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#1 2006-04-02 17:54:24
- Bogert
- Member
- From: Amagasaki-shi, Hyogo-ken
- Registered: 2005-12-05
- Posts: 203
Casting with thin lacquer?
Hello everyone,
I just had a thought, and don't know if it would work or not. Could you cast a bore with a thin type of fast drying lacquer? I don't know the shrinkage rate for lacquer, I have a silicone (I think) reverse mold I made to cast around for the inside of the flute and it is not supposed to stick to anything besides itself. Otherwise I'll probably use epoxy. Thanks for any input on this idea.
Chris
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#2 2006-04-02 22:08:39
Re: Casting with thin lacquer?
Bogert wrote:
Hello everyone,
I just had a thought, and don't know if it would work or not. Could you cast a bore with a thin type of fast drying lacquer? I don't know the shrinkage rate for lacquer, I have a silicone (I think) reverse mold I made to cast around for the inside of the flute and it is not supposed to stick to anything besides itself. Otherwise I'll probably use epoxy. Thanks for any input on this idea.
Chris
Chris,
I haven't attempted using only lacquer because of shrinkage. However, you never know for sure until you try.
I've used epoxy resins to cast bores. I haven't used them all, but the ones I did turned out to be too heavy and brittle for my purposes. I've had better luck with polyurethane resins.
Whatever you use, make sure to use a good releasing agent. Sometimes, even the 'spray on' releasing agents are not enough. A thin layer of Vaseline on the bore negative (reverse mold) has worked for me.
Ken
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#3 2006-04-02 23:17:33
- Bogert
- Member
- From: Amagasaki-shi, Hyogo-ken
- Registered: 2005-12-05
- Posts: 203
Re: Casting with thin lacquer?
ok thanks, I suppose I'll give it a shot just to try. Boatbuilders epoxy dries very hard and is very permanant. My father has built several boats so he let me use some with my flute making, kinda expensive though. The casting material I bought said it doesn't even need releasing agents, but I'll put some on anyway just in case. It came out of the paster cast fine.
理趣経百字の偈
菩薩勝慧者 乃至尽生死 恒作衆生利 而不趣涅槃 般若及方便 智度悉加持 諸法及諸有 一切皆清浄 欲等調世間 令得浄除故
有頂及悪趣 調伏尽諸有 如蓮体本染 不為垢所染 諸欲性亦然 不染利群生 大欲得清浄 大安楽富饒 三界得自在 能作堅固利
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#4 2006-04-04 01:30:13
- edosan
- Edomologist
- From: Salt Lake City
- Registered: 2005-10-09
- Posts: 2185
Re: Casting with thin lacquer?
Just a word of experience:
The shrinkage rate for any lacquer that is not catalyzed (and that covers about 99% of it--catalyzed lacquer is rare and esoteric) is very high.
Lacquer is made up mainly of a solvent, followed by particulates of varying kinds, followed by various amounts and kinds of plasticizers, to keep it flexible (if required--it's another variable) after it cures.
Lacquer cures from the inside out: First a skin forms on the surface, then the volatile solvents migrate out over time, and the lacquer shrinks. The thicker the lacquer, the longer it takes to cure, and the greater the percentage of shrinkage.
The reason epoxy doesn't shrink much at all is that it's a catalyzed chemical reaction, with little or no volatile solvents to blow off and shrink the film. It just gets hot (the degree of heat depending on the thickness of the film) and sets up with little change in dimension.
Another good material for bore casting is polyester resin, some form of which Monty Levenson uses.
eB
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