lacquer blistering

[dmcspence]

Hello

I am new to painting but have always had an interest in it so i am getting started
my base coats are going on fine but I am having some problems with clear coating
I get some slight orange peel but have dealt with this but most anoying is the blistering very slight little lumps

steps I have taken to reduce this are
clearing airtank, hoses filters etc
upping the pressure to between 4 and 5 bar
heating room slightly
adding 5 to 10 percent reducer to a mix of 2 laquer to 1 hardener

I am spraying this through a hvlp with a 0.8mm tip and some times through a Iwata 0.5 tip air brush

Most of what I am painting is small plastic forms so anything bigger would be just to much

hope some one can help

regards





David

 

[TAZ]

I'm not for sure what the blistering would be. Possibly the bumps could be little pieces of paint that gather on the end of the spray nozzle, then they eventually let loose thus creating a bump. Or, it could be just somesort of a piece of dirt.

It may not be in the clearcoat as you mention. It could be in your basecoat, but not really showing up until the clearcoat is applied. Normally the clear builds up and around the lump making it bigger each coat.

Possibly some other sources....
--Your pressure might be too high.
--You have a dusty spray area
--You have trash coming through your air lines. Try a 'filter ball'. This goes on --the end of the spray gun between your air fitting and the gun itself
--You are spraying too dry which would cause it to build up on the end of the gun (or airbrush), then letting loose and landing on the surface

No matter what, you should be able to wetsand these lumps out making a nice flat surface once the clearcoat dries. Or you can try wetsanding the areas with lumps before you clearcoat

 

[dmcspence]

thanks for that Taz
I will sand down with some 2000 grit then wash with panel wipe and finnish of with a tac rag and see how it goes

I have sanded down some lumps in the clear coat in the past but I was unable to get a shine back and had to reapply clear coat is this normal or can you suggest a way that I can get a shine back without applying a further coat

regards





David

 

[nzgrip]

I would think 0.8 is a bit on the small side for clear, try a bigger fuid nozzle/needle or add more reducer. Check the TDS for the paint for the recommended Fluid nozzle size and spray pressure. I know when i used my Iwata air brush with a 0.3 tip i had to add a lot more reducer.

 

[TAZ]

thanks for that Taz
I will sand down with some 2000 grit then wash with panel wipe and finnish of with a tac rag and see how it goes

I have sanded down some lumps in the clear coat in the past but I was unable to get a shine back and had to reapply clear coat is this normal or can you suggest a way that I can get a shine back without applying a further coat

regards
David

As long as you have enough clear on what you are painting, sounds like you'll have to sand it 'flat' without any shine, and then go through the whole process of buffing
If it's real rough with peel and dirt or lumps, you may just want to use 1500 first, then buzz over it with 2000.
Be sure and use a machine buffer with a foam pad at about 1600 to 1800 rpms alone with a good compound (we now use 6085).
This should bring the shine back up. You HAVE to keep buffing until the shine comes up. Don't stay in one area, just go over the whole panel back and forth at a VERY SLIGHT angle until the shine is back up.
:luck: