Sanding timeframe
Sanding timeframe
How long should it take to sand back the guidecoat on a wagon ???
IT's LIKE WATCHING DRUNK MONKEYS TRYING TO HUMP A FOOTBALL.
-
mrs ratbox
i hate sanding 
Hi Finny,
guidecoat - by it's name - it's a tool......
It basically depends on how much work is needed to get the primer ready for top coating.
Obviously, if you guide coat something which has Mt.Everest peaks all over it.... your guide coat is probably going to take forever to get rid of completely.
If you have done a pretty good job of getting your panels straight and building up through the fillers and primers - blocking back guide coat should be a relatively fast lane process..
It was put to me not to apply guide coat until almost ready to block back.... that way it does not "seal" thinners into the primer coats beneath, but affords them opportunity to evaporate....
Depending on how thick the primer build is..... is relevant to how long to leave the primer before blocking back..... guide coat, if applied too soon will seal those thinners in.... and very much prolong them finding their way out through the surface.......
I think that's the best way I can explain it......
It was also put to me that guide coat is not just a one shot affair.....
Some professionals keep a gun loaded with it - and re-apply it over areas where it has been removed from....
The guide coat I use is a "GMH black".... it's Duxone and is probably suited to our dash boards...... at present, this is what I am looking at using when I get to that part of my refurb......
The amount of guide coat applied should only be sufficient for you to watch your blocking down..... putting more, or thick coats of it on - just means more work....... basically, if you can "work" with just a mist coat - and see how much further you need to block to remove it all - that's all that is required.......
If applying some of the more "critical" finishes/colours - the best possible scenario is a "mist" of guide coat over a thoroughly "worked" panel - and only one or two passes with your cutting paper to completely remove it...... this, to me suggests that you have an almost perfect panel ready for top coating......
If you have to "grind and grind" away when blocking back to get all areas - your panel is far from ready for top coats.......
IN essence, don't be afraid to re-apply it over blocked down areas - if the surrounding areas sit too low to get down to them.
If you go too far - you'll see the 1k etch or whatever under the primer begin to show through... this is a clear indication that you need more build on the surrounding areas - along with another coat to cover the etch.......
hope this helps, Adrian....?
frats,
Rosco
guidecoat - by it's name - it's a tool......
It basically depends on how much work is needed to get the primer ready for top coating.
Obviously, if you guide coat something which has Mt.Everest peaks all over it.... your guide coat is probably going to take forever to get rid of completely.
If you have done a pretty good job of getting your panels straight and building up through the fillers and primers - blocking back guide coat should be a relatively fast lane process..
It was put to me not to apply guide coat until almost ready to block back.... that way it does not "seal" thinners into the primer coats beneath, but affords them opportunity to evaporate....
Depending on how thick the primer build is..... is relevant to how long to leave the primer before blocking back..... guide coat, if applied too soon will seal those thinners in.... and very much prolong them finding their way out through the surface.......
I think that's the best way I can explain it......
It was also put to me that guide coat is not just a one shot affair.....
Some professionals keep a gun loaded with it - and re-apply it over areas where it has been removed from....
The guide coat I use is a "GMH black".... it's Duxone and is probably suited to our dash boards...... at present, this is what I am looking at using when I get to that part of my refurb......
The amount of guide coat applied should only be sufficient for you to watch your blocking down..... putting more, or thick coats of it on - just means more work....... basically, if you can "work" with just a mist coat - and see how much further you need to block to remove it all - that's all that is required.......
If applying some of the more "critical" finishes/colours - the best possible scenario is a "mist" of guide coat over a thoroughly "worked" panel - and only one or two passes with your cutting paper to completely remove it...... this, to me suggests that you have an almost perfect panel ready for top coating......
If you have to "grind and grind" away when blocking back to get all areas - your panel is far from ready for top coats.......
IN essence, don't be afraid to re-apply it over blocked down areas - if the surrounding areas sit too low to get down to them.
If you go too far - you'll see the 1k etch or whatever under the primer begin to show through... this is a clear indication that you need more build on the surrounding areas - along with another coat to cover the etch.......
hope this helps, Adrian....?
frats,
Rosco
Thanks Rosco.
I'll post up a pic on my rebuild link, but the car doesn't have any huge peaks and valleys.
The idea of not guide coating until your ready to block back is very smart for other reasons also.
It hardens too much, and becomes really tough to remove.
And yes I was a little over zealous in putting it on, a little to much in too many placed.
It was getting late and I rushed it.
I'll post up a pic on my rebuild link, but the car doesn't have any huge peaks and valleys.
The idea of not guide coating until your ready to block back is very smart for other reasons also.
It hardens too much, and becomes really tough to remove.
And yes I was a little over zealous in putting it on, a little to much in too many placed.
It was getting late and I rushed it.
IT's LIKE WATCHING DRUNK MONKEYS TRYING TO HUMP A FOOTBALL.
Yes Adrian,
we all rush stuff...... just have to get it done etc...... we're all guilty of it...
I can't tell you what I'm spraying at the moment - I'm not supposed to.....
but - guide coat on them has shown up the imperfections in the base metal..... when they were pressed..... right back through all the fillers and primers.... it has come up through the layers....... acrylic thinners is a marvel for solving back into previous coats..... the hotter, the deeper it seems to penetrate........
and I had considered these to be "plate" finish prior to guidecoat showing up the troughs.....
frats,
Rosco
we all rush stuff...... just have to get it done etc...... we're all guilty of it...
I can't tell you what I'm spraying at the moment - I'm not supposed to.....
but - guide coat on them has shown up the imperfections in the base metal..... when they were pressed..... right back through all the fillers and primers.... it has come up through the layers....... acrylic thinners is a marvel for solving back into previous coats..... the hotter, the deeper it seems to penetrate........
and I had considered these to be "plate" finish prior to guidecoat showing up the troughs.....
frats,
Rosco
Last edited by rosco on Mon Jan 25, 2010 10:47 pm, edited 1 time in total.
Oops forgot...
when you spray guide coat on - try not to thin it at all and keep your needle well in....... makes it easier to do with your pressure wound up a bit........it should come out as almost a "spatter" rather than a bodied "coat"....... sort of what you don't want to do when spraying.........
frats,
Rosco
when you spray guide coat on - try not to thin it at all and keep your needle well in....... makes it easier to do with your pressure wound up a bit........it should come out as almost a "spatter" rather than a bodied "coat"....... sort of what you don't want to do when spraying.........
frats,
Rosco