SPRAYFOAM Professional - Spring 2016 - (Page 53)

SPEAKING SENSIBLY HOW TEMPERATURE AND PRESSURE AFFECT SPF QUALITY AND YIELD BY JUSTIN STROMBECK, LAPOLLA INC. Speakers from the highest attended seminars at the 2015 SPFA Convention & Expo share more insight related to the sprayfoam industry in this series, Speaking Sensibly. This article is based on a portion of Justin Strombeck's breakout session at Sprayfoam 2015. A s a field tech for Lapolla, temperatures and pressures are the single most common thing that contractors have set wrong when I do a site visit. No matter what the problem, the first question I ask is, "What are your temps set at?" "What are your pressures?" Experienced contractors that have been around forever take this knowledge for granted and new contractors learn from the school of hard knocks. The most common questions I get from new contractors are: "Why does the foam not stick to the wall when it's cold out?" "Why is the skin of the foam so rough?" "How do I cut down on overspray?" "How do I increase my yield?" The answer to all of these questions is setting the correct temperatures and pressures. In this article I will describe how to get the most out of your foam as well as some common misconceptions that will make you a better contractor. When is the best time to flash the wall with a ½ to 1 inch of foam? When there is a rough or cold surface you should try to put a flash pass of before you spray the full thickness of the spec. The answer lies in the chemistry of how the foam works. As you spray the foam thicker it gets hotter. When the foam gets too hot, and it is cold outside, you can get "thermal shock." When this happens the foam can blister or pop off the substrate. In this scenario a flash pass can be very effective by reducing the maximum temperature of the foam and subsequently the surface will be warmer for the next pass of foam, which promotes adhesion and will increase yields in cold weather. Learning to read the pressure gauges is the most important thing a contractor can to do. Understanding that the gauges are a function of viscosity NOT ratio can be confusing for new contractors. The line pressure gauges are the machine's way of telling you the difference of thicknesses between the ISO and resin barrels. If the "B" gauge is constantly running a couple hundred pounds higher than the other, that is OK in most scenarios. It just means the resin side is thicker than the ISO side. Never open one of the pressure relief valves to "even out the pressures." Keep in mind that the gauges are the symptom of a problem. Often the pressure gauges are inaccurate but can be easily checked for accuracy with most equipment. I have seen many instances in the field where a customer didn't like that his gauges were pumping 500psi apart and after checking the gauges for accuracy they were actually only 100psi apart. Don't "set it and forget it." There are so many variables on a jobsite that change day to day that using the same temperature and pressure setting everyday does not usually give you the best performing foam. To maximize your appearance, yield and production - some of the key items of application - it is best to adjust the machine temperatures and pressures every day. It doesn't have to be much at a time; I usually recommend 3 degrees at a time. Spraying flatter foam will get you will get less scrutiny from building inspectors and home owners and general contractors. If the foam is rough and inconsistent, everyone will check every little spot. But if it is smooth, they will check a few spots and see that it is all the same and leave it alone. "How do I maximize my yield?" is one of the most common questions that I get on a daily basis. Yet again, there are multiple answers to this question. The most effective technique is spraying the thickest passes you can per the manufacturer's recommendation. Density and yield are directly related, so a ½ inch pass of foam where the core temperature gets up to 181 degrees will have a higher density than a 3 inch pass of foam where the core temperature gets up to 330 degrees. I have seen that on a cold day, foam sprayed to metal substrate in a ½ inch pass the foam, can have a density as high as 2.8, and the 3 inch pass in the same scenario was 2.01. Hose temperature can affect your yield, too. A hose temperature that is too low can cause a higher density than normal. Cold foam will also be runny and can cause the line pressure gauges to stay www.sprayfoam.org | SPRAYFOAM PROFESSIONAL 53 http://www.sprayfoam.org

Table of Contents for the Digital Edition of SPRAYFOAM Professional - Spring 2016

EXECUTIVE DIRECTOR’S CORNER
PRESIDENT’S POST
FOAM BUSINESS NEWS
SPFA TODAY
LEGISLATIVE UPDATE
KEYNOTE SPEAKER – RICHARD R. RAWLINGS
OSHA STANDARD FOR CONFINED SPACES:
SUSTAINABLE CONSTRUCTION: TRANSPARENCY AND CHOICE
INDUSTRY’S CHALLENGES SHAPE OUR EVOLUTION
SPF RESEARCH ON AIR QUALITY – PART 2
NEW CONSTRUCTION NEEDS OPEN DOORS FOR SPF INDUSTRY
TOP TRUCKS FOR SPF CONTRACTORS
BEHIND THE FOAM
2015 SPFA CONTRACTOR AWARDS
SPEAKING SENSIBLY
ABAA NEWS
ASK THE EXPERT – How to Write Clear Contracts
UPCOMING EVENTS
INDEX OF ADVERTISERS | ADVERTISERS.COM

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