Ponderosa Protective Coatings™
Surface Preparation
Why Prepare The Surface?
Correct surface preparation is critical to the longevity of any coating system. The life of a protective coating depends
largely upon the degree of surface cleanliness prior to application. Most coating failures can be attributed to inadHTXDWHRULQFRPSOHWHVXUIDFHSUHSDUDWLRQ7KHUHDUHQRFRDWLQJVDYDLODEOHWRGD\ZKLFKZLOOSURYLGHORQJWHUPSURWHFWLRQLQDJJUHVVLYHHQYLURQPHQWVZKHQDSSOLHGRYHUPLOOVFDOHDFWLYHUHGUXVWJUHDVHVRLOVPRLVWXUHPLOGHZPROG
dirt, chalky surfaces, unsound coatings or other forms of surface contamination.
3URWHFWLYHFRDWLQJVDGKHUHE\WKHPHDQVRIWZRPHFKDQLVPV7KH¿UVWLVDGKHVLRQZKLFKFDQEHGH¿QHGDVD
PROHFXODUDWWUDFWLRQRIWKHLQWHUIDFLDOIRUFHVRIERWKWKHFRDWLQJDQGWKHVXEVWUDWH7KHVHFRQGLVERQGLQJZKLFKLVD
mechanical attachment or anchoring of the coating to the substrate. To insure integrity of the coating/substrate interface, both adhesion and bonding must occur. This means that surface cleanliness, and therefore, surface preparation
LVHVVHQWLDO7KHW\SHDQGH[WHQWRIVXUIDFHSUHSDUDWLRQUHTXLUHGZLOOYDU\ZLWKWKHQDWXUHRIWKHVXUIDFHLWVFRQGLWLRQ
the coatings to be used and the type of exposure.
Cost of Surface Preparation
7KHPDMRUFRVWRIDQ\LQGXVWULDOSDLQWLQJMRELVUHÀHFWHGQRWLQWKHSULFHRIWKHFRDWLQJPDWHULDOLWVHOIEXWUDWKHULQWKH
cost of surface preparation materials, labor and the cost of application of the coating system.
Page 1
Ponderosa Protective Coatings™
Surface Preparation
In order to arrive at a meaningful measure of coating value the total cost of the job must be divided by the expected
years of service. This results in a reliable per year cost of protection. For all coating systems there is a certain minimum degree of surface preparation required to insure that premature coating failure does not occur. The degree of
surface preparation or surface cleanliness necessary is dependent upon several factors.
•
Environment, to which the substrate is exposed- if the environment is chemically aggressive, continuously immersed or extremely hot, then a high degree of
VXUIDFHFOHDQOLQHVVLVHVVHQWLDO,IKRZHYHUWKHHQYLURQPHQWLVQRWDJJUHVVLYH
then surface preparation requirements may be minimal.
•
Types of generic coating being used- coatings such as vinyls are intolerant of
VXUIDFHFRQWDPLQDWLRQDQGUHO\KHDYLO\RQWKHGHJUHHRISUR¿OHIRUPHFKDQLFDO
ERQG7KH\DUHQRWRULRXVO\SRRUVXUIDFHZHWWHUVDQGWKHUHIRUHGRQRWH[KLELW
good adhesion, or molecular bonding characteristics.
•
Expected service life- the life of a protective coatings system depends largely
upon the degree of surface cleanliness. An alkyd coating requires only hand or
SRZHUWRROFOHDQLQJDVPLQLPXPVXUIDFHSUHSDUDWLRQ,ILQVWHDGFRPPHUFLDO
grade abrasive blasting is used to prepare the surface, the effective service life
of the same alkyd system can almost be doubled. The cost of commercial grade
EODVWLQJLVDSSUR[LPDWHO\GRXEOHWKDWRIKDQGRUSRZHUWRROFOHDQLQJEXWWKLVGLIIHUHQFHLVTXLFNO\UHFRXSHGWKH¿UVWWLPHWKHKDQGRUSRZHUWRROFOHDQHGVXUIDFH
has to be repainted.
7KHUHODWLRQVKLSEHWZHHQFRVWVLQFXUUHGE\YDU\LQJWKHGHJUHHRIVXUIDFHSUHSDUDWLRQDQGWKHFRUUHVSRQGLQJH[SHFWHG
VHUYLFHOLIHRIWKHFRDWLQJV\VWHPLVFRQWUDVWHGLQWKHFKDUWEHORZ
It cannot be over emphasized that even the best protective coating is likely to perform poorly or even fail if applied
over improperly prepared surfaces.
Page 2
Ponderosa Protective Coatings™
Surface Preparation
Surface Preparation Methods
6XUIDFHSUHSDUDWLRQPHWKRGVKDYHEHHQZHOOGH¿QHGE\RUJDQL]DWLRQVVXFKDVWKH1DWLRQDO$VVRFLDWLRQ2I&RUURsion Engineers (NACE), the Steel Structures Painting Council (SSPC), the American Society Of Testing And Material
$670DQGWKH$PHULFDQ:DWHU:RUNV$VVRFLDWLRQ$::$7KHVXUIDFHSUHSDUDWLRQVWDQGDUGVOLVWHGEHORZDUH
FRQGHQVHGIURPWKH663&DQG1$&(WH[WV)RUFRPSOHWHGH¿QLWLRQVSOHDVHUHIHUWRHLWKHURIWKHDERYHUHIHUHQFHV
7KHIROORZLQJLVDEULHIH[SODQDWLRQRIVXUIDFHSUHSDUDWLRQPHWKRGV
&KHPLFDO&OHDQLQJ663&63Removal of all detrimental foreign matter such as oil, grease, dirt, soil, salts,
GUDZLQJDQGFXWWLQJFRPSRXQGVDQGRWKHUFRQWDPLQDQWVIURPVWHHOVXUIDFHVE\WKHXVHRIVROYHQWVHPXOVLRQVDWWDFN
compounds, steam or other similar materials and methods that involve a solvent or cleaning action.
6ROYHQWFOHDQLQJDORQHLVRQHRIWKHPRVWZLGHO\DEXVHGPHWKRGVRIVXUIDFHSUHSDUDWLRQ,QRUGHUWRSURSHUO\FOHDQD
surface of grease or oil, for example, the solvents and rags used for such cleaning must be continuously replenished
ZLWKFOHDQRQHVLQRUGHUWRLQVXUHWKDWWKHRIIHQGLQJFRQWDPLQDQWVDUHQRWMXVWXQLIRUPO\UHGHSRVLWHGRYHUWKHHQWLUH
VXUIDFH0RUHHI¿FLHQWPHWKRGVVXFKDVVWHDPFOHDQLQJYDSRUGHJUHDVLQJRUFOHDQLQJZLWKDFRPPHUFLDOGHWHUJHQW
IROORZHGE\ULQVLQJVKRXOGEHHPSOR\HGLIWKHFRDWLQJV\VWHPLVQRWWROHUDQWRIJUHDVHDQGRLOFRQWDPLQDWLRQ
Prior to abrasive cleaning of steel substrates, it is imperative to chemical clean for removal of grease and oil. A
misconception exists that abrasive cleaning removes grease and oil. In reality chemical cleaning is required and
VKRXOGDOZD\VSUHFHGHWKHUHPRYDORIPLOOVFDOHORRVHUXVWRUUXVWVFDOHE\PHFKDQLFDOPHDQV,IQRWWKHPHFKDQLcal method chosen may spread the contamination and imbed it in the surface making subsequent removal even more
GLI¿FXOW7KHIROORZLQJDUHVRPHW\SHVRIFKHPLFDOFOHDQLQJSUHSDUDWLRQ
•
Steam Cleaning – This method effectively removes heavy deposits of dirt and
grime due to a combination of high velocity, high temperature steam. The addiWLRQRIFDXVWLFGHWHUJHQWVRUFOHDQVHUVLQWRWKHZDWHUZLOOUHDGLO\UHPRYHJUHDVHV
DQGRLOVE\HPXOVL¿FDWLRQVXVSHQVLRQRIRLOLQZDWHURUVDSRQL¿FDWLRQFRQYHUVLRQRIRLOWRDZDWHUVROXEOHPDWHULDO
•
Alkaline and Detergent Cleaning- this method uses an alkaline material disVROYHGLQZDWHUSUHIHUDEO\KRWZKLFKVDSRQL¿HVDQGRUHPXOVL¿HVRLO\FRQWDPLQDQWVVRWKDWWKH\PD\EHHDVLO\ULQVHGDZD\'HWHUJHQWFOHDQLQJLVDOVRHIIHFWLYHLQUHPRYLQJGLUWDFLGUHVLGXHVVDOWVDQGRWKHUZDWHUVROXEOHFRQWDPLQDQWV
7KHXVHRIDONDOLQHFOHDQHUVLQFRQMXQFWLRQZLWKVWHDPFOHDQLQJRUKLJKSUHVVXUH
ZDVKLQJZLOOJUHDWO\LPSURYHWKHLUHIIHFWLYHQHVV$VXJJHVWHGIRUPXODIRUDJHQHUDOSXUSRVHLQGXVWULDODONDOLQHFOHDQHUIROORZV
Tri sodium phosphate
Detergent
Hot Water
½ - 1 pound
2-4 ounces
1 gallon
,IKRWZDWHULVQRWDYDLODEOHLQFUHDVHWKHFRQFHQWUDWLRQRIWKHFKHPLFDOV
Page 3
Ponderosa Protective Coatings™
Surface Preparation
)RUPROG\RUPLOGHZHGVXUIDFHVDGGDSSUR[LPDWHO\RQHTXDUWRIKRXVHKROGFKORrine bleach (hypochlorite type) to this solution.
$SSO\WKLVDONDOLQHFOHDQHUJHQHURXVO\DQGVFUXEWKRURXJKO\ZLWKUDJVRUEUXVKHV
$OORZWKHFOHDQHUWRUHPDLQRQWKHVXUIDFHIRUDVKRUWZKLOHEHIRUHFRPSOHWHO\
DQGWKRURXJKO\ULQVLQJZLWKIUHVKZDWHUWRUHPRYHVDSRQL¿HGRLOFRQWDPLQDQWV
and residual detergent. If this rinsing is not performed adequately, an alkaline
UHVLGXHPD\UHPDLQRQWKHVXUIDFHDWWDFNLQJWKHQHZFRDWLQJDQGUHVXOWLQJLQD
ORVVRIDGKHVLRQ$OORZVXUIDFHVWRGU\FRPSOHWHO\EHIRUHFRDWLQJ
:KHQSHUIRUPLQJFKHPLFDOFOHDQLQJJRJJOHVDQGUXEEHUJORYHVVKRXOGEHZRUQ
$YRLGWKHSURORQJHGFRQWDFWRIWKHVHVROXWLRQVZLWKDOXPLQXPDVVWURQJDONDOLQHVZLOODWWDFNWKLVPHWDO
•
Emulsion Cleaning – Commercial emulsion cleaners, based on volatile organic
VROYHQWVLQFRPELQDWLRQZLWKHPXOVLI\LQJDJHQWVRUGHWHUJHQWVDUHJHQHUDOO\VROG
DVFRQFHQWUDWHV7KH\VKRXOGEHGLOXWHGZLWKPLQHUDOVSLULWVNHURVHQHRUZDWHU
according to manufacturers’ instructions.
$SSO\HPXOVLRQFOHDQLQJVROXWLRQVWRWKHVXUIDFHDQGVFUXEWKRURXJKO\$OORZ
cleaners to remain on the surface for about a minute before rinsing. An oil containing emulsion residue often remains on the surface after cleaning. Remove it
ZLWKVWHDPKRWZDWHUGHWHUJHQWVVROYHQWVRUDONDOLQHFOHDQLQJFRPSRXQGV
7DNHDSSURSULDWH¿UHSUHFDXWLRQVDQGSURYLGHDGHTXDWHYHQWLODWLRQIRUZRUNHUV
*RJJOHVUXEEHUJORYHVDQGSURWHFWLYHFORWKLQJVKRXOGEHZRUQZKHQHPXOVLRQ
cleaning.
•
Volatile Solvent Cleaning –7KLVLVSUREDEO\WKHPRVWZLGHO\XVHGEXWOHDVW
HI¿FLHQWGHJUHDVLQJPHWKRGLQLQGXVWULDOPDLQWHQDQFH2UJDQLFVROYHQWVDUHDSSOLHGWRWKHVXUIDFHVZLWKUDJVVSRQJHVRUEUXVKHVDQGVFUXEEHG7REHHIIHFWLYHVHYHUDOVXFFHVVLYHZLSLQJVDUHQHFHVVDU\XVLQJFOHDQFORWKVDQGVROYHQWV
each time. This method is based on the principle that the offending contaminant
LVGLVVROYHGLQWKHVROYHQWDQGWKHQZLSHGDZD\8QIRUWXQDWHO\VRLOHGVROYHQW
DQGZLSLQJUDJVIUHTXHQWO\UHGHSRVLWJUHDVHDQGRLODVWKHVROYHQWHYDSRUDWHV
6HYHUDOVXFFHVVLYHZLSLQJVZLWKFOHDQVROYHQWVDQGUDJVDVLQGLFDWHGDERYHZLOO
minimize this problem.
$ZLGHUDQJHRIRUJDQLFVROYHQWVFDQEHXVHGZLWKWKLVPHWKRG6ROYHQWFKRLFH
is generally based on the degree of solvency required to do the job. At the same
WLPHFRQVLGHUDWLRQRIÀDPPDELOLW\HYDSRUDWLRQUDWHWR[LFLW\DQGFRVWLVLPSRUWDQW
Mineral spirits or Stoddard solvent probably represents the best overall choice for
PRVWVROYHQWZLSLQJRSHUDWLRQV;\ORORUPDQ\SURSULHWDU\VROYHQWVPD\DOVREH
Page 4
Ponderosa Protective Coatings™
Surface Preparation
employed. Products such as benzene, gasoline, VM and P Naphtha and chloriQDWHGVROYHQWVVKRXOGEHDYRLGHGHLWKHUEHFDXVHRIWKHLUÀDPPDELOLW\RUWR[LFLW\
6ROYHQWVXVHGLQGHJUHDVLQJDUHXVXDOO\ÀDPPDEOH2SHQÀDPHVVSDUNV
ZHOGLQJRUVPRNLQJVKRXOGQRWEHDOORZHGLQVROYHQWFOHDQLQJDUHDV$GHTXDWH
YHQWLODWLRQVKRXOGEHSURYLGHGWRUHSODFHVROYHQWYDSRUVZLWKIUHVKDLU2SHUDWRUV
VKRXOGZHDUJRJJOHVDQGUXEEHUJORYHV
Vapor degreasing is an example of a very effective solvent cleaning method. Its
use, unfortunately, is generally limited to production setups cleaning parts small
HQRXJKWR¿WLQWRWKHGHJUHDVLQJDSSDUDWXV
+DQG7RRO&OHDQLQJ663&63± Removal of all rust scale, mill scale, loose rust and loose paint to the degree
VSHFL¿HGE\KDQGZLUHEUXVKLQJKDQGVDQGLQJKDQGVFUDSLQJKDQGFKLSSLQJRURWKHUKDQGLPSDFWWRROVRUE\DFRPbination of these methods. The substrate should have a faint metallic sheen and also be free of oil, grease, dust, soil,
VDOWVDQGRWKHUFRQWDPLQDQWV+DQGWRROFOHDQLQJKRZHYHUVDWLVIDFWRU\IRUVPDOODUHDVLVGHHPHGLPSUDFWLFDOZKHQ
ODUJHUVXUIDFHDUHDVPXVWEHFOHDQHGRUZKHQVXUIDFHVDUHKHDYLO\UXVWHGRUFRQWDPLQDWHG8QGHUWKHVHFRQGLWLRQV
SRZHUWRROVRUDEUDVLYHEODVWLQJDUHIDVWHUDQGPRUHHFRQRPLFDO
Prior to hand cleaning remove grease, oil and similar contaminants from the surface by proper solvent cleaning,
VWHDPFOHDQLQJRUE\ZDVKLQJZLWKDVROXWLRQRIDONDOLQHFOHDQHUVDQGZDWHU5LQVHWKHVXUIDFHWKRURXJKO\DQGDOORZLW
to dry. Be sure that the offending contamination has not been spread over the surface during the cleaning operation.
5HPRYHEULWWOHUXVWVFDOHRUPLOOVFDOH¿UVWXVLQJLPSDFWWRROVVXFKDVFKLSSLQJRUVOHGJHKDPPHUV$VXLWDEOHFRPELQDWLRQRIVFUDSHUVDQGZLUHEUXVKHVPD\WKHQEHXVHGWRUHPRYHORRVHO\DGKHULQJUXVWPLOOVFDOHDQGGHWHULRUDWHG
SDLQW&OHDQLQJPHWKRGVDQGWRROVHPSOR\HGGHSHQGODUJHO\RQWKHQDWXUHRIWKHVXUIDFH7KHXVHRIWKLQZLGHEODGH
VFUDSHUVDQGVXEVHTXHQWZLUHEUXVKLQJLVDFFHSWDEOHIRUUHPRYLQJORRVHUXVWZKLOHKHDYLHUVFUDSHUVDUHUHTXLUHGIRU
tighter adhering materials such as mill scale or sound previous coatings.
3RZHU7RRO&OHDQLQJ663&63± Removal of all rust scale, mill scale, loose paint, and loose rust to the degree
VSHFL¿HGE\SRZHUZLUHEUXVKHVSRZHULPSDFWWRROVSRZHUJULQGHUVSRZHUVDQGHUVRUE\DFRPELQDWLRQRIWKHVH
methods. The substrate should have a pronounced metallic sheen and also be free of oil, grease, dirt, soil, salts and
other contaminants. Surface should not be buffed or polished smooth.
3RZHUWRROFOHDQLQJSURYLGHVDVOLJKWO\KLJKHUGHJUHHRIFOHDQOLQHVVWKDQGRHVKDQGWRROFOHDQLQJ7KHVHXQLWVFDQEH
GULYHQHOHFWULFDOO\RUSQHXPDWLFDOO\DQGWKHDGYDQWDJHRISRZHUWRROFOHDQLQJRYHUKDQGWRROFOHDQLQJLVQRWRQO\WKDW
WKHGHJUHHRIFOHDQOLQHVVLVLQFUHDVHGEXWDOVRWKDWWKHUDWHSURGXFWLRQLVVLJQL¿FDQWO\LPSURYHG7KLVPHWKRGLVVWLOO
not generally regarded as adequate surface preparation for long-term exposures of most high performance coating
systems in aggressive environments.
Remove oil, grease or similar contaminants from the surface via suitable chemical cleaning method. Rinse surface
WKRURXJKO\DQGDOORZGU\LQJ:KHQSRZHUFOHDQLQJEHFDUHIXOWRXVHHDFKWRROSURSHUO\3RZHUZLUHEUXVKHVIRU
example, should not be held in one spot too long as they may burnish or polish the surface resulting in a decrease in
Page 5
Ponderosa Protective Coatings™
Surface Preparation
VXUIDFHSUR¿OH$OVRDYRLGFXWWLQJGHHSO\LQWRWKHVXUIDFHZLWKJULQGHUVRUURWDU\LPSDFWWRROVDVWKLVWHQGVWRSURGXFHGHHSSLWVDQGEXUUVZKLFKPD\QRWEHDGHTXDWHO\SURWHFWHGE\WKHQHZFRDWLQJV\VWHP$Q\EXUUVVRSURGXFHG
VKRXOGEHJURXQGÀXVKWRWKHVXUIDFHEHIRUHSULPLQJ
3URSHUVDIHW\HTXLSPHQWVXFKDVVDIHW\JRJJOHVJORYHVDQGGXVWUHVSLUDWRUVVKRXOGEHHPSOR\HGZKHQXVLQJHLWKHU
KDQGRUSRZHUWRROFOHDQLQJPHWKRGV:KHQFOHDQLQJLQDUHDVZKHUHÀDPPDEOHYDSRUVRUDLUERUQHGXVWDUHSUHVHQW
the use of nonsparking tools is highly recommended.
3RZHU7RRO&OHDQLQJWR%DUH0HWDO663&633RZHUWRROFOHDQLQJWRSURGXFHDEDUHPHWDOVXUIDFHDQGWR
UHWDLQRUSURGXFHDVXUIDFHSUR¿OH7KLVFOHDQLQJVSHFL¿FDWLRQH[FHHGV663&633RZHU7RRO&OHDQLQJLQWKDWLWUHquires complete removal of all visible oil, grease, dirt, dust, mill scale, rust, paint, oxide, corrosion products, and other
IRUHLJQPDWWHU6OLJKWUHVLGXHVRIUXVWDQGSDLQWPD\EHOHIWLQWKHORZHUSRUWLRQVRISLWVLIWKHRULJLQDOVXUIDFHLVSLWWHG
,IWKHVXUIDFHLVWREHURXJKHQHGWKHVXUIDFHSUR¿OHSURGXFHGVKDOOQRWEHOHVVWKDQPLODQGVKDOOEHWRDGHJUHH
VXLWDEOHIRUWKHVSHFL¿HGSDLQWV\VWHP
)ODPH&OHDQLQJ663&63±Removal of all loose scale, rust and other detrimental foreign matter by passing
KLJKWHPSHUDWXUHKLJKYHORFLW\R[\DFHW\OHQHÀDPHVRYHUWKHHQWLUHVXUIDFHIROORZHGE\ZLUHEUXVKLQJ6XUIDFH
should also be free of oil, grease, dirt, soil, salts, and other contaminants.
$EUDVLYH%ODVW&OHDQLQJ663&63Abrasive blasting is probably the most effective method of preparing metal and masonry surfaces for coatings. It involves the high velocity propulsion of abrasive media such as sand,
slag, steel shot, glass beads or nutshells against a surface. High velocities are imparted to this media through sevHUDOPHDQV%\IDUWKHPRVWFRPPRQYHKLFOHLVKLJKSUHVVXUHDLUZKLFKLVXVHGWRFDUU\DEUDVLYHVWKDWDUHJHQHUDOO\
QRWUHFRYHUHG6KRSRSHUDWLRQVRIWHQHPSOR\FHQWULIXJDOZKHHOVIRUSURSHOOLQJPHGLDLQDFORVHGV\VWHPZKHUHWKH
DEUDVLYHFDQEHUHFRYHUHGDQGUHXVHG7KHUHDUHDOVRRWKHUPHWKRGVRIDEUDVLYHEODVWFOHDQLQJZKLFKZLOOQRWEH
discussed in detail here because of their more limited and specialized applications. Equipment manufacturers should
be consulted if unusual conditions merit the consideration of specialized varieties of abrasive blasting.
)RUPDQ\KLJKSHUIRUPDQFHDSSOLFDWLRQVVXFKDVZDWHULPPHUVLRQRUKLJKWHPSHUDWXUHH[SRVXUHVDEUDVLYHEODVWLQJLVPDQGDWRU\$EUDVLYHEODVWLQJLVDOVRUHFRPPHQGHGZKHQWKHUHPRYDORIWLJKWPLOOVFDOHKHDY\UXVWVFDOHRU
previous coatings from extensive areas is required. To maximize the effectiveness of a blasting operation the careful
selection of equipment, nozzles, and abrasive media is critical. The proper matching of air pressures and volumes,
QR]]OHVL]HDQGGHVLJQVDQGPHGLDW\SHDQGJUDGHFDQJUHDWO\HQKDQFHWKHHI¿FLHQF\RIWKHEODVWLQJRSHUDWLRQ7KH
UHFRPPHQGDWLRQVWKDWIROORZDUHJXLGHOLQHVRQO\DQGDUHQRWLQWHQGHGWRVXSSODQWWKRVHRI\RXUDEUDVLYHEODVWHTXLSment supplier.
Page 6
Ponderosa Protective Coatings™
Surface Preparation
Volume and Pressure of Air
The air supply is the most crucial part of any abrasive blasting operation. It is important to remember that surface
cleaning is accomplished in direct proportion to the volume and pressure of air passing through the blast nozzle. Air
pressure cannot be considered alone. The volume of air supplied is of critical importance. Assuming approximately
SVLQR]]OHSUHVVXUHWKHIROORZLQJPLQLPXPFRPSUHVVRUFDSDFLWLHVDUHVXJJHVWHGIRUWKHQR]]OHVL]HVOLVWHGEHORZ
It cannot be taken for granted that the reading on a pressure gauge attached to the compressor itself is accurate at
the nozzle. Pressure losses proportionate to the length and diameter of sandblasting hose can nullify a compressor’s
HI¿FLHQF\GXHWRH[FHVVLYHIULFWLRQORVVHV,WLVWKHUHIRUHLPSRUWDQWWRPHDVXUHDLUSUHVVXUHVZLWKDK\SRGHUPLFW\SH
pressure gauge as close as possible to the abrasive blasting nozzle. For most types of metal blasting the ideal
ZRUNLQJDLUSUHVVXUHLVEHWZHHQDQGSVL/RZHUSUHVVXUHVUHVXOWLQVORZHUFOHDQLQJUDWHV)RUH[DPSOHDQDLU
SUHVVXUHRIDSSUR[LPDWHO\SVLZLOOFOHDQRQO\DERXW2/3RIWKHDUHDSHUXQLWWLPHWKDQZLOOWKHVDPHVHWXSRSHUDWLQJ
at 100 psi.
7RDYRLGIXUWKHUVXUIDFHFRQWDPLQDWLRQWKHFRPSUHVVHGDLUXVHGVKRXOGEHIUHHRIZDWHUDQGRLO$SURSHUO\¿WWHGWUDS
LQWKHDLUOLQHEHWZHHQWKHFRPSUHVVRUDQGWKHEODVWLQJXQLWZLOOKHOSDVVXUHDFOHDQGU\VXSSO\RIDLUDWDOOWLPHV
Selection of Abrasives
$EUDVLYHPHGLDVKRXOGEHVHOHFWHGWRSURYLGHDEODVWLQJSUR¿OHGHHSHQRXJKIRURSWLPXPDGKHVLRQDQGVKDOORZ
enough to be adequately covered by the coating system. Avoid using excessively coarse abrasives. A medium grade
RIVLOLFDVDQGZKLFKSDVVHVWKURXJKDQWRPHVKVLHYHZLOOJHQHUDOO\SURGXFHDWRíPLOEODVWSUR¿OHZKLFK
LVVXI¿FLHQWIRUPRVWLQGXVWULDODSSOLFDWLRQV
CROSS SECTION - COATED STEEL SURFACE
Page 7
Ponderosa Protective Coatings™
Surface Preparation
7KHDEUDVLYHPHGLDVL]HDQGFRQ¿JXUDWLRQVHOHFWHGVKRXOGSURGXFHDSUR¿OHGHSWKRIQRPRUHWKDQ1/3 of the total dry
¿OPWKLFNQHVVRIWKHFRDWLQJV\VWHPVSHFL¿HG7KLVLVWRLQVXUHWKDWWKH³SHDNV³RIWKHDEUDVLYHEODVWSUR¿OHGRQRW
SURWUXGHWKURXJKWKHGU\¿OPWKLFNQHVVRIWKHSULPHULQWKHV\VWHPDSSOLHG:LWKVRPHFRDWLQJV\VWHPVPRVWQRWDEO\
]LQFULFKPDWHULDOVWKHUDQJHRIVXUIDFHSUR¿OHJHQHUDWHGLVVRPHZKDWFULWLFDODQGIRUWKHVHPDWHULDOVPLQLPXPDQG
PD[LPXPVXUIDFHSUR¿OHVKDYHEHHQUHFRPPHQGHGLQSURGXFWOLWHUDWXUH
6RPHRIWKHPRVWZLGHO\XVHGDEUDVLYHPHGLDDUHOLVWHGEHORZ
•
Silica Sand – This popular abrasive is available in varying degrees of coarseness.
,IDSSO\LQJDFRDWLQJV\VWHPGHVLJQHGIRUWRPLOVWRWDOGU\¿OPWKLFNQHVVD
JUDGHRIÀLQWRUVLOLFDVDQGSDVVLQJWKURXJKDQWRPHVKVLHYHSURYLGHVIRU
DUDSLGFOHDQLQJUDWHDQGWKHFUHDWLRQRIDSURSHUSUR¿OH&RPPHUFLDOO\JUDGHG
sand is more economical and effective in the long run than common river sand
ZKLFKEUHDNVGRZQWRRUHDGLO\DQGFRQWDLQVH[FHVVLYHGXVWZKLFKPD\LQVRPH
situations, be harmful.
•
Grit- This is a residue of slag produced by generating stations or as a by-product
of lead or copper are reductions. Grit is one of the sharpest abrasives available
DQGLVUHFRPPHQGHGZKHUHDGHHSEODVWSUR¿OHLVGHVLUHGDORQJZLWKD¿UVWUDWH
of cleaning.
•
Metal Shot/Grit- These particles of graded iron, steel or synthetic materials are
relatively costly as abrasives and are generally selected for blasting systems in
ZKLFKWKHPHGLDFDQEHUHFRYHUHGDQGUHXVHGPDQ\WLPHV7KLVPHGLDLVRIWHQ
employed in centrifugal shop blasting equipment.
•
Vegetable or Agricultural Abrasives – These materials are produced from nutshells, fruit pits, corncobs, rice hulls, etc. Agricultural abrasives are most often
XVHGZKHQLWLVQRWGHVLUHGWRSURGXFHDVXUIDFHSUR¿OHRQWKHVXEVWUDWHWREH
coated.
Page 8
Ponderosa Protective Coatings™
Surface Preparation
3DUWLFOH&RQ¿JXUDWLRQ
7KHZRUGVJULWDQGVKRWDUHRIWHQDSSOLHGWRWKHVKDSHRIWKHLQGLYLGXDOSDUWLFOHVRIWKHDEUDVLYHEODVWLQJPHGLDDQG
VHYHUDOW\SHVRIWKHDEUDVLYHVOLVWHGDERYHDUHDYDLODEOHLQHLWKHUFRQ¿JXUDWLRQ
³*ULW´JHQHUDOO\UHIHUVWRDQDQJXODUSDUWLFOHZLWKVKDUSHGJHVWKDWLPSDUWDGHHSSUR¿OHWRWKHDEUDVLYHEODVWHGVXUIDFH³6KRW´LPSOLHVDPRUHURXQGHGRUVSKHULFDOVKDSHZKLFKSURGXFHVDSHHQHGHIIHFWRQPHWDOVXUIDFHV
The following chart indicates the approximate maximum surface
SUR¿OHFUHDWHGE\EODVWLQJDWSVLWKURXJKD/” nozzle:
Page 9
Ponderosa Protective Coatings™
Surface Preparation
Grades of Abrasive Blasting$EUDVLYHEODVWLQJHVSHFLDOO\RIVWHHOVXUIDFHVLVPRVWRIWHQVSHFL¿HGE\WKH6WHHO
6WUXFWXUHV3DLQWLQJ&RXQFLORU1DWLRQDO$VVRFLDWLRQRI&RUURVLRQ(QJLQHHUV6WDQGDUGVFRQGHQVHGEHORZ
•
:KLWH0HWDO%ODVW&OHDQLQJ663&631$&(± Removal of all mill scale,
rust, rust scale, paint or foreign matter by the use of abrasives propelled through
QR]]OHVRUE\FHQWULIXJDOZKHHOV$:KLWH0HWDO%ODVW&OHDQHG6XUIDFH)LQLVKLV
GH¿QHGDVDVXUIDFHZLWKDJUD\ZKLWHXQLIRUPPHWDOOLFFRORUVOLJKWO\URXJKHQHG
WRIRUPDVXLWDEOHDQFKRUSDWWHUQIRUFRDWLQJV7KHVXUIDFHZKHQYLHZHGZLWKRXW
PDJQL¿FDWLRQVKDOOEHIUHHRIDOORLOJUHDVHGLUWYLVLEOHPLOOVFDOHUXVWFRUURVLRQ
products, oxides, paint, or any other foreign matter.
•
1HDU:KLWH%ODVW&OHDQLQJ663&631$&(± Removal of nearly all mill
scale, rust, rust scale, paint, or foreign matter by the use of abrasives propelled
WKURXJKQR]]OHVRUE\FHQWULIXJDOZKHHOVWRWKHGHJUHHKHUHDIWHUVSHFL¿HG$
1HDU:KLWH%ODVW&OHDQHG6XUIDFH)LQLVKLVGH¿QHGDVRQHIURPZKLFKDOORLO
grease, dirt, mil scale, rust, corrosion products, oxides, paint or other foreign
PDWWHUKDYHFRPSOHWHO\UHPRYHGIURPWKHVXUIDFHH[FHSWIRUYHU\OLJKWVKDGRZV
very slight streaks or slight discolorations caused by rust stain, mill scale oxides,
or light, tight residues of paint or coating that may remain. At least 95 percent
of each square inch of surface area shall be free of all visible residues, and the
remainder shall be limited to the light discoloration mentioned above.
•
&RPPHUFLDO%ODVW&OHDQLQJ663&631$&(±Removal of mill scale,
rust, rust scale, paint or foreign matter by the use of abrasives propelled through
QR]]OHVRUE\FHQWULIXJDOZKHHOVWRWKHGHJUHHVSHFL¿HG$&RPPHUFLDO%ODVW
&OHDQHG6XUIDFH)LQLVKLVGH¿QHGDVRQHIURPZKLFKDOORLOJUHDVHGLUWUXVW
scale and foreign matter have been completely removed from the surface and
all rust, mill scale and old paint have been completely removed except for slight
VKDGRZVVWUHDNVRUGLVFRORUDWLRQVFDXVHGE\UXVWVWDLQPLOOVFDOHR[LGHVRU
slight, tight residues of paint or coating that may remain; if the surface is pitted,
VOLJKWUHVLGXHVRIUXVWRUSDLQWPD\EHIRXQGLQWKHERWWRPRISLWVDWOHDVWWZR
thirds of each square inch of surface area shall be free of all visible residues and
the remainder shall be limited to the light discoloration, slight staining or tight
residues mentioned above.
•
%UXVK2II%ODVW&OHDQLQJ663&631$&(± Removal of loose mill scale,
ORRVHUXVWDQGORRVHSDLQWWRWKHGHJUHHKHUHDIWHUVSHFL¿HGE\WKHLPSDFWRI
DEUDVLYHVSURSHOOHGWKURXJKQR]]OHVRUE\FHQWULIXJDOZKHHOV,WLVQRWLQWHQGHG
that the surface shall be free of all mill scale, rust, and paint. The remaining mill
VFDOHUXVWDQGSDLQWVKRXOGEHWLJKWDQGWKHVXUIDFHVKRXOGEHVXI¿FLHQWO\DEUDGed to provide good adhesion and bonding of paint. A Brush-Off Blast Cleaned
6XUIDFH)LQLVKLVGH¿QHGDVRQHIURPZKLFKDOORLOJUHDVHGLUWUXVWVFDOHORRVH
mill scale, loose rust and loose paint or coatings are removed completely but tight
mill scale and tightly adhered rust, paint and coatings are permitted to remain
provided that all mill scale and rust have been exposed to the abrasive blast patWHUQVXI¿FLHQWO\WRH[SRVHQXPHURXVÀHFNVRIWKHXQGHUO\LQJPHWDOIDLUO\XQLIRUPO\
distributed over the entire surface.
Page 10
Ponderosa Protective Coatings™
Surface Preparation
Rate of Cleaning
7KHIROORZLQJFKDUWVKRZVWKHDSSUR[LPDWHFOHDQLQJUDWHVIRUWKHDERYHOLVWHGJUDGHVRIDEUDVLYHEODVWLQJXVLQJ
40-mesh silica sand at 100psi through a 5/16 inch nozzle:
NOTE:7KHVH¿JXUHVZLOOYDU\FRQVLGHUDEO\GHSHQGLQJRQWKHPDQ\FRQGLWLRQVZKLFKDIIHFWEODVWLQJRSHUDWLRQV
Abrasive Blasting Procedure
)ROORZWKLVVHTXHQFHRIRSHUDWLRQVIRUEHVWUHVXOWV
1. Before blasting remove grease, oil, salt, chemicals, dust and similar contaminants by chemical cleaning (SSPC-SP-1).
6HOHFWDEUDVLYHRIWKHSURSHUVL]HFRQ¿JXUDWLRQDQGKDUGQHVVLQUHODWLRQWRWKH
XQGHUO\LQJVXEVWUDWHDQGWKHVXUIDFHSUR¿OHGHVLUHG
3. Blast to the grade required according to coating type and ultimate environment.
Inspect to insure degree of cleanliness.
.HHSDEUDVLYHFOHDQ7KLVLVHVSHFLDOO\LPSRUWDQWZKHQDEUDVLYHPHGLDLVUHcycled or reused.
$IWHUEODVWLQJUHPRYHDOOVDQGGXVWDQGGLUWIURPVXUIDFHVWREHFRDWHGZLWKD
vacuum cleaner, compressed air (clean and dry) or a clean brush. Before applyLQJWKHSULPHFRDWLWLVJRRGSUDFWLFHWRZHWGRZQVXUURXQGLQJDUHDVWRKHOSSUHYHQWZLQGEORZQGHEULVIURPFRQWDPLQDWLQJWKHZRUN%ODVWPHGLDWKDWEHFRPHV
HQWUDSSHGLQVXEVHTXHQWFRDWLQJVFDQDFWDVD³ZLFN´SURYLGLQJDQDYHQXHIRU
moisture and oxygen to reach underlying steel surfaces.
6. Apply coatings to blasted surfaces as soon as possible-before the clean
VXUIDFHVEHFRPHFRQWDPLQDWHGRUEHJLQWRÀDVKUXVW0RVWVSHFL¿FDWLRQVFDOOIRU
WKHDSSOLFDWLRQRI¿UVWSULPHUFRDWWKHVDPHGD\EODVWLQJWDNHVSODFH
)ROORZDOODSSOLFDEOHVDIHW\VWDQGDUGV
A Note on Controlling Dust
7ZRYDULDWLRQVRIDEUDVLYHEODVWLQJDUHFRPPRQO\XVHGZKHUHFRQWUROOLQJGXVWRUFOHDQXSRIVSHQWDEUDVLYHLVDQXLsance.
Page 11
Ponderosa Protective Coatings™
Surface Preparation
•
Wet blasting-LVDYDULDWLRQLQZKLFKZDWHULVDGGHGWRWKHDEUDVLYHVWUHDPDVLW
OHDYHVWKHQR]]OH7KLVPRGL¿FDWLRQVXEVWDQWLDOO\UHGXFHVWKHDPRXQWRIDLUERUQH
GXVWDQGVDQG,WLVXVXDOO\HPSOR\HGRQO\ZKHQLWLVQHFHVVDU\WRPLQLPL]HWKH
FRQWDPLQDWLRQRIDLURUQHDUE\DUHDV:KHQZHWEODVWLQJLWLVQHFHVVDU\WRULQVH
the surface after blasting to remove sand and debris. A chemical rust inhibitor
such as a mixture of diammonium phosphate and sodium nitrate often must be
DGGHGERWKWREODVWLQJDQGULQVHZDWHUWRLQKLELWÀDVKUXVWLQJRIWKHZHWVWHHO
•
Vacuum blasting-LVDQRWKHUYDULDWLRQRIDEUDVLYHEODVWLQJLQZKLFKWKHVDQG
and debris are captured and removed by vacuum resulting in a clean, dust free
operation. Frequently the abrasive employed in vacuum blasting is reused. In
FRPSDULVRQWRRSHQEODVWLQJWKLVLVDYHU\VORZDQGH[SHQVLYHRSHUDWLRQDQG
WKHUHIRUHLVXVXDOO\OLPLWHGWRVPDOODUHDVZKHUHGXVWDQGDLUERUQHFRQWDPLQDQWV
cannot be tolerated.
Water Blasting
:DWHUEODVWLQJXVLQJDQXOWUDKLJKSUHVVXUHVWUHDPRIZDWHULVDYHUVDWLOHFOHDQLQJPHWKRGIRUVWHHOQRQIHUURXVPHWDOV
and other hard surfaces. It generally removes loose paint, chemical contaminants, loose rust and scale, grease and
other materials not tightly bonded to the surface.
7KLVPHWKRGLVYHU\HIIHFWLYHIRUFOHDQLQJLUUHJXODUO\VKDSHGVXUIDFHVVXFKDVYDOYHVÀDQJHVDQGJUDWLQJV:KHUH
DEUDVLYHEODVWLQJLVQRWIHDVLEOHZDWHUEODVWLQJFDQEHDQHIIHFWLYHDOWHUQDWLYH:DWHUEODVWLQJKRZHYHULVXQDEOH
to abrade hard surfaces and thus does not provide the anchor pattern helpful for maximizing coating adhesion. To
SURGXFHWKHGHVLUHGDQFKRUSDWWHUQVDQGRUVLPLODUDEUDVLYHVPD\EHDGGHGWRWKHZDWHUVWUHDP,QDVHULHVRIWHVWV
WRPHVKVLOLFDVDQGDGGHGDWDSRXQGSHUKRXUUDWHLQFRQMXQFWLRQZLWKZDWHUSUHVVXUHVRIWR
SVLSURGXFHGDRQHKDOIWRRQHPLOEODVWSUR¿OH$GGLWLRQDOWHVWVVKRZHGWKDWWRRUWRPHVKVDQGKDGD
polishing effect producing 1/8 to 1/2PLOVXUIDFHSUR¿OHV0RVWPRGHUQZDWHUEODVWLQJHTXLSPHQWSURYLGHVIRUWKHXVHRI
DEUDVLYHVZKLFKJUHDWO\HQKDQFHWKHHI¿FLHQF\RIWKHZDWHUEODVWDFWLRQ
0RVWXQLWVXVLQJK\GUDXOLFKRVHZLWKD3/8 to 1/2LQFKLQVLGHGLDPHWHUFDQGHOLYHUSUHVVXUHVXSWRSVLZLWKD
WRJDOORQSHUPLQXWHZDWHUÀRZUDWH,QWHUFKDQJHDEOHQR]]OHWLSVDUHDYDLODEOHZKLFKFDQSURGXFHDURXQGRUYDULDEOHDQJOHÀDWVWUHDP
7KHZDWHUXVHGLQEODVWLQJPXVWEHFOHDQDQGIUHHRIVLOWRURWKHUFRQWDPLQDQWV7KHVHPDWHULDOVFDQGDPDJHSXPS
valves or leave a corrosive deposit on blasted surfaces. If detergents or other cleaners are to be used, spray them on
WKHVXUIDFHEHIRUHZDWHUEODVWLQJ
:DWHUEODVWLQJWHFKQLTXHVDUHVLPLODUWRWKRVHHPSOR\HGZKHQSQHXPDWLFDEUDVLYHEODVWLQJ+ROGWKHQR]]OHWR
inches from the surface for normal cleaning, 2 to 3 feet for light cleaning. Depending on the material to be removed
XVHDIDQVWUHDPZLWKDSU\LQJDQGOLIWLQJDFWLRQRUDURXQGVWUHDPZLWKDSHQHWUDWLQJDFWLRQ
Page 12
Ponderosa Protective Coatings™
Surface Preparation
To remove heavy rust scale the nozzle should be held very close, approximately 2 inches from the surface. For brittle
substances such as old paint or rust scale, hold the nozzle perpendicular to the surface. A nozzle angle of about 45°
or more generally helps peel off heavy mastics or tar coatings.
7KHPRVWFRPPRQZDWHUSUHVVXUHVHPSOR\HGUDQJHEHWZHHQDQGSVL*UHDWHUSUHVVXUHVDUHRIWHQGLI¿FXOW
for operators to handle.
&OHDQLQJUDWHVZLOOYDU\FRQVLGHUDEO\GHSHQGLQJRQWKHVKDSHRIWKHVXUIDFHQDWXUHRIWKHFRQWDPLQDQWEHLQJUHPRYHGDQGSUHVVXUHHPSOR\HG0XGRUORRVHGLUWFDQEHFOHDQHGIURPÀDWVXUIDFHVDWDUDWHRIDSSUR[LPDWHO\WR
VTXDUHIHHWSHUKRXU7LJKWO\UXVWHGDQGSLWWHGVWHHOJUDWLQJVKRZHYHUFDQEHFOHDQHGDWRQO\DWRVTXDUH
foot per hour rate.
3LFNOLQJ663&63± Removal of all mill scale, rust and rust scale by chemical reaction, or by electrolysis, or by
both. It is intended that the pickled surface shall be completely free of all scale, rust, and foreign matter. Furthermore, the surface shall be free of unreacted or harmful acid alkali, or smut. It is most often used on structural shapes,
beams and plates prior to fabrication. Pickling is a rather specialized process generally employed only at steel mills
and large fabricator operations.
There are three basic steps in the chemical pickling process each requiring a separate tank or bath. All chemical soluWLRQVKDYHWREHUHSOHQLVKHGDWUHJXODULQWHUYDOVRUWKH\ZLOOEHFRPHLQHIIHFWLYH
1. Sulphuric Acid Descaling Bath-7KH¿UVWWDQNFRQWDLQVDFRQFHQWUDWLRQ
RIVXOSKXULFDFLGZKLFKLVKHDWHGWRƒ)+\GURFKORULF$FLGRU3KRVSKRULF
Acid can also be used for pickling, and a chemical inhibitor is frequently added
to minimize loss of sound metal. The steel is immersed in this bath for approximately 15 to 30 minutes until all mill scale is removed.
2. Wash Water Bath-)ROORZLQJGHVFDOLQJWKHVWHHOLVLPPHUVHGLQDIUHVKZDWHU
bath to rinse off remaining traces of the acid used.
3. Phosphoric Acid/Chromic Acid Baths-This tank uses a hot 180°F solution of
phosphoric or chromic acid at a 1-2% concentration. The steel is immersed in
this bath for 2-5 minutes. This step imparts an inhibitive phosphate or chromate
WUHDWPHQWWRWKHVWHHOZKLFKSURYLGHVWHPSRUDU\UXVWSURWHFWLRQDQGLPSURYHVWKH
adhesion and performance of many coating systems.
Priming should be accomplished as soon as possible after the steel dries. Pickled steel that is not immediately
SULPHGLVIUHTXHQWO\WUHDWHGZLWKRLOIRUWHPSRUDU\FRUURVLRQSURWHFWLRQ,WLVLPSRUWDQWWKDWWKLV³SLFNOHGDQGRLOHG´VWHHO
be chemically cleaned to remove oil before painting.
Page 13
Ponderosa Protective Coatings™
Surface Preparation
.H\V7R6XFFHVVIXO6XUIDFH3UHSDUDWLRQ
•
All forms of surface contamination, especially oil and moisture, must be eliminated.
‡
6ZHHSLQJRUEORZLQJGRZQVXUIDFHVPXVWUHPRYHVSHQWDEUDVLYH
‡
5HPRYHZHOGVSDWWHUDQGVOLYHUV
•
Keep abrasive clean.
‡
$SSO\FRDWLQJVSULRUWRÀDVKUXVWLQJRIVWHHOXVXDOO\KRXUVRUOHVVDIWHUEODVWing.
•
Select abrasive of the proper size and hardness in relation to the type steel being
XVHGDQGVXUIDFHSUR¿OHGHVLUHG
‡
)ROORZDOODSSOLFDEOHVDIHW\VWDQGDUGV
Preparation Of Surface Types
Nonferrous metals
7KHVHPHWDOVUHDFWRUFRUURGHZKHQH[SRVHGWRQRUPDOZHDWKHULQJFRQGLWLRQVDQGIRUPDVXUIDFHR[LGHOD\HU:KLOH
WKHOD\HURIR[LGHVZKLFKIRUPVRQQRQIHUURXVPHWDOVLVQRWDVREYLRXVDVWKHUHGDVVRFLDWHGZLWKVWHHOWKLVOD\HU
SRVHVDSRWHQWLDODGKHVLRQSUREOHPIRUFRDWLQJVDQGPXVWWKHUHIRUHEHUHPRYHG3URFHGXUHVDUHDVIROORZV
•
Galvanized Metal-must be clean and dry before it is coated. Non-oily soil and surIDFHGLUWVKRXOGEHUHPRYHGZLWKDVWLIIEULVWOHEUXVKKLJKSUHVVXUHDLUFOHDQDQG
GU\RURWKHUVXLWDEOHPHDQV6ROYHQWFOHDQLQJLQDFFRUGDQFHZLWK663&63
should remove oil, grease and protective mill coatings. In certain cases alkaline
detergents may be used to remove surface contaminants. These surfaces must
EHULQVHGWKRURXJKO\ZLWKIUHVKZDWHUWRUHPRYHDONDOLQHUHVLGXH
:KLWH]LQFR[LGDWLRQSURGXFWVPXVWEHUHPRYHG6ZHHSEODVWLQJXVLQJORZSUHVVXUHVSVLDQG¿QHVLOLFDVDQGLVUHFRPPHQGHG:KHUHDEUDVLYHEODVWLQJ
LVQRWSUDFWLFDOKDQGRUSRZHUWRROFOHDQLQJLQDFFRUGDQFHZLWK663&63RU
SP-3 shall be employed. As zinc oxidation products form rapidly, it is recommended that galvanized surfaces be coated the same day of surface preparation.
%HVXUHWRVHOHFWRQO\FRDWLQJVWKDWDUHFRPSDWLEOHZLWKJDOYDQL]HGVWHHO
Page 14
Ponderosa Protective Coatings™
Surface Preparation
•
Stainless Steel-does not require any particularly specialized surface pretreatments prior to coating. Chemical cleaning should clean these surfaces of oil,
JUHDVHGLUWDQGRWKHUIRUHLJQPDWHULDOV7KHGHYHORSPHQWRIDVXUIDFHSUR¿OH
on stainless steel is highly recommended to assure good coating adhesion. A
SUR¿OHGHSWKRIEHWZHHQDQGPLOVLVVXJJHVWHGIRUPRVWFRDWLQJV\VWHPV
%HFDXVHVWDLQOHVVVWHHOLVDYHU\KDUGPHWDODEUDVLYHEODVWLQJZLWKRQHRIWKH
various grades of angular grit is recommended to impart a continuous surface
SUR¿OH
‡
$OXPLQXPVKRXOGEHVROYHQWFOHDQHGLQDFFRUGDQFHZLWK663&63&KHPLFDO
Cleaning to remove any oil, grease, dirt and foreign material. Brush blast or acid
HWFKWRSURYLGHDQHWFKHGVXUIDFHSUR¿OHWKDWDLGVFRDWLQJDGKHVLRQ
•
Copper-should be solvent cleaned according to SSPC-SP-1 Chemical Cleaning
to remove any oil, grease, dirt and foreign material. Once solvent cleaned sand
to remove oxides.
Wood Surfaces
Use one or more of the Chemical Cleaning Methods to remove dirt, grease, and oil. Scrape off deteriorated coatings,
countersink exposed nails, and repair surface defects. Sand to an even surface. Lightly sand hard or glossy previous
FRDWLQJVWRSURPRWHDGKHVLRQRIQHZFRDWLQJV,IWKHVXUIDFHLVFKDON\ZDVKWKRURXJKO\$OORZVXUIDFHWRGU\FRPpletely before coating.
Concrete and Masonry
1HZFRQFUHWHRUPDVRQU\PXVWEHDOORZHGWRFXUHIRUDWOHDVWGD\VEHIRUHFRDWLQJ7KHPDVRQU\FRQWUDFWRUVKRXOG
UHVXUIDFHDLUDQGZDWHUSLWVVSODWWHUSURWUXVLRQVRURWKHUVXUIDFHLUUHJXODULWLHVZKLOHWKHFRQFUHWHLVVWLOO³JUHHQ´
If a relatively impermeable coating system is to be applied, the concrete should be tested for moisture content and
WUDQVPLVVLRQEHIRUHSDLQWLQJ7RLQVXUHWKDWWKHFRQFUHWHLVVXI¿FLHQWO\GU\WRUHFHLYHFRDWLQJVVHFXUHO\WDSHGRZQ
approximately one square foot of 3 to 8 mil polyethylene plastic to several areas of the substrate. This is especially
LPSRUWDQWIRUFRUQHUVDQGDUHDVEHORZJUDGH$UHDVVKRXOGEHLQVSHFWHGDIWHUDSHULRGRIKRXUV&RDWLQJV
VKRXOGQRWEHDSSOLHGLIDQ\PRLVWXUHLVIRXQGRQWKHEDFNVLGHRIWKHSRO\HWK\OHQH¿OPRULIWKHFRQFUHWHEHQHDWKWKH
SODVWLFDSSHDUVGDUNLQFRORURUPRLVWZKHQFRPSDUHGWRWKHVXUURXQGLQJFRQFUHWHRULIWKHPRLVWXUHFRQWHQWH[FHHGV
SHUFHQW$WVXFKWLPHDVWKHFRQFUHWHLVMXGJHGWREHVXI¿FLHQWO\GU\WKHQDOOVXUIDFHVH[FHSWWKRVHWRUHFHLYH
acrylic, latex, or bituminous sealers) shall be brush blasted to remove all loose concrete, laitance, and provide a tooth
for bonding.
Surfaces must be clean, dry and free from curing compounds, laitance, oil, grease, dirt, chalk, or previously applied
coatings.
Page 15
Ponderosa Protective Coatings™
Surface Preparation
3RXUHGDQGSUHFDVWFRQFUHWHDOPRVWDOZD\VKDVDVXUIDFHOD\HURIXQUHDFWHG3RUWODQGFHPHQWDQGRWKHUSDUWLFOHV
NQRZQDV³ODLWDQFH´7KLVODLWDQFHUHSUHVHQWVDSRWHQWLDODGKHVLRQSUREOHPIRUFRDWLQJVIRUWZRUHDVRQV$VPDQ\
FRDWLQJVFXUHWKH\JHQHUDWHVWUHVVZKLFKPD\EUHDNWKHERQGRIWKHODLWDQFHWRWKHFRQFUHWH7KHXQUHDFWHG¿QHV
DQG3RUWODQGFHPHQWPD\LQWHUIHUHZLWKWKHFXULQJDQGERQGLQJPHFKDQLVPRIWKHOLTXLGFRDWLQJ$EUDVLYHEODVWLQJLV
DQHI¿FLHQWPHWKRGIRUUHPRYLQJODLWDQFHDQGSUHYLRXVFRDWLQJV$FLGHWFKLQJLVDOVRYHU\HIIHFWLYH%HIRUHDFLGHWFKLQJUHVLGXDOGLUWDQGGXVWVKRXOGEHUHPRYHGIURPWKHVXUIDFHE\VZHHSLQJFKHPLFDOFOHDQLQJRUXVLQJDKLJKSUHVVXUHZDWHUVWUHDP
)ORRUVFDQEHDFLGHWFKHGZLWK0XULDWLF$FLGVROXWLRQSDUWDFLGWRSDUWVZDWHU$SSO\DFLGVROXWLRQZLWKDSODVWLF
VSULQNOLQJFDQEURDGFDVWDFLGVROXWLRQOLEHUDOO\RYHUÀRRUDUHD:KHQEXEEOLQJFHDVHVWRPLQXWHVZDVKGRZQ
VXUIDFHZLWKIUHVKZDWHUDQGVFUXEZLWKDVWLIIEUXVK5LQVHZLWKSOHQW\RIZDWHU5XEEHUVTXHHJHHVVKRXOGUHPRYH
ZDWHU,IVXUIDFHLVDFLGLFS+EHORZQHXWUDOL]HVXUIDFHE\ZDVKLQJZLWKDPPRQLDVROXWLRQ)RUPRVWFRDWLQJV
WKHVXUIDFHVKRXOGEHDOORZHGWRGU\WKRURXJKO\OHVVWKDQPRLVWXUHEHIRUHSDLQWLQJ,IKRZHYHUZDWHUUHGXFLEOH
FRDWLQJVDUHVSHFL¿HGWKH\PD\EHDSSOLHGGLUHFWO\WRVOLJKWO\GDPSFRQFUHWHVXUIDFHV
Previously Painted Surfaces
Remove all rust, rust scale, other corrosion products, loose or heavy chalk and loose or scaling paint by hand sandLQJSRZHUWRROFOHDQLQJRUSUHVVXUHZDVKLQJ6DQGRUEUXVKEODVWJORVV\DUHDVXQWLOGXOODQGWKHQGXVWVXUIDFHVFOHDQ
When the surface preparation method employed on a previously coated surface exposes areas of underlying base
PHWDOWKHQVSRWRURYHUDOOSULPLQJEHIRUH¿QLVKFRDWLQJVKRXOGSURWHFWWKRVHDUHDV
Before applying coating over large areas, underlying paint must be properly cured and compatible. Check compatLELOLW\E\DSSO\LQJFRDWLQJWRDVODUJHDQDUHDDVSRVVLEOHDQGDOORZFXULQJ7KHQPDNHFURVVKDWFKFXWVWKURXJKWKH
FRDWLQJDQGFKHFNDGKHVLRQE\¿UPO\DSSO\LQJPDVNLQJWDSHWRFURVVKDWFKHGDUHDDQGUHPRYLQJZLWKDIDVWSXOO,IWKH
FRDWLQJUHPDLQVLQWDFWDQGWKHUHLVQRZULQNOLQJOLIWLQJEOLVWHULQJRUDQ\RWKHUVLJQRILQFRPSDWLELOLW\SUHVHQWFRDWLQJ
ZRUNPD\WKHQSURFHHG
Page 16
Ponderosa Protective Coatings™
Surface Preparation
Surface Cleaning Method Selection
Excellent
Good to Fair
Ineffective
Page 17