1 November 2024
This is for making 1/8" wide lamination from 1/16" balsa sheet.
- Square up the 1/16" balsa sheet.
- Slice thinly through but leave one end intact, repeat 1 more time.
- Now slice the 1/8" strip.
You now have a 1/8"x1/16" balsa strip that has 2 or 3 slits through most of the length.
Wet the slitted length.
Curl the slitted length with your fingers.
Superglue the intact end of the curled strip on to the packing tape protected jig board.
Nudge the curve over the plan and drop a bit of superglue intermittently on the slits to hold the curve.
16 April 2014
For a jig to form curved laminated balsa strips:
- Prepare 2 rectangular pieces of compressed foam. Draw the inner curved line onto one piece cut along this line to separate it to form two pieces of formers, one being the inner former and the other, the outer former.
- Glue the smaller piece of inner former onto the second rectangular piece of compressed foam, this is the base board.
- Select the thickness of the balsa strip. A thickness is suitable if it can be formed readily against the inner former without cracking and the finished product is functional, i.e., 1) not fragile, 2) sufficient strength for intended use, and 3) minimum of 3mm for overlapping of covering. If the strip shall crack while bending free hand, then it is too thick and the strip has to be made from thinner balsa. If the strip is too thin and fragile to be functional, additional strip to be added until the overall desired thickness is achieved.
- Prepare the balsa strip/s by soaking them for a good 15 minutes. Time depends on cross sectional area and hardness/water permeability of individual strip, even the temperature of water. 15 minutes would be sufficient for upto 1/8" balsa strips.
- If using multiple plies of strip, wipe dry the strips, apply white glue to the mating areas and assemble into a single laminated strip.
- Single strip only needs to be wiped dry.
- Place strip/laminated strip flat on the base board and against the inner former. Starting at the end where the curvature is the least, temporary secure strip in position with tape.
- Push the length of strip against the convex curve of the inner former starting at the taped end and lock in position with the outer former.
- There will be a gap between the outer former and the balsa strip except at the two ends of the outer former. This is ok, because only the two ends are required to hold the strip against the inner former. Glue/pin/clamp the outer former to the base board. The force is at the two ends, these are where to put the pins/clamps.
- Leave the strip in the jig for a day to dry out.
- If using super glue for laminated strip, steps 4 and 5 may be omitted, thin super glue is used to tack the laminations after step 9 and the strip may be removed immediately after the super glue is set. After 15 minutes, more of the thin super glue is introduced to the laminating joints to complete the gluing.
- Remove the curved laminated balsa strip (or formed single balsa strip) from jig and trim it to length.
- White glue doesn't bond well to compressed foam, it is easy to prise the strip off, bending the jig slightly may help in stubborn areas. Super glue will bond or may erode compressed foam, but since they are used sparingly to tack glue the laminations, it is ok.
- If jig is still usable, and is should be, repeat steps 4 to 12 for additional laminated balsa strips (or formed single balsa strip).
Notes
Formed single strip will have spring back, laminated strips retain shape much better. The first choice, therefore, is to use laminated strips.
Curved line may be drawn tighter to accommodate the spring back of single strip but the amount of spring back, in the case of balsa, will not likely be consistent.
Laminations may be made from balsa, plywood, bamboo, paper, plastic, compressed foam, carbon fibre and other similar material.
White glue between compressed foam is not suitable, choose another adhesive that doesn't involve evaporation of solvent.
No comments:
Post a Comment