For example: John Smith wrote:
I am going to box the frame so there will be no access to the inside of the
steel, also I would like to powder coat instead of paint or galvanized.

"Tom" wrote in message
...

For example: John Smith wrote:

what can I do to the inside of square or rectangular steel tubing so
that
over time it will not rust from the inside out? I am thinking of making
a
6x10 utility trailer with a boxed frame for extra strength and I live on
the
Gulf Coast of Central Florida where the air is salty and humid and I
plan on
having the trailer for a long time. The process would have to be done
before
welding so whatever the process is, it must stand up to the heat from
welding. Thanks in advance.

What about getting the trailer gavanised after you build it?

Tom


John, you might want to check around on powder coating prices. To do a
item that size will be expensive to do it with the proper powder than
cooked in the oven to cure. The rising price of propane and natural gas
has caused a jump in curing costs for the larger operations with a oven
big enough to do your project.

If you must use tubing, think about drilling and tapping plugs in the
steel. When complete, have a under coating operation use their long
injectors and spray the goo into your chassis and plug it when done.

I would follow the advise of the other posters and change your design to
use angle and c-channel. Prime and paint with POR-15 if you want it to
last a life time. My trailer is c-channel and angle with a flat steel
deck. It was old when I got it and I put another 8 years on it and going
strong.

Good Luck

Jim Vrzal
Holiday, Fl.