Gunsmithing Sandblasting 101 anyone?

[Ratbert]

I'm looking to get some sort of sandblasting setup for stripping rust and finish from small parts (magazines, actions, slides, etc) so I can recoat them, primarily with KG at first. Stopped by Harbor Freight just to look around and figure out exactly how much I didn't know and came away with the following questions:

1) The instructions for KG say very explicitly to only use aluminum oxide media, never ceramic. The instructions for the couple of blast cabinets that they had there had, in bold print, only use ceramic never abrasives like aluminum oxide. Can someone explain the logic behind each and what I should consider when trying to rectify the two rules?

2) I'm not planning on doing this very much, just from time to time and only on small parts. I'd prefer just to use my modest sized compressor, possibly with a standby tank if I want a little more capacity. I had been looking at the pressurized systems vs the siphon just because it appears to use about 1/3 the airflow to operate and so it should work better with my smaller compressor. Is this something I should consider or is the siphon system built into a blast cabinet a better choice?

3)They had 70grit oxide media available for a relatively modest price/lb. 220 grit was also available for much much more. What grit would be good for stripping off rust and finish from gun parts prior to being coated?

If I wanted a small blast cabinet setup to use a modest (20-40lb) pressurized system for cleaning small parts, where would be a good place to go look? Are there hobbyist sized units available or would I be best off just assembling what I need from harbor freight offerings? Don't want to spend a bunch of money on something designed to be used 40hrs a week, but I'd rather not spend money on crap that isn't going to cut it either.

 

[Victor N TN]

Re: Sandblasting 101 anyone?

I have an economy cabinet similar to what Harbor Freight sells. It had no such label on it. I buy my abrasives at a sandblaster supply. Sand Master is the name I think. I have three different types. But the glass beads, ballitini (?) is what I use most.

My cabinet siphons on it's own from the funnel - hopper below.

I have a larger air compressor.

 

[oneeyedmac]

Re: Sandblasting 101 anyone?

You can get a benchtop cabinet that will work for small stuff OK. I have used my cabinet (which is a stand alone but not too big) with a small aircompressor and it isn't very efficient. The compressor will run a lot.

KG suggest Aluminum Oxide because it removes the crud and gives the surface a little "tooth" for the paint to adhere to. I've heard but not seen that glass bead can actually have a polishing effect on metal. I know that aluminum oxide can remove too much metal if you aren't careful. It can smooth corners, remove the word "Remignton" from the side of a receiver and all kind of neat stuff. They may not have wanted it in their blast cabinet because it may be capable of damaging the cabinet.

 

[9sigman45]

Re: Sandblasting 101 anyone?

If parking prior to coating I prefer the aluminum oxide. It also turns SS into a nice matte gray. The only issue I've had with aluminum oxide is that it tends to eat (erode) the spray guns nozzel, but they are easily replaced.

 

[Halfnutz]

Re: Sandblasting 101 anyone?

I borrowed a "portable" sandblater from my father in law. It has a shoulder strap that connects to a briefcase sized plastic container, the nozzle isn't much more than a steel tube. I picked up a bag of blasting media from Lowes, "Black Max" I think it was called, I believe it is made from either garnet or coal slag.
It worked great on a barrelled action, bolt handle, scope base, and trigger gaurd. It left a matte finish that was perfect for Duracoating over.
I would not worry about getting anything more unless I would be doing a lot of it.

 

[858]

Re: Sandblasting 101 anyone?

Aluminum Oxide will erode the tip on the blast gun so make sure you get a cabinet with replaceable nozzles. Just a guess but probably why some setups suggest only ceramic.

Don't waste your time and money on a benchtop blast cabinets, you can't fit a barreled action inside with the door closed. HF has some higher end cabinets that are reasonably priced. If you intend to do a lot of blasting invest in a system with its own evacuation and filtration setup, front entry is nice too.

 

[rmfield]

Re: Sandblasting 101 anyone?

Ratbert, I suspect the labling on your cabinet is the work of lawyers who are trying to avoid the dust liability of aluminum oxide. Take care not to breath the dust and you should be fine.

 

[cozmacozmy]

Re: Sandblasting 101 anyone?

My harbor Freight sandblaster cabinet came w/80 grit alum oxide.

 

[Ratbert]

Re: Sandblasting 101 anyone?

How quickly does 80 grit eat into the metal? Am I going to be able to strip finish & light rust off without fucking it up?

 

[JimT]

Re: Sandblasting 101 anyone?

One bad thing about SB cabinets is that they need a LOT of air flow. I tried using my small compressor but it just didn't cut it. I just bought a big one. I saved money (probably about $1500-2000)by building the cabinet (I wanted one big enough for a car bumper).

 

[rootsy]

Re: Sandblasting 101 anyone?

I wired a few tips out of TC for my harbor freight cabinet. Last a heckuva lot longer than the pink POS that comes with it and you have to go to HF and TSC to buy.

I actually suggest a cabinet other than the HF cabinet. Something that has a front load and a foot peddle to supply air to the gun.

Aluminum oxide works well for stripping finishes, rust etc but will leave a fairly rough finish. For cleaning up machine work, etc I prefer a fine glass bead.

 

[Ratbert]

Re: Sandblasting 101 anyone?

Looks like this would match my needs for small parts blasting (ok, massive overkill) pretty well. Going with 110 and 220 grit tanks.

ProBlast

 

[Ratbert]

Re: Sandblasting 101 anyone?

FYI the ProBlast with the 100 and 50 micron (110 and 220 grit, respectively) media works terrific. It really is the perfect solution to my needs and my little 1.5HP compressor keeps up quite nicely.

 

[prairiehuntr]

Re: Sandblasting 101 anyone?

What's the problast cost?

 

[desertfox01]

Re: Sandblasting 101 anyone?

TP tool company home blast cabinets

I have used several of their commenrcial cabinets at different jobs, and have actually built my own roughly based on their 960 series blast cabinet. I have a older Pressure pot from them when theused to make pressure pots.

Having used pressure pots for many years for Glass Art, I swear by them. They will use less air, provide a constant and steady flow of abrasive. by allowing you to use a lower pressure setting, you have more control on how much material you remove....but a pressure pot is not neccessary. I look at it as an improvement. Aluminum Oxide has a real consistant size and shape to it, giving you a consistant surface etch (sp? it is late)....but a pressure pot will let you get away with a little smaller of a air compressor. My brother built his from plywood years ago and uses it a lot for doing glass etching. he also uses a pressure pot and since it allows a lower pressure, he has not had an issue with cutting/blasting through the wood.

 

[Ratbert]

Re: Sandblasting 101 anyone?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: prairiehuntr</div><div class="ubbcode-body">What's the problast cost?</div></div>

Just under $900, includes everything you need to get started (even a small sample of media.)