Sandblasting and media info

[Warren Lake]

besides the health issues silica sand is an inferior blast medium. If youve used sharp material and try silica again it just feels like tiny tennis balls.

[Wayne Lomman]

I use silica sand in my blast cabinet, it's hooked up to my 3hp dust gorilla for dust removal.
Got rid of all the 1/4" air hose and fittings. Replaced with 1/2" then plumbed it into my 100cfm IR gas powered compessor.

No problems anymore.

Ed

Silica sand is outlawed as a blast medium even in the USA and has been for a long time. The devastating health effects of silicosis which results from respirable silica dust are far more rapid than asbestos disease and just as deadly. You don't have to be exposed to the dust for long either. Dust collection and breathing apparatus are not good enough controls hence the ban. Do yourself and those around you a favour and change to another medium. Sanitise your work area as well.

[Patrick Walsh]

I’m gonna get pictures of the setup Monday. Maybe that will help some guide me.

I know there is a bag of black beauty with the cabinet. I’ll probably start with that unless I’m told otherwise.

[Brian Holcombe]

I’ve only ever used glass beads, but only on aluminum parts. It works well, but you must be absolutely sure they’re completely cleared from the part before it’s put to use. Glass beads in a finished assembly will ruin it very rapidly.

In the machine shop we used a steel shot machine for smaller cast iron parts, like cylinder heads. We used it after baking them in a specialized oven to cook off any paint or grease. Aluminum parts were placed in a heated cleaning solution prior to glass beading.

Large cast iron parts were brushed by hand after cooking, they were neat and clean after the process and ready for new paint.

Media blasting the cabinet is a lot of effort for little reward, if the paint is not loose then remove all grease then sand and fill.

Its important that grease/oil be removed entirely. Paint does not adhere to greasy surfaces no matter what the manufacturer claims and blasting media will get stuck in anything greasy and load up the sprayer.

[Patrick Walsh]

So Brian would you be the “don’t sandblast corner”...

I have had more than one person tell me “sand and fill”.

My carpel tunnel likes the idea of sandblasting. I also like the idea of everything taken down to bare metal and any pitted on rust gone.

I’ve only ever used glass beads, but only on aluminum parts. It works well, but you must be absolutely sure they’re completely cleared from the part before it’s put to use. Glass beads in a finished assembly will ruin it very rapidly.

In the machine shop we used a steel shot machine for smaller cast iron parts, like cylinder heads. We used it after baking them in a specialized oven to cook off any paint or grease. Aluminum parts were placed in a heated cleaning solution prior to glass beading.

Large cast iron parts were brushed by hand after cooking, they were neat and clean after the process and ready for new paint.

Media blasting the cabinet is a lot of effort for little reward, if the paint is not loose then remove all grease then sand and fill.

Its important that grease/oil be removed entirely. Paint does not adhere to greasy surfaces no matter what the manufacturer claims and blasting media will get stuck in anything greasy and load up the sprayer.

[Brian Holcombe]

If the inside is intact and not rusty I wouldn’t. I might spot blast the rust. Blasting has a high risk of a piece of media destroying a finish machined surface after assembly or seizing a bolt. We limited blasting to small parts and cylinder heads because the media can be effectively cleared out. Big castings have lots of places for media to hide.

If you absolutely had to remove the current paint entirely, because it were flaking badly, I would bring it to a place with an industrial oven and bake the paint off, then spot blast rust. Otherwise I would use the current paint as a base filler then work from there.

[Patrick Walsh]

Hmm,

I really don’t know what I’m doing do I?

Ok so it’s not flaking like crazy. I’m sure a spot blast, sand prime, fill prime and a couple coats of paint will do.

Just sounded was more easy to me to blast all the paint off, prime, skim with bonds, sand off prime, coat spot bonds and prime then finish coat.

If the inside is intact and not rusty I wouldn’t. I might spot blast the rust. Blasting has a high risk of a piece of media destroying a finish machined surface after assembly or seizing a bolt. We limited blasting to small parts and cylinder heads because the media can be effectively cleared out. Big castings have lots of places for media to hide.

If you absolutely had to remove the current paint entirely, because it were flaking badly, I would bring it to a place with an industrial oven and bake the paint off, then spot blast rust. Otherwise I would use the current paint as a base filler then work from there.

[David Kumm]

Die grinders with various wire wheels and needle scalers do 90% of my work. When a small part has rust inside that I can't get to with the grinders, I drop it in a bucket of evaporust or esprit for a day. I also depend a lot on a 14" floor standing wire wheel and buffer. A benchtop 8" works too but not as well. Dave

[Patrick Walsh]

See I don’t have any of those tools.

I do have access to about 100hp of compressed air though and sandblasted and cabinet.

Link me a couple of the above mentioned tools and attachments if you don’t mind. Sounds like I should probably invest in them.

Remember I’m not a harbor freight fan lol..

Die grinders with various wire wheels and needle scalers do 90% of my work. When a small part has rust inside that I can't get to with the grinders, I drop it in a bucket of evaporust or esprit for a day. I also depend a lot on a 14" floor standing wire wheel and buffer. A benchtop 8" works too but not as well. Dave

[Warren Lake]

not sure what you plan to do, big stuff wont fit in a cabinet. Small stuff works great, sometimes getting grit into places is a concern. Ive never tried a scaler probably tried a die grinder a few times but sandblasting cuts into a fresh layer or metal and leaves you with good tooth, dont handle parts after with your hands and degrease stuff first if you are reusing medium. On the big scale say car frames cheaper medium is used and disposed of. As an example my 92 rotors before I had them turned. Ditzler Epoxy primer painted inside and out and the inside paint came off when they were turned. Sandblasting got into all the casing and the job will be as good as you paying attention. I loke the old flood light bulbs for light, they are super thick and produce heat, it helps dry the medium probably not much but it works in your favour.

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[David Kumm]

Ebay and CL are good sources for Mac Tools, Matco, Ingersol Rand, etc. You want the ones with larger capacity so they don't slow down when used. Usually 50-75 will get you a decent used one. You can usually tell if they have been abused. A good needle scaler is more like 100-150 unless you do the HF thing. Dave

[Patrick Walsh]

Big stuff I will setup for outside with the Portible tank. I’ll make myself a pop up bubbled in plastic roomer just go to town?

Brian and David have me double guessing the sandblater at all though at this point. Maybe I’ll start with a die grinder and needle scaler.

I also have access to baldor grinders and buffers and polishers that at least right now are setup to polish metals. They are the stand type and used to polish various car parts, normally brass, nickel and aluminum I think?

not sure what you plan to do, big stuff wont fit in a cabinet. Small stuff works great, sometimes getting grit into places is a concern. Ive never tried a scaler probably tried a die grinder a few times but sandblasting cuts into a fresh layer or metal and leaves you with good tooth, dont handle parts after with your hands and degrease stuff first if you are reusing medium. On the big scale say car frames cheaper medium is used and disposed of. As an example my 92 rotors before I had them turned. Ditzler Epoxy primer painted inside and out and the inside paint came off when they were turned. Sandblasting got into all the casing and the job will be as good as you paying attention. I loke the old flood light bulbs for light, they are super thick and produce heat, it helps dry the medium probably not much but it works in your favour.

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[Warren Lake]

get yourself a drum like that and try those tools then show us the results and how long it takes you and all the places you cant get into.

[Patrick Walsh]

So this is what I have,

If better pictures are needed let me know. I took these in a rush just to have something to post I hopes it would help you all guide me.

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[Lisa Starr]

Patrick - That is the exact blast cabinet and dust collector unit we use in our home shop. Make sure you have the final filter that fits on the exhaust port of the dust collector. If you use Skat-Blast, as I posted earlier, you'll find that you have a good "all purpose" media that will allow you to do lots without changing the media. I'm attaching a pic of our set-up. If you need any other info, I'm happy to share our knowledge.
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