Alchatek Blog

It’s the end of the year and soon there will be all kinds of awards being given out for the best this and most valuable that, etc etc.   In that spirit I want to nominate AP Lift 430 as Product of the Year for the polyurethane industry.

Now some of you may think that’s kind of a bold move; but it’s also my blog post and I didn’t hear any other nominations.  Let me make the case:

Why a 3 Pound Density Foam?

We didn’t randomly make a decision to manufacture a 3 lb density slab lifting foam.  This was a calculated decision based on what we were hearing from contractors in the field and what we were able to do in the lab. 

Early in the history of Alchemy Polymers (one of the predecessors to Alchemy-Spetec), we manufactured only heavier density lifting foams to go along with our lines of leak sealing and soil stabilization resins.  The reason being that our focus was on the commercial, industrial, and transportation segments of the market. 

More Lifting Power Than Higher Density Foams

As we became more aware of the potential in the residential market, we decided to make a superior lifting foam for that sector as well.  Feedback from contractors using 2 lb and 2.5 lb density lifting foams seemed to indicate that they experienced too many callbacks - lifting jobs that resettled.  We also found out that some contractors were using foams that were not designed to work in wet conditions.  If they wanted something to work when it was wet; they had to pay a premium.   

Contractors were also told that these lighter density foams would increase in density as they pumped more under the slab, and that is true.  But it also means having to put a lot more material under the slab to ultimately get it to a density strong enough for the job.

From this information we developed AP Lift 430.  Working with our chemist, we were able to create a 3 lb density foam that had higher lifting pressures than even our 4.75 lb workhorse, AP Lift 475.  Clearly, this is not a product for snowflakes or wimps.

We also designed it to meet DOT specifications: Hydrophobic (displaces water and works in wet environments), 90% Strength in 15 Minutes, traffic ready in 45 minutes, and NO shrinkage.  One other thing… we don’t cut corners or put recycled materials in products to save cost.  Our green statement is that you only have to do the job once. 

NSF / ANSI 61 Approved for Contact with Drinking Water

In 2017, AP Lift 430 really shined for us.  Easily our number one product for residential slab lifting, its combination of excellent expansion rate for filling voids and high lifting power has made it the go to product for contractors.  Once you try it; you won’t go back.  It literally gets more done with less material required. 

And now...AP Lift 430 is officially NSF / ANSI 61 approved.  This means it is approved for contact with drinking water and that it is also the SAFEST slab lifting polyurethane to have installed around your family and pets.  Ask your current supplier if their product is NSF approved and I think you’ll find that it’s not.

Tired of callbacks? Tired of foams that shrink and fail in wet environments? Tired of foams made by insulation experts rather than geotechnical experts?  Make the move to something safer and more powerful - AP Lift 430 and the rest of our Lift series foams.

Want more information on Alchemy-Spetec slab lifting products?

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?

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? 

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?

A warehouse is only as good as the foundation it’s built on. And regardless of how well-constructed your warehouse may be, most foundations settle. That’s just a fact of life. Shifting soil, compaction, and many other environmental conditions tend to cause settling. Sometimes warehouse floors settle gradually, and in other cases they may just suddenly cave-in. These situations obviously create problems for property owners, and opportunities for the contractors who know how to fix them.

Alchemy-Spetec manufactures the AP Lift 430, 440 and 475 polyurethane lifting foams for slab jacking and structure lifting. Among the most dependable products for jacking and leveling concrete slabs, these two-component, high-strength, hydro-insensitive structural foams serve as an extremely effective solution for contractors.

Want more info on warehouse and industrial slab repair?

It was about 2 AM when the fire alarm when off in my hotel room.  I have never heard an alarm so loud in my life; all I wanted to do was get out of the room but it was so disorienting that I could barely throw some pants and a shirt on.  My instincts told me this was a false alarm as I trudged down 5 flights of stairs to the bottom level.  I was behind an elderly couple so it was slow going as we navigated our way out.

This particular stairwell brought us out on the side of the building and I noticed it was dimly lit.  This was a nice ocean front resort hotel and the lighting in my opinion should have been brighter.  About the time I noticed that, the elderly lady in front of me tripped and fell right on her face on the sidewalk.  She was about 5 yards in front of me and I was first to her side; she had fallen behind her family.  Fortunately a quick responding fire department rolled up right then and I ran over to get their help.  They got her up and into the paramedic truck. 

It looked like the lady was going to be okay but the point is that this was probably avoidable.  When I ran to her side I could see the sidewalk tripping hazard that had caused her to fall.  Combined with the dim lighting it was a case of dual premises liability.  I give talks to groups like IFMA and BOMA just on the topic of Tripping Hazards and Premises Liability.  The numbers are staggering when you look at the amount of incidents and the costs associated with them.  The toll is financial: lawsuits, settlements, workers comp, bad press.  And the toll is physical: injury and sometimes death.  This is the cost of not knowing that you may have tripping hazards on your property; or worse it is the case of knowing and not doing anything about it.  Those factors weigh heavily in court.

Want more information on slab lifting?

The bane of slab lifting equipment is the iso.  It turns your hands black if you get it on them and it is the main culprit that causes pressure imbalances.  For some reason, in the past few years the problem has gotten worse.  I suspect is has something to do with changes in the chemistry of the raw materials.

Contractors who use their rig on a daily basis have less of a problem.  If your rig sits for any length of time, the iso (A side material) can start to setup in the hose.   We see this most often at the end of the whip hose right next to the gun.  The solution is simple, but you have to be vigilant.  Make sure you have greased up the threads on the A side drum, change your desiccant drum cartridge when the desiccant changes color, and follow the instructions below to recirculate the A side material every 10 days that your rig sits unused.

Step 1:

In the movie "Heartbreak Ridge", Clint Eastwood says his Marines are taught to "Improvise, Adapt, and Overcome".  You gotta love the United States Marines and of course, Clint Eastwood.  So if they don't mind, we are going to borrow that phrase because that's what we had to do when we came up against a tough slab lifting job this past weekend.  

 

A site evaluation told us that this was going to be no ordinary slab lift.  In some areas there were voids over a foot deep beneath the slab!  From the outside, it was easy to see where the CMU (concrete masonry unit a.k.a. concrete block) wall was buckling outwards.   Slab lifting with polyurethane exerts lateral forces too so I was worried about pushing the wall out further (which in turn would cause a collapse of the garage slab, wall, and everything else attached). 

 

This might have been a job to walk away from, but I thought there might be a way to do it.  First we installed bracing on the exterior of the CMU block wall to offer some support against the lateral forces likely to be exerted.  Once that was completed we began injecting in a grid with AP Lift 430, starting at the lowest point and working our way out from there.  

 

 

I won't lie, this job was taking a lot of material because of the voids and the amount of lift required.  There was a lot of creaking and grinding going on as the slab was raising.  At one point we stopped and I decided to try something to give the wall more strength.  Inside the garage there was a cap block that ran along the top of the CMUs.  Drilling through the cap block, I was able to inject and fill the CMU wall cavities with the AP Lift 430, thereby tying those courses of block together with a polymer column. 

 

 

So next time you see a tough looking slab lift, ask yourself if you're going to just walk away or whether you're going to step up to the plate.  Make Clint proud!

Want more information on slab lifting?

People buy the MixMaster Pro because they want the most dependable, high production slab lifting gun on the market. Sometimes they can't wait for hands on training and we have to go ahead and ship a gun to a customer we haven't been able to train face to face. To help get you up to speed on the MixMaster Pro, we captured some footage at recent job where I'm using the MixMaster Pro and discussing best practices.

Want more informaton on the MixMaster Pro?