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Making Plastikard boilers.


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Hi there,

 

has anyone any experience of making plastikard boilers for steam locos?

 

I've had a few goes & can't seem to get a neat complete tube & was just wondering what methods other folks used?

 

Do you laminate several really thin layers together or use 1 thicker layer?

 

Thanks in advance.

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Hi there,

 

has anyone any experience of making plastikard boilers for steam locos?

 

I've had a few goes & can't seem to get a neat complete tube & was just wondering what methods other folks used?

 

Do you laminate several really thin layers together or use 1 thicker layer?

 

Thanks in advance.

 

Well yes, I have. I normally use a circular former of around 1 mm diameter less than the required boiler diameter. I have a variety of these - old cigar tubes, lengths of dowel, etc.

 

I use layers of .010" plasticard which are effectively laminated together. I cut each layer to the correct size - Diameter x Pi, then roll it around the former and hold it with packing pieces and elastic bands. The packing pieces prevent distortion of the plasticard tube when the next stage is done and also spread the retaining forces along the piece. When you have the piece located on its former and suitably wrapped with the elastic bands, dunk it in near boiling water. This will actually fix the roll and you will then have a rolled, plasticard tube. You can actually roll two or three such pieces on the same diameter tube.

 

Once all are rolled, then locate one tube over the former and glue the next one to it. I leave this arrangement set up for at least a couple of days to ensure that the adhesive is completely dry; any evaporated solvent, trapped between the layers, will eat through the plasticard and cause a deformation.

 

I'll try and find a photo or two showing this process. While not a boiler - this is a curved wall and only through 90 degrees, not 360 - this photo shows how the curvature is achieved. This whole lot is dunked in near boiling water for around a minute.

 

For a 360 degree boiler, I would think that six packing pieces, arranged at 60 degree intervals, would suffice. These can easily be positioned after the elastic bands are wrapped around the plasticard tube and they will greatly assist in making a uniform tube.

 

Cheers

 

Mike

post-3150-0-21186200-1330509552.jpg

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khandc_au:

 

thanks for your response. I'd thought of building up the diameter with more plastikard, but the its the method of getting a smooth finish that I was finding problematic.

 

mikemeg:

 

many thanks - thats exactly the kind of detail I needed. I have a piece of 22mm plumbing pipe that will be ideal as a former, but I'd never thought to use packing pieces to get a smooth finish.

 

Thanks again to both of you.

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You can also do it in one piece by heating, 20 or 30 thou plasticard sheet works best in my experience. Drawn aluminium or copper pipe is ideal as a former. Clamp horizontal in a vice with a projecting end, first heat the pipe with a hairdryer or hot air gun, then the flat piece of plasticard on a flat surface so that it just begins to 'drape' under its own weight when balanced on the pipe, a bit more heat from above will see it fall further, then you can ease it right round using two smooth pieces of lath to draw it together underneath, only contacting what will be the off cut area as far as possible. Hold for a minute or two to allow to cool and reset in that form, and then leave on the former till near cold - don't touch the outer surface until cold.

 

This is one of those techniques that once mastered you never look back, it is all in the even heating of the sheet and timing. It is actually advantageous to use a slightly larger diameter pipe than required: then the handled area on the underside can be trimmed off, and a neat joint made by cementing in a fillet on the underside to bring the closed tube to the right diameter.

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Very interesting, hot air guns are fantastic, so far I have repaired our caravan (ABS cracks in panels), resurrected a PS3 (reflowed lead free solder), now I have a modelling use as well.

 

Oh no I am now fully identifiable. :O

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