EASIER METHOD TO GLUE VACUFORMED PLASTIC PART HALVES

[jrepok]

I’ve found that the thin plastic that is used for the various Guillow’s vacuformed parts makes it extremely difficult to line up the halves of propellers, machine guns, pilots, etc. The plastic is so thin that lining up and gluing the edges to mate properly causes a LOT of cuss words. Recently, I discovered a way to make the gluing up of the plastic part halves much easier.

Before cutting out the plastic parts, use a thin-point marker pen to outline the base of the parts where they “rise up” from the main plastic sheet. Next, use your Xacto knife to cut around each plastic part, just outside of the marker line. This will result in each cutout part half having a small flange at its base.

Next, purchase a can of WATER SOLUABLE insulating foam. (NOTE: Make sure the insulating foam is WATER SOLUABLE: the non-water soluable foam expands way too much and is EXTREMELY sticky and difficult to clean up.) I use Daptex Plus Window and Door Foam Sealant. (There may be other brands on the market, but this is the only one that I’m aware of.) Daptex foam can be purchase at Home Depot, Lowes, and TruValue Hardware for about $6 to $7 for a 12 ounce can.

Using the included nozzle extension, carefully spray the Daptex foam into each half of the part to be joined, letting the foam rise slightly above each of the plastic part halves.. Use a putty knife or another type of straight edge and smooth the foam so that it ‘s even with the edges of each part half. Let the foam dry for 24 hours (or until it has set up, depending on the size of the part half).

Once the foam in the plastic part halves has dried, clean/sand any foam that adheres to the flanges around each part half. Then, just match up the halves and prepare to glue them together. Depending on the size and shape of the parts, you may want to hold the halves together with clamps, rubber bands, etc. You could even join the two part halves by applying adhesive directly to the dried foam surface.

Apply small amounts of thin CA glue to the edges of the flanges where the part halves meet. After the glue has dried, file and/or sand away the excess flange material around the joined part halves.

I’ve found that the foam makes the joining and gluing of the thin plastic vacuformed part halves infinitely easier. Additionally, when filing and sanding the edges of the flanges, the expanded, dried foam adds stiffness to the joined pieces, making them easier to hold when sanding, painting, etc.


[kittyfritters]

After you have the parts glued together can you use water to dissolve the foam out (thinking wheel pants here) or is it only clean up with water after you've worked with it? By the way, the technique is brilliant!

[jrepok]

I let the foam remain in the glued-up plastic parts. However, since the foam is water soluble, I suppose you could drill a small hole (or holes) in the glued-up part then let it soak in water to dissolve the foam; drain the foam and water, then seal up the holes.

[elkhart]

Excellent idea. I tried flying each half to a sheet of plastic. The halves don't match up close enough and it didn't work. The seams opened up after sanding away the flange. I'll try the foam .