Alchatek Blog

In this article, I'm providing in-depth technical tips for experienced polyurethane slab lifters. If you're new to slab lifting, you may want to start by browsing the Lift Slabs topic to find more basic articles on the subject. As always you can call us with any questions at 404-618-0438.

For the rest of you, let's take a look at some pressure imbalance troubleshooting tips. Making good foam is all about temperature and pressure.  Sometimes there are issues that cause a PMC Proportioner or a Graco Reactor to get off ratio on pressure.  Graco machines will throw an E24 code requiring you to go to the pump and pressure it back up again.  A PMC machine with pressure imbalance controls will also stop the machine and require a reset.  Sometimes this will happen once or twice when getting going in the morning and then the issue clears up.  Maybe the gun had a few particles in it that needed blasting out.  Other times, the pressure imbalance is persistent and you need to figure out what to do.

Consider what information you have.  When you do a test shot is the material dark in color or very clear in color.  With AP Lift products, the B side is always nearly clear and the A side is dark brown like coffee or tea.  If it is coming out clear, or very light, there is a restriction on the A side somewhere.  Inside the rig you should also see that the A side pressure gauge is reading well above the set pressure and the B side gauge will probably be reading very little pressure if any.  This means A is blocked and not getting into the mix.  The restriction is most commonly in the gun on the A side injector or A side check valve.  This will be your most common pressure imbalance situation; A side restriction due to the nature of the ISO chemical.  If the opposite situation occurs (A side flowing freely while B side is restricted) follow the same steps to check for restrictions inside the gun.  As always, wear safety glasses and gloves when checking and working around this equipment. Use proper depressurization steps of the system before performing gun cleaning or maintenance.

The gun restriction on the A side is most common for slab lifters.  If it’s not the gun, what else can be going on that may cause pressure imbalances.  I am not a master Graco or PMC technician so I always check the easiest stuff first.  

Here are a few quick items to check:

1. Is the air compressor running? Sometimes an electric air compressor will shut off and you can’t hear it over the noise of the generator.  Possibly a low oil indicator because the rig is on a slope or, it’s low on oil.
2. Are the temperature settings at the machine correct? AP Lift foams have correct temp settings on the top of the B side drum.  For AP Lift 430 – it is A side 100F, B side 110F, and Hose Heat 105F
3. Is the material in the drums too cold? We recommend keeping the A side and B side above 60F.  B side is much thicker than A side and if the material is too cold in the drums, the drum transfer pumps can’t effectively push the thicker material over to the reactor / proportioner.
4. Are all the air lines connected to the transfer pumps?
5. Are all the fluid valves open?
6. If the gun was disassembled and put back together, were the check valves installed in the correct direction?
7. Are the foot valves at the base of the transfer pumps sealing properly. If there is trash keeping the bottom check ball from sealing, it can cause a loss of pressure
8. How about the hose heat and primary heaters? Are they still on?  PMC machines have a breaker on the hose heat transformer.  It trips every once in a while and you will lose hose heat and not know it until you start having imbalance issues.  Graco machines that throw an E24 code require the heaters to be turned back on by pushing the panel buttons.  If you forget then you will have pressure imbalance issues at the gun because the material thicknesses / viscosities will never be equalized.
9. Check the wye strainers at the proportioner / reactor. This needs to be part of your weekly / monthly PM.  If you have imbalance issues and other steps do not reveal the issue, disconnect the air lines to the drum pumps, shut the fluid valves off, and remove the plug from beneath the wye strainer.  Have a small pail beneath to catch material; it will not be that much.  When you remove the plug a cylindrical screen will slide out.  If it is clogged with particals this could be the problem.  Clean with a small brush and solvent.
10. This sounds obvious but make sure the valves on the proportioner / reactor are in the same direction. If one is in recirc mode and the other is in spray mode you will surely have an imbalance issue.
11. Are the ¾” bungs on the drums (A and B) venting properly either by being open or via a desiccant cartridge.

If none of this resolves the issue it may be time to call technical support.  They are going to ask you if you have already checked the above listed steps so you might as well save time and check the items first.  Usually you will find the issue. 

A technician will ask you some more questions and perhaps ask you to send a short video clip of the machine gauges as it is pressuring up and as it is trying to spray.  This information is vital to figuring out the problem.  Maybe there is a restriction or blockage mid way through the hose.  Maybe the temperature sensing unit towards the end of the hose is not reading correctly and needs to be checked.  Worse case, maybe there is a restriction or small particles causing the main pump line assembly to lose pressure.

Give one of us here at Alchemy a call and we will try and walk you through some steps.  If we cannot figure it out, we can direct you to our technical experts with PMC and Graco that we work with weekly.

 Want more information on slab lifitng?

Condition the Materials

So how do you fight the cold?

1. Keep the material warm - we consulted with one of our customers on a job in Canada last year and there was a giant void full of approx 45° F (7° C) water right behind a vault we were injecting.  We kept the AP Fill 700 in a hot van and pumped through insulated hoses.  
2. Adjust the Catalyst - on the above project we used the fastest catalyst we have for our AP Fill 700.  With a 10% AP Cat 107 to resin ratio, the material reacted almost immediately and our customer was able to fill the void and push out the water.
3. Inject further away from the leak - sometimes in a buried vault or pit, you may have to grout behind the structure to create a curtain wall effect.  If a joint, crack, or pipe penetration is leaking, and you have slow-reacting resin pushing through, you need to inject further away from the leaking area to give the material more time to react.  These polyurethane foams will find the leak.  Move further away and let the material do the work.
4. Twin streaming - we have twin streamed polyurethane and warm water in some cold weather applications.  This gets the polyurethane reacting as it's being injected, rather than hitting cold water and having a shock to the temperature of the polyurethane.  Click here to read an entire blog article on twin streaming.

Want more information on Alchemy-Spetec products?

How many times this year have we found ourselves saying "they need to try some 700"?  Too many to count.  Time and time again, the AP Fill 700 has stepped up to the plate when other products could not get the job done.  

AP Fill 700 is a single component polyurethane injection resin that reacts when it comes into contact with water or moisture.  It can be premixed with a catalyst which will make the resin react as a foam to fill voids or shut off leaks.  It can also be injected without a catalyst as a pure permeation resin to stabilize soil.  

I thought it would be a good time to emphasize the versatility of this amazing polyurethane resin by highlighting one of its unique applications:

Void filling and water cutoff around buried culverts.  

Concrete pipes, boxes, and corrugated metal culverts are often used to help small creeks and streams transition underneath roadways and rail lines.  In times of heavy rain or just from years of the erosion process, water will find its way beneath the culverts and around the sides.  This causes undermining of the culvert and also erosion of the soils above.  Dips in rails and roadways can become evident as the undermining process occurs.  AP Fill 700 can fill these voids even in times of high water flow.  When mixed with AP Cat 107, the reaction time is barely seconds.  

Several times this year, pipe relining contractors were struggling with these culverts, trying to stop high water flow and fill voids with products that were too slow.  They reached out to us for help and we recommended the 700 with a 10% Cat 107 to resin ratio.  The results speak for themselves as we have won over many converts with this product.  The additional benefits of it being NSF / ANSI 61 approved and phthalate free only add to the appeal.

Want more information on Alchemy-Spetec leak seal products?

Last year in Florida alone, I gave over 30 lunch and learn presentations on the subject of polyurethane as a method of filling voids and stabilizing soil behind bulkheads and seawalls.  These presentations were done at various engineering firms from the panhandle down to Miami.  Besides serving as an opportunity to feature polyurethane in a specific application, it is also a forum to explore other applications that may arise.  I can’t tell you how many times I would be discussing permeation of soils behind a seawall and an engineer would ask, “Hey could that be used in this other situation that I am dealing with?”  At the very least it is an opportunity to plant seeds for projects down the road. 

A lunch and learn is a training and development event that is scheduled during a lunch hour in a work day. This is a great way to give a presentation to engineers, municipalities, or contractors on the latest advancements in polyurethane technology for geotechnical and infrastructure repair applications.

Our lunch and learn presentations are designed to facilitate conversations about the benefits of using polyurethane technology on geotechnical, structural, and civil projects. We aim to be your go to partner and that includes bridging the gap about what tools to use, how to use them, when to use them, and how to market yourself in your field.

We schedule lunch and learns every month at various engineering firms, contractor offices, and municipalities. These sessions are a great way to meet our technical experts in person, ask questions, and even demo a product. And who can turn down a good lunch? We take care of that as well. 

After most presentations we will have contractors or engineers who show interest in our products. Many times we will have engineering consultants approach our team and ask for a private demo to specify our products for future projects.

Benefits of Attending a Lunch and Learn

• Learn about the latest polyurethane technology and tools available.
• Ask first hand questions and receive immediate feedback.
• Networking opportunity and private demos available.
• Complimentary lunch may be provided.
• Sessions are usually kept under an hour

How Do I Get on the Schedule?

Contact us and we’ll have one of our regional managers reach out to set up an appointment.  Let us know the product line you are interested in, and any additional information about possible projects. We will formulate a presentation tailored to your needs. If a presentation on short notice is required, we can even have pizza delivered and give the presentation remotely via a screen sharing program.

Want information on the products we offer?

Alchemy-Spetec will be at World of Concrete 2018 in Las Vegas. Be sure to visit us: Silver Lots - O40551. Click here for a discount on Exhibits-Only Admission.

While there's certainly lots to see and do at the concrete industry's premier trade convention, don't forget to check out some shows while you're there! To make it easy, we've done some research for you. Here's an overview of some of the best entertainment events in Vegas during World of Concrete.

Adam Sandler at the Cosmopolitan of Las Vegas

January 27

Adam Sandler’s films have grossed more than $3 billion worldwide and include box office hits such as Grown Ups, Just Go With It, Bedtime Stories, You Don’t Mess with the Zohan and I Now Pronounce You Chuck & Larry. In 2014, Sandler signed a deal with Netflix to produce and star in four original movies to premiere on the streaming channel. The first three films, The Ridiculous 6, The Do-Over and Sandy Wexler, are the most-watched movies on Netflix to date.

Click here for tickets and more info...

An Intimate Evening with Santana

January 24, January 26 - 28

He's one of the greatest guitarists of all time, and now you can see Carlos Santana up close. Rock out to an evening of greatest hits live when Santana returns to the Las Vegas House of Blues.

Click here for tickets and more info...

The Eddie Griffin Experience

All Shook Up: A Tribute to the King

January 21 - 27

Elvis is definitely in the building — every night to be exact. If you love the King, you’ll love the only All-Elvis show on The Strip, featuring hits that made him the best-selling solo artist in the history of recorded music. 

Click here for more info...

Blue Man Group

January 21 - 27

Blue Man Group will rock your world. Blow your mind. And unleash your spirit. Leave your expectations at the door and let three bald and blue men take you on a spectacular journey bursting with music, laughter and surprises. Electrify your night at the specially designed state-of-the-art Blue Man Theater at Luxor Hotel and Casino. 35 million people of all ages, languages and cultures know what Blue Man Group is really about. Now it’s your turn.

Click here for tickets and more info...

Learn more about Alchemy-Spetec products, so you're fully informed when you visit us at World of Concrete!

Alchemy-Spetec has a reputation for the best technical support in the business. Our technical consultants have years of on-the-job experience and give the best guidance and training you'll find anywhere. No job is too challenging when you know we've got your back.

But what about getting those jobs in the first place? Did you know that we also offer marketing support? If you want assistance finding and reeling in the best, most profitable concrete repair jobs out there, give us a call. The Alchemy-Spetec Marketing Department is very proactive in assisting customers.

Some of the materials and services we offer include:

• Referrals to professional consultants on web design, search engine optimization, online advertising campaigns, etc.
• Illustrations depicting infrastructure repair processes.
• Photographs of jobs, products and/or equipment.
• Videos and/or animations depicting infrastructure repair processes.
• Customizable slab lifting graphic files for large format signs.
• Customizable marketing brochures.
• Guidance in creating sales presentations.
• Ongoing advice on any marketing issues that arise while you’re doing business with us.

These are just a few of many marketing offerings available to our customers. If you have any further questions in this area, please contact our Marketing Department for assistance at 404-618-0436.

Want more information on how to market your contracting business?

Part of managing a stormwater or sewer system involves vacuum, inspection and sealing. Municipalities that own these systems either do this work themselves or sub out a portion or all of the process. Here’s an overview of the process:

Assuming that the pipes have been vacuumed, your next step is to inspect them with a remote operated pipe crawler camera (as depicted in the bottom left side of the graphic below). You can use these types of cameras to thoroughly inspect the area.  In particular you’re looking for separated joints and cracks which exhibit water infiltration. The video is monitored from the street level. 

The images coming from the camera’s location in the pipe are compared with existing plans or blueprints for the sewer or stormwater system. When leaks are observed below, the point on the ground directly above is marked for insertion of a grout pipe. You continue this process until all the repair spots are marked on the  ground above.

After all the points are marked, your injection crew begins driving the grout pipe(s). Once the pipe(s) are in position, you inject AP Fill 700 or Spetec H100, while continuing to monitor via video. When the observed water infiltration is cut off, you stop the grouting process. Your choice of product, combined with your specific amount of catalyst or accelerator, depends on the exact conditions you are working with.

The end result is a sealed system where pipe joints and manhole structures are stabilized, sealed and protected from further infiltration. As always, you can rely on Alchemy-Spetec’s expert tech support for answers to any questions regarding this procedure.

Want more information on sealing leaks?

Even though we sell to contractors, we get a lot of calls from property owners or managers with slab issues after their internet searches lead them to our website. Part of my job consists of talking to them to determine if their situation merits forwarding to one of our contractors in their area. What follows are the most common questions I hear from property owners or managers interested in slab lifting, along with the most accurate answers. This is extremely valuable info for any polyurethane slab lifting contractor.

1. How strong is your slab lifting foam?

AP Lift Foam can support up to 14,000 lbs per sq ft. That's in a free rise foam. Underneath a slab it will be many times stronger than that.

2. Have these products been specified?

Yes. In the later 1990s various Departments of Transportation started testing high density foams underneath bridge approach slabs. These polymers have proven to hold up and are now used by just about every DOT In the United States to support highway loads.

3. How long will the installed foam last?

Polyurethanes are made from derivatives of oil and natural gas. Their lifespan is similar to that of plastics. They have high chemical resistivity and should last a hundred years.

4. What if you over lift?

The lifting is done in a very controlled manner, moving the slab millimeters at a time. A trained slab lifter is usually able to get within one eighth of an inch tolerance.

5. Can the foam lift a very thick slab or a slab with a piece of equipment on it?

Yes that is not a problem. If you run the math and apply PSI (pounds per square inch) over square feet you'll realize that it doesn't take very much pressure to lift something heavy.

6. Is the foam safe for the environment?

Our polyurethane foam does not shrink, degrade, or leach anything into the environment. We are one of only two companies that has an NSF certified (approved for contact with drinking water) structural lifting foam.

7. How is the foam used in a warehouse or industrial facility?

In industrial facilities or warehouses, polyurethane foam is used to stabilize rocking slabs, to lift sunken slabs, to fill voids beneath slabs both in and outside the building, and to fill massive voids that occur right behind loading dock walls.

Want more information on slab lifting? 

What Causes Leaks & Voids in Concrete Infrastructure?

Imperfect Construction

Concrete construction is by no means a perfect science. New construction often requires leak seal treatment follow up work. If the initial construction isn’t properly sealed at the time of construction, leaks are bound to appear sooner rather than later.

Weather and Wear

Concrete naturally decays over time. Exposure to extreme hot temperatures and extreme cold temperatures can take their toll over time. Even structures located in mild climates will begin to decay purely due to the aging process.

Unstable Soil

Unstable soil can undermine the integrity of concrete structures to cause cracks and voids to appear. Loose soil has four main causes: soil erosion, poor compaction, freeze/thaw cycles, and biological decay. If soil is the main culprit, additional stabilization and slab lifting treatments may be required in order to prevent further cracks from appearing.

How Does Injection Grout Help?

Water Activation

Leaking concrete structures can be permanently repaired with concrete crack injection by using a water activated flexible foam.

Pressure Injection

Pressure injection of these liquid polyurethane resins forces the material into leaking cracks, joints, voids and other defects.

Flexible, Watertight Seal

After the polyurethane crack injection is complete, the polyurethane resin rapidly reacts with water to form a flexible, watertight seal.

Want more information on infrastructure leak seal and void fill?

We're happy to announce that Alchemy-Spetec has been featured on SprayFoamInsider.com. This is a good match, since we get a lot of interest from spray foam professionals looking to expand their skill set into slab lifting and other forms of concrete repair. Editor Jay Davidson provides some background on the company and then embeds a nice collection of our slab lifting videos...

"Alchemy-Spetec, a merger between Alchemy Polymers and Resiplast US, is located in Tucker, Georgia. Their CEO Stephen Barton has been in the concrete repair business for over 30 years. In addition to slab lifting foam, they also offer leak seal resins, soil stabilization grouts and water stop products."

You can read more and view the slab lifting videos at this link on SprayFoamInsider.com.

Want more info on slab lifting with Alchemy-Spetec products?