To blast or not .. and then what. Professional advice sought

[Robo McDuff]

I am now going to restore the 1973 (or 1965) M51A2 and want to paint it back into the original colors. The doors need some welding work and also the front and back parts of the left fender, in the bent area. Also, I threw a bucket of cheap water-based paint on top of everything, including the rust, holes were covered with duck-tape which was painted as well, to make it look nice for five minutes (don't ask, it seemed like a good idea at the time, now it seems ).

I am faced with a dilemma now. I do not need a perfect shiny truck looking better than when it came out of the factory, and I am not preparing this truck for the next century; too many technical things are not 100% anyway. However, I do want to get it painted well and good for the next xx years.

I definitely have to get rid of the water-based top layer. Then I have to get rid of some of the old stuff down to a good base for a repaint job. And yes, I have read a lot of threads about this, still not sure what to do.

My first idea was to take off all fenders, doors, and hood. Repair and weld new sheet metal where needed (front of the fender, doors) and then sand blast everything, zinc it, then put primer and paint on top of that. We have a company that does that for my son's forged fences and other stuff that has to be outside 24/7.

Problem is, I cannot drive the truck to the blaster, so the not removable cabin and body parts I have to do differently.

I also read a few threads stating that sand blasting everything might be overkill and/or not that effective (on CARC) at all. Also, removing CARC might not be that healthy. Finally, even doing that here in the Czech Republic, those steps add up in $$.

1) Is there any CARC on this truck at all? Probably not originally, but maybe during a later paint job or was CARC used only after 1985 on new trucks?

2) Is sanding than hot- or cold-applied zinc layers than primer than final layer the best/only way to go in this case or what is a $$ acceptable alternative which does a good job in removing enough layers to get a good starting point for repaint?

Any input is appreciated

 

[topo]

I have found some original military paint is really tough and sand blasting is not needed it makes a ideal under coat . a good pressure washer works to get rid of loose paint and paint not on right .

 

[clinto]

Looking at those pictures, my $.02:

A. I don't think that's CARC. It looks like the original lead enamel olive drab with a newer coat of the MERDC camo, which was pre-CARC. I do not know what the formulation of the MERDC era paint was, but I doubt it's CARC.

B. Kind of doesn't matter. You need to sandblast that thing. You've got to get the rust to stop and all that peeling paint will be a nightmare to properly prep. If you try and prep that thing by any other means, you'll be dead before you ever finish. So many angles, nooks and crannies and so much surface area, there just isn't another practical way to prep these things.

C. Blasting takes longer on CARC-it's a thick paint heavy on solids and when the subsurface is properly prepped, it has good adhesion. So when the blaster hits it, it takes longer to cut through it. This consumes more media, takes more time and therefore costs more money. But other than that, it's no different than any other paint.

D. My '67 M35A2 was rougher than I thought when I bought it. So I took it down to the frame to blast and paint and rebuild it. My '87 is much nicer but it has a crappy tan CARC paint job on top of the whatever the factory 1987 green was. It's not sticking in a lot of places. I don't want to do a ground-up restoration on it, so I think I am going to take the doors off (I have NOS doors for it), take the hardtop off (I have an NOS hardtop), take the front clip off and blast it that way. I can have the fenders and hood blasted top and bottom, paint them on a sawhorse and spray a little topcoat over the hardware once installed. I'll pull all the gauges and glass as well. I'll have it on jackstands as well, so I can get the drums and axles. That's what I'd do to yours.

E. In terms of taking to a blaster, you need to befriend someone who can help you move it. Or hire a mobile blaster.

F. If you can't afford all that, I wouldn't do anything. I've had my truck for 6 years and haven't painted it for just this reason. Cost of blasting and nowhere to keep it once it's done. I just took care of the storage issue, but I still have to come up with the money for the blasting.

G. You've got to keep it out of the sun and rain once you do all this. Or it's a waste of a lot of time and money. The sun and the rain kill these things. A cheap carport, an old barn, anything. Doesn't have to be climate controlled, but you gotta' keep the sun from murdering it. Gillespie or CARC will turn white and chalky in 5 years being out in the sun.

H. I have no experience with zinc bases on bare metal, although I have seen it down (paint shop used it on some bare metal stuff I have them for a recent restoration). My experience has been bare metal, good epoxy primer in 2-3 thin coats, then top coat and I haven't had corrosion or adhesion issues with that.

I. The worst part. When you say you aren't looking for a 100% show truck, here's the problem: in order to do anything, you have got to blast all that crappy paint off. And once you've done all that, you're 80% of the way to the 100% truck. So you're kind of stuck with a choice: do nothing or take on an epic project in terms of scope (money, time, etc.). It stinks but that's the way it is. With 50 year old stuff, there's no "motorpool" restorations any more. The stuff is so old, it has to be done right.

 

[Tinwoodsman]

Robo, you might consider a needle scaler. It works pretty well.

 

[gimpyrobb]

Pressure washer sand blaster.

Start at the front and work your way back. Fix holes as they show up and prime everything with red rusty metal enamel. Once done with that, paint it whatever color you choose with a quality paint. Done well, at your pace, and not one bazillion dollars.

 

[Robo McDuff]

Thanks for all the quick replies.

We did clean with power washer twice, got some loose stuff off, but most of it is rather stubborn. Problem now is we do not have running pressured water at the workshop, so pressure-washing it again is out. Would not work better anyway.

The needle scaler sounds interesting, never heard of that before. I will look into it if you can get them here. Any specific type or brand I can use as reference to find one here in the Czech Republic?

Looking at those pictures, my $.02:

A. I don't think that's CARC. It looks like the original lead enamel olive drab with a newer coat of the MERDC camo, which was pre-CARC. I do not know what the formulation of the MERDC era paint was, but I doubt it's CARC.

I was hoping that would be the answer. I am trying to get in touch with the people from the previous depots and ask them, but I doubt they used CARC or painted them at all.

. B. Kind of doesn't matter. You need to sandblast that thing. You've got to get the rust to stop and all that peeling paint will be a nightmare to properly prep. If you try and prep that thing by any other means, you'll be dead before you ever finish. So many angles, nooks and crannies and so much surface area, there just isn't another practical way to prep these things.

I was afraid of that answer.

C. Blasting takes longer on CARC-it's a thick paint heavy on solids and when the subsurface is properly prepped, it has good adhesion. So when the blaster hits it, it takes longer to cut through it. This consumes more media, takes more time and therefore costs more money. But other than that, it's no different than any other paint.

OK

D. My '67 M35A2 was rougher than I thought when I bought it. So I took it down to the frame to blast and paint and rebuild it. My '87 is much nicer but it has a crappy tan CARC paint job on top of the whatever the factory 1987 green was. It's not sticking in a lot of places. I don't want to do a ground-up restoration on it, so I think I am going to take the doors off (I have NOS doors for it), take the hardtop off (I have an NOS hardtop), take the front clip off and blast it that way. I can have the fenders and hood blasted top and bottom, paint them on a sawhorse and spray a little topcoat over the hardware once installed. I'll pull all the gauges and glass as well. I'll have it on jackstands as well, so I can get the drums and axles. That's what I'd do to yours.

E. In terms of taking to a blaster, you need to befriend someone who can help you move it. Or hire a mobile blaster.

A full-out restoration right now is out of the question for several reasons, but your second way is what I was thinking as well. Doing it bit by bit might actually ending up close to 100%. Wheels have to come off anyway for doing the brakes etc. Fenders and doors need a bit of repair and have to come off anyway to restore the rest. Hood is almost perfect. Those free parts I can bring to the blaster and have them apply a zinc preservation layer. That would probably cost a few hundred $$, but its the easiest and quickest. Then the question is how and where to paint the final layer. Ideally would be to do the "tractor" version all in once.

I have to wait with the dump bed until I have enough free $$ and Dan gets his Russian-made excavator active and lift the bed. These blasting guys count per square meter, so doing the bed would add a lot of $$ to the bill, and is not that essential for preservation at this moment.

Hire a mobile blaster: never thought about that, not sure its possible in our nick of the woods. Dan has two medieval blasters laying around in the rain already a decade, maybe we can make them work for the cabin once he sees the progress being made and he is finished with his current forging jobs.

Moving the thing by third party. That would be possible, but first I have to repair the steering and brakes. Besides, it would jump the price significantly, so I will try other options first.

Do you have a quick link to the restoration of the 67 M35A2?

F. If you can't afford all that, I wouldn't do anything. I've had my truck for 6 years and haven't painted it for just this reason. Cost of blasting and nowhere to keep it once it's done. I just took care of the storage issue, but I still have to come up with the money for the blasting.

This thing has been standing outside doing nothing for 5 years. It's a bit of now or nothing. Besides, 2018 is a big memorial year here with lots of actions, so I want to have it ready and drivable not later than April 2018.

G. You've got to keep it out of the sun and rain once you do all this. Or it's a waste of a lot of time and money. The sun and the rain kill these things. A cheap carport, an old barn, anything. Doesn't have to be climate controlled, but you gotta' keep the sun from murdering it. Gillespie or CARC will turn white and chalky in 5 years being out in the sun.

Oh boy, hadn't thought about sun.

Normal winter storage would not be a problem, but during four summer months, we would like to use it as part of an exhibition. Should be outside, but every day starting it, drive 50 meters into a shed, next morning out again would be a bit of a pain, and not that good for engines. Have to figure that one out anyway to stop vandalism and theft. Maybe a tarp construction for the first summer will do the protection against rain and sun at least.

H. I have no experience with zinc bases on bare metal, although I have seen it down (paint shop used it on some bare metal stuff I have them for a recent restoration). My experience has been bare metal, good epoxy primer in 2-3 thin coats, then top coat and I haven't had corrosion or adhesion issues with that.

The little narrow-gauge wagon was completely rusted but they did a quick and dirty job on it in spring 2009. Blasting, cold zinc, then directly black matte paint. The pic on right was made in August 2018, during our blacksmith meeting attended also by three US blacksmiths (hence the flag). I will get close-ups but today, the biggest issues are the moving parts and rust water coming out from the rotten welds between the edge and the sheet steel, which they did not reach. Set us back $$ 300.



The dragon (made by the US blacksmiths) is about 4 foot long with a span width of 5 1/2 foot. Blasting it with very fine sand, hot-zincing it and applying blacksmith paint all toghether costed us $ 40.

This hot-zinc is a fascinating process. They have a reel of zinc wire being pushed out of a nozzle like mig welding. Attached to the nozzle is an acetylene burner that more or less vaporizes the zinc and blasts it as a mist onto the material. Off course its more expensive than just spraying cold zinc.

I. The worst part. When you say you aren't looking for a 100% show truck, here's the problem: in order to do anything, you have got to blast all that crappy paint off. And once you've done all that, you're 80% of the way to the 100% truck. So you're kind of stuck with a choice: do nothing or take on an epic project in terms of scope (money, time, etc.). It stinks but that's the way it is. With 50 year old stuff, there's no "motorpool" restorations any more. The stuff is so old, it has to be done right.

I hate that kind of answers, always hoping it will be easier but knowing it will be worse.

 

[JDToumanian]

I would replace those doors rather than waste time repairing that cancer...

Jon

 

[gimpyrobb]

My post was about a SANDBLASTER attachment on your pressure washer, but if you have no water, nevermind.

https://www.youtube.com/watch?v=V_cl0hNSF6k

 

[USMC 00-08]

Sandblast it. It will save you so much time.

 

[Robo McDuff]

My post was about a SANDBLASTER attachment on your pressure washer, but if you have no water, nevermind.

https://www.youtube.com/watch?v=V_cl0hNSF6k

How does that work? We don't have pressured drinking water but we do have a well and a lot of other water floating around, including our own fish pond and the water standing in the hole around the steam hammer. Maybe we can rig something up.

Edit: the video did not show up in your post, but suddenly showed up in my reply as part of your post?

https://www.youtube.com/watch?v=V_cl0hNSF6k

 

[Robo McDuff]

I would replace those doors rather than waste time repairing that cancer...

Jon

I am waiting for a price quote on "door assembly left" from Reomie.



Problem is, then it would be nice/better to do the windows as well etc etc and you end up ordering a whole new cabin before you realize that you don't have the $$ to pay for it.

But yes, if the price is acceptable, I will go for it, doors always are a pain.

 

[clinto]

Do you have a quick link to the restoration of the 67 M35A2?

No, I don't like doing "build" threads until I'm actually done. If you look at the majority of build threads on automotive forums, they're unfinished and everyone loses attention before they're done. I'll do one once I paint the '87 next year, because it's 90% done (front winch, rear winch, 12V standalone system, dual A3 seats, A3 shoulder belts, reverse lights, etc.). Like I said, now that I have a place to keep it out of the sun and rain, I can paint it.



I'm in the same boat with the '67. Don't wanna' put a thread until it's done and it's kind of in a holding pattern. I can't bring myself to do all this work and put a used engine in it. NOS can multifuels really got expensive in the last few years, to the point that I'm considering re-powering it with something else. I've already bought most of the stuff (wiring, brakes, data plates, etc.) but if I could get an engine, the project would make a bug jump forward.

I am waiting for a price quote on "door assembly left" from Reomie.

View attachment 700276

Problem is, then it would be nice/better to do the windows as well etc etc and you end up ordering a whole new cabin before you realize that you don't have the $$ to pay for it.

But yes, if the price is acceptable, I will go for it, doors always are a pain.

I realize you're on the other side of the planet, but I have NOS doors that are complete (glass, weatherstripping, etc.) on the rally buy/sell/trade thread. Maybe you need to come to the rally and take one home as carry on luggage: https://www.steelsoldiers.com/showt...trade-thread&p=2056192&viewfull=1#post2056192

 

[Volvo740turbo]

Citristrip...about 100 gallons worth...that truck has a lot of real estate to blast...

 

[SCSG-G4]

The zinc coating is for a 100+ year restoration. Using Rustoleum rusty metal primer in slightly rusty metal (wire brush on a drill) will seal things for your lifetime and probably beyond (Sto Lat), then you can use whatever paint you want as a top coat. Since much of the original paint was semi-gloss, a light sandblasting will roughen the surface enough for the next layer of paint to adhere properly.

A needle scaler is an air powered tool with about 15 or so rods in a tight bundle that is driven by pulses of compressed air against the surface being worked on. it is very good for getting into corners where a rotary wire brush will not reach. Do not use on aluminum, and large flat surfaces can take a lot of time!

 

[jaws4518]

My thoughts and methods

I've been reading some of the new and old threads. Gosh, methods for metal preparation are many and varying depending on paint type and thickness you are trying to remove. Basically, I use two methods, scaling and blasting. The needle scaler is my main stay method. Sand blasting becomes inefficient when you have 1/8 inch thick paint to remove. Also, you can blast into hard to reach areas. Plus you will damage things if you do not take the parts off the truck to be sand blasted. Needle scaling will not damage seals, rubber, plastic etc... You can control the pinging and scaling force with air pressure. Needle scaling goes faster than you think. So I blast or scale as needed. I disassemble my truck body parts as needed. The seams and fastening points is where the rust and corrosion began. If plan to do a complete restoration, I'm going to take things apart. You can needle scale to a perfect metal surface for painting. Go to Harbor Freight and buy the small needle scaler $29.95. Run at 90 to 100 lb max. Anything over 100lbs of pressure will wear out the needles and needle holder internals. Use your bench grinder to keep the needles sharpened "flat" round. NOT a point! It's the 360 degree sharp edge that does the work.

Now, Ospho and/or Loctite Extend like to be applied to bare metal rust. I'm talking about clean rust that is created after a spraying washing or rain storm. Natures rusting method is the best! Let the metal rust for a week or two. You don't apply Extend to bare shiny metal. I think Ospho can be applied either/or, but works best with light rust. Read the instructions for both products. I guess it is the nitrogen and other chemistry of rain that makes the beneficial rust for Ospho, Gem, or "Extend". I use Loctite Extend on parts and areas that I do not want to contaminate with Ospho. It would not be cost effective to use "Extend" on massive or total coverage areas (i.e., like a complete finder well, or cab. Extend is good for seams and metal frame joints etc...

In conclusion, professional preparation is just hard time-consuming work! Sometimes there is not super-fast way to move the job along. Ten people with needle scalers in hand are like "ants" on cake!

 

[jaws4518]

I restore and fabricate for hobby and enjoyment. There is no time schedule, that would ruin the total experience. I buy new sets of parts when it makes sense for me. I will make my own parts if I need too. Like shock-absorber pins (see pics). See anything special about the cab? I could die tomorrow, so I better post something to help others with. I've amassed pictures and HOW-TO videos on this entire build. It takes time to edit video making it concise and to the point. Maybe I'll find time to post some of it this fall. I'm not going to worry about it though. Take it for what it's worth! There is no final paint job until everything is put back together. There's going to be scratches and handling marks on everything that goes back together. In the case of this XM818 build, layers of paint has caused serious problems with everything that opens & closes. (e.g., doors, hood, tool box doors etc...) Clearances are gone! Screw threads are blobs of paint.

Yeah, I added 7-1/2" to the cab. Now I can install those Hemtt air-ride bucket seats. A big 6'-5" 350 pound fat boy can drive this baby when its finished. You won't be able to tell there has been a modification of the cab. Shoot, I've got to have room for that Red Dot AC blower.

 

[Robo McDuff]

I talked with my garage people who also painted my NSU motor cycle (know them for over 20 years). The guy doing the actual paint work, to my surprise, also said that doing the zinc is a good way of trowing away money. He would go for sand blasting, than primer, filler on top of that, and than the final paint work UNLESS I really really very much wanted to do a ground-up restoration.

He also said its getting too cold already for that this year unless I get 5 people to help me and get everything ready and painted in the next five days or so.

Without the zinc, and without time pressure of getting it ready yesterday, getting the parts blasted will not be very expensive.

I will use the winter period to get the simple body parts repaired and blasted, while the truck will be under a new roof.

Below the fender. It has some small holes on the front, rust in the strengthening line/weld underneath and the whole strip to connect the fender to the heavier frame side parts that have the air connectors is missing (see yellow line).





Door is even worse, on both sides the lower front parts of the door both inside and outside are more or less gone. If I cannot get a good price on decent doors in the Netherlands, we will remake the entire lower 4" of each door, inside and outside.

 

[jaws4518]

Looks like your cab structure is gone. You can rebuild it, or replace the whole cab. Patching with filler or tin steel is not going to work. I bet your electrical is in bad shape too. I would find a truck in better condition and use this one for backup parts. Sorry!

 

[Robo McDuff]

I restored way worse when as a student restoring old Volvos and an old Mercedes 508 Postbus made into a camper. The cab structure is a question of taking a high-speed angle grinder with cutting blade, take out the rotten stuff well back into solid steel, then remodel the missing structure (rocker panel?) and weld it in. These are mostly simple and straight pieces, not like a historic car with rounded parts all over the place.

For the doors and rocker panels, I will use 19 gauge (1 mm) sheet metal and for the fenders and reinforcement a bit thicker. With standing in a blacksmith workshop yard and one master blacksmith and two apprentices running around doing historic restorations (including parts for steam trains occasionally) even if I fail, they should be able to help me with it.

 

[Ray70]

I agree you should sandblast, however keep 2 things in mind. Conventional sandblasting will warp large flat body panels, so you have to be extremely careful.
this is due to heat buildup, if you sandblast in the dark you will see thin sheet metal glow dull red where the gun is pointing. Once finished your flat panels will be all warped if not careful.
There are portable blasting services that will sandblast with a water / sand mixture. This keeps down the heat as well as dust. They also do soda blasting in a similar fashion. This is also similar to what GimpyRobb was talking about, just larger scale.
You may also be able to rent a commercial unit but need a tow behind compressor and lots of sand.
The needle scaler is more for thicker metal, you will destroy sheet metal panels trying to needle scale them. and it takes forever!
Only other option would be to blast just the problem areas and either chemical strip or abrasive strip ( mechanically sand ) the large flat good condition areas.
Either way the prep job is the key to a good quality and LASTING paint job.
For primer, epoxy is the way to go, but you need to do it immediately after stripping, don't wait for it to flash rust before priming. Then do your repairs over the epoxy.