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AlexMG
Joined: 30 Oct 2012 Posts: 13
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Posted: Thu Jan 03, 2013 9:58 pm Post subject: Coach painting problem |
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Hi. Has anyone had experience of hand painting a vintage car using Takaloid coach paint? I have completed painting the tub and the topcoat appears not to have keyed onto the undercoats. I can 'tear' it off with my fingernail. Very dissappointing. I used an etch primer, followed by many coats of undercoat (grey and white)sanded smooth with 1200 wet and dry and then 3 coats of red topcoat coach paint. Whilst the finish is great the paint seems not to have hardened or keyed onto the undercoat. I pased this on to the supplier but have not recieved a reply. Anyone else had this problem or can provide an explaination. |
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34HF90
Joined: 07 Feb 2011 Posts: 62
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Posted: Thu Jan 03, 2013 11:46 pm Post subject: |
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Quote: | Hi. Has anyone had experience of hand painting a vintage car using Takaloid coach paint? I have completed painting the tub and the topcoat appears not to have keyed onto the undercoats. I can 'tear' it off with my fingernail. Very dissappointing. I used an etch primer, followed by many coats of undercoat (grey and white)sanded smooth with 1200 wet and dry and then 3 coats of red topcoat coach paint. Whilst the finish is great the paint seems not to have hardened or keyed onto the undercoat. I pased this on to the supplier but have not recieved a reply. Anyone else had this problem or can provide an explaination.
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The only thing that comes close to this is a situation where there has been a barrier to prevent adhesion. A gut feeling says the presence of damp / condensation film making a barrier. Another possibility is contamination of the topcoat, but I'm sure you would have noticed this by the way it went on....
Have you tried a good dose of heat to see what happens? If there is a barrier film under the paint, it may well blister. On the other hand it might secure the adhesion. Worth a try perhaps |
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Bitumen Boy
Joined: 26 Jan 2012 Posts: 1735 Location: Above the snow line in old Monmouthshire
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Posted: Fri Jan 04, 2013 1:14 am Post subject: |
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I'm thinking damp as well - was it painted recently? I avoid painting in the winter if I can as I find it can take days to go off in my garage, not so much due to temperature I fancy as the humid air not letting the solvent evaporate. Another thing that can sometimes give trouble is where there's enough of a delay between undercoats and colour for the undercoat to dry very hard. |
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Kelsham
Joined: 18 Jan 2009 Posts: 349 Location: Llandrindod Wells Powys
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Posted: Fri Jan 04, 2013 10:23 am Post subject: |
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I thought Tekaloid had ceased production? I used to use it and never had any problems. I seem to recall it took about 24 to 48 hours to harden.
I agree with damp being a likely cause of your problem. I have painting jobs piling up waiting for a good dry spell.
Kels. |
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ajlelectronics
Joined: 04 Oct 2010 Posts: 168 Location: Gloucester
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Posted: Fri Jan 04, 2013 11:09 am Post subject: |
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Interesting that you went to 1200 grit. My pro bodyshop goes to 400 for solid topcoat and 800 for metallics. Maybe the 1200 is too fine? _________________ Evans Waterless Coolants
Find this and more at http://www.classicmicrocars.com
Sat TV / Aerial systems etc: http://www.ajlelectronics.co.uk |
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ukdave2002
Joined: 23 Nov 2007 Posts: 4104 Location: South Cheshire
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Posted: Fri Jan 04, 2013 11:19 am Post subject: |
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ajlelectronics wrote: | Interesting that you went to 1200 grit. My pro bodyshop goes to 400 for solid topcoat and 800 for metallics. Maybe the 1200 is too fine? |
I'd agree, 1200 is close to the grade of paper to use on a top coat, prior to liquid cutting, (I think Farecla recommend 1500 with G3), possibly the topcoat didn't have a decent key to adhere properly?
Dave |
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Mitchelld
Joined: 24 Nov 2011 Posts: 17
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Posted: Sun Jan 20, 2013 1:40 pm Post subject: |
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although ive never used that kind of paint and its spraying only for me, im having lots of trouble with drying times as of late due to temperature.
ive found that adding accelerator to my laquer i shelping a lot though. |
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Colourweldukltd
Joined: 12 Mar 2012 Posts: 3
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Posted: Fri Jan 25, 2013 10:32 pm Post subject: |
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Just a though and worth checking with who made it but did they put the driers in the paint?
I used to work for a company called Ludlows Of Luton and we used to make loads of the stuff and it isn't impossible to think that the driers didn't go in. The paint will harden but only after at least a week and by that time moisture etc can get in as the paint hasn't cross linked (hardened) it is open to attacks.
Hope that helps a bit _________________ www.colourweld.co.uk - Suppliers of Paints, Welding Equipment and more. |
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peppiB
Joined: 30 Jun 2008 Posts: 686 Location: Newcastle upon Tyne
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Posted: Sat Jan 26, 2013 10:37 am Post subject: |
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A few years ago I managed to use 1200 instead of 400 grit on undercoat (an age related mental block I think) The top coat just peeled straight off as a result. Ended up using a heat gun to strip all the paint off the car |
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SV8Predator
Joined: 24 Aug 2008 Posts: 136 Location: Further up the creek
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Posted: Sun Feb 03, 2013 4:34 pm Post subject: |
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There will be no problem with the formulation of the paint provided it was mixed correctly in the tin. Damp will not cause an adhesion problem as described.
In this case it was the use of 1200 grade paper. This grade is for final flatting before subsequent polishing. It is not for keying to provide adhesion.
The primer coats should have been sanded with 400 grade before top coating. _________________ 2000 Jaguar XJ8 4.0 LWB
1974 Jensen Interceptor Mk III
1969 Jensen Interceptor Mk I |
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