DIY M repaint

sanmich

sanmich

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Hi all

I am in the process of repainting my M2.
After de-chroming, there are small craters that appear in the brass.
Would someone know what should I do so they don't appear on the finale finish?

Thanks!
 
sanmich said:
Hi all

I am in the process of repainting my M2.
After de-chroming, there are small craters that appear in the brass.
Would someone know what should I do so they don't appear on the finale finish?

Thanks!
Click to expand...


I have not attempted this, but perhaps a body shop approach? If the pits are smal enough and clean enough, perhaps, depending on the paint you are using, they could be filled with paint and smoothed before the top coat?

Solder? If you tin the pits, solder could fill them, and you are left with smoothing, -- I get the feeling this is not going to be a single experiment. ;-)

Keep a photo record, it would be interesting.

I also wonder as you obviously have things apart, if you can send the parts to be painted to a commercial service?

Regards,, J
 
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JohnTF said:
I have not attempted this, but perhaps a body shop approach? If the pits are smal enough and clean enough, perhaps, depending on the paint you are using, they could be filled with paint and smoothed before the top coat?

Solder? If you tin the pits, solder could fill them, and you are left with smoothing, -- I get the feeling this is not going to be a single experiment. ;-)

Keep a photo record, it would be interesting.

I also wonder as you obviously have things apart, if you can send the paats to be painted to a commercial service?

Regards,, J
Click to expand...

I think that may be the answer: if I smoothen the surfaces after each paint layer (primer + paint) I may be able to make them disapear. The paint will stay in a thick layer in the craters, and I will thin it on the rest of the surface, right?
Unless there is some kind of special putty used to smoothen surfaces.
All in all, they seem quite shallow, but still, they are there, and once I start the painting, removing it to fill the tiny scars is expected to be one big PITA. So I better do it right the first time...
Solder doesn't seem to be the right thing. Very high surface tension, don't you think?
 
Automotive bondo brand body filler. It is used to fill dents and other cracks and such on cars. It will bond to most metal, it is easily sanded and worked with and it hold paint quite well.
 
If the craters and pits are small enough, the automotive "Bondo" is the easiest way as it will sand smooth. It is imperative that you clean the parts very well before applying it though. Ultrasonic or thinner will do, but the paint result is about 75% surface treatment and 25% painting skills!
The "leadfill" or "solder" filling of holes.craters etc is a bit tedious as you have to fill and sand several times, but the result is generally better. Be sure to "feather" the fill so that you dont get raised bumps though. It will aslo cover up scratches better than bondo.
The paint fill is fraught with problems as you can have "degassing" of the paint (paint volatiles) lifting the surface where the paint is the thickest (the crater/scratch). Brass is a noriously finicky product to paint - somewhat akin trying to paint an oilslick! Be sure to prime it well with a dull/matter primer and then apply the final coat on that. Try to get a matte black primer (assuming that you are painting the camera black). The primer provides a surface for the glossy/semi gloss paint to bind too and also prevents the top coat from "shrinking" when it dries.
Years ago I did several cameras and Rapidwinders in black paint and I found two things that worked well. A/ an old turntable with a slow turning 33RPM or with the help of a voltage regulator, down to 15-16 RPM. I made a wooden "mold" to hold the top plate and later the winder housing and applied the paint with an airbrush while it was slowly turning. This ensured an even coat of paint. B/ the use of that old toaster oven as a paint drying cabinet. Cut a 1"x5" hole in the back to give some airflow and dry the paint at about 100C+ (212F) for about 30 minutes - then, without touching or moving the parts, open the front "door" of the oven and let it cool naturally. Please. do this in well ventilated space or outdoors as it is smelly! Dont try to heat pizza in the oven after use as it will give a very strange taste to it!
 
Well thanks a lot for the help.

The primer do seem to cover the small defects well. I received help from Akira (zen shooter) that told me that small pitting is normal and should be ok after painting.

I do have problems with the sanding part of the process. I use automotive (Motip) paints. after about 36 hours (the instructions say 2 hrs) I try to sand, but inevitably reach back the metal (1200 grit, dry). For now, I gave up sanding. But I am a bit worried about the primer/paint strength.
I just repaired the small areas where the metal showed, and I intend to wait a couple of hours, reclean with terepentine and apply the black coat. Is it ok or is it very important to wait very long between the primer and the paint?
How many black layers would you advise?
Assuming this process, how much should I wait before reassembly?
Is the paint harder than the primer?

Thanks!
 
Tom, I was afraid to recommend Bondo, but as a plastic filler, it is usually for larger repairs, there are finer fill materials available for scratches from sanding, etc. from the auto paint stores that might give a smoother finish, they are often applied over the primer, and definitely over the bondo.

Leading was the "Factory" quality method of repair, and the factory used to fill the space where the quarter panel was joined to the top, a while ago.

I am wondering if the pits were through the chrome before it was removed, I would think preparation was 99% in the case of re-chroming.

Am talking only from experience in auto body work, I did do a little solder work on my car body, but we are talking a long time ago, and the finishes I used are not used today.

Regards, John
 
Michael, I would use what ever thinners recommended by the paint supplier, I have no idea what type of products you are using, but it is good news to hear the paint seems to be filling the pits. There were specific cleaners recommended as well.

I am thinking rubbing compound for final coats?

On modern cars there is a clear coat, when I used lacquer, I mixed clear and retarder in with the last coats, and then topped with clear, but I probably put on 8 coats and rubbed off 4, or 8 if I was not careful. ;-)

Hope you are shooting photos of the process.

Regards,John
 
JohnTF said:
Michael, I would use what ever thinners recommended by the paint supplier, I have no idea what type of products you are using, but it is good news to hear the paint seems to be filling the pits. There were specific cleaners recommended as well.

I am thinking rubbing compound for final coats?

On modern cars there is a clear coat, when I used lacquer, I mixed clear and retarder in with the last coats, and then topped with clear, but I probably put on 8 coats and rubbed off 4, or 8 if I was not careful. ;-)

Hope you are shooting photos of the process.

Regards,John
Click to expand...

Thanks John,

I use a can spray. So no thinner..
I was thinking that a clear coat is not necessary, as I bought a semi-mat (it says mat but well) paint.
Now that I see how sensitive the primer is, I may reconsider this point.
From your experience, is the paint stronger than the primer?
Is the clear coat working as a hard, protective surface?
 
John, good advice regarding the Bondo for scratches. I used to do solder fill and sand with 1200 grit and a small sanding "block" ( a large eraser - stiff enough to handle the flat, but not so stiff that it would "cut").
Micheal, you might want to run the primer through the oven at low heat to get it to harden - or add hardener to it. The the top coat paint, once dried is harder than the primer as the latter serves more as a "tooth" for the top coat to bind to and also as a micro filler of scratches.
Putting on a clear coat will give you a rather high gloss finished surface (can be dulled down with polishing compound though) but unless you have cleaned out engravings before, applying the white in the engravings will be difficult. Usually the paint will dry hard in 36-48 hours (shorter if you use a toaster oven to dry it and allow the volatiles to evaporate) - but this is dependant on humidity. heat and type of paint used.
The problem with painting camera is that a lot of the parts are small, really small and that they are 3D rather than flat. The accesorry shoe in particular is tricky to paint and you have to clean out threads for screws after each coat as they clog up. Use tooth picks and matches as the wood is soft enough to avoid damaging the surface.
 
Tom A said:
John, good advice regarding the Bondo for scratches. I used to do solder fill and sand with 1200 grit and a small sanding "block" ( a large eraser - stiff enough to handle the flat, but not so stiff that it would "cut").
Micheal, you might want to run the primer through the oven at low heat to get it to harden - or add hardener to it. The the top coat paint, once dried is harder than the primer as the latter serves more as a "tooth" for the top coat to bind to and also as a micro filler of scratches.
Putting on a clear coat will give you a rather high gloss finished surface (can be dulled down with polishing compound though) but unless you have cleaned out engravings before, applying the white in the engravings will be difficult. Usually the paint will dry hard in 36-48 hours (shorter if you use a toaster oven to dry it and allow the volatiles to evaporate) - but this is dependant on humidity. heat and type of paint used.
The problem with painting camera is that a lot of the parts are small, really small and that they are 3D rather than flat. The accesorry shoe in particular is tricky to paint and you have to clean out threads for screws after each coat as they clog up. Use tooth picks and matches as the wood is soft enough to avoid damaging the surface.
Click to expand...

Thanks Tom

Well, I may have made myself a braver man than I really am:D
I only paint the two covers and the back door...
I take it that the clear coat is harder than the paint. I could always clear coat AFTER the lettering, right?
Say, how many paint layers would you advise?
 
There are several automotive fillers that work well over a prime coat. Most come as a semi-paste and are sold in tube form. "Green Stuff" is a name that comes to mind, but any auto parts store should have some. Apply with a thin card, let dry, repeat. Consider wet-sanding. Just dip the abrasive (500 grit or finer) in water. The water lubes the grit and takes away the dust. As Tom suggested - USE a block of some sort to back up your 'wet or dry' paper. Sand LIGHTLY.
I've had good luck with heat lanps, and even ordinary flood lamps to speed up the drying and setting of paints. Keeps the smell out of the food area too... and more importantly, avoids the wrath of the female species. I've had some luck with spray epoxy paints, dulled out with rubbing compound.
 
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be sure about what you want in a painting job. if you want the brass to show like old leica, you must know that clear coated primed brass will stay shiny even if the paint wears off. It won't darken like the beautiful black paint M bodies!. i suggest no primer or clear coat. just a first matte black paint and a second layer of semi gloss black and you should make them thin enough that you can put the parts back together. the small pits in the brass won't show thats sure.
 
edodo said:
be sure about what you want in a painting job. if you want the brass to show like old leica, you must know that clear coated primed brass will stay shiny even if the paint wears off. It won't darken like the beautiful black paint M bodies!. i suggest no primer or clear coat. just a first matte black paint and a second layer of semi gloss black and you should make them thin enough that you can put the parts back together. the small pits in the brass won't show thats sure.
Click to expand...

Hi, thanks for joining.

I did not mean to use a clear coat as a primer but over the paint to protact it.
I already used a grey primer. I hope the grey color won't show too much on brassing...
One thing is clear to me now:
No matter what the result is, I will not reglue the windows so I can re-do things in a couple of months or years if the wear looks bad...
 
sanmich said:
Thanks John,

I use a can spray. So no thinner..
I was thinking that a clear coat is not necessary, as I bought a semi-mat (it says mat but well) paint.
Now that I see how sensitive the primer is, I may reconsider this point.
From your experience, is the paint stronger than the primer?
Is the clear coat working as a hard, protective surface?
Click to expand...

In modern paints, the clear adds smoothness and depth, as you are using spray cans, you are limited in your choices, I would have recommended an air brush, but have gotten good results from lacquer in spray cans, it was difficult though. No point in final polishing if you are using matt finish, am assuming you are going for a matt finish, which will cover any of the pits you were worried about.

If this is off the shelf paint, am guessing it is some kind of oil base enamel, so air dry enamel can be removed by solvent. You can use it over lacquer, but not the other way around.

As to strength, it depends on the types of paint, the epoxy paints are very hard.

If you do not like the results, you can strip it all off and start over.

Regards, John
 
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