Making Gutters
Having proved the concept earlier this week, today has been spent trying to refine the process of making gutters and brackets so its repeatable and a bit more accurate than the last lot.
First up are the two formers required. The one of the left is a piece of 2mm x 10mm brass strip with a 0.9 mm hole drilled through and then flats filed on to create the external shape of the bracket (the gutters are turning out @ 0.75mm in diameter so the 0.9mm hole allows for the thickness of the bracket material). The right hand one is a scrap of 0.5mm thick brass etch, filed to a semicircular profile along its top edge.
A strip of thick foil is cut over length, then sanded on both sides to remove the plastic coating. Its an idea borrowed from Jerry - he uses disposable BBQ trays to form corrugated iron sheets but unsurprisingly at this time of year BBQ bits are difficult to source so I'm using thick baking trays instead.
The foil is clamped behind the former in a small vice with approx three quarters of a mil of material showing above the top of the former.
A wooden clothes peg is used to start rolling the foil over the top of the former.
Once the basic shape is right, the peg is used on end to push the foil around the former - multiple passes create the right shape within the peg end.
The former and foil are then placed flat on a cutting mat so that the formed shape now finishes on the mat side of the former (former and foil tend to stick together well at this point). A ruler is laid across the top and a sharp knife used to trim the gutter (you can also see the groove worn into the end of the peg in this shot).
If all goes well, you end up with a very thin strip of curved foil attached to the former.
Whilst everything is well supported, I use a piece of 600 grit wet and dry paper wrapped around the peg to gently smooth the cut edge (sanding from right to left in a diagonal motion in this photo).
The foil strip is then carefully removed from the former and sanded with both cut edges face down on the wet and dry paper, gentle finger pressure is all that is needed to remove the last of any burrs. The inside of the gutter is gently cleaned using a glass fibre brush. Any deformation in the gutter as a result of the clean up can be removed by putting it back on the former and using the peg end to get it back into shape.
Trimming to length is done by putting the gutter back on the former with the waste material protruding over the end. This is then held into the bracket making former and a sharp blade used to trip off the excess. Correct any distortion and a light pass with the wet and dry and its good to go.
Hopefully, at the end you have a strip of thick foil at the correct length with a good profile along its length..
As for the ends, well they are so small that trying to form a piece of foil to fit is a recipe for madness so a spot of paint will do the trick I should think
Brackets next when I've made more and photographed the process.
Steve