Fixing inside bumper rust with POR 15 on 48 DeSoto

[MarcDeSoto]

I finally thought it was high time to get my bumpers out of the weather and starting cleaning them up.  I cleaned the bumpers and then started the three step POR 15 method of fixing the inside bumper rust.  That area is not chromed, so it is always rusty back there.  First, I got my hand drill and a wire wheel and knocked the loose active rust off.  Then, I used Marine Clean to clean the area.  After washing the Marine Clean off, I used Metal Prep, which acts as a rust neutralizer and a pre primer.  Then I applied the POR 15 gloss black.  After two hours, I applied a second coat.  On the first bumper I did, the rear, I forgot to put masking tape over the bolt holes.  As a result, paint ran through the hole and ran on the chrome side of the bumper.  Bummer!  This paint is so tough, you can't take it off, even after just 30 minutes.  You are supposed to top coat it if it will get any sunlight.  I don't think the inside of the bumper gets much sunlight, but I could paint it will Rustoleum silver if necessary.  I even did the same process on the insides of my bumper brackets.  I'm thinking of also doing the insides of the doors and any other hidden place that might rust.  I think the chrome side of my bumpers are good enough to clean up just with using some chrome polish and steel wool 0000 fine on them.  In fact, the rear bumper was purchased 40 years NOS for about $75.  I was covered with hardened cosmolene.  I had to use paint stipper and spatulas to get it off.  I have two front bumpers and three rear bumpers, so I chose the best of each for my restoration.  I wonder what the going price is today for getting a pair of bumpers rechromed?  

[plymouthcranbrook]

I did the exact same thing on the interior bumpers on my 1980 Volare. The factory left it partially painted in primer and partly bare steel. The fact that it had never spent much time on the road kept it from being really bad. I did not paint over the POR-15 as it rarely gets bright direct sun. That was 10-12 years ago and no rust ever shown up.

[MarcDeSoto]

There are a few videos on Youtube saying POR 15 is crap and don't use it.  I watched one of those videos and this guy had painted his frame that was so bad the rust had worked its way almost all the way through!  The metal was coming off in 1/4" sheets, which he blamed on the paint!  

[andyd]

A good tip if you decide to get your bumpers rechromed is to ask the chrome shop at the very least to buff the inside or back of the bumper bar when they are polishing the front.........rust starts when water sits on metal...........if the back of the bumper is smooth even if not polished it will reduce the chance of rust starting there........ideally its worth making sure that the bumper back has a good coating of wax or polish of some kind as further protection.......andyd    

[Sniper]

I do not believe it is possible to not plate the inside of the bumper.  Those things are dipped in a tank to plate them.  In any case, I think Andy is on to something.

[MikeMalibu]

To Andy’s tip, I sent bumpers to be chromed without cleaning up the back side. They came back with flakey chrome on the back side (front side was perfect), so I cleaned up the surface, primed with epoxy, and coated with “chrome” paint. No problems after nearly 20 years, but could have saved time and had chrome plating if I had done some cleanup before sending out.

[busycoupe]

12 years ago I had the front bumper of my Dodge plated. When I got i back I decided to paint the backkside of the bumper with Por 15.   No problem since then.  

 

[andyd]

The issue I mention is that while when a piece, say a bumper gets chromed, its dipped in the solution to remove rust, scale, paint etc then the bare steel bumper is polished to end up with a perfectly smooth finish that is then, copper(hopefully)/nickel/chromed however unless the back is polished or at least smoothed then the rough back side while it will take the plating process will still be "rough" and offer water a place to sit and eventually start to etch into the plating then the base metal......POR15 would be as good a coating as you could find........but something is needed............andyd   

[MarcDeSoto]

If I did send my bumper out to the plater, I don't think they could take the POR 15 off.  And when they dipped the bumper to plate it, I don't think the plating could bond to the POR 15.  I think I remember plating bumpers cost about $500 a pair back in the 80s.  Today, I don't know.  I don't think plating shops are allowed in California anymore.  Maybe they still have them in Nevada or Arizona?  I've the heard the cost of plating has skyrocketed into the thousands.  And my bumpers I think are still good enought to buff out.  My diecast chrome pieces, and there is a lot of it on a 48 DeSoto, like the big toothy grille, the front fender moldings, the tail light and brake light frames, etc. are good enough to also buff out and polish.  There will be some minor pitting, but it would look fine I think, unless I was going for a 100 pt. concours restoration.  It's expensive to get there though.  

[LazyK]

three years ago the bumpers for my 51 plymouth cost me 750.00 ea to have plated. They chemically stripped and removed a few dents before replating. 

The bumpers were the most reasonable cost. All the extra misc parts added several thousand to the final price. Items that I thought were ok looked like junk next to the new bumpers. Snow ball effect, where does one stop once you start.

places doing the work are getting hard to find. 

 

Edited February 26, 2023 by LazyK

[DJ194950]

I bet the Por 15 comes right off at the replaters in the hot acid stripper tank! 

A quick call to a local company will get you a quick answer, most likely they have the experience with paints of all types.

 

Let the forum know what you find out!

I thought I was was wrong once , but I was wrong! ?

 

A year or so ago a friend that used to have a 47 Plymouth had the front bumper replated.

 

It was quite  straight but needed slight work, had some smallish rusted areas where the old bumper guards were. Came out beautiful, but Cost?

 

Cost in the Lodi ,ca.( Just South of Sacramento) . One bumper.

 

$650!

 

DJ

[desoto1939]

todays cost run from 500-700 depending on condition and how must grinding and repair is required.  The back of the bumpers were never ground smooth but had a ruogh surface and were painted silver.

 

Rich Hartung

Desoto1939@aol.com

[Eneto-55]

Electroplating any part that has deep depressions on one side (like the back of the bumpers) will not get a really good coating of metal on the convex side, because the electrical current takes the shortest route possible.  It is possible to get better plating inside those areas, but it requires either a custom set up with anodes positioned in those areas, or lots of hand work with an anode on a portable wand, which the plater must hold in those hard to reach areas.  The only other option I know of would be to turn the amps up right at the beginning, but that can cause "burning" on the protruding side.  Where you would see this on a bumper would be the edges of the bumper.  Then the amps would be lowered to finish plate the exterior areas, but that roughness might not even out. 

 

Well, a third option.  The exterior areas could be coated with a sort of wax or soft rubber (or taped off) while the inside is plated.  Then the exterior areas of the piece would be cleaned before going back into the tank to finish plate the outside area.  But my experience with chrome plating was limited, and most of the chrome that shop did was industrial chrome, like on the journals of aircraft crank shaft journals.  (The only chrome plating I did there was on pot metal pieces - crank handles for fishing reels.)

 

I doubt that I will have anything re-plated, because of the expense.  I'm hoping that there will be great improvements in chrome paints.....

[harmony]

I was rebuilding/reconditioning a '47 Chrysler a few years ago.  This car was turned into a static car.  Meaning it was never going to be driven.  It was a project initiated by an Extended Care unit of a local Hospital.  Specifically to add a smile to the patients that had memory issues.  They get to sit in in and bring back memories.  Our car club took on the project and we got most of the things done that I couldn't do at material costs only.

As for the cost of the bumpers, because of the long sides on the bumper the local chrome shops couldn't take on the job because even though length wise they would fit in the tank, they were just too wide.  So that would mean they would have to go to a larger chrome shop on the mainland in an extra large tank.  The price for that was $2000.  Plus the ferry fees both ways adding another $300. 

So I decided to make some changes that nobody really notices unless it's pointed out to them, by looking in behind the bumperette where you can see the split in the bumper.  I cut the bumpers right where the bumperettes are.  Then welded on some brackets and studs, making them a bolt together bumper.  That way the local chrome shop could do the job since they were now much more condensed.

Probably not everybody's cup of tea.  But it worked fine for the purpose of the car, and saved a huge amount of money.  The chrome shop donated the labour costs, so their bill was minimal. since they didn't charge us for the chemical use either.

The bumper brackets are positioned so that the end pieces are supported, so once it was all bolted together it was just as sturdy and strong as if it was one piece.  

[MarcDeSoto]

That's an ingenious solution!  Bumper looks great, but are you missing the middle bumper bracket?  

[harmony]

2 minutes ago, MarcDeSoto said:

That's an ingenious solution!  Bumper looks great, but are you missing the middle bumper bracket?  

When we got the car, it was in many pieces, and multiple cardboard boxes full of stuff,  and that was one of the items that didn't show up.  So I decided to go without it and nobody has ever mentioned it,,,,,,,,,,,,,,,, until now!!  ?

12 minutes ago, MarcDeSoto said:

That's an ingenious solution!  Bumper looks great, but are you missing the middle bumper bracket?  

 

[MarcDeSoto]

Well, Chryslers are well known for three front bumper brackets, I think from 1941 to 1948.  No one can get anything past the great Marcus the Magnificent!  

[Dodgeb4ya]

Front center 1946-48 Chrysler bumper guards were an additional cost accessory item except on the top of the line car models...

A hard to find good one if needed now days.

[harmony]

5 minutes ago, Dodgeb4ya said:

Front center 1946-48 Chrysler bumper guards were an additional cost accessory item except on the top of the line car models...

A hard to find good one if needed now days.

What is that book that you have there?

[MarcDeSoto]

That's a salesman's Data Book.  They were property of the dealership and not given out to customers, so they are rare.  I have one for my 48 DeSoto.  It shows all the features of the car in case a customer asks about the transmission or the horsepower or the brakes, or how wide the seats are, the Data Book would have it.  My DeSoto Data Book also shows comparisons between DeSoto vs. Pontiac, Buick, Mercury, etc.  

[Dodgeb4ya]

1 hour ago, harmony said:

What is that book that you have there?

Yes as Marc said it is a 1946-47 Chrysler Salesman's Data Book.

A rare book especially for the C38/C39 Chryslers.

I don't think a 1948 Chrysler data book was produced. I have never been able to find one in over 35 years.

[LeRoy]

10 hours ago, harmony said:

I was rebuilding/reconditioning a '47 Chrysler a few years ago.  This car was turned into a static car.  Meaning it was never going to be driven.  It was a project initiated by an Extended Care unit of a local Hospital.  Specifically to add a smile to the patients that had memory issues.  They get to sit in in and bring back memories.  Our car club took on the project and we got most of the things done that I couldn't do at material costs only.

As for the cost of the bumpers, because of the long sides on the bumper the local chrome shops couldn't take on the job because even though length wise they would fit in the tank, they were just too wide.  So that would mean they would have to go to a larger chrome shop on the mainland in an extra large tank.  The price for that was $2000.  Plus the ferry fees both ways adding another $300. 

So I decided to make some changes that nobody really notices unless it's pointed out to them, by looking in behind the bumperette where you can see the split in the bumper.  I cut the bumpers right where the bumperettes are.  Then welded on some brackets and studs, making them a bolt together bumper.  That way the local chrome shop could do the job since they were now much more condensed.

Probably not everybody's cup of tea.  But it worked fine for the purpose of the car, and saved a huge amount of money.  The chrome shop donated the labour costs, so their bill was minimal. since they didn't charge us for the chemical use either.

The bumper brackets are positioned so that the end pieces are supported, so once it was all bolted together it was just as sturdy and strong as if it was one piece.  

you could make a months worth of ice cubes with that grill, if you had a big freezer....

[harmony]

8 hours ago, Dodgeb4ya said:

Yes as Marc said it is a 1946-47 Chrysler Salesman's Data Book.

A rare book especially for the C38/C39 Chryslers.

I don't think a 1948 Chrysler data book was produced. I have never been able to find one in over 35 years.

I love that kind of publication.  Too bad there wasn't one for my car.

[Dodgeb4ya]

I'm sure the Chrysler Data book up thru  1947 is correct ans aplicable  for the 1948 cars too.

Not too many changes for the 1946-48 cars.

 

[Dodgeb4ya]

2 hours ago, LeRoy said:

you could make a months worth of ice cubes with that grill, if you had a big freezer....

The 1946-48 Chrysler grilles were called the "Harmonica" or egg crates grilles.

A real chore to polish up.