Sand blasting

Started by ducfan, August 04, 2018, 09:55:21 AM

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ducfan

I'm a new member here I acquired a 69 1750 MK1 a while ago and have now stripped it back to the bare chassis IE: all external panels where either severely rusted and/or damaged or poorly repaired the entire car had been ground with a coarse sanding disk and the entire car covered in body filler varying in thickness between 2 mm and 20 mm
I was warned that these cars were prone to rust but could not believe the severity I guess 50 years takes its toll
Anyway I am at the stage I need to get the car glass blasted
I was hoping a Brisbane member could recommend a media blaster who is familiar with the fragility of the 105's
Any and all advice /help greatly appreciated

bazzbazz

Send Craig_m67 on the forum here a PM, he will be know who to go to, or at least someone who does.

He knows ALL about rust . . . . . .oh soooo much rust . . . . .  ;)
On The Spot Alfa
Mobile Alfa Romeo Diagnostic/Repair/Maintenance/Service
Brisbane/Gold Coast
0405721613
onthespotalfa@iinet.net.au

julianB

I would search out a plastic or media blaster if I were you.

The main reasons I would go down this path, as opposed to sand blasting are:

Sand blasting can deform the panel if not done correctly. Media blasting doesn't create the same heat and the result is supposedly more sympathetic to the metal.

The media blasting starts out coarse and finishes fine, so that when a corroded area gets blasted through and you're left with a hole, they can use progrsssively finer media until the weak spot is removed.

It has been told to me by numerous panel beaters, that the finish of media blasting leaves a surface which allows primer to key onto in a way that sand blasting doesn't.
This means that if the area is generally ok, it's possible to go straight to primer.
Sandblasting will require refinishing, regardless.

My step nose 105 has been media blasted and then had a coat of workable sealer sprayed over it. It's sitting under cover waiting its turn for some TLC but the car is very much workable.

My mate sandblasted his HQ ute years ago, and wine day in a storm, a hole bunch of water came gushing into the passenger footwell.
We got it under cover , drained all the water out and started pulling the dash out.
It turns out that the sill vents were caked up with sand, both sides, from the blasting done years before.
The clean up with sandblasting can be horrendous!
85 GTV6 "Juliet"
GTA conversion-
AHM ITB setup, Jim K manifolds & 10.3 cams, M84
17" Work Meister S1R
330mm Brembo front, vented rears
RS coilovers and bits
Recaro LX mesh headrest buckets

'68 step nose Junior "Romeo"
bare metal project

Craig_m67

#3
Quote from: bazzbazz on August 04, 2018, 12:16:16 PM
Send Craig_m67 on the forum here a PM, he will be know who to go to, or at least someone who does.

He knows ALL about rust . . . . . .oh soooo much rust . . . . .  ;)

I know all about rust, so do you.. it's everywhere in a 105.
Anybody who thinks it's not, is in denial

The key (as mentioned above) is that whoemever does the blasting knows that they need to be gentle with large flat panels as they may warp via the heat/force etc. and/or use appropriate blasting media.  And obviously remove all the fucking sand (that's just stupid).

Personally, If I could have found somebody (locally) I would have had the car alkaline dipped, stripped and neutralised, then dip painted.  But nobody does the last step in Aust. that I could find. There is a place in Sydney (and SA) with a strip tank, but they don't dip coat in primer.  There is a place in UK that does this, shells look amazing, I even considered shipping it over (about $6k all in).

In the end, time and life got in the way and I've ended up going a completely different route (organically, not by plan) with the Duetto.

Stripping the body by hand (3M strip wheels, very quick, safe) to find all the hidden panel rust under layers and layers of bog and more than three red paint jobs (I counted nine layers of paint, three reds plus original ar514)

I just accepted from the outset that there would be rust in all the places that 105's rust. Or, that where repaired previously, it wouldn't have been repaired properly to (Pininfarina) standard, given the cars age and worth at the time.

With this mindset, I budgeted to replace ANY panel that was, or could have been affected by rust with a replacement piece, NOT a patch.  Preferably NOS if I could find it, otherwise the best reproduction piece available.

There isn't a single part of the body that has remained enclosed or hidden.  Any box construction in the body has been separated (piece by piece), there's actually not that many so not as scary as it sounds.  The cars are quite intelligently put together compared to say a Torana or HQ (these are in the same shop).

Whilst an expensive initial capital outlay, this has made assembly faster and easier for my metal guy as we're just stitching the car back together (on a jig) as Pininfarina intended.  So the labor is cheaper, he's not fucking around too much with previous repairs etc., instead spending his time creating panels and bits that are made of unobtanium.

So currently my car hasn't been blasted, it's been taken completely apart (had much less rust than expected surprisingly) and is now being reassembled. When the internal body (sans front/rear clip and outer sills etc) is complete, we will blast, prime and seal.. probably body paint the hidden internal bits. If you're going to be this OCD, why not :)

The important bit for me about this step, is that the blaster and the (final) painter work together.  The painter needs to guarantee the paint, so needs to know the surface from bare metal up.  The products (paint system) chosen needs to work as a system. Frankly I don't care if it's PPG, Glasurit, etc... whatever the painter loves and can get the best, high quality, durable finish for me is the KPI. Also, the price difference between cheap paint and top quality is negligible given the hours of labor and parts going into the prep.

So, I'm letting my painter choose the media blaster - the final finish is up to them.

That said, they're using sand  - because they understand how to use it
 

How you fix your car is up to you
I didn't want any patches, weak spots.. the body should be as it was, perfect
That said, I'm not a stocknazi with regards anything else, it's going a different colour, getting a different engine and updated parts.
'66 Duetto (lacework of doom)
'73 1600 GT Junior (ensconced)
'03 156 1.9JTD Sportwagon (daily driver)