Floyd111 Posted April 27, 2013 Share Posted April 27, 2013 I have 62 linear feet of forged railing to prep and need a fast way to remove all forge and mill scale. What grade of Black Beauty to use, medium, fine, or extra-fine? The medium would be fastest, but requires 1/4" blast nozzle, and 80 CFM at 90 psi, which means renting a bigger compressor than my 5hp 80 gal. Please help!! Quote Link to comment Share on other sites More sharing options...
Alan Evans Posted April 27, 2013 Share Posted April 27, 2013 Man hours versus equipment cost, always a toss up. I have to say I was so pleased with the purchase of a Hydrovane compressor which could keep up with the pressure pot shot blaster. The classic thing of a couple of minutes of full pressure blasting and then the 5 minute gradual taper off of efficiency as the 5hp piston compressor tried to keep up. Then the 3 minute wait for the tank to refill.... Just wonderful to press the button and blast until the job is done and then turn it off! Huge asset psychologically...let alone practically/financially! I always let the job buy the equipment, any chance you could buy second hand rather than hire....be even cheaper next time! Alan Quote Link to comment Share on other sites More sharing options...
cavala Posted April 27, 2013 Share Posted April 27, 2013 When I sand blasted we used medium grade black beauty. Gets the work done fast. I also liked to stack all the railings, the overspray does a lot of the work for you. I couldn't stand wearing that space suit. Quote Link to comment Share on other sites More sharing options...
Alan Evans Posted April 27, 2013 Share Posted April 27, 2013 When I sand blasted we used medium grade black beauty. Gets the work done fast. I also liked to stack all the railings, the overspray does a lot of the work for you. I couldn't stand wearing that space suit. On jobs too big for my cabinet I have made up an envelope of clear plastic film with gaffer tape and left a small hole to poke my arms and the nozzle through. You can see and manipulate the work piece through the plastic, it keeps all the dust and grit contained so you can reclaim and recycle all the media and it is not sprayed around the yard...kind of like a photographic film loading black bag, but see through! Alan Quote Link to comment Share on other sites More sharing options...
Glenn Posted April 27, 2013 Share Posted April 27, 2013 If you have 2 small compressors you can gang them together into a common tank. With any compressed air set up be extremely careful of the pressures involved and the ability of the equipment not to overload the system. Also be careful to be safe with proper protective gear for both breathing and for protection against flying media. Always wear ear protection both for hearing protection and to keep sand out of the ears. If you add your location to your profile, there may be someone close with an air compressor. We nust need to know where close is. Quote Link to comment Share on other sites More sharing options...
Alan Evans Posted April 27, 2013 Share Posted April 27, 2013 I have just looked up Black Diamond media and see it is furnace slag...I found that it is much better economically to use chilled steel grit rather than expendable / semi-expendable media like slag or aluminium oxide on mild steel. The chilled steel was by far the most agressive and efficient in use and provided you can contain and collect it, it just goes round and round. Slag, Aluminium Oxide and Glass bead I only use on Stainless Steel or Non-ferrous metal. Alan Quote Link to comment Share on other sites More sharing options...
Floyd111 Posted April 27, 2013 Author Share Posted April 27, 2013 Thank you, Alan, for your quick and thoughtful reply. I have often let the job buy the equipment, but a 20hp 80 CFM compressor, used, would run $6 - $10k, and take up valuable shop space. Though I'd have a great blast system! My 5hp two-stage Saylor-Beall 80 gal is continuous-duty rated; how long do you think it would run a 1/4" nozzle before I'd have to wait for it to refill? I'm guessing not very long, if at all. I suppose I will try it when my pressure blaster arrives and see. I can always rent a big rig (by the day) if the S-B won't run the system well enough. Maybe that's the solution. But, what I really want to know is what grade of Black Beauty to use, medium, fine, or extra-fine, to get the best mix of speed and surface texture for priming. Quote Link to comment Share on other sites More sharing options...
Floyd111 Posted April 27, 2013 Author Share Posted April 27, 2013 Many thanks to everyone who responded!!! Very helpful information. This is my first post, as I just registered, and really appreciate the responses. I'll do my profile ASAP, but for now in case anyone has a portable 80CFM compressor they'd rent I'm in Pawtucket, RI and have a truck that can tow or carry a compressor (and forklift to unload it). Thanks again!! barrettmetal@yahoo.com Quote Link to comment Share on other sites More sharing options...
Alan Evans Posted April 27, 2013 Share Posted April 27, 2013 (edited) Thank you, Alan, for your quick and thoughtful reply. I have often let the job buy the equipment, but a 20hp 80 CFM compressor, used, would run $6 - $10k, and take up valuable shop space. Though I'd have a great blast system! My 5hp two-stage Saylor-Beall 80 gal is continuous-duty rated; how long do you think it would run a 1/4" nozzle before I'd have to wait for it to refill? I'm guessing not very long, if at all. I suppose I will try it when my pressure blaster arrives and see. I can always rent a big rig (by the day) if the S-B won't run the system well enough. Maybe that's the solution. But, what I really want to know is what grade of Black Beauty to use, medium, fine, or extra-fine, to get the best mix of speed and surface texture for priming. I will check on my set up later to give you the specs. Off the top of my head it is a 10hp (maybe 10 Kva) Hydrovane which I feed into the tank of my (now defunct seized) two stage 5hp. 35 or 40CFM rings a bell. Actually has a similar/smaller footprint than the piston compressor and tank. Cost 1200 sterling reconditioned. The pressure pot obviously trebles/quadruples the efficiency over a suction system, I will check the nozzle size and report. Cannot advise on the Black Beauty brand slag, but if you get the most aggressive, the coarse or medium you can always reduce the pressure to make it less aggressive...Maybe one of your local colleagues will have a bit you could borrow to try? Edited April 27, 2013 by Alan Evans Quote Link to comment Share on other sites More sharing options...
Floyd111 Posted April 27, 2013 Author Share Posted April 27, 2013 Alan, you've been so helpful -- thanks a million!!!!! I got a deal on 300# of new Black Beauty medium grit and looked up the nozzle spec which is 1/4". Brut mfg says 1/4" requires minimum 80CFM @ 90psi, as did Texas Blasters. Both seemed to know their business. I happen to have lots of clear sheeting and will follow your advice setting up a big booth. Thanks again, David Quote Link to comment Share on other sites More sharing options...
Floyd111 Posted April 27, 2013 Author Share Posted April 27, 2013 Thanks Glen for the safety advice. I will follow it for sure. Quote Link to comment Share on other sites More sharing options...
Alan Evans Posted April 27, 2013 Share Posted April 27, 2013 I have just looked at my Hydrovane and it is 7.5kW so 10hp. 35CFM. It keeps up with the nozzle which was 1/4" but is now worn much larger! But as I said, this is using a pressure pot and not a suction gun system. Those are quite cheap now if you do not yet have one. Quote Link to comment Share on other sites More sharing options...
Floyd111 Posted April 27, 2013 Author Share Posted April 27, 2013 Thanks for checking the specs on your system Alan. I've got a Brut pressure pot kit on its way, and can rent a towable compressor for about $100/24hrs if mine is insufficient. I'll let you know how it turns out. Appreciate your time. Quote Link to comment Share on other sites More sharing options...
Glenn Posted April 27, 2013 Share Posted April 27, 2013 Look for a rotary compressor as well as a piston compressor if you decide to rent. Quote Link to comment Share on other sites More sharing options...
Judson Yaggy Posted April 28, 2013 Share Posted April 28, 2013 I respectfully suggest that you not worry about compressor size or type. Rather, find a company or individual that specializes in media blasting and SUB IT OUT! Even here in a semi-rural small market there are 2 or 3 people who specialize in media blasting. They have all the equipment and experience, and no matter how many times I run the numbers they are cheaper than keeping it in-house for all but the smallest jobs. This includes transportation and handling. Plus sand blasting is about as miserable a job as you could wish for, I don't care how good your air supply, tyvek suit and goggles are, that stuff gets EVERYWHERE! Don't wash your work clothes with your wife's underware after sandblasting. Quote Link to comment Share on other sites More sharing options...
Richard Furrer Posted April 29, 2013 Share Posted April 29, 2013 I must second what Yaggy has suggested. It may be a good way to locate an offsite asset for future work as well. I have gotten jobs from both the folk I have sent my work to. I have my local steel supplier/fab shop do some blasting for me and when it comes to paint I have a powder-coating place 50 miles away which blasts and paints. The two of them have large tooling which I do not have the space or need to have here and when they have the project I can move on to other things. On large jobs I forge some parts and assemble and then take it to them to do their subwork while I am back at the shop making the rest of the rails. That said I am a HUGE fan of having everything in house, but as a one man shop the house gets crowded with tools I use an hour a month if that. For specialty work like that I prefer to let others do the gig. I just subbed out some machining which I may have done here in a few weeks time with great effort....the machine shop will have them all done in a matter of days and a higher quality. Ric Quote Link to comment Share on other sites More sharing options...
Alan Evans Posted April 29, 2013 Share Posted April 29, 2013 Much of my blasting work has been done by other companies but I have never found it that cut and dried. Every project is different and whether it is in house or not is a decision taken at the time based on a range of factors. Unfortunately (for my bank balance) when I run the numbers the best result invariably trumps cheapest cost. Most steel things I make are for an outdoor site and tend to zinc sprayed or galvanised. The galvanisers just galvanise, so any subsequent finish has to be done by me or others. The zinc sprayers do powder coat and wet paint and in the past have let me be in attendance to burnish graphite paint and armour bright lacqquered finishes, other times it is better/easier for me to do the wet painting and burnishing in house. Some projects I have had shot blast at one place and shipped to a welding company for assembly then back to the finishers to be re Shot blast, zinc sprayed and painted. The heaviest use I put the system to in house is when preparing for the TIG welds around punched hole joints. One advantage of doing it ourselves is that we can just do the area we need on both punched hole and through bar. Another advantage is that the forged surface detail and edges are are not damaged in the extra shipping and handling. It all depends on many factors and having the option in house should not be excluded or dismissed out of hand. Quote Link to comment Share on other sites More sharing options...
Judson Yaggy Posted May 1, 2013 Share Posted May 1, 2013 Alan, you make some very good points in your post. Maintaining the quality of one's product is of course paramount. If I had bothered to write a longer post I suspect we would agree on the breaking point between economy and quality control. Some situations do call for clean metal between each step and that's when it's time to don the gear and break out the blaster. But if you can develop a good relationship with a subcontractor and be sure of his quality and ability to coordinate with a finisher then it will be better for the bottom line to go with the sub. And then your standard 5 or 10 horsepower compressor will usually suffice for those occasional blasting requirements. I stand by my assertion that sandblasting is a miserable job, have often wished to pay someone a premium so I don't have to blast (despite the accountancy) even on the small jobs. But money is money and a good long shower at the end of the day will wash away the grit from who knows where. The trick is finding the balance point. Quote Link to comment Share on other sites More sharing options...
Alan Evans Posted May 1, 2013 Share Posted May 1, 2013 (edited) True. I agree, and have advised lots of people similarly to get profiling or finishing done elsewhere. I have always been grateful that someone else is prepared to work in amongst zinc fumes to galvanise stuff on my behalf... Ric's point about someone able to do a better job than you can do yourself is obviously a major factor. The OP in this thread I thought had already made those decisions and was exploring the best way to do it in house. It is always a problem trying to get all you want to say into a short response. In my case I was struggling squinting at my iPhone while waiting for the coffee to brew and when too-thick fingers lost the bit I had typed about the advantages of investing in equipment I did not bother to put it back. It picked up on what you said about your partner's underwear and suggested we might get brownie points if we invest in His and Her washing machines, before we invest in blasting kit! Alan Edited May 1, 2013 by Alan Evans Quote Link to comment Share on other sites More sharing options...
Richard Furrer Posted May 1, 2013 Share Posted May 1, 2013 It is always a problem trying to get all you want to say into a short response. In my case I was struggling squinting at my iPhone while waiting for the coffee to brew and when too-thick fingers lost the bit I had typed about the advantages of investing in equipment I did not bother to put it back. It picked up on what you said about your partner's underwear and suggested we might get brownie points if we invest in His and Her washing machines, before we invest in blasting kit! Alan If I had water in the shop I'd have a washing machine out there...of course the neighbors would not appreciate the walk from the shop to the house, but..or is that butt..... Floyd, Have a look at auctions in your area..you may be able to locate good kit cheaply. I rather like the idea of screw compressors, but I got such a deal on a large dual compressor unit that I could not say no. Ric Quote Link to comment Share on other sites More sharing options...
Alan Evans Posted May 1, 2013 Share Posted May 1, 2013 I don't know whether you can get Hydrovane machines in the U.S. they were original a U.K. company, but I think they are now owned by some mega "Engulf and Devour" U.S. corporation (compair out of Gardner Denver inc). They seemed to have a better track record than some screw compressors but still had the same pulse free, relatively quiet, dry air, oil free qualities. Anyway I went for an old refurbished one and have been very pleased with it. Probably only does a hundreds hours a year so it is hardly being stretched. The forge is five miles from home so in my case it would not just be the neighbours... Quote Link to comment Share on other sites More sharing options...
Floyd111 Posted May 5, 2013 Author Share Posted May 5, 2013 Many thanks to all who responded to my OP about blasting! I've been working so hard I didn't see the additional discussion. 16 hr days plus all-nighters painting to meet deadlines for the biggest commission of my career. I've got a perfect alcove in my shop to convert into a blasting room, with only two 9'-high sides to wall off with roll up tarps; one will be clear plastic sheeting with holes for my arms as Alan suggested. The exhaust system is easy to make. (The rest of my shop has a 16' ceiling.) The $750 it would cost here to sub out the rail blasting pays for a commercial pot kit purchase, plus screw compressor rental for a week. Then the next part of the commission, large double gates and big grills to secure a porch, will only require the compressor rental. I actually enjoy painting with a spray gun, so after galvanizing I'll do the rest. Knowing me, I'll likely enjoy the blasting, too. And the added capacity. But I do agree there are advantages to subbing it all out. Always good to have more contacts for potential work, as Rick said, and others made many good points as well. Thanks again to everyone. I really appreciate the time people took to respond. PS: my name is David Barrett. Floyd is my loyal canine companion. Quote Link to comment Share on other sites More sharing options...
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