Paint gurus?, How to fix? |
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Paint gurus?, How to fix? |
Cracker |
Jul 23 2017, 05:42 AM
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#1
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Advanced Member Group: Members Posts: 2,148 Joined: 2-February 10 From: Atlanta (area) Member No.: 11,316 Region Association: South East States |
This is well outside of my wheelhouse! I am assuming this is the clear succumbing to the last 5-years of (my ownership) exterior storage and beat by the sun. I've never seen clear literally peel and lift (like this). It is only happening to the top radiused edge but is on all four sides - it is metal. Can this be wet-sanded down and then re-sprayed with clear? What to do and how to do it? Thanks in advance...
Tony PS: My main concern is not being able to salvage the paint - multiple colors would be a PITA to respray. |
rick 918-S |
Jul 24 2017, 07:59 PM
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#2
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Hey nice rack! -Celette Group: Members Posts: 20,477 Joined: 30-December 02 From: Now in Superior WI Member No.: 43 Region Association: Northstar Region |
The EPA forced safer paint product with less VOC ( Volatile Organic Compounds) This caused many issues from the assembly line to the refinish industry. The manufactures in high production were seeing the delamination of the base coat from the sealer and in some production lines the clear from the base coat.
We saw the beginning of this as early as the 80's when Honda came out with HLSA. (high Tensile Strength Low Alloy Steel) All steel is porous to an extent. The thinner, lighter steel has tightly packed molecules. Conventional lacquer based primer was not hot enough to create a bond to the steel. To continue with this type of product you would need a 36 grit scratch to lock the product onto the metal. The industry came out with etch primers to solve this problem. Acid etch to the steel and soft dried finish to hold the primers. Here's the layman's explanation. The VOC's in the Solvents used to mix the color and thin the paint should create enough chemical bond to lock one layer to the other. In your case the base flashed off hard. Likely, partially from too long of a drying time for the base. It is likely the base should have been lightly scuffed to allow a tooth for the clear. With metallic paint we would use a mid coat adhesion promoter. Kind of like the etch primers but a clear product that would slightly soften the base and allow a chemical bond to take place. The secondary issue is likely the clear coat used was unable the create a chemical bond due to low VOC's. The Repair? There are a couple ways to do it. Careful soda blasting could remove the loose clear on the upper surfaces. Mask and cover the lower parts that have a good bond and re-clear the affected areas. Strip it all off and start over. |
Wdunster |
Jul 25 2017, 05:50 AM
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#3
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Panel beater Group: Members Posts: 172 Joined: 10-June 14 From: Monroe,nc Member No.: 17,469 Region Association: South East States |
Great insight but not accurate. Sorry, please don't take offense. I normally don't get too involved with these conversations but this isn't correct. 36 grit sandpaper hasn't been recommended to use on any of the modern metals or especially the metal or fiberglass used on an RV. It will destroy the substrate. Typically on all the delamination issues we have seen over the years (dodge, ford, Chevy, now Honda) is due to the lack of material. When the suns uv Penetrates through the clear with to low of UV protection (either due to cheap clear with out uv protection or too little clear) it will degrade the base color (which is happening here) or the base is even applied too thin and allows the ecoat to degrade and release the base and clear. Manufacturers skimp as do companies that have an RV to paint in order to save material costs. Premium Clears today even with the VOC law changes are leaps and bounds better than they were before the changes. Agreed this isn't an easy fix but with the right person doing it there may be a chance to rescue some of the colors.
B The EPA forced safer paint product with less VOC ( Volatile Organic Compounds) This caused many issues from the assembly line to the refinish industry. The manufactures in high production were seeing the delamination of the base coat from the sealer and in some production lines the clear from the base coat. We saw the beginning of this as early as the 80's when Honda came out with HLSA. (high Tensile Strength Low Alloy Steel) All steel is porous to an extent. The thinner, lighter steel has tightly packed molecules. Conventional lacquer based primer was not hot enough to create a bond to the steel. To continue with this type of product you would need a 36 grit scratch to lock the product onto the metal. The industry came out with etch primers to solve this problem. Acid etch to the steel and soft dried finish to hold the primers. Here's the layman's explanation. The VOC's in the Solvents used to mix the color and thin the paint should create enough chemical bond to lock one layer to the other. In your case the base flashed off hard. Likely, partially from too long of a drying time for the base. It is likely the base should have been lightly scuffed to allow a tooth for the clear. With metallic paint we would use a mid coat adhesion promoter. Kind of like the etch primers but a clear product that would slightly soften the base and allow a chemical bond to take place. The secondary issue is likely the clear coat used was unable the create a chemical bond due to low VOC's. The Repair? There are a couple ways to do it. Careful soda blasting could remove the loose clear on the upper surfaces. Mask and cover the lower parts that have a good bond and re-clear the affected areas. Strip it all off and start over. |
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