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Painting problem solver
Rai tingprablem saver How TO ACHIEVE A GOOD-LOOKING AUTOMOTIVE FINISH
orange peel, but on the other you don't want the paint to be so thin that it runs down the doors and vertical surfaces. The label on the can should tell you the maximum amount that you can add. Bear in mind that your local environmental agency might have VOC regulations that prohibit you from adding any thinners to your paint.
(Editor's note: thefoUowing question isfrom theMarch issue of Metal Finishing. Due to errors, the equations have been
reprinted in their correctfonnats.)
Q:
FORMULA FOR CALCULATING VOC I am using ASTM D3960-0S to calculate theVOC ofa waterborne coating that does not contain any exempt volatile compounds. The fonnula is:
voc =
(Wv - WW)(Dc) 100%- (Ww)(DcJOw)
Wv=68.S4% Ww=56.2% Dc = 1039.2 gil Ow 997 gil
=
The units areasspecified in the method. I cannot understand theunit cancellation thatmakes this equation work. IfI am to justignore theunits then so beit, but I need to knowthatwhen I plugin my numbers I am getting thecorrect answer. This is very confUsing. Please help, asthis iscausing megriefand nooneseems tobe able toanswer [my question].
A:
The formula is:
voe (gil) =
(WV - Ww) (Fraction) (Dc) (gil) 100%- [(Ww)(Fractlon) . (Dc(gIl)/Ow (gil) = gil
Hope this helps.
ACHIEVING A GOOD-LOOKING AUTOMOTIVE ANISH I am trying topaintmy carwith Rust-Oleum semi-tJoss bLuk paint. The label on the can says to mix thepaint wit mineral spirits. Howmuch should I use togetagoodfinish?
: 2
ALTERNATIVES TO CHROMATE-CONTAINING PRETREATMENTS I am writing to ask ifyou have any infonnation about specific plumbingfixture companies thatuse alternatives to hexavalent chromium in their finishing processes. We area ''green'' design and consulting finn, and we currently have a client who isinterested in usingproducts thathave such alternative finishing treatments.
Q:
A:
I don't have any dealings with plumbing fixture companies, but there are several non-chromate pretreatments that can be used in finishing processes. Chemical companies, including Henkel Surface Technologies and Chemetall, sell non-chromate products. You can find both companies and many others on the Internet. (Be sure to listen to Chemetall's recent webinar on www.metalfinishing.com.)
: g
CORROSION-RESISTANT PRIMER FOR AUTOMOTIVE REFINISHING I live in England and I am about to rustproofmy 36year-old Mark 2 Ford (Mercury) Capri. Whatwould be the estprimer touse afterI have takenit back to bear metal? I can get my hands on red oxide fairly cheaply) but I was wondering whatwould bethe most effective primer? After experiencing a few days under nry car with a grinder, I never again wish torepeat this tiresome task.
A:
An inexpensive red oxide primer is not what you want. In my opinion, I would apply an epoxy primer that contains an effective rust-inhibitive pigment, such as zinc chromate. Bear in mind, however, that the use of zinc chromate is being limited in some areas due to its potential toxicity (it is a known carcinogen). Alternatives are strontium chromate, zinc phosphate, and other inhibitors. I suggest you check with your local automotive paint store.
A : You should add as little mineral spirits as possible. I"\I suggest that you try spraying some of the paint
810
without adding mineral spirits. If you get too much orange peel then add a small amount and try again. On the one hand you want to avoid getting unacceptable
RonJoseph is a paint and coating consultant with Exponent, Inc., of Menlo Park, Calif. You may e-mail your questions directly tohimat [email protected]
62 Imetalflnishlng' April 2009
www.metalfinishing.com
orange peel, but on the other you don't want the paint to be so thin that it runs down the doors and vertical surfaces. The label on the can should tell you the maximum amount that you can add. Bear in mind that your local environmental agency might have VOC regulations that prohibit you from adding any thinners to your paint.
(Editor's note: thefoUowing question isfrom theMarch issue of Metal Finishing. Due to errors, the equations have been
reprinted in their correctfonnats.)
Q:
FORMULA FOR CALCULATING VOC I am using ASTM D3960-0S to calculate theVOC ofa waterborne coating that does not contain any exempt volatile compounds. The fonnula is:
voc =
(Wv - WW)(Dc) 100%- (Ww)(DcJOw)
Wv=68.S4% Ww=56.2% Dc = 1039.2 gil Ow 997 gil
=
The units areasspecified in the method. I cannot understand theunit cancellation thatmakes this equation work. IfI am to justignore theunits then so beit, but I need to knowthatwhen I plugin my numbers I am getting thecorrect answer. This is very confUsing. Please help, asthis iscausing megriefand nooneseems tobe able toanswer [my question].
A:
The formula is:
voe (gil) =
(WV - Ww) (Fraction) (Dc) (gil) 100%- [(Ww)(Fractlon) . (Dc(gIl)/Ow (gil) = gil
Hope this helps.
ACHIEVING A GOOD-LOOKING AUTOMOTIVE ANISH I am trying topaintmy carwith Rust-Oleum semi-tJoss bLuk paint. The label on the can says to mix thepaint wit mineral spirits. Howmuch should I use togetagoodfinish?
: 2
ALTERNATIVES TO CHROMATE-CONTAINING PRETREATMENTS I am writing to ask ifyou have any infonnation about specific plumbingfixture companies thatuse alternatives to hexavalent chromium in their finishing processes. We area ''green'' design and consulting finn, and we currently have a client who isinterested in usingproducts thathave such alternative finishing treatments.
Q:
A:
I don't have any dealings with plumbing fixture companies, but there are several non-chromate pretreatments that can be used in finishing processes. Chemical companies, including Henkel Surface Technologies and Chemetall, sell non-chromate products. You can find both companies and many others on the Internet. (Be sure to listen to Chemetall's recent webinar on www.metalfinishing.com.)
: g
CORROSION-RESISTANT PRIMER FOR AUTOMOTIVE REFINISHING I live in England and I am about to rustproofmy 36year-old Mark 2 Ford (Mercury) Capri. Whatwould be the estprimer touse afterI have takenit back to bear metal? I can get my hands on red oxide fairly cheaply) but I was wondering whatwould bethe most effective primer? After experiencing a few days under nry car with a grinder, I never again wish torepeat this tiresome task.
A:
An inexpensive red oxide primer is not what you want. In my opinion, I would apply an epoxy primer that contains an effective rust-inhibitive pigment, such as zinc chromate. Bear in mind, however, that the use of zinc chromate is being limited in some areas due to its potential toxicity (it is a known carcinogen). Alternatives are strontium chromate, zinc phosphate, and other inhibitors. I suggest you check with your local automotive paint store.
A : You should add as little mineral spirits as possible. I"\I suggest that you try spraying some of the paint
810
without adding mineral spirits. If you get too much orange peel then add a small amount and try again. On the one hand you want to avoid getting unacceptable
RonJoseph is a paint and coating consultant with Exponent, Inc., of Menlo Park, Calif. You may e-mail your questions directly tohimat [email protected]
62 Imetalflnishlng' April 2009
www.metalfinishing.com