Yet another media blasting & compressor question...

Hey guys, let me start by apologizing for starting yet another thread about media blasting and compressors. My name is Jacob Rea and after spending the day on the internet, reading forums ad nauseam, I found (and registered with) Garage Journal and am certain that this board is by far the best resource in cyberland.

I live in Dallas and have just broken down a 1978 BMW R80/7 motorcycle that I am retro modding. I'm semi-retired and have time on my hands, interest in all aspects of the project, and have just enough knowledge to be dangerous so I'm hoping to keep as much of the work in house as possible...including blasting & painting. I don't know that there will be a follow up rebuild project after this one so I'm not super interested in breaking the bank with new equipment, but then again there could, so...

Here's my question. I think I can handle all blasting outside of the frame and wheels with a small tabletop blasting cabinet (I'm thinking TP, Eastwood, or ALC) and I've almost convinced myself that buying a cabinet and compressor isn't crazy because I'll get use out of each of them with future stripping/cleaning, painting, and/or woodwork projects. The media blaster will for sure be the biggest air hog in the garage so that is my baseline for the compressor. The cabinets that I mentioned require 7.5-15 CFM at 80 psi and I believe that means that ideally I would want output in the 11-25 CFM range? The problem is, in addition to not loving the idea of spending $1,500+ on a compressor that will be used infrequently, I'm really not sure that I have the room for a large tank. I've read repeatedly that undersized compressors will leave you frustrated by frequently forcing you to stop and allow the compressor to catch up. But what does "frequently" really mean. Every 1 min? 5 min? 20 min? Other? I would love to be able to get by with a smaller 2-3 HP compressor and am fine working in 15-ish minute spurts but is that feasible? If so, what kind of rest/catch up time would I be looking at? Do y'all have any recs on a compressor that may not be ideal but would satisfy my limited needs? Have any of you tackled a similar project and am I an idiot for thinking that I could handle it in such a small cabinet? I know that at a minimum I am going to need a compressor for painting the bike, but maybe I'm better off going small for that and outsourcing all of the blasting?

Thanks for reading guys and sorry for the long first post.

I can't answer your questions....but, I blast at the home/hobbyist level. I'm connected to a 60 gal. tank, 5hp, 2-stage. And...it's rated at 15.8 cfm @ 90psi.

When I'm blasting continuously, the compressor cycles on at least every 4 minutes.

Unless you're using it a lot it might not be worth the expense to set up a blasting cabinet properly. Call Stripco in Dallas to get an estimate on blasting your parts.

First, the number of interest in the rating of the compressor is free air delivery, that is what determines everything else, not the horsepower of the motor or how many stages the compressor head is. Put simply it is the measure of the compressors ability to supply air from the compressor head only. That number needs to be as big as you can afford for any form of media blasting.
Second, a table top cabinet requires the same amount of air whilst blasting as what a floor standing cabinet will as air consumption is a product of the Venturi effect required to produce the suctioning action to lift your media choice into the gun.
Third, expect to spend at least what the cabinet costs you again in actually getting it to be properly usable, for things like getting rid of the media surge issue you will have out of the box, lights etc. If any of those cabinets you are considering have the style of gun that has the large round pink ceramic nozzle then factor in the cost of a decent gun as well. In effect, by buying a cheap blast cabinet you are buying a starter kit of parts to give you the majority of the pieces you need to set yourself up to do it.
Fourth, when you buy a compressor you will soon realise you have just expanded your working capacity in a bunch of different ways so expect to find yourself looking at buying air tools for different things once you have compressed air availability. Seriously, I would buy the compressor regardless, the additional capacity to do things you can’t currently do is worth it alone.

I’ve just been there done that with the blast cabinet thing, happy to try and help with any further questions.

Enjoy

You should read this thread for lots of blasting info. You can blast on a small scale, but you won’t like it.

https://www.garagejournal.com/forum/showthread.php?t=237844 The abrasive blasting resource thread.

I have the old TP 780 blast cabinet. I am a hobbyist. It is one of the best and most useful tools I have owned. I got a deal on a used 80 gallon 5hp Black Max compressor used. I think about 17 cfm. I bought these maybe 15-20 years ago. The compressor runs the blast cabinet quite well enough. One thing I learned is that you never have too much air, but many times not enough.

TP has been great with product support. If you use it you will need parts over time.

racingtadpole is right that once you have compressor, you will find many other uses, air tools, etc., although I think this is somewhat mitigated by cordless tools today. I am more likely to grab my Milwaukee cordless ratchet than the air ratchet most times.

I also have the good fortune to have some land behind my shop. Why is this important? If you have plenty of air, and somewhere for the abrasive to land, you can put on a hood and blast bigger items that won't go into the cabinet with a siphon blaster, like your frame. I am thrifty on some stuff and abrasive can be expensive to send into the wind. But you can buy sand cheap, send it through a sifter (TP has a nice one), put it into the bucket, get the siphon blaster, and let it rip.

I hope I don't get too much push back on letting the blast material go into the wind or using non approved blast material, but it has worked for me.

Good luck with your choice and your project.

Bruce

For a continuous process, you cannot overcome insufficient compressor displacement with storage capacity. If you need 15 cfm, and have a 30 gallon tank at 150 psi, that tank will give you about 1 minute before it drops to 90 psi (not accounting for the compressor output during that time). You then will need to stop for as long as it takes the compressor to recharge the tank, and you will need to account for compressor/motor duty cycle as well. If you double tank capacity, you get one more minute, but recovery time also doubles.

A smaller compressor is much more likely to handle painting, where your air consumption is much less than blasting, so as others have said, outsourcing the blasting could be the solution.

Thanks everyone for your answers, that was EXACTLY what I was looking for. As most of you suggested, I think my answer is to outsource the blasting and buy a smaller compressor for all other duties. Appreciate the help!

I can get you into this blast cabinet set up, 60" wide.

I have a question re soda blasting.My street rod 28 chevy that I built in 1963has SW blue line gauges in the dash.The car (and the gauges) have been in my pole barn since 1969 when I parked to pursue other interests.I am resurecting it now and the dash and gauges i want to keep the way I built it in 63.The chrome bezels on the gauges have white powdery residue on them, but the rest of the gauges are fine.Has anyone cleaned up SW's that were like this and what do all think about soda blasting to do the deed?

Out sourcing blasting on your project is a real pain. Plus your don’t have control of the surface finish.

The TP cabinet has multiple nozzles and jets to match the compressor. You might have slow production down.........but ........on motorcycle parts that rarely a problem.

Yes 5 HP 20 cfm two stage 80 gallon compressor would be a great choice. There are alternatives and compromises and still get the job done, with excellent results.

I have the TP table top cabinet with a 10 cfm@90psi 220v 25 gallon compressor. It runs continuously when blasting........but.......its not an issue. Yes, it working to it’s limits, but has not complained. I have used the same setup for over 25 years. After 25 years it could blow up tomorrow and not owe me a dime. Restored dozens of motorcycles, 2 boats and 5 vehicles.

Not matter the setup controlling moisure in the air system is important.......even more important when it comes to painting and powder coating. When painting with this same setup I use auxiliary 30 gallon tank as a buffer and air chiller/cooler witha filter and trap. Air supply size and output is not important on DIY powder coating .......but.......a great choice for small parts.