[Refinsihing] Waterbourne PU on Collars

[Robvandam]

Ok hi guys wondering if any of you can give me a hand with this
Heres what happened :

1. Stripped cue of current finish (Sanding)
2. Clean with Spirit
3. Apply Sealer / couple of coats and let dry at least over night
4. Lightly sand away sealer untill all shiny bits become matte.
5. PROBLEM IS HERE :
6. Apply Waterbourne PU over and over again with proper drying times inbetween coats.
7. Lightly sand away PU untill shiny bits become matter.
8. PROBLEM IS HERE :
9. Apply appropriate polishing compounds to buf it up.

The problems i am facing are at steps 5 and 8 where i have to lightly sand down the coatings, be it PU or SEALER. Problem is that the coatings on the collar near the joint always seem to be sanded away very quickly when i am lightly sanding away my coats (at point 5 and 6), thus resulting in those sections sometimes having bare spots. Infact i notice that all sections that are not WOOD, be it ring works / silver rings, phenolic collars .. etc etc all have a tendency to have this problem.

I know that one way is obviosuly to make sure the coatings are much thicker before i embark on any light sanding. Or the other way is to hand sand those points rather than use a lathe ?

Any ideas or suggestions would be much appreciated .... no matter how elementary it may seem...

 

[rhncue]

Ok hi guys wondering if any of you can give me a hand with this
Heres what happened :

1. Stripped cue of current finish (Sanding)
2. Clean with Spirit
3. Apply Sealer / couple of coats and let dry at least over night
4. Lightly sand away sealer untill all shiny bits become matte.
5. PROBLEM IS HERE :
6. Apply Waterbourne PU over and over again with proper drying times inbetween coats.
7. Lightly sand away PU untill shiny bits become matter.
8. PROBLEM IS HERE :
9. Apply appropriate polishing compounds to buf it up.

The problems i am facing are at steps 5 and 8 where i have to lightly sand down the coatings, be it PU or SEALER. Problem is that the coatings on the collar near the joint always seem to be sanded away very quickly when i am lightly sanding away my coats (at point 5 and 6), thus resulting in those sections sometimes having bare spots. Infact i notice that all sections that are not WOOD, be it ring works / silver rings, phenolic collars .. etc etc all have a tendency to have this problem.

I know that one way is obviosuly to make sure the coatings are much thicker before i embark on any light sanding. Or the other way is to hand sand those points rather than use a lathe ?

Any ideas or suggestions would be much appreciated .... no matter how elementary it may seem...

I don't use water type finishes but it is very apparent that your coats are way to thin. Iether your adding to much thinner or your putting on to thin of coats. Each coat should always be a good wet coat.

Dick

 

[BLACKHEARTCUES]

Ok hi guys wondering if any of you can give me a hand with this
Heres what happened :

1. Stripped cue of current finish (Sanding)
2. Clean with Spirit
3. Apply Sealer / couple of coats and let dry at least over night
4. Lightly sand away sealer untill all shiny bits become matte.
5. PROBLEM IS HERE :
6. Apply Waterbourne PU over and over again with proper drying times inbetween coats.
7. Lightly sand away PU untill shiny bits become matter.
8. PROBLEM IS HERE :
9. Apply appropriate polishing compounds to buf it up.

The problems i am facing are at steps 5 and 8 where i have to lightly sand down the coatings, be it PU or SEALER. Problem is that the coatings on the collar near the joint always seem to be sanded away very quickly when i am lightly sanding away my coats (at point 5 and 6), thus resulting in those sections sometimes having bare spots. Infact i notice that all sections that are not WOOD, be it ring works / silver rings, phenolic collars .. etc etc all have a tendency to have this problem.

I know that one way is obviosuly to make sure the coatings are much thicker before i embark on any light sanding. Or the other way is to hand sand those points rather than use a lathe ?

Any ideas or suggestions would be much appreciated .... no matter how elementary it may seem...

Dick is right, your coats of finish, are too thin & not enough of them. I don't use water base clear either, but I put on 3 coats(that's down, up, down). I let it dry, til I can just barely make a finger print, in the coating. Then repeat the 3 coatings of clear. Let that dry again, til I can barely make a finger print. Then 3 more coats. Waiting time between the sprayings with my DuPont clear, is about 2 minutes. Next day, I sand about 6 of the 9 coats off , wipe it down & reapply 9 more coats as I did before. Then sand & if ALL of the holes & grain is filled in, I sand & finish with wet sanding using 1000 & finish with 1500 or 2000. THEN use the compounds & polishes...JER

 

[Robvandam]

so what grit do u use to sand it down to matte ? before bringing it up with 1000 ++. because i currently use 320 and it seems to take off too much.

Also how do u know when its thick enuff to sand? Do you use Vernier calipers to measure the original Diameter and than use it again to measure after you have applied the coats ?

 

[ragbug74]

I spray a PPG auto clear coat per the method Blackheart describes above. When sanding between applications, I like to stick to 600 grit, but sometimes if I don't have it on smooth enough, I have to hit it with 400. If you are using 320, that may be part of your problem.

 

[BLACKHEARTCUES]

so what grit do u use to sand it down to matte ? before bringing it up with 1000 ++. because i currently use 320 and it seems to take off too much.

Also how do u know when its thick enuff to sand? Do you use Vernier calipers to measure the original Diameter and than use it again to measure after you have applied the coats ?

320 is too course. After my 1st 9 coats have dried, I sand it lightly with 400. (If you have a run in the paint sand it out, with 400 1st, with the lathe off). Then with the lathe running you can hit it lightly with 400 then 600. After each sanding in the lathe (with the lathe off), sand WITH the grain to take out the scratches. At this stage it doesn't have to be perfect, because your next spraying will fill in any small holes or grain. DO NOT WET SAND UNTILL THE SURFACE IS SMOOTH OR THE SANDING DIRT ,WITH THE WATER, WILL FORM INTO MUD, THAT WILL SETTLE INTO THE LITTLE HOLES & WILL SHOW AS WHITE DOTS. Remember you're not sanding just, to be sanding. You're sanding to eventually get the surface smooth. After I've sanded with 400, then 600. I wipe it down with mineral spirits & spray a second time. When the second spraying is cured I sand with 600 both with the lathe running & then with the grain. If you still have voids, SPRAY AGAIN. When you can sand with 600 & there are no shinny spots, you can start to wet sand. I use 1000, then 1500 or 2000. Always ending up sanding, WITH THE GRAIN. Then I use Meguiar's no. 1, then no. 5, then no. 9. Again always ending, with the grain. You are acctually making the scratches smaller & smaller until you can't see them. Your coats of clear should be WET, BUT NOT RUNNY. If you let the paint DRY between coats, they will not bond to each other. They will just lay on top of each other. That's not good. GOOD LUCK...JER

 

[BLACKHEARTCUES]

By the way what does "PU" stand for?...JER

 

[Craig Fales]

By the way what does "PU" stand for?...JER

I was wondering that myself...but I'm thinking polyurethane...
________

 

[Robvandam]

I was wondering that myself...but I'm thinking polyurethane...

yup tats right...

anyway thanks for all advice will take note of that.

update u again on my status (for those who want to know ... heh heh )

 

[WRHaynes]

Nice info...very handy... Thanks