Nice Fit

Final assembly: When all the parts are assembled.

Sounds logical. But . . .

Before parts are assembled for the "last time" there is lots to be done. Each part has to undergo a test fit because if the part doesn't fit, you really want to know before you glue and nail everything together.

Below, a rib and a couple of compression struts are in place and ready for inspection.

Powder Coating - Part II

Paul powder coated these pieces.

It was tricky. There was a problem. It's called Faraday's Cage.

Faraday, a really smart scientist from long, long ago, found that electrical charges accumulate on the outside of an object, but not on the inside. These metal parts don't look like a cage, but because there are parallel surfaces, they act like a cage, and the electrical charge (and powder) doesn't stick to the inner sides of the parallel surfaces. The powder coating bounces off the inner walls and jumps to the outside surfaces.

How did Paul get it to stick?

Paul heated the parts before painting, then he held the gun close to the inner surfaces, and before the powder could jump to the outside they melted from the heat and stuck. 

They look good, don't they.

You can't powder coat wood

Last week we looked at powder coating and the advantages. But can it be used on wood? Nope. Wood cannot conduct electricity, and it typically doesn't want to be heated to the temperature required for powder coating.

Ribs require a traditional varnish applied with brushes. It's a bit slow, since the varnish has to be applied into all the nooks and crannies of the rib, including inside the gussets. Somethings never change.

The new guy (Rishab) and Leo

Clarence had to help out; the young guys got tired and had to take a break :-)

Powder Coating - Part I

Powder Coating 101

The piece of metal Paul is showing above has been powder coated (by Paul). It looks like it was spray painted, but there was no liquid applied, just powder.

How's that work?

Powder coating uses thermoset plastic (heat will melt it) mixed with coloring, and pulverized to a powder. It is usually sprayed on the metal parts with an electrostatic spray gun that applies a high voltage to the metal part, which attracts the plastic spray. As a result there is little, if any, overspray. Also, there are no runs, and no VOCs (volatile organic compounds) or smell.

Also, if you have never seen powder coating in action, it's really cool. The spray from the gun comes out like a regular spray gun, then it all magically redirects itself towards the part being coated, due to the magic of high voltage electricity. There is no (or very little) overspray. 

The part is then placed in an oven for a while, and voila, the plastic melts forming a nice surface that is tougher than paint.

In summary:

1. no smell or VOCs

2. thicker coatings with out drips or sags

3. overspray can be recycled.

4. less hazardous waste.

5. equiptment is low cost, if your wife lets you use her oven!

Paul ordered these samples to see which one matched the fuselage tubing on the glider.

Yup, you buy it by the pound, or in the case of this company, 1.2 pounds is the standard size

Paul laid the samples on the fuselage to see which one matched the best

Preeeeety close, what do you think?

Paul's been busy