How to replace a door skin

Photograph by Tom Suddard

[Editor's Note: This article originally appeared in the November 2015 issue of Classic Motorsports.]

Replacing a damaged door skin: It can sound so daunting at first, like some epic struggle rife with jagged metal and flying sparks. But this job is considered simple in the world of bodywork. 

Why not just replace the entire door? Sometimes beneath that rusty, damaged or poorly repaired outer skin is a perfectly good inner door frame. That was the case with our Mini Cooper S. Now consider the fact that new and used doors for our car trade in the $1000 range, while properly fitting skins sell for around $100 from places like Mini Mania. The choice seems pretty obvious, doesn’t it?

Our expert body man, Tom Prescott, showed us how to properly replace a door skin using modern adhesive. We chose adhesive instead of old-fashioned welding because it’s quicker, doesn’t distort the metal, and has less of a tendency to rust later on. 

Step 1.

Our bodywork guru, Tom Prescott, came up to our shop one evening to show us how to properly change a door skin on our Mini Cooper S. Notice that we used a clean, open work area for this job and rested the door on a good, level stand.

Step 2.

The next step was to grind the crease off of the old door skin. We used a 40-to-50-grit grinding wheel and were very careful not to eat into the door frame. Spot welds can also be drilled or ground out on the door’s backside. Hammering with a chisel, however, will likely damage the delicate frame.

Step 3.

Once the crease was ground off and welds were removed, we gently started prying off the door skin with a chisel and grinding away the last little bits.

Step 4.

Soon the badly damaged skin peeled right off, revealing that the frame needed a little bit of repair. 

Step 5.

The door frame’s surface must be absolutely flat and smooth to receive the new skin, so we cleaned up any sharp edges and the remains of the spot welds. We then painted the raw metal with Eastwood Self-Etching Weld-Thru Primer. 

Step 6.

Next, we test-fit the new skin from Mini Mania. This company offers high-quality panels for old Mini Coopers, and their door skin fit very well.

Step 7.

For better adhesion, we ground away a bit of the new skin’s primer—just the areas that would attach to the door frame. We test-fit the skin for a second time, then test-fit the entire door on the car.

Step 8.

Time to apply glue. We laid down a bead of 3M Automix Panel Bonding Adhesive along the entire door skin and door frame. A glue brush smoothed it out into an even layer.

Step 9.

Door skin, meet door frame. Clamps can be useful at this stage—just make sure they don’t damage the door. Pieces of wooden paint stirrer sticks sandwiched between the clamps will help protect your work.

Step 10.

To fully attach the skin, we used a special door-skin hammer and dolly designed to get into the awkward areas that this job produces. These tools are available online or at any auto body supply house. We source this kind of stuff from Eastwood. 

We started at the top and gently hammered our way around the door, tapping just hard enough to fold the skin around the frame. Then we went around the door again, making sure the skin was perfectly flat against the frame.

Step 11.

That’s it: Our door is as good as new. We checked the fit on the car before the glue dried to make sure none of the pieces had shifted. From here the door could be primed, cured of any slight imperfections, then sanded and painted.

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Comments
klharper
klharper New Reader
9/2/20 8:43 a.m.

This is great if you have a door skin available, but can you show us how to make a door skin

GothamCityMini
GothamCityMini
4/5/21 9:50 p.m.

I have a question at the end...but first, I just wanted to say "Thank You So Much!" for posting this article.

I do not have welding equipment and have been trying to figure out how I might economically replace my door skins myself and this article reinforces with what I found here about glue being an option: https://www.minimania.com/How_to__Mk1_Aluminum_Door_Skins

They, however, limit the "glue only" tactic to aluminum skins, saying:

"With aluminum, you can use epoxy glue made specifically for bonding panels.  With folded over seams and the panel adhesive, no welding is needed.  So in a sense, replacing your steel panels with aluminum is easier for us journeymen than the OEM steel!  The newly repaired frame also lends itself to a replacement steel skin, by the way.  Not much difference in how the aluminum vs. steel skin goes back on, other than a couple of welded spots on the steel version, rather than adhesive used on aluminum.  The folded edges do most of the work."

So my question is: with what looked like a steel skin in your article, how did you deal with the two seam welded spots at the two top edges of the Mini door?

What did you do in those two spots to keep the steel skin flush with the frame?

Thank you in advance for considering my inquiry!

GothamCityMini
GothamCityMini New Reader
4/2/22 2:17 p.m.

Saw this pop up again in the daily newsletter and realized that no answer was ever posted for the question:

Q. Without welding, how did Tim address the two top corners/edges of the classic Mini door that he was demonstrating with?

Do you just use the bonding glue to handle where the factory had originally welded the two top corners to the door frame?

Can anyone please answer / suggest a "weld-less" solution for a classic Mini door skin?

Thanks in advance!

bencii
bencii New Reader
6/28/22 1:20 p.m.

In reply to GothamCityMini :

I'm not familiar with the mini door skin, but I would think the glue and clamps might work in the area where there was a seam. Also glue around the entire skin isn't necessary as the door will be help in place with the piece that is folded over. You can only fold a little at a time so don't try and fold on one go. Also you will want to use some caulk where the skin contacts the frame prior to putting the skin in place as it is subject to water. Make sure the drain holes in bottom of door are open. Any time you use clamps be sure to use thin strips of wood on both sides to avoid dents. Use seam sealer on the outside of the folds to keep water out.

GothamCityMini
GothamCityMini New Reader
1/3/23 12:42 p.m.

Thanks so much for replying bencii! (and Happy New Year to you!)

I've got other body panel work to do now because of other rust that has crept up on me and so I've gone ahead and purchased an inexpensive flux core welder.

So at this point I intend to weld the two top corners to the door frame just like the factory did, but I suspect for the folks without welding equipment, like you've suggested, some clamps and a good panel adhesive like 3M Panel Bonding Adhesive (08115 or 38315) or maybe even U-Pol Products Tiger Seal Adhesive/Sealant might do the job.

I also received the recommendation to just A) screw the panel into the door frame in those two placed with a self-tapping machine screw; B) find a local body shop or welder who'll do piece work and C) have them perform the welds (and fill in the screw hole for you).

So I guess there are many ways to "skin the cat" here, uh, I mean "skin this door"...  (sorry I couldn't resist :-) 

Thanks again for posting an answer - it's always disheartening when someone asks a question of the author of an article but then doesn't receive any answer back :-(

Tim Suddard
Tim Suddard Publisher
1/12/23 5:54 a.m.

I believe we did glue it where we couldn't get to it any other way. It was a while ago when I built this car.

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