Clay, Application to Refinement


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 Corvette Scale Model (pt 2)

Armature build (pt 3, page3) (pt 1) (pt 2) (pt 3)

In the previous section Armature Build ( pt 3, page 2) I had started gluing the Styrofoam? together with Gorilla Glue holding the sections together with wooden sprigs to eliminate any sliding. This process should be done in a methodical manner and in a reasonably quick time to prevent any expansion problems from the glue curing too quickly.

Foams stacking up in the gluing process.

As you can see from the image on the left the foams have been stacked together during the gluing process. The underside of the foam has been cut out on the bandsaw to the shape of the baseboard making for easy fitment at a later stage.

The image to the right is a close-up prior to the next foam being fitted. As you can see I have purposely tried to stay clear of the outer lines as this will prevent any major expansion of the glue during the curing process.

The good thing about Gorilla Glue is you can use it sparingly as it will expand considerably with the addition of water, the thicker the glue the more it will expand so a good clamping system is a must for good sound joints.

Close up of the Gorilla glue on foam.

Close-up of the foams being glued together with wooden spriggs holding them in place.

Complete foam showing the underside that will match to the baseboard.

As the foam gluing progresses care has to be taken to prevent any unnecessary sliding. This can be taken care of by sprigging the foams together with wooden picks made from wooden off cuts or tongue depressors. I find oddments of wood make a good job for this and uses up any small bits that would normally be thrown away. 

Once the glue is dried a sharp rap on the top of the sprig with a hammer will dislodge it enough so that it can be pulled out with a pair of pliers.

The underneath image shows minimal penetration into the baseboard cavity by the Gorilla Glue making for easier clean-up. If there were a lot of excess glue it would take more time to carve out the excess before the baseboard would fit properly, with the risk of slicing through the thin side foam.

Adequate clamping keeps the Styrofoam together.

With the foams all coated with glue and sprigged together to eliminate sliding the quick release bar clamps are placed along the length of the foam model.

I have placed pads of cardboard at the point of impact to reduce the amount of squash to the foam. This will also aid in keeping the pressure on rather than sinking into the foam. The only exception is around the cabin area where there is an angle for the side glass. I let the clamps sink into the foam to prevent them from sliding off due to the angle.

Top view of quick release bar clamps on the foam model.

The top view shows the angle for the side glass of the cabin, I've used enough clamps to hold this area stable while the glue cures. I was a little concerned that the clamps may slip during the expansion of the glue when curing so my theory was the more clamps, the better.

The quick release clamps that I have are reasonably priced from Harbor Freight, they are not the best quality but are more than adequate for the job of holding the foams firmly. If you go to the coupon page you may be able to get a deal on some of the tools.

A good selection of 6 inch and 12 inch quick release clamps were just wide enough to do the job. I will have to make sure that I get the next size up for the next project.

On the plan shot of the foam construction you can see that I had to place a 3/4" strip of foam down the center. The reason for this was that the four inch foam was just too small to cover the width and I didn't want to have to add additional clay later and make the model probably an extra 20lbs heavier. I'd rather try and keep a clay thickness of 25.0mm to 30.0mm as plotted out on the initial drawing. 

When I start to round off the edges of the foam later after the glue has dried, it will give me additional clay anyway. I find when I cut the foams I tend to cut undersize to ensure they are adequately under the finished surface.

Continue foam armature on Armature Build ( pt 3, page 4 )

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