. If pulling unglued frets causes extensive chipping, i found that heating them reduces chipping on the same fingerboard to near zero.
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#7
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Yeah so it's probably the oils in the wood as mentioned. I wonder if the heat somehow reduces friction too.
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#8
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Actually, heating the frets, causes the local area to loose, or drive off moisture. This localized heating, causes the wood gripping the fret to contract or shrink very slightly, not expand. This effect, besides softening any glue that may be present, allows the fret to pull up with less friction and less chipping.
Now, if you were to heat the whole neck or a larger portion than just the frets, then yes, some expansion is going to occur, simply because the amount of moisture retained in the wood can not escape all at once. However, given enough time and heat, this structural moisture will be driven off, and then the neck wood will shrink, usually cracking the neck somewhere. Interestingly, the opposite effect is used to repair dents. You simply dampen the dent with water and apply heat. The technique is simple, wet a cotton rag, lay the dampened rag over the dent, apply a hot clothes iron tip to the damp rag, wait a few seconds, observe the progress, rinse and repeat. Basically, the wood absorbs the heated moisture in the dent and the wood fibers expand, kinda like inflating a flat tire .
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Leonard 1918 Gibson L-1 1928 Gibson L-4 (Blond w/Ebony Fret-board) 1930's Kalamazoo KG-32 1930's Gretsch F-50 1934 Gibson L-7 1934 Gibson L-50 (KG-11/14 Body Shape) 1935 Gibson L-50 (Flat-back) 1935 Gibson L-30 (Flat-back) 1942 Gibson L-50 (WWII Banner Head) 1948 Gibson L-50 1949 Epiphone Blackstone "a sharp mind cuts cleaner than a sharp tool" |