Tue Nov 2 2010

Flame testing CS-1900 and fabricating new brackets

Today I mixed up some CS-1900 firewall sealant. This stuff is about the consistency of Silly Putty in the can, so I mixed it with laquer thinner to thin it out. It took about 15 minutes of mixing before I could spread it on the sheet.

Here's the goo spread on the target sheet. The stuff wasn't setting up very fast, so I put it in the oven on warm heat (~250 degrees) to speed up the process.

While that was curing, I unpacked my antennas from Delta Pop Aviation. I met the fellow who runs this business at Oshkosh. He seemed knowledgable and his antennas are very competitively priced compared to the Comant equivalents. Pictured here are two COM antennas, a transponder antenna, and an ADS-B 976 MHz antenna.

Here's his info if you want to buy some antennas from him.

After letting the sample sheet sit in the oven for a few hours, it seemed pretty well cured, with only the thick areas being somewhat soft still. I hooked up the propane torch and fired up the rig. Within about 10 seconds, there was quite a bit of flame on the CS-1900 side of the sample.

...but that flame went out within about 10 or 15 seconds and then the sealant just sat there while the torch blasted away. No smoke...nothing.

Here it is after about a minute of torching.

The backside was glowing a nice cherry red. I think I'm going to redo this test, but allow several days for the sealant to cure. I suspect the flame was from leftover laquer thinner that hadn't cooked off in the oven. Although the results are inconclusive at this time, I decided to move forward with the plan of using CS-1900 to seal the screw holes. At some point I've got to move forward on these floors.

Out of curiosity, I decided to mix up a batch of proseal since I've heard of quite a few people using this instead of CS-1900. I'll give this a couple days to cure before testing it.

In the meantime, now that the shear holddown is installed, I started fabricating the brackets to hold the insulation to the floor. First was to cut them to width and length.

Then after deburring, I used my little brake to bend them up.