Prep frame for paint media blasting what type ?

[Digging4treasure]

Best media blast to prep frame for paint

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[ammorest]

I use 30/65 silica sand in a pressure pot sandblaster with about 100 PSI. That grade of sand provides a good surface for the primer. Courser sand will require more primer to attain a smooth finish. Probably are several other methods for doing this job but this works for me.
Dave

[Digging4treasure]

Glass bead too abrasive?

[T. Cotten]

Glass bead too abrasive?

What I was told, Digging4treasure,

Beads hammer a surface clean, a bit smooth for paints to grab onto.
Sharp media etches a "mill profile", some more destructive than others.

I hate paint.

....Cotten

[aumick10]

Abrasive blasting with silica sand has been banned in some countries due to the possible exposure to the dust which can lead to Silicosis. This exposure is similar to asbestos exposure. Both can lead to lung disease.
Another reason it is not used in most industries is that it was found out that the silica sand was impregnating the substrate with silica, causing problems with paint adherence.
There are a number of alternative abrasives these days.
If you are using a pressure pot, Garnet is a direct replacement for silica sand. It is a bit more expensive, but it is safer to use, and can be reused a couple of times, depending on the grit you start with.
Cheers,
Mick

[larry]

I use coal slag. It works fine.

[tfburke3]

I realize the question is about blasting a frame,but I like paint remover,wire brush and a phosphoric acid rinse.
I have glass beaded plenty of parts over the years but no longer have access and a frame never fit in the cabinet,plus I like the results.
Tom

[exeric]

I'm with Tom on frame preparation if the frame is in good shape. If the frame is going to need straightening, and welding then I believe an industrial sandblasting will also have the important benefit of stress relieving. I just finished painting the frame for my '66 Honda 450 and used all the techniques Tom suggested.

[T. Cotten]

I'm with Tom on frame preparation if the frame is in good shape. If the frame is going to need straightening, and welding then I believe an industrial sandblasting will also have the important benefit of stress relieving. I just finished painting the frame for my '66 Honda 450 and used all the techniques Tom suggested.

"In good shape"?

That's relative, Eric!

Preventing further corrosion requires thorough removal as well as encapsulation.

Even if its straight.
(Nobody should mess with OP of course.)

Frankly, for safety's sake on warhorses, frames should be blasted to 'gray metal' for inspection.
That could be a thread in itself.

....Cotten

[tfburke3]

Back to blasting.
The more paint you remove with a stripper the finer media can be used,with less effort and expense and good metal removal.And round tubes sand so easy by hand.
For safety sake dont hang the frame over your head with string.
Tom

[aumick10]

I have always blasted any frame I am going to paint.
Blasting can open up any cracks or issues that you can't normally see if you are don't blast, sanding or wire wheel can cover them up.
"Good" paint is specified to be applied over a specific surface profile. Blasting is the only way to generate this surface profile.
Any other procedure usually smooth out the profile "peaks", resulting in lesser adhesion.

Mick

[T. Cotten]

Anybody ever magnaflux with a generator growler?

Got the powder, but never found a crack,..

So I don't know if it works.

...Cotten

[aumick10]

I have done it successfully with the proper magnet, don't know what sort of magnetic field a growler puts out.
You usually want the magnet to be hand held, a growler is too heavy to move around easily.
From my school days, I think a growler has a north and south pole on either side of the core.
A magnaflux magnet uses the metal being tested as one of the poles.
Don't quote me on this as school was a long time ago.
Cheers

[T. Cotten]

A long time ago for me too, Mick,..

I routinely used a Magnaflux-brand hand-held pushbutton thingy, found many a faulty auto rod, head, or block, and got paid for it.
It seemed like it had two "feet". But a growler may be just one big one.

The boss said I should put down newspapers to make clean-up and throwing the espensive powder away easier.
(That was over three decades ago, and I have a lifetime supply! He was a genius.}

Used it for rods and tranny gears religiously, but if there was never a crack to begin with, I don't know if it works, for sure...

...Cotten

[exeric]

I've had parts ruined by sandblasting companies so choose your vendor wisely. I had a Flying Merkel wheel run over by a fork lift at a blasting company, and friends who dropped off good frames and got bent frames back. I've done countless frames and I try to use good judgment, and my own experience. Good surface prep applies to any object that will be painted, and that is based on common sense.