shot blasting

How much of a learning curve for shot blasting existing warehouse lines? Any advice for an experienced striper that has never done shot blasting? Thanks

There is a large learning curve when dealing with line removal in a warehouse. Shot blasting is one method but not always the best method especially when there is more than one layer of paint or epoxy. We have seen trenches cut in warehouse floors over 1/8" deep exposing large aggregate by inexperienced shotblast operators. We have seen where other contractors used a 12" shotblaster used to prep for 4"lines and a 12" shotblaster used to remove 4" lines. Once you begin using a process that can remove the troweled surface of a concrete floor, you need to understand when alternate methods might be a better option.

There was a thread here some time back about applying a coat of concrete sealer, then stripe, then a top coat of sealer, sandwiching the stripe. Randy, I know you are an expert on warehouse striping and wondering if you've ever tried this? I did one this way 2 months ago, letting the owner know what I was trying. He was fine with it and will let me know how it holds up before doing other warehouses of his.

Gauxt, I have never tried it. Unless you read and research the concrete sealer you are using, the process may be destined for premature failure. Concrete sealers are designed to close the pores of the concrete, make it easier to clean and keep things from sticking to it or staining it. Just the opposite of what you need for proper adhesion. My thoughts on using sealers is that they are for protecting the concrete and making it look shiny if that is what the customer wants. Sealers are not designed to protect paint or epoxy and not designed to make a flat traffic paint look shiny, stick better or last longer. Urethane or other clear materials designed for hardness and wear on a concrete surface are or may be a different matter. They are not "concrete sealers". If you are using them to protect a substandard paint (like traffic paint), then you are using the incorrect colored paint to begin with. Furthermore, they don't increase adhesion which is different from "wear" or abrasion. If the customer wants the lines to be and remain clean, glossy and easy to clean, a high gloss epoxy is really the best product and a better cost alternative to using traffic paint covered with a premium and expensive clear product like a urethane on top. Adhesion on any concrete surface is best accomplished when the pores of the concrete are open. This means no curing agent, sealers, dirt, grease, oil, detergent residue, tire rubber etc etc. The best ways to accomplish this are with a mechanical prep (usually shot blasting) or some sort of acid etch (vinegar, muriatic acid etc). Power washing with a turbo nozzle will remove curing agent for parking ramps & outdoor surfaces but this is not a practicable solution for indoor warehouse or manufacturing operations. Without the proper surface prep, you can't guarantee the customer any sort of longevity of adhesion no matter what material you apply. The most durable epoxy, urethane, enamel or any other high end coating can't be guaranteed to perform well if the surface on which it is to be applied can't be prepped properly.

Gauxt Gauxt- F Gauxt- For the most part, I agree with Randy. However, most of the warehouses that I have striped do not have the budget or time to shut down for proper prepping and cure time for epoxies. When I present a customer with the options for applying lines in an older warehouse and their costs, most will say they would love to go with the complete package of proper prepping and epoxies. [/size] T hey wind up instead opting for the more inexpensive methods even though they know the lines may fail faster than the more expensive methods. Sometimes the impetus for striping was a visit from their insurance agent or OSHA telling them they had to designate the aisles and exits. All they want is some lines to satisfy the request. If you are doing a FedEx, Nike, Amazon or other high profile facility where looks and longevity are of utmost importance and they know to do it right they have to spend the money, the money is spent. Any new facility does need to have at least the proper prep of the concrete. If the floor still has the curing agent on it, it must be removed. A gloss sealer may not have to be removed depending on what type of coating you are placing on top. [/font] The most common method that I use for a lower end project is traffic paint covered by a good coat of clear urethane type paint. I have tried several method and types of paints and this method has produced the best results. I normally leave the cleaning for the lines up to the maintenance department of the client. As we always say on the Forum, the best method for solving a problem is the one that works best for you.

The part that got left out from my previous post was that warehouse managers will opt for the more inexpensive methods even though they know the lines might fail prematurely because they do not have money and time.

I have to respectfully disagree with Dennis on a couple points. First, Urethane I am familiar with has a full cure time measured in days just like epoxy. Maybe it is dry to foot traffic but it is far from cured and hard enough to resist damage for several days. Good urethane is also over $70/gallon which is the cost of epoxies. The net result is a 2 coat operation that ultimately costs the customer more with a full cure time equal to epoxy and typically an adhesion that is not as good as using epoxy in the first place. Second is that in our experience, we don't seem to miss out on jobs because of price or cure time of epoxy. We work 24/7 and that often means starting work after the 2nd shift leaves on Friday so we can layout, shot blast (if that is elected by the customer) and get epoxy on the floor asap. Many projects at operating facilities require multiple mobilizations because of their operational schedules but that is all part of this type of work. After educating the customer on the options available, if they decide they can't deal with cure time of epoxy and/or urethane, we do use quicker drying markings with them being fully aware of the shortcomings associated with lower quality materials or materials not particularly designed for indoor striping. I do agree with Dennis on his statement about new concrete needing proper prep and will extend that to "all" concrete needing proper prep if we are going to guarantee adhesion. Sorry, this thread has taken a turn from the original question.

I think it's still on topic as far as it being informative to the original post. Good points Randy and Dennis. In my case, the owner was being pressed by OSHA and just wanted it done (every year if necessary), so I was up front about it being a trial. He didn't want the proper prep, shot blasting, scarifying, etc . So jury still out, I'll find out soon. Armor seal was what I used and I think that was the thread I was referring to. Thanks for the replies, it's interesting.....at least to me.