ORIGINAL: MTK
Dave,
The rear of any layed-up fuse may be stiffened in several ways. One way is to laminate a composite sandwich with 1/32'' balsa and with lower weight glass. The resultant fuse will actually be lighter than ones that are 100% glass. Another way is to lay carbon tow on bias at about 1'' centers.
Neither method will preserve the original build method so neither would be a pure copy. But either method will result in a better product. Take your pick and choice
Most 2 part epoxy systems we use have an amine based part B. This material is photochemically sensitive and will turn amber with age and light and air exposure. Some yellowing is no big deal. But if the catalyst part B turns dark amber to brown, the resulting polymer will not have the same properties (weaker) as the fresh ingredients will make. I've found shelf life of good epoxy systems such as Pro Set to be around 4-5 years with good sealing practice of the containers
Other catalyst systems such as that used in John Greer epoxies, are not photochemically reactive since they are not amine based. The resultant epoxy color is clear and stays that way. Speaking from personal experience with this type of epoxy system, strength is there but stiffness is not as good as with a good amine based systems such as West Systems, EZLam, or Pro Set
Matt,
thanks for the very enlightening info. Always eager to learn something new regarding mold making. One day I'll make one if none other than the experience.
The CF comment I was making regarding the P5 (or P6 not sure) in reference to Tipo's and Illusions was intended to be a "fast" way to stiffen up the rear without Don having to get into more complex and expensive laminating techniques. I know he already uses CF tow for certain areas so I thought it might be an "easy" option.
Coming back to your comments though, other than what Don mentioned regarding the "speed" of the hardener, is there any validity in considering a deep amber fuse to be weaker or of less quality than one that is clearer? I'm only venturing on this thought based on the idea that the epoxy might have been mixed with a more aged and exposed hardener. Possible?
Otherwise, if the fuse is deep amber compared to light or clear, can we argue that the fuse is "fresher" or otherwise was laid up with slower hardeners?
All this of course assuming that amine based hardener epoxies are being used.
TIA, David.