strenthening plates and paint

[bigdry]

Hello all, im in the process of restoring an old Lancia delta rally car. I have previously had the shell acid dipped to remove all traces of paint and rust. Im now doing all the body work which includes adding a lot of strengthening plates, roll cage etc. I intend to have the shell re dipped after this work is completed. The dipping process will re dip in acid to remove any surface rust, hen a complete jet wash to rinse, then has a zinc phosphate layer added (via dipping) and finally it is electrostatically primed like a new production car (also via dipping process). The company I am using is called SPL in Dudley.

My question to you guys is:
What, if any, coating would you put on the back of the reinforcing plates?
i.e. zinc or copper weld through primer maybe? I know from existing plates that are on the car, that i have removed, that the process, despite dipping the complete shell, does not get in-between some layers fully so i cannot rely on acid, zinc and primer to penetrate between the stitch welded plates. However as some liquids some will get in, will this ruin my zinc primer? it’s a quandary i know, and if i leave it bare im sure something will get in there? but can’t be sure.
I think seam welding everything is over kill and there could still be some pin holes in the mig welds.

 

[MG David]

Are you going to do a complete seam weld around the edge of the plates?

Will there be vent holes in the plates?

 

[steveo3002]

i reckon anything you put on will contaminate the coating process or be washed away anyhow

if you can maybe a couple of well placed small holes to allow the coatings in ? then seam sealer during the paint stage

 

[Robotstar5]

The e-coat process (if done properly) will get in anywhere water could and seal it so you shouldn't have any problems.

A proper e-coat dip runs the bodyshell in and out at an angle to prevent air pockets.

 

[bigdry]

hi thanks for replies, i must admit i was surprised that when previously dipped the acid didnt get in behind all the plates (the strengthening plates that were already on the car and not very well at that!) or if it did it didnt get all out.
i guess i'll have to either seam all edges or just accept that some of the plates will not be fully covered, i guess after all the dip processes, seam sealer, primer paint etc they will still last a long time. the car wont be living out side either.

 

[the snooper]

as an example if you are using a 1mm plate to sit on top of existing 1mm steel to add strength couldnt you just cut out the area and weld in a 2mm plate ie double the thickness that way you would have no cavities

 

[MG David]

as an example if you are using a 1mm plate to sit on top of existing 1mm steel to add strength couldnt you just cut out the area and weld in a 2mm plate ie double the thickness that way you would have no cavities

I am not sure that would comply with the Blue Book. As I believe this is for motor sport it needs to.