To Dip or not to Dip??

[Chuck Miller]

That's new information to me... excellent post Chris

[endo911rs]

Photo of a phosphate applied surface

[The MetalSurgeon]

Plastic media on external sheet metal
Regular media on structural metal

[Longballa]

This decision for me is also based on how bad of shape the car is in. Condition of the car helps with the decision. If car is in really bad shape and you're removing inner rockers on a LWB then dip is the way I'd go. Media blast just the bottom and hand strip the panels if the car is in better condition. Need to see the car to make that choice.

[endo911rs]

For once, I completely agree with Scott!

[VintageExcellen]

I just started using dry ice blasting for undercoat removal. Very promising for that application.

[michaelaiellosr]

The acid-base dip was by far the best process for me. After the dip process the chassis has to be baked thoroughly to eliminate any seepage. The problem becomes one of immediate oxidation in anything over 40% relative humidity....the surface is so active that you can see surface rust within 60 minutes....get a primer coat on immediately.

[VintageExcellen]

Actually it is the rinse after a dip that is critical. Washing out all the active chemical to prevent seeping from the seems. Then a phosphate rinse to stabilize from flash rusting. Then baking the body evaporates the rinse.

Trouble is phosphate is very temporary. A good coating is needed fairly quickly. E-coat does appear to be one of the best options but there are only a couple places in the country than can do this service. Like the dry ice blasting I am using - only a few people do it. If a cavity is left uncoated then you have bare metal and that is the problem with any stripping where you can’t access after the process.