Thinning paint

[Kez]

I finally got the set up in my garage to do some painting. Between two moves and a new job, I have not painted anything in 5 years. Getting a little rusty.

I am using the Klasskote epoxy paint. I am using an inexpensive external mix siphon fed gun about the size of a touch up gun. I used to mix 1 part paint, 1 part hardener and i part thinner. But I ended up having a sandy finish with orange peel. It is just the primer coat that I am going to sand anyway so no big deal there. But I want to spray the color this weekend. Should I thin the paint some more?

In the past I have found that thinning it too much with sometimes result in blushing on a humid day...and of course the paint would run more easily. I have also found that clear coat requires more thinning than color to have a smooth finish. Does it make sense?

Thanks,

kez

 

[Kez]

Since I have not received any feedbacks, I tried different thinning ratios. I am painting several boats and I experimented with the smaller .20 size first. I am sharing what I learned (re-learned, have not painted in many years) FWIW. I believe members of this forum probably already know all this.

1. Thinning 30% (1/3 paint, 1/3 hardener, 1/3 thinner) works well if I have enough pressure and an internal mix guns. It is too thick for a hobby type gun.

2. Thinning 50% works best for me.

3. It is counter intuitive but I have found that I need to thin more on a hot day.

4. Clear (Hobbypoxy, Klass Kote etc) requires more thinning than color.

 

[Richard H. Parshall jr.]

Since I have not received any feedbacks, I tried different thinning ratios. I am painting several boats and I experimented with the smaller .20 size first. I am sharing what I learned (re-learned, have not painted in many years) FWIW. I believe members of this forum probably already know all this.

1. Thinning 30% (1/3 paint, 1/3 hardener, 1/3 thinner) works well if I have enough pressure and an internal mix guns. It is too thick for a hobby type gun.

2. Thinning 50% works best for me.

3. It is counter intuitive but I have found that I need to thin more on a hot day.

4. Clear (Hobbypoxy, Klass Kote etc) requires more thinning than color.

KLASS KOTE Recomends 1-1-1 mixture for spraying... a HVLP Gun usually wwill need it a bit thinner than a siphon feed gun,and also likes a bit more air pressure.. sanding the substrate is very important also.. wet sand primer down to 600grit,wash with laquer thinner of a good quality. as a autobody guy i found it hard to wash with laquer thinner because we usually used laquer or enamel based paint and it would eat the stuff under paint and paint. but it dosnt effect epoxy paint so following K/Ks instructions wash with their thinner or a quality laquer th. to start with a light coat just dusting the surface,this gives the next coats somthing to stick to... be sure to use a tack rag before starting to paint.. typical siphon feed guns like to run at around 35-45lbs pressure.. second coat is heavier and holding gun at 90 deg. to surface and equal distance with smooth fluid motions do the third coat heavier,then i usually go the other direction to remove dry spots.. so last coat is actually a double wet coat. after a few times you get the feel of the running point..stay below that and you should have a shiny even finish... i also find that starting around the edges and tight spots...(cowls,scoops, bow and cockpit )first then feathering around them on each coat to work well.. as long as you dont blast extra paint on those spots because they will run.. i usually mix the paint till it is a cross between a run and a drip off the stir stick,with cars and full guns it was 18-22 seconds with a viscosity cup(usually with the models you dont mix enough to do this..) i know you posted this a while ago,wish i had seen it then hope you have some sucess painting and i hope this might have helped you out!! good luck, any questions message me i will try to help.

 

[Kez]

Thanks Rick for the advice. I did finish the several projects this summer but I am not happy with the results so I am going to lightly sand and add one more coat this spring.

Good information on the prep cleaner. I have always prepped the boat using the same thinner that I reduce the paint with. I have never had any problem with KK or Hobbypoxy thinner. Recently, I have found isopropanol (not the rubbing alcohol, which is 70%) to be a good prep solvent and it is easier on your lungs.

I did have problem with tag cloth, however. A few times, the tag cloth leaves residue and the paint fisheyed on the area with the tacky stuff. I guess the trick is not to rub with the tag cloth or it will transfer the adhesive to the project you are trying to paint. I stopped using tag cloth for final prep before paint for this reason. I still use it when I am sanding a bare wood hull to pick up the wood dust.

Just like anything else, painting takes practice and I have not painted in a few years. I will certainly PM you before I redo my projects. I can use some advice.

Thanks,

kez

 

[glenng]

Do not rub HARD with the tack cloth- just very lightly. 600 grit is too fine to let the new paint bite into the hull, primer or old paint, Use 360 or 400 grit wet and dry. Follow by washing with soapy water. Alwaws use new sandpaper not old-even if it looks good it may contain wax or grease. Ditzler and PPG make a good wax and grease remover that will precent fisheye.

 

[Ron Jefferson]

Just a tip on the tack cloth. Open it up totally and don't use it the way it comes in the package. What I mean by that is... Pull it all apart so none of the cloth is stuck together. You should have a ball like cluster when you're finished that you can lightly pass over the piece to be painted. Don't actually wipe it like you would a rag but simply pass it over the surface lightly. The tack cloth is more to remove tiny particles and not to clean the part. It will work way better this way and not leave residue. Also, make sure you use pre-cleaner and follow up with a clean lint free cloth. And most important, don't touch the surface with your hands in any way as the oils will cause the paint to fisheye.

Ron

 

[Richard H. Parshall jr.]

Just a tip on the tack cloth. Open it up totally and don't use it the way it comes in the package. What I mean by that is... Pull it all apart so none of the cloth is stuck together. You should have a ball like cluster when you're finished that you can lightly pass over the piece to be painted. Don't actually pipe it like you would a rag but simply pass it over the surface lightly. The tack cloth is more to remove tiny particles and not to clean the part. It will work way better this way and not leave residue. Also, make sure you use pre-cleaner and follow up with a clean lint free cloth. And most important, don't touch the surface with your hands in any way as the oils will cause the paint to fisheye.

Ron

I totally agree on the tack cloth un raveling.. in the wood working finishing business, when doing poly and with this epoxy paint, we refrain from using a tack rag... take the rag (lint free and CLEAN)you used to wipe off the pre cleaner (slightly damp)and wipe the surface off while blowing with air... also clean hands... your fingers contain oils that will cause fisheyes...as will moisture from air compressor dirty rags,etc. DUPONT has a fisheye killer they sell for automotive enamels and laquers,not sure of compatibility with epoxy paint... best bet is to have a clean dust free surface.I usually have a cloth in both hands so when i steady the model,my hand is not touching the surface but the clean rag is..this may help.Rick

 

[Richard H. Parshall jr.]

Since I have not received any feedbacks, I tried different thinning ratios. I am painting several boats and I experimented with the smaller .20 size first. I am sharing what I learned (re-learned, have not painted in many years) FWIW. I believe members of this forum probably already know all this.

1. Thinning 30% (1/3 paint, 1/3 hardener, 1/3 thinner) works well if I have enough pressure and an internal mix guns. It is too thick for a hobby type gun.

2. Thinning 50% works best for me.

3. It is counter intuitive but I have found that I need to thin more on a hot day.

4. Clear (Hobbypoxy, Klass Kote etc) requires more thinning than color.

KLASS KOTE Recomends 1-1-1 mixture for spraying... a HVLP Gun usually wwill need it a bit thinner than a siphon feed gun,and also likes a bit more air pressure.. sanding the substrate is very important also.. wet sand primer down to 600grit,wash with laquer thinner of a good quality. as a autobody guy i found it hard to wash with laquer thinner because we usually used laquer or enamel based paint and it would eat the stuff under paint and paint. but it dosnt effect epoxy paint so following K/Ks instructions wash with their thinner or a quality laquer th. to start with a light coat just dusting the surface,this gives the next coats somthing to stick to... be sure to use a tack rag before starting to paint.. typical siphon feed guns like to run at around 35-45lbs pressure.. second coat is heavier and holding gun at 90 deg. to surface and equal distance with smooth fluid motions do the third coat heavier,then i usually go the other direction to remove dry spots.. so last coat is actually a double wet coat. after a few times you get the feel of the running point..stay below that and you should have a shiny even finish... i also find that starting around the edges and tight spots...(cowls,scoops, bow and cockpit )first then feathering around them on each coat to work well.. as long as you dont blast extra paint on those spots because they will run.. i usually mix the paint till it is a cross between a run and a drip off the stir stick,with cars and full guns it was 18-22 seconds with a viscosity cup(usually with the models you dont mix enough to do this..) i know you posted this a while ago,wish i had seen it then hope you have some sucess painting and i hope this might have helped you out!! good luck, any questions message me i will try to help.

and also... too thin and also,a too fast drying thinner, can result in a dry (sandy)finish... need to find that ballance.usually between a run off mixing stick and a drip off the stick when stiring .. also be sure to run the mixed paint thru a clean strainer into gun..