oologahan
ArboristSite Operative
I bought a mini sand blaster from HF, it needs 3.5 CFM at 50 psi, what would be the best media to use on Homelite magnesium chainsaw parts? Thanks
What Media for Small Blaster
- Thread starter oologahan
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Wow.
3.5 ain't much. I hope you report back on how it goes.
I'm guessing...the least abrasive media you can shoot with your blaster. Soda? Corn cob?
Whatever you try...buy a small amount and test. I have a big HF blaster, and it only wants to shoot a limited range of grits.
3.5 ain't much. I hope you report back on how it goes.
I'm guessing...the least abrasive media you can shoot with your blaster. Soda? Corn cob?
Whatever you try...buy a small amount and test. I have a big HF blaster, and it only wants to shoot a limited range of grits.
Try baking soda, it's the least aggressive blasting material and you likely have some in the house so you're not out much if it wont remove enough material.
Next is fine glass beads, I've only seen them in 50 pound bags tho.
Then there's #00 (fine) silica sand, it will pit the magnesium if you're not careful.
Next is fine glass beads, I've only seen them in 50 pound bags tho.
Then there's #00 (fine) silica sand, it will pit the magnesium if you're not careful.
Baking soda for blasting isn't ground as fine as household stuff. It won't clean much of anything and is a 1 time use media. Only benefit to it is its super easy to remove out of small passages with water based cleaners.
There are tons of media out there, all depending on what you want to blast, and the finish you want to achieve. We use several here at work, but for softer metals we're pretty much required to use corn cob, walnut shell or glass bead, all 3 at low pressure mind you. They worry a lot about surface finish here. I like glass bead the best, but it leaves a satin like slightly rough finish. Walnut shell leaves a pretty smooth finish but not as smooth as corn cob. The walnut shell holds up better then corn cob media. We have aluminum oxide, and iron oxide (we call them gritt) as well for steel parts, but they are really aggressive. Just use for heavy rust/paint removal on stuff thats getting re finished or painted over again.
There are tons of media out there, all depending on what you want to blast, and the finish you want to achieve. We use several here at work, but for softer metals we're pretty much required to use corn cob, walnut shell or glass bead, all 3 at low pressure mind you. They worry a lot about surface finish here. I like glass bead the best, but it leaves a satin like slightly rough finish. Walnut shell leaves a pretty smooth finish but not as smooth as corn cob. The walnut shell holds up better then corn cob media. We have aluminum oxide, and iron oxide (we call them gritt) as well for steel parts, but they are really aggressive. Just use for heavy rust/paint removal on stuff thats getting re finished or painted over again.
I use silica, 100 PSI and whatever my 7.5 HP Porter Cable 80 gallon compressor can deliver. I did some aluminum and magnesium parts this week; this silica has been in there a while and is getting pretty fine so it is not too aggressive. As long as you avoid coarse, very hard grit I think you will find it does not rough up aluminum or magnesium too badly. In general, the media must pass through a 30 mesh screen in order to flow through the gun so coarse grit is not really a concern.
I have never used soda or soft abrasives but for my purposes, the silica works and has not damaged any parts. I have done a few carburetor parts with lower pressure just to be sure and keep unnecessary erosion to a minimum.
As Sean has pointed out, the more aggressive abrasives will leave a satin finish. If you are painting parts it does lead to pretty good adhesion. For unpainted parts you will need to be careful to avoid leaving dirty fingerprints if your parts will be on display.
Mark
I have never used soda or soft abrasives but for my purposes, the silica works and has not damaged any parts. I have done a few carburetor parts with lower pressure just to be sure and keep unnecessary erosion to a minimum.
As Sean has pointed out, the more aggressive abrasives will leave a satin finish. If you are painting parts it does lead to pretty good adhesion. For unpainted parts you will need to be careful to avoid leaving dirty fingerprints if your parts will be on display.
Mark
oologahan
ArboristSite Operative
This is what I bought, https://www.harborfreight.com/air-t...ning/portable-abrasive-blaster-kit-37025.html I have been sanding most parts down to bare metal by hand which is time consuming. Some of the harder to reach areas I use aircraft stripper on which is messy and extremely toxic. I may try soda.
oologahan
ArboristSite Operative
Great INFO, Thanks a BUNCH!!! Which is reusable if any corn cob, walnut shell or glass bead?
MudgeHollowBeaver
ArboristSite Member
It can all be reused until it breaks down into dust and won't do it's job. The softer media like corn cob breaks down very quickly. There are even some plastic based blast media that are safe to be used near glass surfaces without risk of etching. Just make sure that you have enough compressor capacity...as the blast gun nozzle wears it will require more air to operate properly. Also remember to rotate the blast gun tip occasionally as they do not wear evenly which will distort the blast pattern and can cause the gun to consume itself internally . High quality guns can come equipped with long life carbide nozzles instead of the economy ceramic nozzles.
A shop vac is not the best choice for a dust collector as most use the vac air once it has gone through the filter to cool the motor. The fine grit that manages to get through the filter will kill the bearings very quickly. Actual dust collectors have an extra fan and air path for the cooling air.
( I used to design and build custom blast cabinets until the China stuff flooded the market)
I’ve been using a small soda blaster for cleaning carbon out of combustion chambers, exhaust ports, and off pistons for a little while now. Works great for what I’m doing and won’t remove metal.
All three, in order you mentioned. Corncob typically will be the shortest lived, walnut shell and glass bead last pretty long. Beaver pretty much hit it bang on.
I used to have a sand blast cabinet that was too big, along with my other stuff, for my little garage so I got rid of it. Now that I'm at a bigger place with all kinds of garage space I wish I'd kept it. I could use just about any media I had in it.
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