Document rp113Rp0gK712pNL57bLNK29E

SI. IB MARSHALL IJBB1M ` itroexEtfV*** In&o&ed M, P. Fisher, WlXn, 9-8G20' T, J, Mitchell, Chicago (?) T, McCreary, Cleveland (3) J, B. Pickens, Flint W. h. Lawson, Chicago H. M. Lean, Jr. Mai St. (3) H. J. Stuart, Lab. S. L, Godshftlk, Lab. B, A. Moorehsad, Lab, Piles Marshall laboratory .September 3.7, 1952 MSMagAHPPa REPORT #M-501 Introductions THE SPRAt-COH COMPAK? PRIMER "FLOCOTIian TEST'S FOE V-; t-i--- cv . >-* m momma This report covers tests in the flooote paint applicator at the Chicago Plant of the Spray-Con Company. The purpose of these tests was to determine if the primers which we had developed - would be satisfactory for the Troy Sunshade Company in the nm SprayCon paint applicator being installed in connection with their new Finishing Department. The flocoting paint applicator used was a regular pro duction slated unit equipped with a conveyor and baking oven. It was installed a year or two ago by the Spray-Con people in their new plant for conducting tests by themselves and by paint companies to determines (l) the feasibility of flocoting the war of prospec tive customers and (Z) for paint companies to test and experiment with flocoting materials. The Troy Sunshade Company is primarily interested in a flocoting primer to be used on metal lawn furniture. For this pur pose we had developed a gray analogue for tlocoting of 828-01iCcoded P-828-M-24314) and a gray analogue of P-764-IT-24228 white urdercoater originally developed for the Barcalo Manufacturing Company for flocote application coded P-764-U-24308, Since Troy Sunshade Company had not determined on whether they wished a white or a gray color for their primer P-764-11-2422:8 white ms also tested.. Both P-7&4-IJ-24228 whits, and P-764-M-24308 gray, are underco&ters with a very low gloss for good enamel adhesion developed merely to act as a first coater to get good enamel hiding. They were not developed to give any parti cular degree of rust protection. We learned however, that Troy was planning to consider flocoting windshield frames for trades and metal awning sections where good .durability would fee required no the testing of 828-Line with its good moisture and rust insistence was .considered of particular interest. N35455 sonmunr sm coacggstoass * Test Results* Troy had shipped to Chiago for test practically all of the various sizes and shapes which they planned to flocote. These parts included an odd shaped .chair-batik fabricated from cold rolled steel, tubular and hot rolled heavy metal chair-sides, .glider springs, a lattice type seat and chair-back assembly, a complicated round shaped seat and chair-back assembly, and a large round table top. Also two tyres of truck windshield frames and a metal awning section were to be flocotecl. These were the first set of parts which had actually been floeoted in a Spray-Con unit and Mr. Deisenroth, Engineer in charge of this new finishing equipment was more than pleased with the excellent results which were obtained on all three primers. The best results mare obtained with the two .gray colors, as would be expected because of better hiding but from a purely flocoting stand point the white gave satisfactory results. Based on the fact that an all-purpose primer, may be required, as outlined above, Mr. Beisenroth .favors the 828-Line gr&y but perhaps may want a slightly lighter shade. The 8g8-B-243ih being slightly higher in gloss than the 764 Line primers gave .a smoothes?1 finish but it showed some silking and flooding. Since this Is a prime coat this is not considered objectionable... Beisenroth seemed impressed by the fact that these "one-Shot" teststurned out so well because it shewed that both the materials and the process were quite foolproof and practical. Because of the limited number of articles to work with, the beat hanging procedures, etc., could not be worked out,but JO?. Beisenroth was satisfied that the results would be okay on their proposed pro duction set-up. The Troy Sunshade people apparently realize that there will be some pocketed areas, drips tel areas where two pieces come together .and give a "blow-out" of material when baked, and they are providing an area after flocoting, and lust before baking, to evacuate and remove excess paint where required. it is the writer's, .opinion that the appearance obtained .on the flocoted work in this Spray-Con applicator is equal to or batter than could be obtained by either hand or slow withdrawal dipping. The secret seams to be in the use of a solvent laden area immediately following the actual floeotlng operation at which point bubbles have time to break-and the finish to uniform or level itself out. (See description of applicator).. The Troy installation will have ..a six minute period in the solvent laden area followed by 6 minutes in a zone with controlled ventilation, and finally a 3 minute period In a hot seme (15QP) . All three primers were reduced approximately 30 to 35$ with T-8844 thinner (Solvesso #150) to a floeotlng viscosity of 19 to 24 seconds ..at yosP, in a ftafan #2 cup. Description of faint Applicator 'The Spray-Con paint applicator is basically a floeotlng operation. Instead of a great number of stationary nozzles flooding the .paint on to the article,it employs a 'rotating arm with a nozzle * DUP030003422 at each end. A typical installation would consist of, first a ventilated splash area at tM entrance end of the unit. Next is the flocoting operation proper which consists of 3 .rotating arms - on is placed at the bottom with nozzles pointing, upwards and one on each side. At the top are placed three or four stationary, or flooding nozzles. She arms are rotated at 0-100 epm end are hollow allowing the paint to he fed through to the nozzles at each end. Faint is pumped at 10 to 20 pounds pressure. Pressures are shown on guages and may he regulated, These rota ting arms .are very efficient in coating relatively inexcesBible areas. The unit has a heat exchanger so that'flocoting temperatures of the paint may he properly controlled. Faint is pumped from a paint supply tank holding up to 200 gallons,thru the nozzles, and excess paint flows back' thru pipe lines to the same tank. Provi sion is also made to merely circulate the paint within the supply tank so as to keep it from settling. Adjacent to the paint tank is a thinner tank of like capacity, so piped that thinner an he fed into the paint, tank for normal reducing., and also so that it 'may he hied slowly into the tank while flocoter ia in operation to replace evaporated solvent. Provision is also made for the thinner to be pumped, through the nozzles in the flocottr proper to flush down the whole system titan the unit is being shut down, The flocoting zone is 'not ventilated. Silhouettes are placed between the splash zone, flocoting zone, the solvent laden area, and the controlled ventilation areas. She solvent laden area which follows the flocoting operation is equipped`with ventilation .for purging' as desired,hut normally this area is kept laden with solvent .fumes to help level out the finish and to accelerate the breaking up of bubbles. The control ventilation area is an area .equipped with recirculation and exhaust ducts similar to an oven ventilating and circulating system, except that fumes are withdrawn for reoireula*. tion.or exhausting from the bottom of the zone.. Length of time in the solventladen, area and the controlled ventilation area is depen dent upon individual requirements and is usually determined by experimentation. It usually varies from .6 to 12 -minutes. Conveyor speeds of up to 20 feet per minute can be used. Our tests were conducted at 15 feet per minute. The Spray-Con, Company has had some trouble in getting fire underwrite* approvals because of the heavy concentrations of solvent fumes in the .unit* It. is argued, however, that these areas are way .above the explosion level and are no more hazardous then would be a ventilated area which was around the explosive'level or under. The Ohio Fire CMrwrtte3?s- have approved the, .Troy install lation based on this contention but are to run some explosive level tests. Based on what we ware able to learn from this demonstra tion and from discussions with Spray-Con personnel the following are some of the advantages of this type of paint applicators DUP030003423 1* A relatively small amount of 'material can Is employed to coat relatively large objects where a dip tank would foe much too large'to"be practical. .2. The Spr@y-Co fiocoting application mill satisfactorily coat recessed areas that might pocket under normal dipping operations and he very difficult to hand spray. 3. .The same high coating efficiency is obtained as.for dipping. .4. The unit has lower power cost for operation than a spray-"booths and, of course, labor costs would be much lower. Some of the 'disadvantages ares 1. Because of initial cost, size of the unit, the necessity for continuous oonveyorlsinfe, , this type of paint application is best adapted to large and eontlupous finishing operations only. B Considerable floor area and head room is required since the overall height must he too to three times the height of the actual article to foe coated. 3 Conveyor shut-downs for lunch periods etc.jWiXX give extra time in the solvent laden area whlph may in some cases give an unsatisfactory coating due to solvent washing, etc. An unsatisfactory appearance and too thin a film may result. This mesas therefore that the unit is not too flexible, and will not allow momentary shut-downs, and shut-down for lunch or rest periods, unless the conveyor is cleared through the applicator. , 4, As Is true with all flocating operations there is a large amount of solvent' lo.se due to evaporation, . 5. There is believed to foe more of a fire hazard with this type of unit than is usually -present with dipping or spraying installs* tions, and at present the Spray-Con applicator does not .have 100$ .underwriter approval. Cf@ne.ral Comments The Spray-Con personnel wore very cooperative and seemed anxious for us to utilise this' unit for as much experimentation as we wished. They have a feeling that we have not done as much work.on their application method as we should or as much work as other paint people, notably (Hidden and luM&n. it was stated that Olldden .and Hufolan have spent as raue_h as $20,000. on experimentation in this unit in their formulating work and for customer test:. It mas obvious that someone has been orperimenting with one coat white enamels and the Sprey-Con people stated that one or two paint companies were getting very close to a satisfactory one coat fiocotiiig white enamel for use in this type of paint applicator. It is the writer1 s opinion .as stated above that this DUP030003424 4 < j *5paintlng process is entirely practical for many uses particularly for priming ,snd where large coating operations are involved ,t is bound to have extended acceptance,. This unit has one drawback for experimental uses in that around 45 gallons of reduced material is required to run a test, it has been stated, however, and we are forced to agree, that no small laboratory unit can give the final answer as to whether the material will work satisfactorily for J&ray-Con application, As a matter-of-fact it is claimed the .15 to 20$ better work can be obtained in an actual production unit ,wifeh conveyor chain loaded and the solvent laden area .functioning. properly*tbe can be obtained in an experimental unit with only a 'few pieces being coated. AOTIOH BB50H ED: It is recommended that industrial Sales give consideration to the following? 1. Development of a one coat floeotimg white enamel. 2,, Determine the flocotlng -properties of our standard refrigerator primers, 3, Investigate the feasibility of flocotlng colored enamel, At the present time silicone containing products bubble badly but with some new types of silicone and other anti-flooding agents it la- possible that something might be developed, fills type of enamel- would be of great value for flocating lam and porch furni ture and other industrial uses. MIG s EMM 9-17-53 9-16-52 DUP030003425