JoeSimcoe@aol.com wrote:
>
> Am now leaning towards having the frame of my TR250 dipped instead of
> blasted. (in order to get at the rust on the inside)
>
> Dipping shop won't prime it when it's done, but has offered to powder coat
> it.
>
> Am personally leaning toward just painting it - anyone care to comment on the
> pro's and con's of powder coating????
>
> TIA
> JoeSimcoe
Listers,
When I was restoring my TR6 a few years ago, I was fortunate to have access to
a powder coat gun. It was homemade, using a siphon feed sand blasting gun and
some teflon pipe. I have the article (somewhere) upon which it was based. The
technique we use is fairly simple. After thorough bead blasting and
degreasing, we apray on the powder coat and bake the part in a 400 F oven for
10-15 minutes (depending upon the thickness of the part). The gun only needs
30-40 PSI and very little volume of air. The gun must be grounded to earth and
the part. The powder picks up a static charge as it is forced through the
teflon, and sticks to the part. Once the part is baked and cools, it is ready
to bolt on.
As I see it, there are several advantages to powder coat. It is very tough,
and will withstand over a minute of sand blasting at 100 PSI (where most paint
would last seconds). You can use epoxy, polyester, or hybrid powders depending
upon your need (chemical/solvent resistance vs. durability of finish). There
are numerous choices of color and texture. It worked great on my suspension
parts, bumper braces, numerous clips, pipes, interior trim pieces, the steering
column...
The down side is that if it chips, it tends to lift around the exposed area. I
found this to be a problem where bolts go through a piece without a washer, as
they crush/chip the coating. The chip can be touched up with paint, but not
with more powder coat. Once the finish is cured, reheating will damage it.
Also, the size of your oven and how much stink it can withstand are limiting
factors for the do-it-yourself type. Also, many parts won't withstand 400F.
Masking areas, such as threads or bearing surfaces, is difficult as the powder
tends to get into everything and can be easily brushed off until it is baked.
I decided to paint the frame, hoping that the primer would help protect the
metal even after the paint chips off. Powder coat is hard to chip, but it goes
to the metal when it does. In my experience, powder coat doesn't bond as
firmly as paint once it is damaged.
Hope that wasn't more than you wanted.
Joe Seward
'73 TR6
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