08-02-2016, 11:03 AM
A few more pics.
I mentioned that I cast a new chassis fixing screw using an original Bakelite headed one to cast a replica. A few comments on that might be of interest. I used 'Alginart' colour change standard set moulding alginate. It's 'skin-safe' and is used for such things as casting moulds of new-born babies feet and hands, which apparently is a thing that some parents like to do! It came in a 450G pack, and you mix one part powder to three parts water. You add the powder to water and mix it while the colour is bright pink, then as it turns place pink you put the object into the mixture and leave it in place till the alginate turns white, which takes two or three minutes. For something such as screw-head I wished to cast, or a radio knob say, the screw (or for a knob the securing boss), must be accurately concentric. Hence, I made a simple little jig to hold the original pattern screw central, then did likewise with the M3 screw onto which I wanted to cast the new head. I made a couple to be sure.
Roll on the day when we may be able to get parts made on 3-D printers at a sensible price. Not quite there yet.
There's also a pic of the ventilated base that I've made. (I offset the holes, but I think the original holes might have all been in line).
I have one knob - the other is missing, so I intend to use the knob to make a mould, and whereas the original knobs are push on types (not a good idea on what is basically, an live chassis radio), I'll turn some brass shaft inserts drilled 6mm, and cast them into the new knobs, then fix them with a 4 BA grub screw, which can be sealed with wax. I'll make a pair and will most like use two part Ronseal wood-filler as the casting medium. It's quite fluid when mixed, sets rock hard and is 'natural' in colour, so hopefully, will spray up nicely in the desired colour of beige. Time will tell!
Sorry the pics of the screw heads are indistinct - that's due to the limitations of my cheapo digital camera. )I have no interest in photography beyond taking 'snapshots').
The first pic is of an original screw used as a pattern, the second pic shows it suspended in the alginate, the third pic is the vacated mould, the fourth is of the newly cast screw ready to remove from the mould, and the fifth pic shows the original screw alongside two that I cast. The final pic is of the baseboard that I made.
Lots of fun for little cost - if I keep doing this stuff, maybe one day it might stop my kids putting me in a home!
I mentioned that I cast a new chassis fixing screw using an original Bakelite headed one to cast a replica. A few comments on that might be of interest. I used 'Alginart' colour change standard set moulding alginate. It's 'skin-safe' and is used for such things as casting moulds of new-born babies feet and hands, which apparently is a thing that some parents like to do! It came in a 450G pack, and you mix one part powder to three parts water. You add the powder to water and mix it while the colour is bright pink, then as it turns place pink you put the object into the mixture and leave it in place till the alginate turns white, which takes two or three minutes. For something such as screw-head I wished to cast, or a radio knob say, the screw (or for a knob the securing boss), must be accurately concentric. Hence, I made a simple little jig to hold the original pattern screw central, then did likewise with the M3 screw onto which I wanted to cast the new head. I made a couple to be sure.
Roll on the day when we may be able to get parts made on 3-D printers at a sensible price. Not quite there yet.
There's also a pic of the ventilated base that I've made. (I offset the holes, but I think the original holes might have all been in line).
I have one knob - the other is missing, so I intend to use the knob to make a mould, and whereas the original knobs are push on types (not a good idea on what is basically, an live chassis radio), I'll turn some brass shaft inserts drilled 6mm, and cast them into the new knobs, then fix them with a 4 BA grub screw, which can be sealed with wax. I'll make a pair and will most like use two part Ronseal wood-filler as the casting medium. It's quite fluid when mixed, sets rock hard and is 'natural' in colour, so hopefully, will spray up nicely in the desired colour of beige. Time will tell!
Sorry the pics of the screw heads are indistinct - that's due to the limitations of my cheapo digital camera. )I have no interest in photography beyond taking 'snapshots').
The first pic is of an original screw used as a pattern, the second pic shows it suspended in the alginate, the third pic is the vacated mould, the fourth is of the newly cast screw ready to remove from the mould, and the fifth pic shows the original screw alongside two that I cast. The final pic is of the baseboard that I made.
Lots of fun for little cost - if I keep doing this stuff, maybe one day it might stop my kids putting me in a home!
Regards, David.
BVWS Member.
G-QRP Club Member 1339.
'I'm in my own little world, but I'm happy, and they know me here'
BVWS Member.
G-QRP Club Member 1339.
'I'm in my own little world, but I'm happy, and they know me here'
