How to remove Hysol from spar and ribs?

[southwind32]

Due to a critters nest in one of the wings, I'm going to replace the front spar because of corrosion. I'm trying to remove the ribs where they hysol to the spar. I've been using a small chiesel, but it's taking hours to do 4 false ribs. I tried a heat gun I have for shrinking monocoat on model planes. I didn't have any luck at all with the heat. I got it hot enough that it discolored one of the false ribs. The hysol never did get soft..........am I doing something wrong? I just read where someone used a hair dryer. Perhaps I'm getting to much heat for a short period of time with the heat gun. Do I need less heat for a longer period? Will the heat soften the hysol, or will it just allow the bond between the hysol and the spar to break loose? Any ideas? I'm open to suggestions. Thanks
Brian

[efwd]

I have not had to remove Hysol but I understood that heat gun would soften it. Remember that the spar is going to be a huge heat sink. So if your applying the hot airflow directly in the Hysol you'll likely burn wood while the aluminum is not heating up and therefore not softening the Hysol immediately in contact with it. See if heating the aluminum adjacent to the Hysol will improve your situation.. maybe?

[southwind32]

I have not had to remove Hysol but I understood that heat gun would soften it. Remember that the spar is going to be a huge heat sink. So if your applying the hot airflow directly in the Hysol you'll likely burn wood while the aluminum is not heating up and therefore not softening the Hysol immediately in contact with it. See if heating the aluminum adjacent to the Hysol will improve your situation.. maybe?

Tried that, didn't have any luck. I think after dinner, I'll go out and try it again. Thanks for the suggestion.
Brian

[southwind32]

I have not had to remove Hysol but I understood that heat gun would soften it. Remember that the spar is going to be a huge heat sink. So if your applying the hot airflow directly in the Hysol you'll likely burn wood while the aluminum is not heating up and therefore not softening the Hysol immediately in contact with it. See if heating the aluminum adjacent to the Hysol will improve your situation.. maybe?

Tried it again. This time I kept the gun pointed to the spar only, about an inch from the rib. After a minute or less the hysol started to get a little soft and with a very small screw driver I'm able to peel it up. Works about 100 better then what I was doing before.
Thanks
Brian

[ppilotmike]

Thanks for posting the solution. Mike

[David47]

When you're removing the Hysol with a screwdriver, be careful not to gouge the aluminium spar. If you do make any scratches, suggest you use scotch brite (forgotten the number but I think it's maroon in colour) to carefully remove them, and then only by scrubbing along the spar, not circumferentially.

[southwind32]

When you're removing the Hysol with a screwdriver, be careful not to gouge the aluminium spar. If you do make any scratches, suggest you use scotch brite (forgotten the number but I think it's maroon in colour) to carefully remove them, and then only by scrubbing along the spar, not circumferentially.

Good Point, DON"T USE A SCREWDRIVER, In my case it's ok, because this spar is being replaced and will never be used. Anyone reading this in the future, and they're going to be using the spar, perhaps using a piece of wood sanded in the shape of a chisel. Don't use anything that could mark, scratch, or damage your spar in anyway.