Rookie Mistake....

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pensmyth

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Well I have a really nice FX blank I got from Exotic Blanks for a cigar pen and while I've turned a bunch of pens I haven't turned a cigar pen in quite some time. It would be a bit of an understatement to say I was embarrassed when I finished them and realized I'd reversed the upper and lower blanks! (face palm moment). So the blanks are cast with alumilite and I have some Alumilite clear slow set. Can I recast these to build them back up and turn them again? Do I need to abrade them or do anything to them to cast over the turned blank?
 
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jttheclockman

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The cigar pen is one of those kits that requires full attention throughout the process of making. Now I do not use that resin but I would say no to recasting on top of. My thoughts are if you put tooth into the blank it may show through and you could not polish out. If cast on top the layer will be so thin it may just crack off. If you took the blanks off the pen is there anyway to just reverse the blanks and still reshape?? Some times people do bulging shape finishes. Without seeing your pen it is just a suggestion.

I have to tell you I had to look at EB site to see what a FX blank is. As I looked through some of the watch part blanks I saw a few that I would be worried about but I know sometimes it is an optical illussion from the angles, but it looks like the casting would be too thin in certain areas. Being a caster that is a problem that always needs to be addressed when casting to keep the tube dead center when vertical casting. Just an observation. A little off topic.
 
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1080Wayne

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Alumilite Clear does not bond well to itself once it has lost tackiness . I have done it on castings over 1 inch dia by creating teeth , but optical effects tend to show up . Alumilite Amazing Clear Cast epoxy might work over top , but epoxies tend to yellow over time . I have not yet experimented with it .
 

Kenny Durrant

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I think I'm in the same boat as Wayne. I do know that the Alumilite Clear won't stick to itself. I've tried it it it seemed to work until it was close to finishing and the thin spots just peeled off. The epoxys yellow so I wouldn't mess with those. I haven't tried PR resin but I might try that. As far as scuffing the Alumilite to give the next layer something to hold onto I'd use scotch bright to knock the glossy sheen off and call it good. If you don't already have the resin you might be better off to buy new blanks and start over. I usually keep the old blanks for a while to remind me to double check before I start turning. That's not necessarily a tip that's just what I do when I've done the same thing.
 

JohnU

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I have experienced this issue... as said above, recasting is not an option with urethane resin, but I have fixed the problem with layers of CA to build up the lower areas to fit the larger top bushings. Make sure to use nonstick bushings and depending on your choice of CA- very little activator. I use GluBoost for building up layers because it doesn't react to its activator and is made to fill. If using another brand, be sure to keep your layers thin. Too much activator with other brands may crack on you down the road. I hope this helps!
 

JohnU

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...... but it looks like the casting would be too thin in certain areas. Being a caster that is a problem that always needs to be addressed when casting to keep the tube dead center when vertical casting......
The resin definitely magnifies the objects inside giving them the illusion of being thin but there is plenty of resin thickness outside the objects. Lol.

As for having to be dead center.... not true at all. Although it's good practice to try and be center, it doesn't have to be "dead center" since the objects are attached to the tube and you use the tube ends to turn it. Even in extreme out of round blanks, they will be perfectly round when you turn away the excess resin. As long as there is resin past the bushings you are fine with turning it. Remember the objects are on the tube, not floating in the resin.
 
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jttheclockman

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The resin definitely magnifies the objects inside giving them the illusion of being thin but there is plenty of resin thickness outside the objects. Lol.

As for having to be dead center.... not true at all. Although it's good practice to try and be center, it doesn't have to be "dead center" since the objects are attached to the tube and you use the tube ends to turn it. Even in extreme out of round blanks, they will be perfectly round when you turn away the excess resin. As long as there is resin past the bushings you are fine with turning it. Remember the objects are on the tube, not floating in the resin.
John will have to disagree with you to a point there has to be enough resin so as to not turn into parts but also the kit will matter. I looked at some of those and would be definetly worried. As I said I do this kind of casting also. Just because there is resin past the bushings when you set up on a mandrel does not mean the parts are not sticking past the bushings. If slanted then you probably have no chance to even make it bulbous. I just ran into a situation that the tube was slanted after it came out of the pot and with the kit I used I just clipped an end and needed to add CA. These are MY THOUGHTS as I have to keep making this statement here because I get so many people disagreeing with everything I say. Just my thoughts. Good luck.
 

JohnU

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I see your point but as long as the objects are against the tube there is no issue of out of round. No blank maker can be dead center. Curing resin can shift tubes a little side to side. The blanks are then turned into centers as you remove excess resin on the outside of the blanks. Since I make these I know the parts are tight along the brass tube and won't be hit by turning unless you turn them lower than the bushing diameter. Most of us turn from the bushings and then slightly larger in the middle. This way there is never a problem. If they turned them under the bushings there may be an issue. It's just hard to see because the resin magnifies the insides in the photo.
 

jttheclockman

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I see your point but as long as the objects are against the tube there is no issue of out of round. No blank maker can be dead center. Curing resin can shift tubes a little side to side. The blanks are then turned into centers as you remove excess resin on the outside of the blanks. Since I make these I know the parts are tight along the brass tube and won't be hit by turning unless you turn them lower than the bushing diameter. Most of us turn from the bushings and then slightly larger in the middle. This way there is never a problem. If they turned them under the bushings there may be an issue. It's just hard to see because the resin magnifies the insides in the photo.
I know about the optical illusion thing. Hey they are your work and your product and I know you know what you are doing so they should be fine. Yes it is hard to keep perfect when casting that way. I have gone and made some quick holders to keep those need to be straight castings. As long as all parts are below busing height when assembling then there is a good chance that will come out well. Sorry I even mentioned it.
 

jttheclockman

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No problem, and a valid concern when buying a clear cast. since I have first hand knowledge about these I just thought I would set anyone's concerns to rest.
Not to belabor this point but a very good example of optical illusion is in Warren's blank posting, You look at the multicolored blank and see where you would cut off excess on top and bottom of the blank where the bushings go in. It looks like the material is flat against the outside of the resin. Now you hope when you put your bushing in and turn down to bushings that material was below the bushing level. Just because there is resin outside the bushing when set up on mandrel does not mean the material was below it. I am sure it it is but from the naked eye it does not look like that.

https://www.penturners.org/threads/blank-identification.170113/
 

JohnU

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Yea with the resin optical illusion it can be deceiving. I didn't make that blank but like you, I'm sure it is fine or they wouldn't have sold as many as they did.
 
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