Sand blasting

[Matt]

Hi
I'm hoping for some advice on the best way of stripping a truck which has several layers of post war paint back to bare metal. I know some use a sandblaster but I have been warned that if used on bodywork this can cause panels to warp. obviously I don't want to cause damage but I need to find a way of removing all paint from difficult areas such as inside the cab.

I'd be interested to know what others have done and with what result.
Thanks!
Matt.

[gordon]

Sand blasting is the way to go, Matt. What you want to avoid is GRIT blasting which has a lot more potential to damage.

Mask off or remove instruments, stuff a rag in the carb and take the air cleaner off, and make sure you have a word with the guy who is actually doing the work so he knows how precious it is. let him know that if he uncovers and records any markings on the lower paint levels there's at least one pint per marking in it for him too.

Gordon

[Matt]

Thanks Gordon! masking etc won't be a problem as the running gear will be removed as will all cab fittings.just a rolling chassis with a cab on it.by the way did you sell your Ford MH snowblower? we could do with one! 6inches in the last day and a half and it's sticking! we didn't get a white Christmas so maybe it's going to be a white easter....
Matt.

[gordon]

Definitely sandblast it, no question.

The MHF is still at the back of the garage, waiting on some kindly new owner to give it a good home. The basic truck is running fine now, just needs the footbrake and some attention to the blower gear.

Gordon

[Pete Ashby]

Matt

I've had trucks grit blasted, sand blasted, slag blasted, spent hours using chemical strippers and a scrapper, wire brushes on drills and angle grinders, I've even burnt the $$££### stuff off.

All these methods work and they all have a place in restoration.
Like Gordon says with blast cleaning it depends what material you are trying to clean with regard to what you hit it with. In my opinion blast cleaning if it is done properly is effective particularly in semi closed sections.
Remember however that you are eroding the surface and therefore an immediate application of a good two-pack primer is advisable in our damp northern climes here in the UK.
Standard red oxide will become porous with time particularly if a flat topcoat is applied over the primer and you will end up with the dreaded brown spot, I speak from experience here with a jeep tub a few years ago.
Get a professional to do the job, preferably someone who specialises in vintage motors, not just an odd job with a compressor and a blast pot, this is a recipe for disaster especial on relatively thin cab sheet work like you have. The best blast operators have heated indoor blast booths, expensive but worth it in the long run.

One last point for posterity, be prepared for an unpleasant surprise or two in the form of metal moth showing up as a result of blasting, I was doing a jeep for a guy who was nearly in tears after his good body tub came back from the blasters looking like a lace curtain after all the filler and grot had been blown out of it.
Good luck and choose wisely

Pete

Originally posted by Pete Ashby
Matt

I've had trucks grit blasted, sand blasted, slag blasted, spent hours using chemical strippers and a scrapper, wire brushes on drills and angle grinders, I've even burnt the $$££### stuff off.

All these methods work and they all have a place in restoration.

One last point for posterity, be prepared for an unpleasant surprise or two in the form of metal moth showing up as a result of blasting, I was doing a jeep for a guy who was nearly in tears after his good body tub came back from the blasters looking like a lace curtain after all the filler and grot had been blown out of it.
Good luck and choose wisely

Pete

Pete is absolutely right and this is very good advice.

I just don't have the wherewithal to do the number on a FV623 but I have seen the Ballards in action on various pre-war cars and their own trucks.

There is no substitute for a complete strip-down until the vehicle is just an illustrated parts list, parts can be boxed and carried piece-meal to the blaster. Even the chassis and its brackets can be de-riveted and cleaned. This way every little widget gets the treatment, the parts are treaceable in small quantities and stuff doesn't get lost/forgotten so easily - blasters like platers have a habit of loosing that unique bracket. Also the cost is spread since you need to be ready to spend several hundreds doing a complete vehicle in every detail.

You retain the oily bits for re-work and to keep them from possible grit ingress, axles can have precision areas masked, diff apertures blanked with a ply disc and half-shaft tubes plugged.

To underline the warning, you may fairly expect some parts to return like filigree lace and need re-making; at least you know but the process will be been a waste of money on some parts.

You do need to know, however, just what the chassis is really like and apparently excellent examples tell another story when the previously eclipsed areas have been exposed and blasted.

Having it all apart will find some hidden and unexpected problems (more money), road spring shackle plates and pins are a favourite.

The best blasters do immediately use a good primer after cleaning and this is essential.

Just how you find a really competent blaster is another matter of course.

R.

[Bob Moseley (RIP)]

Hi Matt
For the ultimate restoration and a field trip, take the truck to the desert where Kuno does his photography and let Nature take its course.
Bob

[Matt]

Hi Bob
It would probably cost less than having it done here.......!
By the way did you see my question about doing resto work on early Dodge instruments? I can source the NOS guage units if you are interested. I have two that need doing.

[Mike Kelly]

As the erudite MLUers have stated , there is more than one way to achieve good results .

For delicate parts e.g. thin panels like engine covers , I use a Caustic Soda bath . Caustic is dirt cheap , you mix it with water , it strips paint off effectively .

The battery charger / caustic trick work well too . This method has been discussed on this forum before .

Living in a isolated location , I have done my own blasting . It is best done by somebody set up to do it , it is very messy , extremely noisy , can be unhealthy . You need good ear protection , a well ventilated work area .

For the larger bits like chassis , axle housings , I would use a professional . A small cabinet is ideal for the myriad of small fiddly bits , these you can do yourself if you have a decent compressor .

Good quality primer is absolutely essential , otherwise your wasting your time . Single pack etch prime is OK , or these days you can buy cold galv paint , its enriched with zinc .

Mike

[Rolf S. Ask]

Have been an industrial painter/sandblaster for many Years on oil rigs, new and old ones.... there is one thing to remember, the sand (and sanddust and old paint and rust) gets in everywhere. If you are blasting an axelhouse make _sure_ you have masked the parts that don't like sand extreemly good. And blasting a frame will blast places you will have problems getting paint into after.
And make sure you have removed/cleaned everything for old oil before blasting, otherwise you just blasts the oil in to the steel and it will be swetting oil after you have painted it. And if you have blasted I recommend using a zincbased paint. But remember, the zinck is not air-/waterrproof, you need another coating on top of it.
And save the expensive zinckpaint if you don't have sandblasted. The zinck requires ruffnes in the steel to fasten good. If the steel don't have any ruffnes there are many paints that are meant to be used as a etch (?) primer.
I never use sandblasting on cabsheatmetall or other thin parts. What I like the best on such items are the grinder with a sandpaper covered disk (lamels???), or the rotating steelbrush.
And then if there are any rust caves left, the best thing is acid. But the welding pick can also be of good use.
And there are many compunds to use that will penetraite rust and seal it.

Rolf

[Rolf S. Ask]

R

I do have a water/sand attachment here but have never used it so far.

People who have and reported on other large MV lists have nothing but praise but there are some quirks and drawbacks.

The device replaces the lance tip on most commercial pressure washers and we are advised to use the larger petrol/diesel engine powered pressure washers to get the huge flow/pressure rate needed.

Media (sand) pick-up is temperamental as it invariably gets damp but making a 50/50 water/sand mix cures this apparently.

The upside is a total lack of airborne sand going everywhere, the cheapest media ever can be used and thin or alloy panels are not at risk from over-heating and warping owing to media friction. You do not need to buy specialist equipment or services, just hire a big pressure washer. Users report that the strip rate is stunning.

The downside being that you now have wet, clean, bare metal that can rust as you look at it and a specialist water based primer is needed immediately. A local firm here does ship hulls with HP water alone and has a primer that is applied wet that will stand up to salt water for at least 12 months with no further paint. It doubtless has a price to match.

R.

[Snowtractor]

...is used for thin metals on classic cars as it won't expand the metal just remove paint and rust. There is also glass beads, crushed nut shells ( I think they use pecan ) and several other types of media used in North America for blasting. Chemicals are fine but remember to completely neutralise them or they will eventually eat a hole and they may get in to areas like folds where you will not get them out. The same with water blasting , the water will get everywhere and is a hellova solvent. Ship sides are steel plate with no folds for the most part. Good for stripped down frames or axles though.
Lastly remember to wear masks,preferably clean air supply, as the paint probably has lead and heavy metals in it and if you use silicas the dust can cause some sort of lung/nerve condition.
Sean

[Erik Jostad]

I'm working in the aircraft business, and we're using plastic-particles for paint-stripping instead of sand, glass, GRIT etc.

-The plastic will not develop heat, and will therefore not deformate sheet-metal.
-It doesnt change the surface of the metal as sand does.
-Its far more effective than sand etc to remove paint, but leaves the rust.
-You can blast your complete vehicle, as the plastic is softer than glass, an therefore dont damage instruments, ligths, windows etc.
The plastic dust will never damage bearings, seals, U-joints etc.

You can use ordinary blasting equipment, but the plastic is off-course more expencive than sand.
My experience is that the local sand-blaster often destroys more in a minute, than mother nature did the last 50 years.

[Pete Ashby]

My experience is that the local sand-blaster often destroys more in a minute, than mother nature did the last 50 years.

Erik
couldn't agree more, like the idea of plastic blasting that sounds interesting, what do you use on the rust?

Pete

[Erik Jostad]

Hi Pete,

There are several ways of removing the rust, most methods are mentioned here earlier.

Sand or glass-blasting are good methods, and probably the best way to really remove the rust. Disadvantages are also mentioned earlier.

I prefer the glass-particles, as they are more handsome to the metal than sand. The glass also develop less friction-heat, and the chance of ruining your sheet-metal parts are smaller.

The glass is also very suitable to remove corrosion on aluminium and brass details.

Erik
(U.S, Canadian, German, British and French WWII M.V's)

[cletrac (RIP)]

I've found that if you use around a 5 hp compressor and a small sandblaster it pretty well eliminates any of the adverse effects. It takes a lot longer than a big commercial unit but seems to be worth the effort.